Q: I am looking to gain an understanding on what is a better design for an overmold (TPE) shutoff area. Is it better to have the TPE butt right up against the substrate, or would it be easier to control with an intentional reveal line that is a 1mm x 1mm groove?Here attachment are the two options, both are just general ideas (ie no draft, radii, etc. Just a made up block so i can convey my idea)

A: Hello Rick! It depends on the parting line and shape of the part. We have parts with over mold is finished at a radius at the end of the substrate. We fight the shut off for flashing and end up shimming or welding the tool. The stationary half has spring loaded cavity blocks due to part shape.

Q: I am working to create a new product that uses ABS plastic and TPR material. But the first T0 samples the TPR material alongside the ABS plastic (thus avoiding the use of glue), for some reason that the TPR material and ABS plastic are not sticking well together. Does you have any recommendations on how to solve this issue? Is it possible to transfer our tools to you?

A: ABS is never sticking well to TPR that is coming from their nature behavior.TPR plastic are used to produce the soft material like soft toys and plastic handle etc. However, you still can force them to stick together which is to intently design certain "undercuts" on slier location so that to force them stick well. Our customer's project has had one plastic part similar to yours and using double injection.

Q: We have a new project, there are only two parts (like handle ,Material is PC), We have made the mold (two molds)already, the first trial sample is not good, one of these part is too thick (about 6mm), which makes it deformed, so they can not assemble perfectly. We add some rids inside, but no different! How to solve this problem?

A: You have to be sure of the root cause of the deformation. It could be from sticking in mold or in new ribs, too short cooling time, too hot or cold mold temp, over packed, under packed, wet resin, and so on. All of these will require different methods to solve long term. 

Q: Thank you for you reply. We have found out what the problem is. There are so many reasons can lead to deformation just as you said (sticking in mold or in new ribs, too short cooling time, too hot or cold mold temp, over packed, under packed, wet resin, and so on), but the critial reason is one of these part is too thick (about 6mm) and there are no rids inside. How could it be! We added rids and adjusted parameter of the injection machine then we can install two parts easily!