Engel pairs Xmelt with LSR for injection molding first

Joachim Kragl, Engel's manager of processing technology told PlasticsToday that his company always saw a potential synergy between X-Melt and LSR. "Based on what we learned on the thermoplastic side, there are quite a few advantages if we go into micromolding or small-shot molding with LSR," Kragl said. "The shot-to-shot consistency is a big issue there, and X-Melt, naturally, takes care of that."

The X-Melt technology works by compressing the shot in front of the screw tip, or alternatively in the hot runner. Because of the high compressibility of the LSR, something Kragl calls its "spring" characteristic, LSR is actually more suited to X-Melt than thermoplastics. "You have a lot less pressure and you still have a very decent expansion rate," Kragl said. "You can minutely adjust via pressure to fill the part."

Just like in thermoplastics, Engel says X-Melt brings LSR greater consistency, saying that X-Melt LSR is between five and 10 times more repeatable on the shot weight compared to conventional LSR molding.

Engel was supplied tooling for the cell by Roembke Manufacturing & Design Inc. (Ossian, IN), with metering technology from Fluid Automation. During the show the technology will run in a fully automated cell, including a six-axis robot and vision-inspection system, and mold a tiny seal.