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Twin-screw control system simplifies compounding

A twin-screw control system (TSCS) for extrusion compounding systems incorporates recipe management into the software and is said to allow the operator to recall and store specific product setpoints. Electrical items and software for control and startup sequencing are included in the system architecture for feeders and underwater pelletizers. Users have several options for data acquisition. Process information may be downloaded to an external device in a spreadsheet format or serially interfaced to a data acquisition system.

American Leistritz Extruder Corp.
Somerville, NJ
(908) 685-2333

Automated air ring offers segmented volume control

The WesJet air ring is now automated to offer segmented air volume control, eliminating the unwanted heating of the die lips that causes buildup and long-term process problems. Segmented air streams are regulated through a gateway actuator to affect film thickness. The automated air ring can reportedly be used on stationary or oscillating dies and is available on new lines or as a retrofit.

The design was developed to give processors greater control of the gauge profile while maintaining high-performance cooling. The WesJet is said to offer excellent bubble stability and a range of blow-up ratios and film thickness combinations. It has air inlets with a wide tangential sweep design and a machined vane network for air velocity and volume distribution, reportedly increasing cooling effectiveness by 10 to 20 percent. The negative pressure field around the bubble surface pulls outwardly on the film, allowing increased air-cooling as the air stream stabilizes the bubble.

Other reported advantages of the automatic lip configuration include the addition of flow control on individual segments that increase or decrease the film thickness at that segment, reportedly correcting the profile by 50 percent. The air ring?s aircraft-grade aluminum cast structure is said to provide rigidity, close dimensional tolerance, and durability. An adjustable deflector gap offers velocity control and blow-up ratio compatibility, and built-in oscillation seals and bearings also come standard with the WesJet air ring.

Davis-Standard, Pawcatuck, CT
(860) 599-1010

Moldmaker goes lean

Global competition from lower-cost toolmakers, abundant competition from a highly fractured industry in the U.S., and pricing pressures from OEM customers have all put mold shops in a precarious position over the past year. However, one moldmaker has decided that there is a better way to rise to these challenges: lean manufacturing. 

Roger Klouda, president of MSI Mold Builders, a moldmaking company that Klouda's father founded 30 years ago, says that the "business of moldmaking is rapidly changing, and successful companies use a true manufacturing process." To enhance MSI's manufacturing methods, Klouda and his operations manager, Steve Kimm, began implementing lean manufacturing techniques at the company's Cedar Rapids, IA headquarters. This plant specializes in building large molds up to 50,000 lb for the material handling, medical, transportation, sporting goods, computer and business machines, and appliance end markets. 

Lean manufacturing methods have helped MSI organize manufacturing flow and opened up floor space the company didn't realize it had.

Typically, lean manufacturing is something that most people think of as effective only in a mass production environment such as molding. However, Kimm, whose background is in manufacturing, says lean principles work even in a customized, build-it-one-at-a-time setting. "I don't know machining, but I do know manufacturing," Kimm says emphatically, "and lean can work in the moldmaking shop." 

Employee Buy-in 
Lean manufacturing means something different to every company, Kimm comments, adding that it's "like an eternal journey" because it is an ongoing process that must be worked at continually, rather than a means to an end. The first step on this journey was convincing MSI's 80 employees at the Iowa plant that "lean" not only was good for the company, but also would benefit them directly. 

To get buy-in from the employees, Kimm chose a journeyman moldmaker as the champion for lean at MSI. Together, they visited a manufacturing plant in North Carolina that machines custom pumps on a one-at-a-time basis. They looked at how this company implemented lean principles and how those could be translated to MSI's operations. Since moldmaking isn't a high-production environment, Kimm says it was critical to know what aspects of lean could be implemented and what wasn't practical. 

The process was kicked off at MSI in August 2001 after about a year of exploring the principle of lean manufacturing. To initiate the process, the company hired an outside consultant. However, Kimm notes that consultants come with a hefty price tag, and most small companies can't afford them long-term. 

Ridding the production floor of waste has reduced lead times for molds.
Implementing Lean Principles 
The first event, notes Kimm, involved a couple of hours of employee education followed by many hours of hands-on work, such as rearranging the floor of the 35,000-sq-ft facility to begin accommodating lean principles. MSI also got rid of some older equipment that wasn't being used to free up floor space. This meant equipment could be placed in a manner conducive to continuous flow production. 

MSI also relocated a central tool crib that had been positioned away from the moldmakers' work area. "We found that the toolmakers were making a 20-minute trip to the tool crib several times a day, so we decentralized the tool crib and put things closer to the moldmakers," explains Kimm. "The parts the guys use on an everyday basis went to the moldmakers, rather than them going to the parts." 

Every machine's placement was examined and the question was asked, "Why is this here?" Since implementing its lean principles, MSI is getting more "departmentalized," notes Kimm. "Everything has a purpose and place. We opened up at least 10 percent of our plant space right away. Before, we thought we had to put an addition on the building. Lean principles helped us discover space we didn't know we had. That was the immediate result we saw." 

Currently, Kimm is working on implementing a kanban system for tool cutters, which will allow inventories of cutters to be easily replenished based on demand. In addition, the company has focused on eliminating waste using Toyota's recognized Seven Forms of Waste: 

1. Overproducing.
2. Waiting.
3. Transporting.
4. Processing itself.
5. Stock in hand.
6. Unnecessary motion.
7. Producing defective goods. 

MSI is also looking at the five Ss as outlined in lean philosophy: Simplify the work area by keeping only what's needed in that area; straighten and organize so that all workpieces are identified and put away in specific areas that workers can easily find; scrub the area clean; stabilize and maintain the area; and sustain the discipline needed to maintain established procedures. 

Keeping tools put away when not in use and organizing them by size saves moldmakers time when they need something in a hurry. Before lean, shown on the left, things at MSI weren't as easily found as they are now (right).

Seeing Results 
Concentrating on ridding the production floor of waste has helped MSI reduce its lead times for molds even more. Recently, one customer needed two molds that required 450 hours each to build, and it needed them in 16 working days. "We took on the project because we were confident that we could meet that schedule," Kimm says. He notes that as soon as MSI gets the lean process defined at its Iowa facility, it plans to implement lean at its other plants in Arkansas and South Carolina, where another 45 are employed. 

Kimm comments that it doesn't take long to realize the benefits of lean manufacturing, but the effort to maintain it is continuous. "Once you get people [to accept lean], you can't let them let down," says Kimm. "The guys are seeing results, and are now saying their jobs are easier. But this is just our initial start on the journey." 

Contact information
MSI Mold Builders
Cedar Rapids, IA
Steve Kimm
(319) 848-7001
[email protected]

Vibration control tailored to machine requirements

Isolation vibration control pads come in a variety of configurations, and can be combined with leveling mounts to protect floors and reduce noise. Isolation pads reportedly meet requirements for low frequency, high damping, high loading, level stability, and a high coefficient of friction. Available with smooth or nonskid profiles from 2 to 25 mm thick, the pads measure 500 by 1000 mm or can be cut to fit and combined with freestanding leveling mounts. Isolation pads and machine leveling mounts are available for different functions in up to 100-ton weight capacities. The Series 400 Pads isolate down to 5 to 20 Hz, which is said to be ideal for precise measuring equipment. The Series 700 pads offer high damping from 40 to 80 Hz for stamping presses and other high-impact equipment; the Series 900 Pads are meant for high-load and high-frequency applications that require stability and isolation from 60 to 130 Hz.

Airloc, Franklin, MA
(508) 528-0022

Plastic blast cleaning method considered fast, effective

Processors of engineered plastics such as PEEK and polyacetal molding compounds traditionally have trouble cleaning molds, dies, tooling, and processing screws. PEEK and acetal compounds easily foul molds, dies, and screws, and PEEK resins readily adhere to metal substrates, making cleaning difficult. Conventional methods of hand cleaning and chemical soaking are inefficient and require hours scrub-bing the tooling.

On the other hand, blast cleaning tooling surfaces with soft, nonabrasive plastic particles is said not to pit or roughen steel surfaces and does not cause the tooling degradation associated with conventional sandblasting or bead blasting. The plastic blast cleaning method cleans a mold, die set, or processing screw in approximately 30 minutes and leaves no dust or residue. The Maxi-Blast machine is priced between $8000 and $10,000, and the manufacturer estimates that the cost can be recovered within six to eight months, even if only one item is cleaned per day.

Maxi Blast Inc., South Bend, IN
(574) 233-1161

Editorial: Notice: You are not a molder

Jeff Sloan

In February, I chaired the IMM Management Conference in Anaheim, CA, and after digesting everything our speakers had to say, I began to wonder if this magazine is no longer properly named. The seed for this thought was planted by Bob Alvarez, an experienced, vocal, and opinionated molding veteran and current vp of application engineering at United Plastics Group (UPG). Among many of the startling things Bob had to say came this statement: "You are not an injection molder. You are a contract manufacturer." Is injection molding passé? Should we rename IMM as Contract Manufacturing Magazine? 

This view, that injection molding is evolving away from being a stand-alone process and becoming an integral (and vital) part of the larger manufacturing process, is not a new one. Sizable contract manufacturers like Flextronics and Celestica have been encroaching on the molding industry for several years now. But the pendulum swings both ways, and smart molders likewise are slowly waking up to the fact that they need to start encroaching on the contract manufacturing industry. Trend Technologies, for instance, calls itself an integrator. Nypro flat out calls itself a contract manufacturer. 

Several speakers at the conference, in addition to Alvarez, reinforced this assessment of the trend. What emerged is a picture of how the molding industry might look 10 years from now. More importantly, what emerged was a road map to survival for injection molders:
• Manufacturing, particularly labor-intensive work, will continue its migration toward Mexico and China.
• Most present-day molders will become less manufacturers and more product and technology developers and managers; actual manufacturing will be performed in other countries.
• Manufacturing (and molding) that remains in the U.S. will do so primarily to meet domestic demand that cannot be cost-effectively met with manufacturing in other countries; likely end markets are automotive, medical, and packaging.
• Molders that are still manufacturing in the U.S. will rely heavily on value-add services like insert molding, overmolding, coinjection, and automated assembly to attract customers and turn a profit.
• Finally, no matter where you do your manufacturing, lean principles are a must.
Also, consider these selected quotes from the conference: 

"Fifteen percent of the U.S. economy is in manufacturing; it was 45 percent after World War II. Manufacturing is moving out of the Midwest, into the Southwest, across the border into Mexico, and across the Pacific Ocean to China."—Bob Alvarez 

"The problem is that most of our custom molders don't even know what lean manufacturing is."—Jerry Szczech, vp of production development and manufacturing, Civco Medical 

"Contract electronic manufacturers are moving up and down the manufacturing supply chain."—Bradford Frank, vp strategic business, Trend Technologies 

Like it or not, this industry is evolving, and that means change. My hope is that molders will change with it, but my fear is that some will be left behind. Now, more than ever, it's critical that you know your markets, your customers, and the strategy that you'll use to set yourself apart from the competition. 

Jeff Sloan 

Self-tuning 1/16 DIN temperature and process controller

The Model PXR4 controller features a large LED display that is reportedly larger than in any other 116 DIN controller on the market. Options include RS485 communications, digital input, timer function, heater burnout alarm, dual outputs, and programmable alarms. The faceplate is watertight and corrosion resistant. A screw terminal on the back is said to eliminate the need for sockets.

The controller comes with a self-tuning feature in addition to autotuning and fuzzy logic control capabilities. Self-tuning allows for retuning the controller under certain conditions without reverting to autotuning. The standard ramp/soak feature has two patterns that can be linked to create a 16-step profile. The controller accepts temperature and process inputs with two control outputs and two programmable alarms. The RS485 option uses the industry-standard Modbus protocol and enables remote monitoring of up to 31 controllers at a time.

TTI Inc., Williston, VT
(802) 863-0085

Gearless single-screw extruder features new drive design and pelletizer

A new single-screw extruder has been designed to be 20 percent shorter and lower in weight in comparison with conventional extruders. The drive motor is built for continuous operation and is directly mounted on the screw shaft, making conventional speed reduction gears and belt drives unnecessary.

A maintenance-free design with a reduced number of components reportedly improves uptime during production. The conventional oil cooling system has been replaced with a water cooling system, the bearings are lubricated with grease, and there are no repeated oil lubrications. The extruder screw can be removed through the front in the extrusion direction or through the rear through the drive unit. The extruder is designed for coextrusion lines, compact laboratory applications, mono use for low outputs, and recycling processes. When used as a coextruder it can be mounted in various positions.

The extruder has a screw diameter of 25 mm, a screw length of 25:1 L/D, a 4-kW drive with an a-c torque motor, and three heating and air cooling zones. Screws are available in diameters up to 60 mm.

Reifenhauser Inc.
Ipswich, MA
(978) 412-9700

Market Snapshot: Medical

Medical markets, and particularly disposable products, have long been coveted by injection molders who know that demand is constant and quantities large. Still, medical has not been without changes and challenges. 

The advent of the HMO created pressures on medical device companies to pare down pricing. No longer operating with carte blanche, molders had to accommodate these pressures by reducing costs to manufacture. Consolidation in the industry in the form of acquisitions by some of the larger players in an effort to expand product lines and broaden market reach has provided new opportunities for manufacturers. 

Tyco Inc. has proven to be an active player in medical equipment acquisitions. Some of its major purchases over the past four years include U.S. Surgical and Sherwood-Davis & Geck, two companies that Tyco acquired in an effort to become a leader in the disposable medical products business, and Mallinckrodt, which catapulted Tyco toward the top of medical device makers with its purchase in June 2000. 

Medtronic has been active with acquisitions as well. The company bought Sofamor Danek and Arterial Vascular Engineering, companies that complement Medtronic's heart products. Medtronic also purchased Physio-Control Inc. for $485 million in stock. 

Table 1. Plastic materials consumed in disposable medical supplies (DMS) by type, million lb
DMS plastic materials, $ million12601625199524052850
• $/lb1.101.221.321.441.58
DMS plastic materials, total11451330150816651800
• Polyvinyl chloride431492550595625
• Polypropylene193240285325365
• Polystyrene189206221235245
• Low-density polyethylene104121137150160
• Thermoplastic elastomers3239486178
• Acrylic3238434852
• Polycarbonate2933384144
• High-density polyethylene2831343638
• ABS2630333537
• PET2024283234
• Other617691107122
Source: The Freedonia Group Inc.

Industry Trends 
An industry report put out by US Business Reporter notes that demographic changes will have the most profound effect on the health care products industry. A large and aging baby boomer population along with longer life expectancy is expected to be a boon for the medical device and equipment industry. Also, less healthy lifestyles such as alcohol/drug abuse and obesity will continue to boost the need for medical products. 

Changes in the managed care industry mean that many purchasing and sales activities are increasingly being done by managers of HMOs, preferred provider organizations, large hospital consortiums, and government agencies. Since the clout of these entities is big, they have a lot of leverage when evaluating, selecting, and buying medical devices and equipment. 

A recent report by The Freedonia Group shows both consumption of plastic materials (Table 1, above) and U.S. demand for disposable medical supplies (Table 2, below) increasing through 2010. The latter is expected to rise 6 percent annually to $65 billion in 2005, with real (inflation-adjusted) growth advancing 3.6 percent per year. The strongest growth opportunities, says the report, are anticipated for prefilled inhalers, prefilled syringes, transdermal patches, and hematology, nucleic acid, and immunochemistry diagnostics. 

Home health care will be the fastest growing market for disposable medical supplies as consumers broaden self treatment and preventive medicine activities; also, look for medical providers to increase the range of services available to home patients. 

Demand for catheters, infusion products, and related supplies will advance 7.5 percent per year to $27.3 billion in 2005, according to Freedonia. This demand will reflect the expanding availability of high-value-added products (such as prefilled inhalers and transdermal patches) as well as increasing opportunities for cardiovascular catheters spurred by advances in angioplasty and related procedures. Demand for diagnostic and laboratory disposables will increase more slowly as breakthroughs in instrumentation and reagents make patient tests less material-intensive. 

Currently, there are about 500 companies active in the disposable medical supplies industry, and demand is concentrated among eight leading producers that held a combined 45 percent U.S. market share in 2000. Based on estimated U.S. sales in 2000, Johnson & Johnson, Tyco International, Cardinal Health (through Allegiance), Abbott Labs, Becton Dickinson, Kimberly-Clark, Baxter International, and 3M are the largest producers in the field. 

Demand for plastic resins in this market is expected to increase 3.8 percent annually to $2.4 billion in 2005, accounting for consumption of nearly 1.7 million lb (Table 1). In spite of the bad rap PVC has taken lately, it remains the most widely used plastic material in disposable medical supplies. In 2005, a projected 595 million lb of the resin will be consumed in single-use medical goods, up 1.6 percent annually from 2000. 

However, other materials are available that address issues of biocompatibility, chemical and infection resistance, clarity, sterilization compatibility, processing, and overall quality and cost. 

Table 2. Disposable medical supplies demand, $ millionAnnual growth, %
Disposable medical supplies, total35,02448,59065,00086,1006.86.0
• Catheters, infusion products, and related12,19219,02027,30037,5009.37.5
• Diagnostic and lab disposables10,09412,89016,90023,1005.05.6
Source: The Freedonia Group Inc.

The medical industry still holds opportunities for custom molders in spite of the fact that many of the big OEM players, such as Becton Dickinson, have in-house molding operations. Bill Gerard, gm of Tech Group Puerto Rico, a medical molding facility in Cayey, PR, notes that some economic pressures have been brought to bear on custom molders. 

"We certainly have seen even fiscally solid [medical OEMs] cutting back capital expenditures during the past 12 months," he says. However, he adds that many customers plan to implement programs this year that were held over from 2001. 

The Tech Group's Puerto Rico plant is counting on that. The plant recently underwent a $5 million renovation in which 2500 sq ft were added, along with 21 new Roboshot electric presses and three high-speed Netstal Synergy presses. Additionally, two silos were installed with a plantwide material handling system that enables the material to move from either silo to one of the plant's 40 press drops. Gerard says he plans to purchase another eight to 10 presses this year to accommodate anticipated growth. 

Although the industry has gone through some pricing pressures of its own, Gerard says that having fewer players in the medical molding segment helps keep business strong. "At the end of the day, there are fewer molders with cleanroom and validated [manufacturing] processes to do that work," says Gerard. "We may feel some of those price pressures that molders for other industries do, but we can still be more competitive." 



Which way to factory automation? Take the bus

If you have not yet gotten into it, chances are you will be looking at factory automation (FA) quite soon. We're not talking about installing robotics. We're talking about data and the benefits of networking every molding machine, granulator, dryer, and accessory device in a molding or moldmaking facility. With just a few mouse-clicks or keystrokes you can look at what's happening in any part of your operation. Up-to-date inventory; real-time machine process parameters; output by machine, department, or the whole shop; scrap rates; and more are literally at your fingertips. 

An FA system is at heart a data network. Therefore, armed with the information it provides, you can use that same network to tweak and adjust anything attached to it. And thanks to the Internet, you can do this from almost anywhere in the world. 

Because FA is data networking technology, there is a learning curve to be scaled and new terms and acronyms to sort out. You most likely have heard some of these already since machinery and peripheral suppliers are building FA capability and conformance into their products. Does it seem like many of them end in "bus"? Many do, and at first that may seem confusing. The most important thing, however, is that your computers and machinery can speak to each other, which requires that they be able to ride the same bus. 

Which Bus? 
Profibus, Modbus, Interbus, Fieldbus . . . there is a large variety of networking protocols and standards on the market—some better known than others. Go to for an idea of how many protocols have been developed. Also, see Table 1, below. 

Since the numbers can be a bit daunting, let's try to simplify this a bit. In a data network, the data transport mechanism between nodes (equipment, control, computer) is called a bus, so named because data packets, like bus passengers, can enter and exit at any station on the line. 

The FA networks, also called industrial automation (IA) networks, mostly—but not always—fit into one of three categories: general purpose information network; fieldbus, which is sometimes referred to as a control bus; and device bus, also called bit-level bus. The image on this page provides examples of each type. 

The device bus is the simplest of the three levels, offering basic connectivity between robots, molding machines, and material handling devices via an I/O device that is usually in the control unit. 

A fieldbus goes beyond basic connectivity to permit the exchange of periodic
data from and to the I/O devices. A fieldbus also supports point-to-point messaging and network management tasks that assist in coordinating the I/O devices through configuration and diagnostics. Many fieldbuses employ a technique called virtualizing to create a network identity for each I/O unit, thus allowing use of equipment from different manufacturers. 

These days it is a fieldbus name or standard that is most commonly included in the specs of plastics molding equipment makers. Some of the most frequently cited include Fieldbus Foundation, CANopen, DeviceNet, Interbus, Modbus, and Profibus. As an example, Maguire just announced an adapter module for its weigh scale blenders that supports DeviceNet, Modbus, and Profibus (see "Adapter Module Helps Blenders Communicate," January 2002 IMM, p. 112). 

Although there are a variety of fieldbus standards available, a molding professional is ultimately at the mercy of machinery and software suppliers that decide which protocols their equipment will support. Most suppliers have a lot of information on fieldbuses, and we have included websites in the list of fieldbus types in Table 1. If you are looking at factory automation, it is worth the time and effort to try to understand network structures and specifications—and to see where they are going. 

Table 1. Common industrial fieldbus protocols
CAN In Automation
CiA DS 301
Multiple chip and product vendors
Chips from Allen-Bradley, 17 product vendors
ISO 11898, 11519Multiple chip and product vendors
Foundation Fieldbus FoundationISA SP50/IEC 61158Chips, software, products from multiple vendors
Interbus**Phoenix Contact
Interbus Club
DIN 19258
EN 50.254
Products from more than400 manufacturers
EN 1434-3 (layer 7)
IEC 870-5 (layer 2)
Open specification
EN 50170/DIN 19245 part 3 (DP)/4 (PA),
IEC 1158-2 (PA)
ASICs from Siemens and Profichip, more than 300 product vendors
*Ethernet/IP info is at DeviceNet website.  **Providers with Ethernet solutions.

Rewriting the Rules 
The three-level structure shown above—information, fieldbus, and device—is not rigid. A number of buses have taken on tasks of several levels, but not all. For example, AS-interface (AS-i) reaffirms its dedication to the device level. They say simplicity and low cost are their advantages when all that is needed is to connect devices for signal passing. 

DeviceNet and CANbus began life as device buses, the latter in automobiles, and each has been enhanced to offer some of the performance of a fieldbus. Some fieldbus suppliers have integrated simple device interconnection. In general, network suppliers are enlarging the capabilities of their offerings to cross the levels, and many of them say their ultimate objective is to support the network of an entire enterprise. 

One of the biggest obstacles to a full-enterprise network has been the differing architectures among the three bus types. The largest gap has been between the general data networks and the field and device buses. 

The most ubiquitous data corporate networking standard is Ethernet, unless you count the Internet, which in this case you should. It was the very structure of Ethernet that created difficulty with the other levels. Ethernet is subject to data collisions and delays that mean little in a business environment, but could play havoc with sequenced control signals. The technical details of how this has been solved could fill this magazine. What is important is that many leading fieldbus protocol developers have begun to offer full data network solutions based on Ethernet or Internet protocols, or a combination of the two. 

Fieldbus Foundation's high-speed Ethernet is an open, fault-tolerant 100 megabit/sec backbone for connecting device buses, subsystems like control nets, and enterprise data servers. Interbus with Ethernet connects from sensor to Internet using the TCP/IP protocol you probably use for e-mail. Modbus now has Modus TCP that combines the Internet's TCP/IP protocol with Ethernet. Profibus has standardized Profinet, an Ethernet-based open concept integrated with Profibus control networks. Ethernet/IP (industrial protocol) shares an application layer protocol with DeviceNet, and the two can combine to provide networking from sensor to enterprise level. 

Alphabet Soup 
No matter how you decide to implement FA or IA, be it a simple device-level system or a network spanning your entire business, you will need to take a bus, and perhaps several. 

A quick glance at the bus standards may seem like someone spilled a pot of alphabet soup. The standards and protocols in most cases are created and managed by organizations, associations, institutions, or quasi-governmental entities of various size and import. After they've been developed, protocols are typically submitted for approval by international or regional standards-making bodies like ISO, IEC, EN, or IEEE. 

Some standards are more common in Europe than North America, and vice-versa. They are virtually all trying to globalize, and as with computer operating systems and video recording formats, the standards are contending for supremacy, each thinking itself destiny's child. Besides educating yourself about networking technology, it makes sense to keep your chosen equipment suppliers close during any automation project. Their hardware has to ride whatever bus you choose.