New turns for multicomponent mold revolution

Stack molds that use a horizontal turning system to drive rotating core sets and core plates are drawing considerable attention around the world from multicomponent molders that want to lower part costs, and from monocomponent molders that want to raise their bottom line. 

Representatives of two different types of this European approach to multicomponent stack molding have been busy promoting the benefits of their respective technologies to interested parties in the U.S. all year.

In Europe, multicomponent molding is frequently referred to as "2K," a nickname for two-component molding. One of the biggest benefits of 2K stack molds with horizontal turning systems is that they reportedly allow molders to double cavitation without doubling clamping force. 

Unlike machines running 2K stacks with vertical turntables, there is less mass to move, reducing space and clamp force requirements. That means a smaller capital investment and labor cost as well as reduced part costs. These molds may cost hundreds of thousands of dollars, but they save millions, according to two proponents of two different approaches. 

A 2K 4x64 
Hermann Plank is the managing director of Ferromatik Milacron Europe's U.S. operations in Cincinnati, OH. Plank promotes systems that Milacron has developed in conjunction with German moldmaker Foboha. More than 50 systems are already in operation. The latest concept is called the Cube. Four identical core plates are mounted on a center platen that rotates in the horizontal axis (see "Rotating Center Plate in Mold Turns Some Heads," November 2000 IMM, pp. 70-72). 

"Because of the positive reaction to this technology that we have been receiving from the major U.S. moldmakers and molders, we are going full steam ahead," says Plank. "A growing awareness of its potential is opening new doors for our company." 

Word of the latest developments in this technology and its potential leaked out at a Ferromatik Milacron Europe press conference in September where the company previewed its K 2001 exhibit. A 4x64-cavity Cube has been built to run multicomponent toothpaste tube shoulders for Colgate out of HDPE (70 g/shot) and PET (48 g/shot) in a 500-ton (4500-kN) Ferromatik K-Tec racer running at 10-second cycles. Again, that's 256 cavities running in a 500-tonner. 

To meet the annual requirement of one billion parts, 8000 hours, and 95 percent availability and yield using conventional methods, Milacron estimates it would take 21 production systems. These would include 11 175-tonners for the PE, 10 140-tonners for the PET liner, 21 molds, plus auxiliaries and assembly stations. In would take only six 500-tonners running 4x64 2K Cubes to make the order in 300 sq m less space. 

Rotating Just the Cores 
Another option comes from Gram Technology of Denmark. Jes Gram, managing director of the company, promotes his company as being a one-stop shop in the multicomponent molding business, serving customers at every point in the value stream from design to production with the help of a network of strategic allies, and with its patented and patent pending technologies. "It's all about people adapting to new ideas," Gram says of his efforts. 

He is recruiting part of his network from an exclusive number of experienced toolmakers around the world. They are being asked to pay a licensing fee, which shows their commitment and pays some development costs. It also buys them access to global marketing, technology transfers, and jobs. After that the toolmakers are expected to pay 10 percent of each mold they build using the technology. 

Molders do not pay extra. And Gram Technology also has nonexclusive working agreements with several machine makers. 

When it comes to 2K technologies, only the cores rotate in the middle block of the stack mold in one of Gram's latest concepts. With it far less mass is moved, so molding machines can be smaller and less expensive. Also, no complicated runner system through the middle platen is required. 

As IMM went to press, Gram was planning to showcase another concept at K 2001. A 2K Demag Ergotech Multi was to be converted to a 3K. A center plate rotating 90°/cycle on the twin-barreled, 50-metric-ton machine would then produce a 3K medical component. 

Both the Milacron/Foboha and Gram Technology systems are designed to enhance part value before ejection. Overmolding, insert loading, inmold film insertion, inmold assembly, and any number of functions can be done every time the mold closes. 

Also, faster cycles and higher output in 1K stack molding can be achieved using multicomponent technology. For instance, parts could simultaneously be injected, cooled, and ejected.