ENGEL Introduces Liquid Silicone Micro Molding

14 Dec 2007 • by Natalie Aster

YORK, Pa. ENGEL North America's liquid silicone micro molding system offers the precision of an electric injection molding unit combined with a 12 mm, specially-designed LSR screw and check disc assembly and the flexibility of a tiebarless clamp design. The new system, with integrated automation, will be featured in ENGEL's exhibit at Plastec West, 29-31 Jan., 2008, in Anaheim, Calif.

ENGEL North America, a world leader in the design and manufacture of injection molding machines and part-handling automation systems, has applied its micro molding expertise to a new system for liquid silicone micro molding. Based on the ENGEL VICTORY 80/30 Electric US, the system uses ENGEL's patented tiebarless clamp design which provides a larger, specially-supported platen area, combined with a specially-engineered platen with the flexibility to run small to large mold bases. The electric injection unit offers the ability to run shot volumes down to fractions of a gram.

"There has been a great deal of interest in the micro molding of liquid silicone, and we are seeing this requirement on machines with higher tonnage and a larger platen area," explained Mark Hammond, ENGEL North America technology group manager. "Five and 10 ton machines don't offer the flexibility or platen space required, so we've applied the technology to our ENGEL e-victory 80/30 US hybrid machine."

The mold is a flashless four-cavity open nozzle medical LSR umbrella valve with a total shot size of less than 0.5 gram. This micro shot size is accomplished by using a 12 mm screw and check disc assembly specially-designed for LSR, guaranteeing the repeatability required in micro molding applications. A Kuka six-axis robot is integrated within the machine footprint for automatic part removal and to perform quality inspection on the parts. The machine also has the capability to mold a shot size up to 55 cc with a simple barrel and screw changeover. The Fluid Automation LSR dosing system is specifically designed for small shot sizes, and is mounted directly to the machine feed throat.

"The ability to properly mold sub-gram shots, combined with the ability to also mold more traditional shot sizes, is very important," Hammond said. "Quite often molders are not utilizing a micro machine 100 percent of the production year. ENGEL's solution allows the ability to change over to larger molds and injection volumes."

The LSR machine is also configured with ENGEL North America's Basic Clean Room Package, including: Stainless steel panels around a stationary platen; countersunk screw heads; stainless steel panels in the drop-out chute area; guide rails for the safety gate in stainless steel execution; and the machine base raised by 100 mm. In addition, the machine's paint provides special lacquering for clean room production.

Special partners include

Roembke Manufacturing and Design, Ossian, Ind.; mold production. Fluid Automation, Wixom, Mich.; LSR pumping system. Wacker Chemical Corp. USA, Adrian, Mich.; LSR material. Kuka Robotics Corp. USA, Clinton Township, Mich.; six-axis robot.

ENGEL North America

From facilities in the United States, Canada and Mexico, ENGEL North America provides its customers a single source for design and manufacture of injection molding machines for thermoplastics and elastomers, a full range of plastics processing technology modules and a full scope of automation solutions. With eight production plants in Europe, North America and Asia (China, Korea), subsidiaries in 17 countries and representatives in over 70 countries, ENGEL North America provides is customers the global support they need to compete and succeed with new technologies and leading-edge production systems.