To shrink the cycle time molding a housing for a medical device, Engel (Schwerberg, Austria) implemented a two-step process, proving, the company said, that sometimes more can be less. It will showcase the process at stand C 58 in hall 15 during K 2019 in Düsseldorf, Germany, in October.
Cooling time is a key consideration when molding housing parts, explained Dr. Georg Steinbichler, Senior Vice President of Research and Development. “Since the wall thickness cannot be decreased for stability reasons, conventional one-component production leaves no opportunity to reduce the cycle time,” said Steinbichler. “But in the two-component process, we inject two thin layers, each of which quickly cools. Since both injection molding steps are carried out at the same time, overall production efficiency increases.”
At the K, Engel will demonstrate the process using an eight-cavity mold from Hack Formenbau on a cleanroom version of its electric e-motion 310H/170W/160 press.
The machine is equipped with a vertical indexing shaft with four positions: The first for injection molding the bodies, using a transparent polypropylene from Borealis; the second for cooling; the third for applying a second layer of a green-colored polypropylene to the pre-molded parts; and the fourth for a viper 20 speed robot to remove the parts. The linear robot reaches down to remove the eight housing parts from the closed mold, another factor contributing to the extra-short cycle time, said Engel.
The servo-electric, two-component mold is the first to use newly developed software from Engel. It allows servo-electric movements, such as core pull, to be controlled in the same manner as hydraulic systems. “We’re paving the way for increased use of servo-electric molds,” said Dr. Gerhard Dimmler, Senior Vice President of Product Research and Development. “They are more precise in many applications and allow for completely oil-free production when combined with all-electric injection molding machines."