Method and apparatus for forming a thermoplastic part with injected elastomer seal
AssigneeKrauss-Maffei Kunststoffftechnik GmbH
InventorPeter Lichtinger
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Abstract
The invention relates to a process for manufacturing a thermoplastic part (1) with an injected seal (3) as well as to an injection molding apparatus and a corresponding thermoplastic part. For injecting the seal, a groove (2) is formed during molding of the thermoplastic part (1) in which groove liquid crosslinked plastic as material for the seal (3) is injected. Sealing projections (12) are formed on the groove edge and/or on the injection mold in order to prevent an overflowing beyond the groove edges during injection. When closing the mold, undercuts (6) are formed on the upper edge of the groove for holding the solidified seal (3) in the groove.
Claims14
A process for making a thermoplastic part, comprising the steps of:
- molding a thermoplastic part with a groove and at least one undercut for bounding an edge of the groove;
- and
- injecting an elastomer into the groove to form a seal which is retained in place by the undercut, and heating a mold core in a region covering the groove to a temperature of 170° C. to 230° C., while leaving a remaining area of the mold core at a lower temperature than the region covering the groove.
An injection molding apparatus for making a thermoplastic part, comprising:
- at least one female mold;
- and
- at least two cores;
- wherein the female mold and a first one of the cores define an injection mold for injection molding a thermoplastic part with a groove,
- wherein the female mold and a second one of the cores define an injection mold for injection molding an elastomer seal into the groove of the thermoplastic part and for formation of at least one undercut for bounding an edge of the groove to thereby hold the elastomer seal in the groove,
- wherein the second core includes a region which matches a profile of the groove and is heatable to a temperature of 170° C.-230° C., and which is thermally insulated from a remaining region of the second core.
Dependencies are inferred from the claim text.