Molders put hot runner systems to the test

Hot runner technology has long been the target of innovations, enhancements, and variations. Each variation claims to be better than the last, and the technology does not lend itself very well to objective side-by-side testing due to the time and expense involved. Each application has its unique characteristics, and preferences for one kind of hot-runner technology or another are built up over time by those designing and using the molds. For this article, therefore, we have decided to focus initially on instances where hot runner systems are actually in place and running.

These are in effect snapshots, not only of what hot runners can do, but of what they are actually doing in real-world production settings. We obtained referrals to these molders from hot runner suppliers. Naturally, the hot runner suppliers provided referrals to companies they expected would give favorable reports on their products. On the whole, the reports have been positive, but these are nevertheless not testimonials. We asked different questions, and got different answers, than if we were going about the process of soliciting testimonials. Our quick looks at equipment in place are followed by reports of various product introductions.

Eliminating Finger Pointing
Garrett Gardner, senior process engineer at Phoenix Closures (Naperville, IL) says the firm values reliability highly, as it does not have time to deal with mistakes related to new molds and hot runner systems. Phoenix runs two plants every day of the week, around the clock. The second plant is in Davenport, IA. Naperville runs about 3.4 million bottle caps/day for the food industry, and Davenport runs about another million. Most of the caps are in PP, some in HDPE. Cavity counts range from 32 to 96.

The caps Phoenix molds are mostly used on store-brand merchandise, which is typically priced below national brands, and therefore tends to be increasingly in demand during difficult economic times. Thus Phoenix tends to be in a recession-resistant business.

Phoenix is a dedicated Husky (Husky Injection Molding Systems, Bolton, ON) hot runner user. It uses all fixed-probe systems and uses only a few valve-gate systems that are still around from an earlier purchasing approach. From Gardner? s point of view, there are fewer maintenance problems to deal with on fixed-probe systems as compared to valve-gated systems.

Phoenix also uses Husky hot runner controls, which are brand-named Gammaflux controls, and says that use of hot runner components and controls from the same source eliminates finger-pointing if problems arise. The component supplier can?t very well blame the control supplier and vice versa, if the component and control supplier are the same.

While food closures may seem to be a prosaic product, there is a recurrent urgency about getting the caps to market. Gardner says that by the time the company gets a mold built by its moldmaker, it?s already late for the production schedule. Expensive molds need to come online immediately, and there is no time for fussing with temperamental hot runner systems, or anything else for that matter.

Toshiba, Husky, and Van Dorn injection machines are used, mostly straight hydraulic systems, in tonnages from 250 to 750. Gardner reports having had problems in the past with toggle machines, but says they are still best for the few three-plate molds run by Phoenix.

Converting a Mold
Karl Wintersteller, mold services manager and part owner of Techno Plastics in Puerto Rico, reports that Techno recently converted a standard mold to a hot runner version. Techno essentially salvaged an old mold by adding a hot runner system to it in order to meet increasing demand from its customer for blood donation equipment.

An eight-cavity mold, run on a 375-ton Niigata all-electric machine, produces a blood collection device with a rotor and case of Lexan PC. The base of the part is for blood collection, and the rotor separates the plasma. A 5-inch long cylinder has a 1.375-inch-diameter wall with a thickness of .006 inch.

The old mold was ?temperamental,? and existing nozzles didn?t have enough room to shoot the plastics. The hot runner system needed to have small enough nozzles to fit the existing mold.

Two major hot runner suppliers declined to be involved with the project, and Techno subsequently chose a Thermoplay hot runner system?nozzles, manifold, and heaters?available in the U.S. through Alba Enterprises (Rancho Cucamonga, CA).

Cost Justification Not a Problem
A medical device manufacturer in the Midwest that chooses not to be identified in print has standardized on Gammaflux (Sterling, VA) controls, but still has some others in use, according to its tooling manager.

The company makes syringe components?one PP, one PE?for diabetics, in molds of up to 128 cavities. The molder also runs PA, PC, ABS, PS, copolymers, and homopolymers, and uses a lot of stainless steel in molds.

The molder considers itself to be almost a Beta shop for Gammaflux. When new features become available, it tries them out. Service is a compelling interest, and parts can be there on a next-day basis. As a medical supplier, they validate everything in the process, including zone temperature. They evaluate actual material temperature vs. heater temperature and say that the Gammaflux electronics seem to prevent much undershoot or overshoot.

The shop routinely considers hot runners for new molds, and cost justification is not a problem. The hot runner system itself is chosen depending on the product, material, and gate location with hot runner systems from half a dozen sources currently in use.

The plant has nearly 100 injection molding machines, in the 60 to 500-ton range. The company ?loves all-electrics? and is going that direction.

Flexibility of Control
The Cardinal Health Co. (McGaw Park, IL), Div. of Cardinal Health Medical Products and Services, of Chicago molds medical products, specifically respiratory products, using material that it describes as proprietary, on a 200-ton injection machine. It recently added two Altanium controls (American MSI, Moor Park, CA) of the most recent generation. Cardinal says the controls are characterized by a minimum number of components, which lend them to easy upkeep.

Cardinal can use the same controls for every hot runner mold in the house, since they are preprogrammable. It can slave zones if a transducer goes out. An engineer at Cardinal says limitations that they encounter are inherent in the hot-runner systems, not in the controls. Cardinal is ?not yet? running all-electric injection machines, but is likely to do so when business considerations call for acquiring new machines.

Reliability is Critical with Seasonal Markets
Ben Rebenold is plant manager at the privately held KW Plastics (Allentown, PA). The firm specializes in plastic cans in pint, quart, and gallon sizes, all molded in polypropylene. The gallon can weighs 204g, for example, and the quart-size can weighs 65g. The pint/quart/gallon cans are used to store coatings and adhesives for such clients as Home Depot, Lowe?s, Wal-Mart, and PPG.

They use two-, six-, and eight-cavity molds and Milacron machines. Two 550-ton machines are all-electric and seven more 550-ton machines are hydraulic. The company manufactures its own resins as part of the process of recovering car batteries on a major scale at its Troy, AL location. Therefore, all of its PP material is battery-grade. Overall production is more than one million cans/year, produced on three shifts/day, five days/week.

The business is somewhat seasonal, in that the home improvement retailers tend to have big sales on Memorial Day weekend. March and April are big ?filling times? for suppliers of household paint?getting the paint into the plastic buckets in time for spring sales. Rebenold cites reliability and ease of maintenance as motivations for KW?s choice of Incoe (Troy, MI) hot runners in about 40 of its molds.

Raft of New Products on the Way
The NPE 2003 show to be held in June has inevitably become a point of reference in timing the release of new product information, and a number of hot runner suppliers have chosen to announce new products in the months preceding the show. Other companies are holding information for June magazine issues, or even for the show itself. The following are some preshow developments.

EMI Plastics Equipment (Wickliffe, OH) is now representing the Korea-based Yudo hot runner control system. Control modules and mainframes are interchangeable with those from other manufacturers. Processors can remove a defective control module and replace it with a new module without having to replace the whole control system. Processors can also reuse their present control modules in the new EMI mainframe system. Components are both physically and electrically compatible with most existing hot runner systems. Control modules are listed at $189, or $179 each for 12 or more.

Autotuning compensates for environmental changes, and heater damage is prevented by raising the temperature of the mold slowly at startup, allowing any moisture that may be trapped in the system to slowly evaporate. Standard mainframe units are available in two-, four-, six-, and eight-zone units, as well as a single, portable unit. Larger sizes are available in multiples of four.

Fast Heat (Elmhurst, IL), has developed a new microprocessor-based device that stores information on how to optimize the processing of parts in a specific hot runner mold, according to Peter Kalantzis, controls engineering manager. Slated for formal introduction at NPE, the Mold IQ device stores mold setup and hot runner system information.

J-Tech Hot Runner (Toronto, ON) has introduced the Type 01.11 miniature hot runner nozzle for demanding engineering resins with critical temperature profiles, and for applications with shot weights of less than 1g (.35 oz). The nozzle offers fast color and material changes through reduced gate well requirements and multiple sealing methods to eliminate resin leakage. This nozzle has reportedly been successfully used with LCP, POM, PMMA, PC, nylon 66, and PES. J-Tech is a North American company that works closely with Heitec Heisskanaltechnik GmbH (Burgwald, Germany) to develop hot runner components.

Kortec (Beverly, MA) has announced plans to build the industry?s first 144-cavity co-injection system for multilayer PET preforms. The target market for this Ultra Series system is small carbonated soft drink containers. Kortec will provide more details on this development at NPE 2003 in June. The move coincides with Husky Injection Molding Systems? launch of its newest machine platforms at NPE 2003. The new Kortec system is scheduled for introduction by mid-year 2004, according to John Kermet, Kortec?s VP of sales and marketing.

Seiki Spear (Gloucester, MA) will feature its new ESP Series hot runner systems at NPE 2003. Designed especially for molding engineering resins, the ESP system features externally-heated, internal flow nozzles that each have two heaters?one on the nozzle body and another at the nozzle tip. This ensures close temperature control, which is especially critical when running sensitive engineering resins. The ESP Series comes with Seiki?s S2000 temperature control, designed especially to manage tip heater temperature. Minimum pitch between nozzles is 28 mm. Typical applications for these systems are automotive components, gears, connectors, and other parts made of engineering resins.

Ewikon Hotrunner Systems (East Dundee, IL) has released a new line of externally heated hot sprue nozzles with 230V operating voltage for direct gating of parts in single applications. All single tips are based on HPS III standard nozzles. An adapter with an integrated heating element and thermocouple, in conjunction with a separate locating ring, ensures proper connection with the machine nozzle.

Synventive Molding Solutions (Peabody, MA), has enhanced its Dynamic Feed, which offers the ability to individually control the fill and pack rates at each gate of a multicavity or family mold, or at each individual gate in a large multigated mold. Synventive has developed and will promote at NPE 2003 a molding cell that ties together a Dynamic Feed hot runner system and an all-electric molding machine.

In combination with Moldflow (Wayland, MA), Synventive has created the first Dynamic Feed process simulation that allows processors to see hot runner fill, pack, and processing profiles, in addition to showing how changing pressure at individual gates can optimize the process.

RJG (Traverse City, MI) and Synventive have produced a quality control system that incorporates a Dynamic Feed hot runner system and a specific RJG eDART process control. This new product places process sensors in each cavity of the mold, monitoring the quality and processing of each individual part and offering a means of changing the process to improve the quality of parts from each cavity individually.

Melt Design (St. Charles, IL) will introduce at NPE 2003 a new line of hot runner valve gate systems. The systems feature an adjustable valve pin design. This simplifies pin adjustment by allowing the operator to reach in through the back of the mold to access the pin control.

Mold-Masters (Georgetown, ON), announced early this year that online quoting and ordering of hot halves and temperature controls are now available to users of the Merlin online hot runner Wizard for its complete Dura product line. Pricing for hot halves and controls is now provided for all systems configured using the Merlin Wizard. Processors will also have online access to multilanguage support tools including hot runner and control user manuals.