Looking to learn more about better shut off technology. We mold over large stamping with inconsistent edges and are trying to think of a flexible material to insert into the mold that will accommodate the edge changes.

thanks

Dave,
You will have to specify tighter tolerances ± .001 on your metal stampings in order to gain consistency in your molding process. Also, do you have spring loaded inserts to accomodate the tolerance variances in metal stamping? We have extensive experience in insert molding, overmolding, etc.

Thanks,

Aaron

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Amelia

Aaron is correct. Tight dimensional tolerances of the stamping (or other) are required in over molding or insert molding. Spring loaded inserting in specific areas is one method for accommodating variation on the stampings under certain conditions. I had one application (encapsulated glass run channel) where we worked with the supplier to completely redesign the metal insert which was a combination roll formed and stamped (then toggle locked) design in order to improve dimensional stability in their manufacturing process. We also placed inserted "stand offs" in the A and B side of the tooling in order to "push" the stamping into the desired position to achieve uniform wall thicknesses of the plastic. The inserts needed to be replaced periodically due to wear but it ended up being a very nice solution overall.

Shut off is shut off...not to oversimplify but you either have it or you don't (which can be verified by a good spotting of the tool up to temp and under tonnage) and if variation in the stampings is what is holding you "off"....you have to solve that issue. Some flexible (TPE, TPV, PVC) materials do have marginally better "viscosity or flash point" characteristics if the design can tolerate but it usually involves going to a higher durometer material and I don’t want to mislead you that this can solve a parting line shut-off issue caused by variation in the stampings because it most likely would not.

Hope this helps…