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Articles from 2000 In February


IMM's Plant Tour: Moldmaker, molder, machine OEM

Akira Nagamatsu is full of surprises. He surprised many of his Japanese competitors in the 1990s. Rather than follow customers to China and Southeast Asia like they did, on his own initiative, Nagamatsu, president and ceo of one of Japan’s leading moldmakers and custom molders, chose to establish a manufacturing facility in Anaheim, CA (see March 1998 IMM, p. 25). In doing so, he sidestepped the worst of the Asian economic downturn and has prospered. Startup of his U.S. operation, Meiho Technology Inc. (MTI), was in August 1997. Sales are expected to reach $12 million by 2001.

Nagamatsu is still full of surprises. For example, last year he shocked the semiconductor industry with an ingenious idea. MTI introduced an all-electric, all-in-one molding system it designed and built for packaging integrated circuits faster, better, and cheaper in thermoplastic PPS than in thermoset epoxy (see July 1999 IMM, p. 131). MTI’s MIPS-30 molding system has been met with rave reviews in Japan. It has yet to catch on here. Meanwhile, though, Nagamatsu has a few other surprises.

For one thing, MTI is preparing to launch its own compact, servodriven vertical and horizontal injection molding machines for more general-purpose precision molding of small parts (see March 2000, page 141). Another surprise is that, in essence, MTI has evolved into a U.S.-based transnational company. MTI has become the key decision maker in Meiho’s family of companies. Meiho Japan uses its abundant capacity to support decisions made in Anaheim.

"Meiho" means "bright" and "abundant," as illustrated by MTI’s logo—the sun rising above the water. As you will see, this enlightenment and richness of resources is reflected in the layout of MTI’s plant. But the company’s true luster comes from the abundant talent of its human resources. The corporate culture Nagamatsu has established encourages all employees to use their ingenuity and to act on their own initiative. As a result, the consistent quality of the parts and services they provide comes as no surprise to MTI’s customers. Let’s tour.

Precision Molds
Harry Nakamoto, executive vp, and Miki Imai, general affairs manager, are our guides. A diverse array of molded parts is on display in glass cabinets that seem to go on forever in MTI’s spacious two-story lobby. The parts bear witness to the company’s 27 years of experience in material selection, precision molding, and moldmaking. As noted in our March 1998 article, the president’s motto is, "Simple parts can be done anywhere." Gazing at the parts, it is apparent this means anywhere but MTI.

The toolroom is our first stop. Tooling is where it all began for Meiho 27 years ago. The same origin story is heard anywhere around the world: The company was asked to test some of its molds by a customer and, after a couple of years of sampling, Meiho was molding better parts than its customer. Today, Meiho Japan runs more than 35 molding machines and has grown to become the number one Japanese supplier of PET injection-stretch blowmolds. It has also become the country’s leading supplier of tooling for integrated circuits, and one of Japan’s largest moldmakers.

"We intend to build smaller, simpler molds here, and leave the work on bigger and more complex molds to Meiho Japan. We generally go from 90 to 400 tons," Nakamoto says. Meiho Japan has 200 mold and die engineers. "We also intend to move our mold design engineering department with 3-D CAD/CAM to MTI before the end of the year."

The toolroom is well equipped for its mold manufacturing and maintenance plans. A Sodick CNC EDM is the shop’s centerpiece. It shares the room with an Okamoto precision surface grinder, a Makino CNC mill, an Ikeda radial drill, a Birmingham lathe, and a 9-by-16-inch Rong Fu horizontal bandsaw. MTI uses Topcon measuring microscopes and Osaka Seimtsu gear testers for inspection. The toolroom also has fixed and portable gantry cranes and Thermal Care water management systems.

No Time for a Warehouse
Near the toolroom is an area with boxed parts. Both Nakamoto and Imai are quick to point out that this area is not a warehouse in the traditional sense. MTI ships parts daily from stock, supporting JIT deliveries. The plant was intentionally built so there would be no warehouse. Nakamoto says he will soon install FIFO racking for the boxed parts to speed things up even further.

Nearby is MTI’s quality assurance room. While looking around, Imai tells us obtaining ISO and QS certifications went more smoothly for MTI than it had anticipated. "Maybe that’s because we are a newer facility—it’s easier for us to write new procedures as we go along, but we definitely had a good leader, too!" she says.

If there was an internationally recognized certificate just for cleanliness, MTI would have little trouble earning one. From the plant’s glistening PUR-coated flooring to its brightly lit, 25-ft-high ceilings, nothing is out of place and everything is spotless.

MTI even prefers copper electrodes, believing them to be cleaner. Nakamoto and Imai agree that the company’s insistence on keeping work areas clean and organized creates an environment that encourages employee involvement and improves quality. Kaizen continuous improvement and kanban systems for smoothing scheduling help customers reap the rewards in high-quality parts delivered on time at a reasonable price.

Self-contained Cells
MTI’s main molding room may be the best showcase of its dedication to cleanliness and order. Its molding machines are all Nisseis, including a recently purchased Nissei all-electric it runs in a cleanroom area. Other presses also feature Nissei’s latest technology, including Triple-Melt and ultrahigh-speed injection. All run in self-contained cells.

One reason MTI standardized on Nissei machines is because Nissei America is located in the same industrial park. That speeds delivery and service. Another reason is that President Nagamatsu was a close personal friend of Nissei’s founder and chairman, the late Katashi Aoki.

All robots are from Yushin and Star. All loaders and dryers are from Matsui and Nissui. Nissui also supplied all of the plant’s beside-the-press granulators—regrind is immediately recycled wherever possible. Temperature controllers are from Mokon and Nissui. Crizaf conveyors are used. MTI has installed automatic good/bad parts separators on its nonrobotized machines.

Encouraged Initiative
We catch up with Tony Murillo, molding supervisor, in the company’s new cleanroom. He explains that although the room is "cleanroom ready," MTI has yet to switch on its Hepa filters. "We need space to do other molding right now, we’re so busy. The A, B, and C lines are full. But we’re going to go after medical work." Murillo is quite proud of the extra air compressor he talked MTI brass into installing outside. "It’s for backup. We can’t run the business without air and can’t afford any possibility of downtime."

MTI supports the initiative of its employees. For example, Murillo teaches injection molding and basic English part-time at a local school, Cerritos College. MTI helped him talk Nissei into leasing an all-electric press identical to its own to the school. "We’ve already acquired five full-timers from the College," explains Murillo.

"This is only the third job I’ve had in my life but it’s the right company for me," he adds. "It’s the wrong company for anyone who doesn’t like to work, but it’s the best I’ve ever worked for."

In addition to targeting the medical market, MTI has several other surprisingly ambitious plans. "Our automotive customers, primarily, are already asking us to build another plant in the U.S. We haven’t even started looking yet," Nakamoto says.

A Bright, Abundant Future
Meanwhile, MTI definitely plans to manufacture and maintain its dies for integrated circuits, precision press cutting, and injection-stretch blowmolding in the States. MTI also wants to move into beverage bottle and integrated circuit production. It expects to increase its molding press capacity to 50 units and its machine tools to 15. It will intensify its quality systems and circles, while adding a 3-D CMM and pursuing ISO 14001 certification.

Then there is MTI’s planned entry into the molding machine business (p. 141). There is no telling how many more surprises Nagamatsu and company have in store, but one thing is for sure—we may not have to wait too long to find out. After all, MTI has been up and running only for a little more than two years, and look what it has done already.


Contact information
Meiho Technology Inc.
Anaheim, CA
Miki Imai
Phone: (714) 777-8787
Fax: (714) 777-8792
E-mail: [email protected]

Molders Economic Index: Growth in manufacturing benefits molding sectors

The first two months of 2000 brought molders a flood of good economic news. The bottom line: The resurgence in manufacturing is continuing with considerable strength. Right now all injection molding sectors are poised to meet their growth targets. Even more, provided the good news continues—and right now we can’t spot any storm clouds—we will have to raise the year-end projections soon.

Technology is the key. A surge in American workers’ productivity during the final three months of last year helped boost productivity growth for all of 1999 to 2.9 percent, the best performance in seven years. Productivity—defined as the amount of output for each hour of work—rose at a 5 percent annual rate in the fourth quarter, the strongest showing since the last three months of 1992, according to the Labor Department.

At the same time, in 1999, growth in unit labor costs slowed. Those costs rose 1.8 percent last year compared with 2.4 percent in 1998. For the fourth quarter, unit labor costs fell at a 1 percent rate, after declining .3 percent in the previous quarter.

The heavy rate of capital investment over the past few years—new injection machines, advanced computer controls and manufacturing systems, and increased automation—has boosted productivity for molders.

Taking into account the somewhat inadequate sector data issued by the Department of Labor (these are not data that apply just to injection molding), it appears that productivity in manufacturing sectors with a lot of injection molding grew even faster: 3.1 percent in 1999 and 5.4 percent in the last quarter of 2000. The U.S. industrial sector grew in January for the 12th consecutive month, though at a slightly slower pace than in December, the National Assn. Of Purchasing Management reported.

Other data confirm that manufacturing in the U.S. has been expanding for at least 12 months. In some cases, particularly in appliances and consumer goods, most manufacturers have reported 14 and 17 months of growth, according to Commerce Department data.

Yet another set of data for January 2000 shows that overall manufacturing is again creating jobs. Some 13,000 new manufacturing jobs were created in January, mostly in electronics and automotive. That follows 1999 when almost 250,000 manufacturing jobs were lost.

Automotive: Strong
The automotive molders we speak to all say that overall 1999 has been a year of growth and that prospects for the next few months are either "excellent" or "very good."

While U.S. Government data show that imports of car parts remain at very high levels, growth of such imports has slowed sharply in the last part of 1999 as the economies of Asia consume more car parts domestically.

Thus, say molders—and detailed manufacturing data from the Commerce Department confirm this—any new growth will go to U.S. molders. And more growth is very much in the cards. New vehicle sales in January picked up where last year left off, with General Motors Corp., Ford Motor Co., and most foreign automakers reporting robust gains. Current forecasts project up to 4.5 percent growth in U.S. production of vehicles.

Computer, Electronics Grow
Despite concerns about the Y2K bug, personal computer sales surged 22 percent worldwide last year, show data released by the San Jose, CA-based research firm Dataquest. The first set of rough data for January 2000 shows that PC sales as well as sales for all types of electronics—including those for personal use—surged by almost 28 percent over January 1999. Most projections now see electronics and PCs jump in sales by more than 22 percent in all of 2000.

While U.S. molders in this market have not enjoyed the full measure of this growth, the outlook for more business here is good. Most PC leaders are U.S. firms, and life cycles for products such as PCs, mobile phones, scanners, and printers have shrunk to less than 7.5 months on average. This favors U.S., Canadian, and Mexican molders that can bring new designs to market swiftly.

Another big vote of confidence in the future of U.S. manufacturing came from Intel. The company announced plans to build a new $2 billion microchip plant in Arizona and will invest $1.5 billion in a just-acquired chip plant in Colorado Springs, CO. That plant was recently acquired from Rockwell. Intel typically locates chip-making plants close to PC and electronics assembly plants.

Surge in Durables
Orders for goods surged in December, led by the biggest jump in demand for airplanes and other transportation equipment in more than a year, the Commerce Department reported. Orders for durable goods—items expected to last at least three years—rose 4.1 percent in January, the biggest increase since July, to a seasonally adjusted $212.9 billion.

For the year 1999, orders for durable goods, including items from air conditioners to airplanes, rose 7.1 percent, matching the increase posted in 1997. In 1998, durable-goods orders rose 3.6 percent. In practical terms, this means that manufacturers of durable goods—and we estimate that almost 60 percent of all molding plants turn out goods for durable products—will have a solid six or more months.

A 4.6 percent jump in orders for electronic and other electrical equipment including semiconductors, circuit boards, telecommunications equipment, and home appliances also contributed to the big gain in overall durable-goods orders in December. Electronic and other electrical equipment has been up six of the last seven months.

Shipments of durable goods, a reliable signal of current demand, rose .7 percent in December, the seventh increase in the last eight months.


The Molders Economic Index is prepared exclusively for IMM by Agostino von Hassell of The Repton Group, New York.

Expanding the reach of RP and RT

While rapid prototyping and tooling are not exactly new, they can still be classified as emerging technologies. As such, keeping up with the frequent breakthroughs and improvements to these methods can be daunting.

With an eye toward keeping our readers informed, IMM presents highlights of a conference on the benefits and risks of rapid technologies held at Euromold’99 (see February 2000 IMM, pp. 40-42). Organized by Terry Wohlers, Wohlers Assoc., the seminar presented findings on RP/RT methods currently in use, along with several case studies.

Wohlers opened the conference session by referring to RP as a child experiencing growing pains as it moves toward its adolescent years. "Slowed growth in the past three years has confused many," he says, "but compared to the CNC and machine tool markets, RP has done very well." He cites a recent success story at Caterpillar, in which the company was able to produce a tractor cab mock-up in 31/2 months using 32 RP parts. "They had never done this in less than a year before," he adds.

Currently, three segments of the industry appear the most dynamic, according to Wohlers. "First, there are 3-D printing applications, which produce inexpensive models for evaluation early in the design cycle when engineering changes are less costly," he says. "Next, some believe RP can and will be used for directly fabricating production parts in a layer-by-layer manner. This is known as rapid manufacturing. Finally, we have rapid tooling, the name adopted by the industry to describe RP-driven tooling and core and cavity inserts created directly from RP processes. As many as 20 methods of RT have developed over the past few years, so we are seeing a lot of interest in the area."

Replicating in 3-D
As a less costly variation of RP, 3-D printers are also easy to use and small enough to fit on a bench or tabletop. Their primary goal is to provide engineers with validation models early in the design process so that changes can be made upfront, and therefore, inexpensively. These systems function much like an inkjet printer, taking a solid CAD model and rendering it in a thermoplastic such as wax.

The beauty of these replicators is that most models can be produced in a day or less vs. the multiple days it may take to build a stereolithography model. "After a CAD solid model is created, the data often changes quickly during the concept phase of development," Wohlers says. "Expensive RP models just can’t keep up with the pace, and discourage designers from building them as concept models. With 3-D printing, time and cost obstacles are overcome."

On the other hand, the variety of materials available and better part quality give higher-end RP systems an edge over 3-D printers for demanding applications. Brock Hinzmann, director of SRI International’s TechMonitoring, lists some of the material improvements in a paper titled "The Personal Factory":

  • New epoxy materials—greater strength than early acrylic materials (produced for 3D Systems by Ciba).
  • Nylon and composite materials—greater toughness over the original acrylics or the epoxies (DTM Corp.).
  • Polymeric composites (Helisys).
  • ABS (Stratasys—some developed in partnership with 3M).
  • Material suppliers such as DuPont Somos (now DSM Somos), Japan Synthetic Rubber, and others also offer variations that can be soft, almost like rubber, or can be filled with additives that give other desirable properties.

Production Parts
Ready for yet another abbreviation? Try RM, for rapid manufacturing. Boeing/Rocketdyne did, and the results were amazing. ‘They used a DTM Sinterstation to produce 200 retainer parts for an electrical assembly, creating all of them within two days," Wohlers explains. "These were not models, but actual production parts in glass-filled nylon."

Wohlers speculates that RM may be the next frontier for RP. "While it’s unlikely that RM will ever reach the production capacity of injection molding or sheet metal stamping, there are those industries where low volumes are the norm. For example, consider the customized work of those who make prosthetic devices or replacement limbs, and the low-volume production of parts for space applications."

Another category where RM may triumph is that of nonappearance parts, those hidden from view. Currently, the surface finish of RP parts doesn’t meet most production standards, but as stair steps and layer thicknesses decrease, this issue may be less critical.

Mass customization also comes into play when looking at RM. Some experts predict that, for expensive products, the entire production run may consist of one product, customized to suit the end user. "While mechanical properties of RP materials don’t suit all products," says Wohlers, "some of the new epoxy resins, nylons, ABS, and composites offer impressive strength."

However, he cautions those interested in RM to watch as it develops. "One consideration is cleaning the parts and removing support structures. Also, the speed of fabricating production parts using an RP process will be critical to the success of RM. Finally, CNC machining will remain the technology of choice for many applications. It’s a proven and widely accepted option that offers a wide material selection."

Fast Tools
With an estimated $39 billion in sales worldwide, the tooling market appeals to many RP manufacturers. A host of new and seasoned companies have joined the fray, producing a wide variety of options for creating prototype and production tooling from RP processes.

Driving this growth are time-to-market pressures, especially critical for long-lead-time injection molds. "Developers see the opportunity to slash cost and time, with possibilities for prototype, bridge, short-run, and production tooling," says Wohlers. "In addition, RT offers the option of embedding conformal cooling lines in the mold to remove hot spots and reduce cycle times."

RT can be broken into two main categories: indirect and direct tooling. Indirect methods, which account for the majority of tools, start with an RP pattern and build the tool from it. Direct methods, of course, build the tool directly using an RP process. Joel Segal, formerly of Rover/BMW, David Tait, ARRK Product Development, and Philip Dickens, De Montfort University, summarized the existing methods being used for rapid tool construction.

Spray metal tooling. A three-part process for depositing metal onto a substrate. An energy source is used to melt the metal, and then a gas atomizes the molten metal and propels it onto a substrate (i.e. a pattern). Costs are typically less than 50 percent of conventional tooling, and lead times are 65 percent less. Geometry limitations exist due to line of sight issues. Work done at Pera (Melton Mowbray, England) has produced arc-sprayed steel tooling from RP patterns. Also, Ford is commercializing a patented process called Sprayform for steel production tooling.

RP/RT on the web

Not surprisingly, rapid prototyping and tooling sites are a significant presence in the Net universe. Many of the sites stem from universities that perform research in this area. Others are developed by companies providing RP/RT equipment. As with any evolving technology, research and development efforts are still going strong, and surfing the Web proves it.

Most of the research-oriented websites offer information on the various types of RP systems, along with links to manufacturers’ sites. Here are a few that IMM reviewed:

  • Wohlers Assoc.: www.wohlersassociates.com
  • Rapid Prototyping: www.cc.utah.edu/~asn8200/rapid.html
  • Rapid Tooling: www.cc.utah.edu/~asn8200/rt.html
  • NASA RP: nasarp.msfc.nasa.gov
  • Rapid Prototyping Center: www.rpc.msoe.edu

    In addition, we found an extensive list of RP technologies at the Rapid Prototyping Family Tree page (ltk.hut.fi/~koukka/RP/rptree.html). Compiled by Henri Koukka, a researcher at the Helsinki University of Technology in Finland, the list contains a key as to whether the method is commercially available, under research, or defunct. The table below, excerpted from this site, lists several systems that are currently available.

  • 3D Keltool. (3D Systems) Uses an SLA master pattern to create RTV silicone rubber molds, which are then filled with tool steel powder, tungsten carbide, and epoxy to form green parts. These are sintered and infiltrated with copper to form a fully dense mold insert. Benefits are a 20 to 30 percent faster cycle time than P-20 steel inserts, greater than one million-shot lifetime, and accuracy to within .2 percent. Inserts can be produced in as little as eight days.

    RapidTool. (DTM Corp.) Uses the SLS process to create solid inserts by fusing powders with a CO2 laser. For tooling, RapidSteel 2.0 material is used most often. This is a direct RT process in which there are two furnace cycles—one to sinter the steel particles, and the second to infiltrate with bronze. Segal notes that one company in England saved 21,000 euro (28 percent) and 10 weeks (80 percent) vs. a conventional tool by using this process for a telecommunications product.

    DMLS. (EOS) Direct Metal Laser Sintering, an RT method that produces metal tools by laser sintering metal powders. The latest material, DirectSteel 50-V1, has been used to produce injection mold inserts. Time and cost savings over traditional molds range up to 80 percent.

    ProMetal. (Extrude Hone Corp.) Another direct process in which solid objects are created by printing polymeric binder onto thin layers of metal using an inkjet printer. This green part is heated to 1200C to burn out the binder, and then is infiltrated with bronze for a fully dense mold insert. Beta tester Motorola in Ft. Lauderdale, FL is using this process to fabricate mold inserts. According to Tait, Motorola reports it is looking at ProMetal as a strategic option for future bridge tooling, and is targeting build time at four days, including sintering and infiltration.

    TABLE 1. Commercially Available RP technologies
    Material  General method Specific method  Providers 
     LIQUIDS  Photocurable liquids Curing by light through masks Solid Ground Curing (SGC)/Cubital Inc.
    Design-Controlled Automated Fabrication
    (DESCAF)/Light Sculpting Inc.
    Curing with a UV laser (single beam) Stereolithography (SLA)/3D Systems
    Stereolithography/Aaroflex Inc.
     POWDERS  Melting powder Sintering with a heat-transferring laser Selective Laser Sintering (SLS)/DTM Corp.
    Direct Metal Laser Sintering (DMLS)/EOS
    Melting with a heat-transferring laser Laser Engineered Net Shaping (LENS)/
    Optomec, Sandia National Laboratories
    Lasform/AeroMet
    Direct Metal Deposition (DMD)/
    Precision Optical Mfg.
     Binding by adhesives Methods based on MIT's 3-D printing 3D-Printing/Z Corp.
    ProMetal/Extrude Hone Corp.
     SOLID MATERIALS  Extrusion of melted material  Plastics Fused Deposition Modeling (FDM)/Stratasys
    Melted Extrusion Manufacturing (MEM)/
    CLRF, Tsinghua University
     Inkjet techniques Multi Jet Modeling (MJM)/3D Systems
    3D Plotting/Sanders Prototype Inc.
     SHEETS  Bond-first lamination  Cutting material with a laser Laminated Object Manufacturing (LOM)/Helisys Inc.




    Contact information
    Wohlers Assoc. Inc.
    Fort Collins, CO
    Terry Wohlers
    Phone: (970) 225-0086
    Fax: (970) 225-2027
    Web: www.wohlersassociates.com

    Market Focus: Packaging

    Molding for the packaging market may lack the excitement and verve of, say, the electronics market, but over the years it's been a consistent producer, steadily trending upward at a modest but respectable pace. According to the IMM Molders Economic Index, growth for the packaging market climbed a healthy 5 percent in 1999.

    Like many high-volume commodity applications, the packaging market tends to rise and fall with the overall economy. And amidst some speculation that the economy is bound to slow down sometime in the next year or so, one might expect that the packaging market will slow as well, right? Maybe not.

    Chiming in on the subject is The Freedonia Group (Cleveland), which last year published a new report assessing the current state of the packaging market as it relates to injection molding. The report starts by noting that the effects of an economic slowdown on the packaging market "will be offset by secular growth of the foodservice sector and selected packaged food industries." Products benefiting from this upswing include such molded components as food containers, caps and closures, shipping pails, totes, and crates.

    In fact, the report says, plastic packaging shipments are forecast to increase 3.5 percent annually through 2003 (after adjustment for inflation), hitting 4.5 billion lb. That number is expected to increase to 5.3 billion lb by 2008.

    This growth is expected thanks mostly to advantages over paper and other packaging materials, growth in nondurable goods shipments, and expanding export opportunities. Additionally, given the increasing pace of daily life and the decline in personal free time, a premium will continue to be placed on convenience, fostering demand for value-added packaging.

    Gerald Sommers, president and coo at packaging molder Courtesy Corp. (Chicago), knows a thing or two about the market. His company operates 170 presses in 1.3 million sq ft, employs 1500 people, and provides design and tooling services. Sommers says 2000 is off to a promising start now that the market has left behind the Y2K jitters that bogged down the last half of 1999. Of greatest concern to him now is the looming spectre of inflation and steadily rising oil prices.

    Still, the outlook is promising. He anticipates another good growth year of 15 percent or so, much of that fueled by material conversions from glass and paper to molded plastic products. More than ever, Sommers points out, products in general, and food products in particular, rely on attractive packaging to enhance market share. "Packaging is an instrumental part of selling a product," he says.

    His one regret in these go-go, high-tech times? "I just wish I could find something to mold for the Internet," he says.



    Tamperproof polypropylene bottle cap molded in one piece

    If you have kids you might already be familiar with this cap concept. It's used on Sip and Snap caps for children's cups to help prevent spills and enhance portability. Injection molder Allied Mold & Die Corp. (Fontana, CA) has ported the same design to the water bottle market with the Sip and Snap Water Closure.

    Designed by company president Richard Dark, the cap will compete with push/pull valve caps and is molded of a copolymer polypropylene in one piece that requires no assembly. Also, unlike push/pull caps, the cap snaps permanently onto the bottle and cannot be detached (see illustration). Because of this, Allied reports, filling facilities can switch to the new cap without changing neck finishes.

    It also does not require a tamper-evident plastic ring around the neck, nor is shrink-wrap a necessity. The cap operates as a flip-open straw that can be snapped closed repeatedly. The tamper-evident seal is self-contained, created by welding the spout where the tip of the straw meets the cap in the closed position.

    As IMM went to press Allied reported that only a single-cavity prototype tool had been produced, with a production tool under construction. The company has also licensed the cap to other manufacturers. The cap will be available in a variety of sizes.

    For more information:
    Allied Mold & Die Corp.
    Fontana, CA
    Phone: (909) 357-8381
    Fax: (909) 357-9580
    Web: www.alliedmold.com







    Creativity lends upscale look, function

    A successful cosmetic product becomes such by combining a high-quality product in an attractive package. This fact is not lost on cosmetics manufacturers that are in constant search for new designs and package features to set products apart visually from the competition. This was the case at Revlon with its Custom Eye Shadow product line.

    Sussex Plastics Inc. in Sussex, WI molds the polystyrene cases for the eye shadow and says that the gold hot stamps used on the product help give it a distinct look. The cover and base are created using three decoration passes-two gold hot stamps and one pad print. Sussex molds the compact using an eight-cavity mold that automatically loads the decorating equipment. Sussex also custom-designed and built automation equipment to achieve the new look without additional labor costs.

    For Almay's Stay Smooth line of makeup (photo), Sussex designed and created what the company says is an industry-first hermetic compact. The compact uses a special sealing mechanism that keeps moisture in the product. The cover and base of the compact are molded of an undisclosed grade of ABS/SAN; the sealing mechanism is molded of what Sussex calls a special polypropylene.

    The sealing mechanism, developed over two years by Sussex, is molded in a four-cavity mold that can produce up to 18,000 compacts a day. Dimensions are held to within .001 inch to help the seal retain 99 percent of the product's moisture in a shelf life test. The seal fits directly inside the compact and has been patented.

    For more information:
    Sussex Plastics Inc.
    Sussex, WI
    Phone: (414) 246-8022
    Fax: (414) 246-8423
    Web: www.sussexplastics.com



    Copolyester finds a niche in perfume packaging

    Eastman's Eastar copolyester was the material of choice for Giorgio Armani's line of Emporio Armani perfumes. The perfumes, for men and women, are sold in distinctive tin-can style packs molded by SAF (Blotzheim, France) and Rexam Cosmetic Closures (Simandre, France).

    Giorgio Armani needed a way to segregate the perfume from the metal exterior and developed the clear container in the top photo to do the job. Testing revealed, however, that some thermoplastics were degraded by the perfume. Other materials actually corrupted the chemical composition of the perfume.

    Jean-Jacques Wicky, production and technical manager at SAF, says, "We carried out our own comprehensive evaluation to establish compatibility of materials for this purpose and found that Eastar copolyester lends itself to efficient injection molding, making it perfect for the job." At perfume-maker Yves Saint Laurent, the company designed the cap on its new Vice Versa eau de toilette with an eye-catching red heart, intended to attract consumers to the new scent. It is the first part of the bottle the consumer sees and it's featured in all of the advertisements for the perfume.

    The heart itself is injection molded of Eastar PCTA copolyester from Eastman. Manufacturer MT Packaging (Challes, France) provides to Yves Saint Laurent the bottles, caps, and packaging for the product line. Around the red heart shape a small metallized band is positioned; MT reports that PCTA's flexibility allows the band to be easily slipped into place during assembly. The resin also demonstrated chemical resistance when exposed to the perfumes, and it offers good scratch resistance.

     

    For more information:
    Eastman Chemical Co.
    Kingsport, TN
    Phone: (423) 229-4853
    Fax: (423) 229-8595
    Web: www.eastman.com

     

    Elastomer provides soft armor for CDs

    Lugging CDs around in their cases can be a cumbersome drag, but once they are out of that protective shell it's easier to damage your favorite album. To rectify matters, the Discus CD storage system, made by CD3 Storage Systems Inc. (Round Rock, TX), is designed to hold up to 20 disks in a soft, rugged, protective enclosure. It uses accordion-like folds to separate disks from one another.

    The Discus case is molded of a Santoprene thermoplastic elastomer (TPE) from Advanced Elastomer Systems (AES). "The Discus is made to be carried around, so we needed a combination of materials that would provide exceptional protection while withstanding drops and mishandling," says Shari Hunt, marketing and sales manager at CD3.

    The TPE provided the look, feel, colorability, and performance the company desired. It also came in handy when incorporating a molded-in living hinge into the Discus. The hinge allows the user to open and close the unit repeatedly without performance degradation. "The living hinge is critical to the overall performance of the Discus because it helps hold the unit together and provides access to its contents," says Hunt. Santoprene's flex fatigue performance appealed to the manufacturer.

    The clasp on the Discus is molded of a silver polypropylene and is designed to act as either a latch or a hinge. The unit also features windows for storing labels and other graphics.

    For more information:
    Advanced Elastomer Systems LP
    Akron, OH
    Phone: (330) 849-5000
    Fax: (330) 849-5599
    Web: www.aestpe.com



    Packs dispense with ABS, HIPS

    The birth control pill has been around since 1960, and pill dispensers almost as long. But the introduction of the Personal Pak, says manufacturer Ortho-McNeil, is the first disguised as a compact and intended for reuse.

    The Personal Pak holds a month's supply of pills in a sealed dispenser ring that rotates around a one-way dial marked with the days of the week. The cover and base are made of an ABS from Dow; the calendar and hub in the center of the pack are molded of HIPS. Larry Lambelet, principal engineer, technical development at Ortho-McNeil, says previous products were molded of polystyrene, but the Personal Pak demanded a tougher material. "We used the ABS to get a hard, polished surface that would stand up to use and not scratch easily," says Lambelet. Also, previous products were gated in the center of the cover and base; this produced a blush that was disguised on the polystyrene version but would be obvious in the Personal Pak. To fix that, Ortho-McNeil moved the gate to the hinge area. "So the switch to ABS was for both functional and aesthetic reasons," says Lambelet.

    The calendar and hub are molded by The Tech Group at its Puerto Rico facility. The cover and base are molded by West Pharmaceuticals, which also does assembly and decorating. Some of the designs on the Personal Paks are applied via the patented hydrographics process. With it, a decoration is printed on a water-soluble carrier; the carrier is immersed in a water bath, leaving the decoration floating on the surface. The Personal Pak is then pressed through the decoration in the water. As the water wets the surface, so do the inks in the decoration. The Personal Pak is available in lapis, garnet, jade, amethyst floral, onyx, and sapphire.

    For more information:
    Dow Plastics
    Midland, MI
    Phone: (517) 636-1000
    Fax: (517) 638-9752
    Web: www.dow.com



    Compound improves display clarity

    The success of a retail product display is dependent to a point on the appearance and aesthetics of the surrounding environment. That is, an attractive, clean display case, shelf, or stand can enhance the appeal of the products on it.

    Such is the case with this display base for a line of mobile phones. It uses a multipolymer compound, Cyrovu HP2, made by Cyro Industries. The material reportedly provides designers and molders the clarity of acrylic with good impact strength and mechanical properties.

    Cyro claims clarity and ease of processing as two of the primary benefits of the material. In molded form the material is also designed to resist breakage during assembly, handling, and transportation. It has a 90 percent light transmittance, 3 percent haze value, and is available in a range of colors and tints to meet specific needs.

    For more information:
    Cyro Industries
    Rockaway, NJ
    Phone: (973) 442-6000
    Fax: (973) 442-6117
    Web: www.cyro.com

    Vented barrels for small machines

    Vented barrels don’t work on small tonnage molding machines, right? Screw and barrel size restrictions on small machines cause vent flooding, and few custom molders today have time to waste in cleaning out plugged vents.

    Take Nypro Carolina, for instance. Nypro Carolina II runs lights-out, 24/7 in Burlington, NC. It runs 16 30-ton all-electric molding machines custom-built for Nypro by Ferromatik Milacron. Each is equipped with a three-axis servo robot and produces small, tight-tolerance parts in cavity-pressure-sensitive tooling. Nypro Carolina II also runs fully automated QMC systems that allow it to do changeovers and be up and running again in less than 5 minutes.

    So, Nypro Carolina II cannot afford four to five hours of predrying lead time. It wanted to use vented barrels like the other two Nypro facilities in Burlington running bigger machines. But vented barrels don’t work on small machines . . . or do they?

    Jay Needham, the molding group leader at Nypro Carolina II, wanted to find out. He found his answer online.

    Cyberspace Solutions
    "We had been looking at vented barrels for small machines for about two years," Needham recalls. "I’d tried using cavity-pressure control to compensate for screw recovery inconsistencies, but it didn’t work. The vents still flooded."

    "The operating costs of our electric machines are comparable to the cost of running our dryers," he continues. "We felt that the savings we could achieve eliminating dryers could be used for better things. Of course, I still wanted to dry my material, but we do 5-minute mold changes. How could I get around predrying downtime?" He went to the Net and asked.

    Needham posted his question in a popular Web forum. He wanted to mold gears in his quick-change 30-tonners, 24/7, with no predrying. A PTFE and carbon-filled PC compound was the specified material. The gears, with an OD tolerance of only half a mil, were to be run in a two-cavity mold with a 28g shot. The screw had to have a 20:1 L/D and a second set of pumping flights to work. Its diameter could go down to 18 mm.

    Carriage-retract limitations in the design of its custom-built all-electrics added further restrictions. Nevertheless, either there had to be zero drool, or vents should have to be cleaned only once every 24 hours. Can it work? Needham asked. Harmut Jahnke, vp of technology at Xaloy, responded by e-mail that he had an idea. Offline, they started talking.

    Balanced Screw Staging
    "Usually it’s not easy to get such small diameter screws to work with a vented barrel. Small screws do not follow all of the conventional rheological models," Jahnke explains. "Because of the size limitations, you get restrictions. It is extremely difficult to optimize root diameters and make them small enough."

    Jahnke continues, "Also, the channel height is very small. These restrictions affect the behavior of the melt, often resulting in inconsistent recovery and part quality problems, not to mention uncontrollable vent flooding. It is difficult to get the screw geometry tweaked to achieve good flow and also decent venting characteristics. The trick is to balance the output from the first stage of the screw with the receiving ability of the second stage."

    In time, an optimized 22-mm, 20:1 L/D screw was built by Xaloy to run in Nypro’s existing vented barrels. Xaloy had never installed such a small vented barrel set before.

    "In three months of run time, we’ve never once had to clean vents," Needham says. "My process techs are the best judge and jury in the world. They were skeptical, and I didn’t say anything to influence them. After watching it run, they came back to me and said, ‘Man, this thing is great.’ I’ve ordered two more sets. The implementation of the vented systems will significantly decrease downtime caused by material drying, which will increase revenue. That’s the key thing. But, the elimination of drying will also save Nypro $1000 a year on energy costs per machine."

    Needham says he intends to order more, each optimized to run different types of filled and unfilled hygroscopic materials. He’s done his math: "If we had them on only 10 machines, we’d save $10,000 in a year. That’s a good slush fund for me to buy more cavity-pressure transducers.

    "I intend to have every machine daisy-chained into an RJG Dartpak monitoring network, so my customers can dial in and watch their parts running, right along with me," he adds.


    Contact information
    Nypro Inc.
    Clinton, MA
    Jay Needham
    Phone: (978) 365-9721
    Fax: (978) 365-4352
    Web: www.nypro.com

    Xaloy Inc.
    Newburyport, MA
    Harmut Jahnke
    Phone: (978) 462-3163
    Fax: (978) 463-9842
    Web: www.xaloy.com

    Software trips the light fantastic

    Free enterprise is a wondrous concept . . . except when it comes to software. One almost wishes that a major player would buy up the other vendors and make them all speak the same language. Blasphemy? OK, the idea is a bit harsh and improbable. But when it comes to sorting out the finer points of new engineering software offerings, many designers are caught between the robust and the newest revision. What you may be searching for, instead of software conflicts and jargon, is a clear explanation.

    This quest becomes especially pertinent in light of the countless new packages that have danced their way to market recently. Several are highlighted here, with descriptions of the general class of software to which they belong. (For more details, please check the contact information at the end of this article.) Spanning categories from CAD to collaboration, these virtuoso performers stand out—they’re well worth the time it takes to get to know them.

    Pay as You Go
    And you thought all the good ideas were already taken. Although free enterprise spurs a confusing variety of software, it also fosters pioneering moves among vendors. A recent example is the emergence of ASPs, or application service providers. Basically, these are software vendors that supply a myriad of pay-as-you-go services, from renting software on a monthly basis to repairing a solid model for a fee, by using the Web as a means of distribution.

    One such ASP that offers model translation and healing on a per-use basis is 3Dmodelserver.com from Spatial Technology Inc. Customers need a standard Web browser (Navigator 4 or higher, Internet Explorer 3 or higher) and an Internet connection to access the site. Once there, users click on the option to register, complete the log-in information, and follow the instructions to upload a model in either SAT or IGES format. Users are then prompted to indicate their translation and healing preferences and to submit a 3-D model.

    Customers are notified by e-mail when the model has been successfully uploaded, and the progress of each model can be tracked through a status page on the website. When processing is complete, an e-mail notification is sent out, and the customer can log onto the site and download the model. On download of the file, the site provides a comprehensive report of the repair activity and the processes used.

    CollabWare is an ASP and software developer that recently announced the availability of GS-Design, a high-end solid-modeling CAD system designed from the ground up for use over the Internet. Originally developed at Lockheed Martin for aerospace programs such as the F-22 Stealth fighter, this package can model ultralarge assemblies with ease.

    By renting GS-Design on a monthly basis, designers from separate geographic locations can get together in cyberspace to work concurrently on the same project (can you say "virtual meeting"?). The program manages revisions and configurations, and provides secure central storage of design data. Each user can see the state of the design in real time, making version control problems a thing of the past.

    Cyber Meetings
    While collabware.com is a site specific to one CAD system, others allow design review meetings using any and all systems. Not unlike high-tech chat rooms, these programs enable OEMs and suppliers to work together without leaving their desks.

    One of the front-runners in this new field is Framework Technologies’ ActiveProject 5.0, software that builds and manages project websites, or extranets. Any type of information—documents, CAD files, photos, spreadsheets, project schedules—can be published and maintained on the site. Participants can review, mark up, and add comments directly using a Web browser. An integrated search function makes it easier to navigate, and users can define tabs as needed to mark separate project areas.

    According to Framework’s Brian Giuffrida, in its most basic form, a project extranet is a modern-day proxy to the filing cabinet. "But with its basis in the World Wide Web, the project extranet offers several extras that can prove invaluable to projects that span multiple firms, disciplines, and locations," he says.

    Unlike the traditional filing cabinet, the project extranet centralizes project information, giving teams the right information at the right time and place and reducing or eliminating costly, time-consuming manual distribution by mail or fax. It also delivers information in electronic form so that it can be manipulated and modified, integrates information in external applications or databases, and permits project documents to be shared with individuals from other firms. Activity is automatically catalogued, and the program manages access rights and security issues.

    Designing the Best
    In its earliest incarnations, moldfilling simulations were mere ballpark estimates of whether or not a mold would fill given a particular part design. Fast forward to today’s sophisticated packages and you’ll find that a lot has changed. Software vendors now aim for optimizing designs automatically, providing tools that guide designers toward the lowest cycle times and best processing conditions.

    Moldflow’s newest offering, MPA 4.0, is the latest in the Plastics Adviser series, and consists of both Part and Mold Adviser packages. Its intent is to raise the bar by taking the guesswork out of part and mold design. Automatic gate location, for example, identifies optimal gate placement based on geometry and filling patterns. Another feature, process condition optimization, lets users automate the selection of these para-meters based on their choice of part geometry, material, and gate location.

    In addition to the confidence-of-fill plot available with previous MPA versions, 4.0 adds a quality plot that gives insight into resulting quality of injection molded parts. Automatic runner balancing completes the picture to ensure that each cavity fills at basically the same time and pressure for better part consistency.

    Take Two Aspirin
    Mold designers often feel the impact of this issue most keenly, but part designers are no strangers to it either. The issue? Repairing imported CAD models, otherwise known as the dreaded interoperability problem.

    Here’s the scenario: An OEM designer sends CAD files out to suppliers. The file is sent in an IGES format and then imported into the suppliers’ systems. Often, the originating CAD system and the receiving one are different. When the supplier tries to work on the imported file, its designers find a variety of errors in the 3-D model, from missing and duplicate surfaces to gaps and leaks. Downtime associated with rebuilding these models is a major frustration.

    Fortunately, help isn’t hard to find. Cadkey, for example, realized that its mold designer customer base needed tools to overcome model repair problems. In its newest release, Cadkey 99, it has included two interoperability tools that significantly reduce the time spent on model rework.

    One, called the solid body healer, fixes missing and duplicate surfaces, bad surface normals, warped and self-intersecting surfaces, and low-tolerance models. This feature can be run manually or in interactive mode. The second tool, a tolerant edge function, selectively loosens tolerances at small leaks in a 3-D model and assigns new properties to these areas. If the tolerance adjustment can close the gap, the model will behave as a closed body and designers can use traditional solid modeling operations on it.

    CADfix for Ansys (through a joint collaboration with International TechneGroup—ITI—and Ansys), another new package, specializes in repairing models for finite-element analysis (FEA) within Ansys. Aimed at Catia users initially, this software improves interoperability by automatically repairing models from a wide range of leading CAD systems to get them ready for FEA.

    Eric Underwood, product manager for Ansys, explains, "Most CAD models built today cannot be used ‘as-is’ by downstream applications such as engineering simulations. CADfix for Ansys attempts to repair most of these problems in an automated process. If these problems cannot be fixed, then the specific problem areas are displayed in a manner that guides the customer through a manual repair process."

    Easing the 3-D Switch
    Going from 2-D to 3-D in CAD can upset even the most stable of engineering departments. Two software suppliers are letting you know that the ground doesn’t have to shake when you make the switch.

    Unigraphics’ Solid Edge, for example, contains fully integrated 2-D and 3-D design functions, so that users can still create drawings from scratch in the 2-D drafting system while also being able to create 3-D solid models using parametric feature-based techniques. Support for AutoCAD files means that these 2-D models can be imported and exported. Creating 2-D drawing views from solid models can also be done automatically. Finally, demos walk users through the process of using 2-D CAD data to create 3-D solid part models.

    Through its Origin program, Unigraphics makes limited function copies of Solid Edge available at no cost to designers interested in trying solid modeling. Since its inception in August 1999, the program has gained 36,000 users, and is now sending out 4000 copies per week.

    Unlike some 3-D modelers, Solid Edge was designed with a full 2-D drafting module. Former 2-D users report faster drawing times with this module. One customer is creating drawings for complex parts eight times faster. Other advantages revolve around the 3-D capability—being able to check part fits virtually, avoid errors in an assembly, and export the 3-D file for use in downstream processes.

    Microcadam’s new Helix2000 lends a hand to 2-D users with its Helix Capture function, which lets designers create solid models based on 2-D AutoCAD drawings in as little as five minutes. Users can choose between automatic mode or generative design. While in AutoCAD, users define views for Capture’s structure (i.e., first and third angle views), and then click on Capture to load the views automatically. If generative design is preferred, designers can make intelligent feature picks with the cursor.

    A dual-hybrid modeler within the program also integrates surfaces with solids, and combines both parametric and topological design change. Major customer Sony, with 1200 seats, has been able to cut design times for new television sets down to four months.

    What About the Cost?
    Living in a bottom-line world as we all do, designers often face trade-offs between the optimal design and the most cost-efficient one. At times, the decision comes down to the best that can be done at the target cost. In any case, the more information on costs a designer can get in the early stages of product development, the better. Need some assistance in this area?

    In its newest version, DFM Concurrent Costing 1.1 (Boothroyd Dewhurst Inc.) has added injection molding to the list of available processes. The software isolates the major cost drivers associated with a wide range of processes, and guides decisions about materials and processes during the concept and detailed design stages. One intent of cost-estimating, according to BDI, is to help engineers consider how individual part features might be modified to reduce manufacturing costs.

    If you’re already using solid models, the program now accepts 3-D files from all major CAD systems, using the geometry to calculate estimated manufacturing costs. This feature is supported by the Solid View/Pro 3-D viewer from Solid Concepts.


    Contact information

    Boothroyd Dewhurst Inc.
    Wakefield, RI
    Phone: (800) 424-3362
    Fax: (401) 783-6872
    Web: www.dfma.com
    E-mail: [email protected]

    Cadkey Corp.
    Marlborough, MA
    Liz Rombek
    Phone: (508) 229-2020
    Fax: (508) 229-2121
    Web: www.cadkey.com
    E-mail: [email protected]

    CollabWare Corp.
    Idaho Falls, ID
    Scott Cullins
    Phone: (208) 552-4701
    Fax: (208) 552-4703
    Web: www.collabware.com
    E-mail: [email protected]

    Framework Technologies Corp.
    Burlington, MA
    Brian Giuffrida
    Phone: (781) 359-3370
    Fax: (781) 270-5023
    Web: www.frametech.com
    E-mail: [email protected]

    ITI
    Milford, OH
    Bob Farrell
    Phone: (513) 576-3845
    Fax: (513) 576-3994
    Web: www.iti-oh.com
    E-mail: [email protected]

    Microcadam Inc.
    Burbank, CA
    Beth Leitner
    Phone: (818) 253-2274
    Fax: (818) 253-2250
    Web: www.microcadam.com
    E-mail: [email protected]

    Moldflow Corp.
    Lexington, MA
    Al Duff
    Phone: (781) 674-0085, ext. 229
    Fax: (781) 674-0267
    Web: www.moldflow.com
    E-mail: [email protected]

    Spatial Technology Inc.
    Boulder, CO
    Rachael Dalton-Taggart
    Phone: (800) 767-5710
    Fax: (303) 544-3003
    Web: www.3Dmodelserver.com
    E-mail: [email protected]

    Unigraphics Solutions Inc.
    Huntsville, AL
    Phone: (800) 807-2200
    Fax: (256) 705-2690
    Web: www.solid-edge.com
    E-mail: [email protected]

    The Materials Analyst, Part 30: How usable is your regrind?

    This series of articles is designed to help molders understand how a few analytical tools can help diagnose a part failure problem. Michael Sepe is our analyst and author. He is the technical director at Dickten & Masch Mfg., a molder of thermoset and thermoplastic materials in Nashotah, WI. Mike has provided analytical services to material suppliers, molders, and end users for the last 12 years. He can be reached at (414) 369-5555, ext. 572.


    Two and a half years ago we began this series with an article on some polycarbonate parts that were brittle because poor processing, in this case inadequate drying, had reduced the molecular weight of the material. We documented the change in molecular weight with a relatively simple melt-flow-rate (MFR) test. Since then, we have come back to this theme of the connection between molecular weight, melt viscosity, and properties several times.

    It is difficult to emphasize this correlation too much since it remains the number one problem with plastic product performance and it is perhaps the most fundamental tenet of polymer behavior. It is an 80-year-old idea that was revolutionary and controversial at the time of its advent, but by now we should all have gotten it.

    Usually we back into this subject of molecular weight as a way of explaining a quality problem that has been sent to us by a client. But this month’s study focuses more on planning and forethought. The purpose of this investigation was to determine the progressive effect of recycling a material through the molding process several times.

    This is a technique that material suppliers have used for many years to demonstrate the robustness of their materials. They will run a standard sample shape like a disk or a plaque in virgin material, grind some of the parts and make some more product in 100 percent first-pass regrind, and repeat this step until they have parts made from virgin material and five generations of regrind. Then they will lay these parts out on a white background and take some pictures so that everyone can see how good the color retention is. Normally they will also conduct the same trial on their competitor’s material, which of course performs much worse. Seldom, if ever, do we see any property information on these repeated passes.

    Using Scrap Effectively
    Our client had performed just such a trial on its product, a part molded in a 4-MFR polypropylene homopolymer, and wanted to review the melt flow rate of each pass to determine the change occurring in the material with each pass through the machine. In these competitive days, effective use of regrind is obviously a key factor in managing costs. Some processors, either because of regulatory dictates or out of habit, simply throw out any scrap generated in the form of runners and bad parts as though it were a thermoset. Others add it back to virgin material at a particular percentage like 20 or 25 percent. This spreads out any detrimental effects of processing and ensures that material from a second, third, or fourth pass will be watered down.

    Still others adopt what has become known as a cascade process. They collect all the first-pass regrind from a given lot of material and then run it straight. While this first-pass material is being run they are collecting the second-generation scrap, which they then run at 100 percent and so on, just like the material suppliers in the tests we described. The supposed benefit of this method is increased traceability. Assuming very good handling procedures are employed to ensure cleanliness, it can be made to work for many materials, but under this system it becomes even more important to understand the effect that the process is having on the material.

    TABLE 1. MELT FLOW RATE SHIFTS IN POLYPROPLYLENE PARTS

     Sample  MFR, g/10 min  Shift from previous, % Shift from
    original pellets, %
     
     Parts-100% Virgin  5.43    35.8*
     Parts-1st Regrind  6.66  22.7  66.5
     Parts-2nd Regrind  9.22  38.4  130.5
     Parts-3rd Regrind  10.60  15.0  165.0
     Parts-4th Regrind  13.71  29.3  242.8
     Parts-5th Regrind  16.44  19.9  311.0
     *Assumes an initial melt flow rate of 4.0g/10 min

    Our client could see that by the third trip through the injection molding machine, its parts, which were being run in natural material, were beginning to yellow. We ran a simple melt-flow-rate determination on parts made from virgin material and all five generations of regrind. We had no virgin material, so the assumption was made that the particular lot the client was working with had the nominal melt flow rate of 4.0.

    The results of the investigation appear in Table 1 and in graphical form in Figure 1. Remember that the guideline for good processing of an unfilled material is an increase in the melt flow rate from pellets to parts of no more than 40 percent and preferably less than 30 percent. While no single pass through the molding machine exceeded the 40 percent limit, the cumulative effect on the material is striking. The parts made from first-time regrind are already out of bounds, and the problem spirals rapidly out of control from there. By the time the last set of parts has been made, the 4-melt material has become a 16-melt material with color problems.

    Often, these changes are also accompanied by a loss in critical additives such as antioxidants, ingredients that are designed to protect the polymer from the rigors of aggressive field service conditions. Fortunately, in this case the stabilizers were still intact. A test designed to assess oxidative stability was run on virgin parts and those made from fifth-generation regrind and the change was a surprisingly small 10 percent.

    Nevertheless, the parts varied greatly in molecular weight. Now, there is nothing inherently wrong with a 10-melt or a 16-melt poly-propylene, but it simply will not have the properties of a 4-melt. If a 4-melt material is needed, then parts made from the higher-flow regrinds are likely to run into performance problems. The good news is that much of the change that we saw in this case is avoidable and usually arises from running the melt temperature too high. We were able to reproduce our client’s results using a simple tensile bar mold and running a melt temperature of 249C (480F). We then repeated the experiment using a melt temperature of 204C (400F).

    The results appear in Table 2 and in Figure 2, and they are dramatic. Although each step changes the material to a slightly different degree, the overall shift in the material processed at 249C is 330 percent. But the material molded at 204C has only moved 25 percent after five passes through the molding process. In other words, it will still have the intended properties and after five runs through the press it is in better condition than after one run at 249C. The starting melt flow rate of this particular lot of raw material was 3.98g/10 minutes.

    TABLE 2. EFFECT OF PROCESSING TEMPERATURE ON MELT FLOW RATE

     Sample

     MFR @ 204C, g/10 min

    Cumulative shift from virgin, % 

     MFR @ 249C, g/10 min

     Cumulative shift from virgin, %

     Parts-100% Virgin  4.19  5.3  5.35  34.4
     Parts-1st Regrind  4.33  8.8  6.73  69.1
     Parts-2nd Regrind  4.51  13.3  9.37  135.4
     Parts-3rd Regrind  4.65  16.8  10.78  170.9
     Parts-4th Regrind  4.84  21.6  14.16  255.8
     Parts-5th Regrind  4.99  25.4  17.11  329.9

    Improved Processing Through Material Analysis
    If you engage most processors in a discussion about their selection of an optimum melt temperature, most of them will cite the need to fill the cavity as their rationale for running the material at a particular setting. In most cases, this selected temperature is higher than it needs to be because molders do not take full advantage of the other method for reducing viscosity—shear.

    All plastic materials exhibit viscosity reduction with increasing shear rate, and one of the tasks of process optimization is to arrive at the best balance of shear and temperature. For some amorphous materials, notably polycarbonate and polysulfone, the balance is clearly on the side of temperature. But for most materials, and especially a material like polypropylene, shear rate provides a much more effective route to viscosity reduction.

    Figure 3 shows a viscosity vs. shear rate plot for a 4-melt polypropylene at 204C (400F), 227C (440F), and 249C (480F). You don’t have to be a rheologist to understand the implications of this graph. Simply look at how closely spaced the viscosity curves are for the three temperatures. Even though this is a logarithmic plot, something many of us don’t use every day, a close look at the region between 1000 and 10,000 sec–1 is an education that we can take back to the molding machine.

    For example, look at the viscosity of the material when the melt temperature is 204C and the shear rate is 2500 sec–1. You should come up with 55 Pa-sec. Now look at the same shear rate point for the curve generated at 249C. The viscosity has dropped to 40 Pa-sec. Now comes the good part. Go back to the curve for 204C and follow it from 2500 sec–1 to the point where it crosses the viscosity of 40 Pa-sec. What is the shear rate? That’s right, 4000 sec–1. How do we change the shear rate from 2500 to 4000 sec–1? We increase the injection speed by 60 percent, for example from 1.25 inches/sec to 2 inches/sec.

    Processors that find themselves raising the melt temperature because they have run out of speed, or because the speed setpoint is not obtainable due to a pressure-limited process, should realize that the price they pay is huge. Not only does it require much more energy to put all that extra heat into the material (energy consumption), it takes more time to get it back out (cycle time). And as the data above have shown, you get degraded material in the bargain.

    Right about now some of you are probably thinking that you have skipped a page in the magazine and are no longer reading an article about material analysis. But that is exactly the point. The best material analysis relates directly back to improved processing; it is not an activity that takes place in a vacuum. The practice of optimizing a process and coming up with test data that certify a healthy process are activities that should be joined at the hip.

    We recommend that a viscosity comparison between pellets and parts be done as part of the first article inspection, because the part can be to print in every respect, but if it is made from degraded polymer, it’s still no good. And sound management of regrind is impossible if you don’t know what your process is doing to your material.

    Saving time in mold design

    The push for reduced time-to-market from OEMs affects both part and mold designers. Many of the success stories concerning software, however, seem to focus on part design. Details from a recent interview with Tycos Tool & Die (Concord, ON) point out the time savings possible when mold designers make use of a hybrid CAD modeler, that is, one that offers both 2-D surfaces and 3-D solids.

    Tycos is a leading automotive moldmaker with a 40-year history of specializing in fascia and large exterior body panel tools. The firm employs more than 200 people as a division of Magna International under the Decoma umbrella. In fact, a majority of its tools are built for Decoma. Ron Nesselberger, assistant general manager, and Ted Visser, design supervisor, tackle duties including engineering, program management, estimating, and customer service.

    "Tycos designs and manufactures molds for virtually any type of exterior vehicle part including fenders, quarter panels, bumpers, door skins, cladding, and rocker panels for the automotive industry," says Nesselberger. "Typically, we receive CAD data from our customers, and the geometry originates from a myriad of CAD systems. Data is sent to us via IGES files."

    Competitive Environment
    It's no secret that automotive moldmaking is one of the most challenging industries today. For example, with the increasing importance of sleek exterior aesthetics and sexy styling, moldmakers such as Tycos face increasingly ambitious mold designs. Nesselberger notes, "We also must address complex parting lines and locking mechanisms in an effort to exceed customer expectations." Prior to beginning a new mold design, Tycos carefully scrutinizes moldfilling analysis to determine the needs of the molder. As a rule, the molder supplies this data, and the results of that analysis are applied to the mold design.

    Like most moldmakers, Tycos faces design and fabrication issues including timing of the tools, costs, and flexibility. "In terms of flexibility," notes Nesselberger, "from the time that we receive the initial CAD information to the time that we export our design to manufacturing, we can realize several levels of changes. The design cycle time may not change, however, so we have to be flexible enough to modify our design or the part data and still meet the deadlines. The design changes can originate from the customer or from our end as we complete a feasibility of the data supplied."

    Tycos aims for on-time delivery, cost-effectiveness, and design innovation, addressing each of those challenges individually. "Innovation is driven by a need," adds Nesselberger. "We always sit down with our customer and go through a process of open-ended questions to determine exactly what the needs of the program are, such as downstream process requirements, or paint and molding issues. Our in-house design team determines the solutions to eliminate or reduce the problems that the molder may have."

    Some engineering challenges are part-driven and some are process-driven. Tycos also tackles a lot of feasibility and development work at the beginning of the program to make sure that the engineers clearly understand the goals of each project. Then, Nesselberger, Visser, and their team of moldmakers, mold designers, engineers, and machinists communicate those goals throughout the company so that Tycos can comprehensively meet the customer's design goals as well as the CNC machining goals in the final tool.

    "We also benchmark all of our tools in production," Nesselberger says. "That's one of the advantages that we have over most of our large competitors. Because we are an internal entity to our customers, we have complete access to benchmark the tooling and its performance for the life of the program. That incentive generates a tremendous amount of continuous improvement toward durability and maintainability. In addition, we invest heavily in technology that will generate the best return for our company."

    Hybrid Switch
    Until 1994, Tycos engineers worked in a 2-D drafting environment. "We didn't use 3-D software before then because we didn't have a customer base that generated CAD geometry from which to cut tools," says Nesselberger. Six years ago, Tycos implemented a popular commercial 3-D solid modeling package and a CAM product. While the move brought some productivity gains, mold designers still wanted to be able to design in both solids and surfaces.

    A hybrid CAD package (thinkdesign by think3) has given designers the best of both worlds. "The hybrid surface and solid modeling functionalities enable us to utilize the most effective tool design so we can combine both 2-D surfaces and 3-D solids instead of being restricted to one or the other. As a result, we can opt between whatever process is best suited for the condition that we are trying to design," Nesselberger reports.

    Six engineers were trained to use the software within a few weeks, and are using the hybrid modeler on front and rear fascia designs. Plans are to train all of the mold designers. "We estimate that the switch saves us 15 percent in design time, and as all of our users get more comfortable, we are expecting a savings of 35 percent."

    Tycos has been using a CAM system (HyperMill from Open Mind) that production operators chose for its performance. To speed productivity further, the CAM software is compatible with the hybrid modeler. There is no translation required downstream at the CNC machines.

    Training takes a turn

    How did Tycos get six engineers up and running on new CAD software in just a few weeks? At least part of the credit goes to an innovative, video-game-based tutorial that is shipped with every copy of thinkdesign. Called the Monkey Wrench Conspiracy, the CD is designed to get mechanical designers comfortable in no time.

    "Games bring a level of entertainment and fun to the experience," says think3's Joe Costello, chairman and ceo. "Once you've captured the imagination, the mind is much more open to real learning. That's true for both children and grownups."

    Like its training CD, think3 has taken a revolutionary approach to the CAD market. First, it is the only vendor offering its software on a yearly subscription basis at a price of $1995 (no ups, no extras), and the program can be purchased online. A lower price, however, doesn't mean lower performance. The thinkdesign product is a fully functional midrange CAD package based on a proprietary software kernel.

    "Having our own kernel allows us to have a hybrid modeler in which users can simultaneously work in 2-D, solids, surfaces, and wireframe," says Andrea Nassisi of think3. "Not only can we take in geometry from 2-D, but the whole 2-D drawing becomes part of the 3-D database, including surface finish and annotations."

    Being able to use older 2-D files in the new system is one of the features moldmaking customers require. "Our customer base has told us that other software suppliers that want them to migrate to 3-D are asking them to change their process overnight and throw out 2-D legacy data," says Nassisi. "We're committed to avoiding this pitfall."


    Contact information

    Tycos Tool & Die
    Concord, ON
    Ron Nesselberger
    Phone: (905) 669-2350
    E-mail: [email protected]
    think3
    Santa Clara, CA
    Lisa Washington
    Phone: (408) 987-6808
    Web: www.thinkthree.com
    E-mail: [email protected] thinkthree.com
    Open Mind Software Technologies GmbH
    Unterfoehring, Germany
    Beatrice Desimoni
    Phone: +49 (89) 950 0305
    Fax: +49 (89) 950 6979
    E-mail: [email protected]
    Web: www.openmind.de

    The mystery of the cracked stadium seats

    Editor’s note: Peter Lantos is president of The Target Group, an industrial consulting firm located in Erdenheim, PA. The following story describes his company’s recent experience helping a molder solve a product failure.


    Not long ago a Japanese businessman in the U. S., having seen an attractive baseball stadium seat in the states, arranged to have 30,000 such seats produced at an injection molder in Japan for installation at a stadium in Nagoya, a city 200 miles from Tokyo. Within a week of installation, a large number of seats began to crack, and the entire lot had to be replaced with freshly molded seats produced by the same molder. These held up without cracking. The businessman blamed the molder for the product failure and turned to our company, The Target Group, to find the cause of the problem.

    The Target Group was given 12 seats—six with cracks, six without. We started our examination by evaluating factors that might cause cracks.

    We eliminated design as the problem, as it was identical for both sets of seats. In fact, the same mold was used to produce all seats. Seat design was also deemed basically sound: It was rigid, had a curved contour that provided good load support and impact resistance, and it contained no sharp corners.

    Installation was also eliminated as a factor, as was seat location. The cleaning process was the same for both good and bad seats. Finally, all seats endured similar end-use conditions—it seemed unlikely that the bad seats all had the misfortune of encountering crack-causing, overweight spectators. The seats (Figure 1) were rectangular, about 12 by 15 inches, and gated at the center. Substantial cracks, about .125 inch wide at the base and 7 inches long, emanated radially from the gate, along the flow lines. This suggested a problem in the molding process. Unfortunately, the molder and the stadium businessman had become adversaries; thus no information was made available about either the molds or molding conditions.

    The Testing
    We decided first to conduct resin tests. The seats were supposed to have been molded from orange-pigmented HDPE of .965 density and 5.5 melt index, and tests confirmed this. Ground-up resin samples were tested at Springborn Laboratories (Enfield, CT). Results are in Table 1. The data also showed that there was no significant difference in density or melt index between resin from good and bad seats. We concluded that neither the wrong resin had been used, nor was there a difference in the moldability of the resins.

    Chemical testing was performed by Jordi Assoc. (Bellingham, MA). Resin samples from each seat were frozen in liquid nitrogen and ground up, extracted with toluene and filtered, after which the liquid was evaporated. The residual solids were dissolved in isopropyl alcohol and analyzed via reverse phase high-performance liquid chromatography. The results (Table 1) indicate that identical stabilization systems had been used in each resin. But there were also trace amounts of byproducts showing fluorescence in the bad seats. These byproducts are associated with resin degradation, suggesting that some degradation and/or oxidation of the HDPE had taken place. No such byproducts were found in the resin of the good seats.

    Also, resin taken from each kind of seat was ground up and test bars were injection molded. Izod impact-strength tests (Table 1) showed that cracked seats had roughly half the impact strength of the good seats. This was significant and we hypothesized that the resin of the cracked seats had encountered excessive heat in the molding process.

    We performed additional investigations. Resins were examined at Structure Probe (West Chester, PA) using light microscopy (LM) and transmission electron microscopy (TEM). The results of TEM indicated that the pigment in each resin was dispersed equally well. Thus the low impact strength was not caused by poor pigment dispersion. The LM results, however, showed a major difference between the two resins. The good resin had a spherulitic crystal structure of relatively large size. The bad resin was made up of fine crystal spherulites, which could be caused by the presence of a nucleating agent, or by rapid cooling resulting in rapid crystallization. No nucleating agent was detected, and pigment concentrations (pigment can act as a nucleating agent) were identical. Thus it seemed the fine crystal structure must have been the result of rapid cooling.

    We hypothesized that the bad seats had been heated excessively and then cooled too quickly. This would then have set up internal stresses in the part, resulting in cracking during use.

    We decided to test the hypothesis by checking for residual stress. Polarized light microscopy would have been the best method, but for that parts have to be transparent or translucent, and these weren’t. So we placed the seats in an oven to see what would happen. Table 2 shows that 15 minutes in an oven at 95C (203F) caused the cracks to become significantly enlarged. Corner warpage of the cracked parts, significant to start, became worse. Corners on good seats had no initial warpage and did not warp while in the oven. This movement of sections of the cracked seats was taken as further evidence of locked-in stresses, while the good seats apparently were stress-free.

    The Answer
    Internal stresses resulted from the molding conditions: excessive melt temperature and too-low mold temperature. Reduced impact strength resulted from the excessive heat encountered by the resin during molding. Judging from the fact that cracking took place soon after installation, and that the cracks were large, we determined that the molding conditions were quite bad.

    There is a lesson here: Overheating a resin to improve flow, and running a mold too cold, may speed the cycle in the short term. But in the long term part quality suffers, and the cost to the molder exceeds any initial savings.


    Contact information
    The Target Group Inc.
    Erdenheim, PA
    Peter Lantos
    Phone: (215) 233-4083
    Fax: (215) 836-2518

    The Troubleshooter, Part 38: Acetal flow lines

    This article continues our series of troubleshooting reports from one of the leading on-the-spot problem solvers in the molding industry. Bob Hatch is manager of technical service and customer support for Prime Alliance, the Des Moines-based resin distributor. Before his present assignment, Bob managed a molding operation for 25 years.


    Some parts that arrived recently made me think not only was I going to call the customer with some suggestions for corrective action, but I was probably going to have to schedule a flight to go and stand by the machine to get the problem solved.

    The material was an acetal copolymer, and the molder was getting some flow lines on a round, flat surface just inside the gate on the part (see Figure 1). Just what was causing the flow lines was something I didn’t really know for sure. It could be jetting at the gate; or, since this was a hot runner mold it could also be that the land of the gate had not been relieved at a 45-degree angle back up into the flow path of the material. Possibly the injection speed was too slow or even too fast for this gate configuration. It could be a dozen possibilities, so rather than guess I went to see for myself.

    The reception committee consisted of molders, toolmakers, and design engineers, all anxious to see if I could solve the problem. We looked at all the bad parts that had been molded. I listened to all the corrective action attempts they had tried, such as higher barrel heats, lower barrel heats, faster injection speeds, slower injection speeds, drying the acetal, not drying the acetal. From what I was hearing they had tried everything I would normally try to correct the problem.

    So what was left? I asked if we could look at the gate areas in the mold itself. We then all visited the toolroom where we found one of the most knowledgeable toolmakers I have had the pleasure of meeting. He was a student of my On the Road with Bob Hatch troubleshooting book, and he claimed to have followed my suggestions exactly. Not being one to step on a student’s toes, I asked him to show me the gate detail to see if he had the hot tip diameter and 45-degree land relief as it should be. If it was less than 45 degrees, it would cause premature freeze-off of the material as it flows from the hot runner drop into the gate—something that also happens to tunnel gates when the angle is too sharp on a two- or three-plate mold. He quickly picked up a block of steel that had a gate insert in it, but the angle was not visible.

    However, there was a Micro-Vue system in the quality control lab that would make the gate area easy to see, so we paraded over to the QC lab for a look. What a difference! We zoomed in on the gate land area and it was easy to see that they did indeed have the land at a 45-degree angle and the taper went right down to the gate diameter. The land angle was sharp, as it should be, and I’m sure if we had measured the land dimension it would have been at the .002 inch we recommend. (I say we, but it is a recommendation that I picked up at Mold-Masters when I last attended one of their seminars.) The gate diameter was 90 percent of the thick-wall portion of the molded parts and the land was relieved properly back into the flow path of the material.

    Both the mold and what had been done to troubleshoot the parts seemed first-rate and thorough. Now it was time to move to the molding floor to watch the mold run. The molding technician was as good as any I have run into and he showed me around the press and reviewed the control panel displays for me. We looked at all the heats, speeds, and pressures, but I still couldn’t find anything unusual after spending 20 minutes at the machine. The material was not being dried, but that is really optional with a low-moisture material like acetal, especially in the winter. Besides, the cosmetic defect on the flat round part looked more like flow lines than splay so I didn’t jump on the lack of drying as the cause of this problem.

    I watched the feed indicator as the material was being injected into the mold and thought the process of injecting plastic and recovering the screw was OK. Then something caught my eye. The mold temperature was only 140F. Acetal is a funny material in how it reacts to certain injection speeds and mold temperatures. Fast injection gives you a glossy part, which is what we wanted in this application, and a 180F mold will give you a more rigid part, which we also wanted. By contrast, a slow injection speed will give you a matte finish and a cold mold, such as 50F, will give you a more flexible part. So what does the 140F mold temperature give us?

    The molding technician thought the 140F mold water was OK because the data sheet provided by the material supplier suggested mold temperatures from 75 to 180F. So much for some of the information you receive from material suppliers. Most of it is right on target but here was one that was too broad. We needed more information on which to base our temperatures settings—such as whether or not we wanted a rigid or flexible part.

    I suggested they run the mold temperature up to 180F and walk away for 20 minutes to see what would happen. When we returned to the machine, the flow lines were gone. Just to be sure, we ran the heats up to 200F and waited to see if it got even better; it didn’t, so we dropped them back down to 180F.

    Since the hot runner system was optimized, the parts did not warp when we raised the mold temperature, nor did we have to slow down the cycle. Optimizing a hot runner system means drilling the molding machine nozzle out to the same diameter as the flow tube diameter in the hot runner, which is a 1/2-inch diameter in this mold.

    For the record, in this mold the flow tube diameter is 1/2 inch, the crossover tube is 3/8 inch and the drops are 1/4 inch tapered down to 1/8 inch, then tapered again to the .090-inch gate diameters that feed into the part. Hot runners are pretty easy to run when the tool is optimized. Of course the nozzle stays with the mold after this sizing operation, but that is a small price to pay for a mold that runs good-quality parts at an efficient cycle.

    This is about all we had to do. The venting was adequate, and with the barrel melt temperatures at an optimized 350F we were getting good parts every shot. These techniques will work with most materials and they are easy to incorporate. The proof that all was well was the molder’s phone call a week later. He said the customer was extremely happy and glad the problem was resolved. The parts looked better to him than anything they had run since the mold was brand-new.