A technology called Vario-Mold can make better micromolded parts, according to Battenfeld GmbH of Meinerzhagen, Germany.
Battenfeld offers Vario-Mold on its all-electric injection presses. The technology allows complete filling and prevents thermal degradation of the resin.
Here is how it works: Shortly before injection, the mold gets heated to near-melt temperature. That insures the plastic will continue to fill out the tiny part until the entire mold is filled. The mold is cooled down again before demolding.
Vario-Mold uses up to 26 heating circuits to heat the mold. Because mold-cooling circuits can be emptied by vacuum before the heating begins, the process uses water instead of oil.
Vario-Mold does require longer cycle times — which presents the danger of thermal degradation, since resin stays in the screw longer. To avoid that, the process purges the material without interrupted the production cycle. Another option: using a special screw geometry, which reduces the residence time.
Battenfeld's U.S. unit is Battenfeld of America Inc. in West Warwick, R.I.
Tel. (401) 823-0700, fax (401) 823-5641, e-mail battenfeldusa @aol.com.