I am starting an injection molded plastic part design using the ubiquitous "soft-touch" elastomeric co-molding method. I'd appreciate some basic advice:
1. How does the method work? Is the part completely ejected from the TP mold, stockpiled, and manually placed in the TPE mold? If so, is the core on the TPE mold identical to that of the TP mold but with shrink?
Or, is the part held on the core while the cavity is switched?
I am sure all kinds of methods have been attempted - what is the present, mainstream, state of the art?
2. Materials: I observe the majority uses amorpous TP/TPE pairs like ABS/Santoprene. I assume the bond is better and shrinkage less than with crystalline plastics. Does the PP-based system work as well?
3. The gate on the TPE portion seems to be large - I assume this is because it has a viscous melt. Can a TPE patch go to a feather edge? How thin can it be? How thick?
Is a tunnel gate possible for better appearance?
Lastly, what are the pitfalls that I haven't yet even considered?
1. How does the method work? Is the part completely ejected from the TP mold, stockpiled, and manually placed in the TPE mold? If so, is the core on the TPE mold identical to that of the TP mold but with shrink?
Or, is the part held on the core while the cavity is switched?
I am sure all kinds of methods have been attempted - what is the present, mainstream, state of the art?
2. Materials: I observe the majority uses amorpous TP/TPE pairs like ABS/Santoprene. I assume the bond is better and shrinkage less than with crystalline plastics. Does the PP-based system work as well?
3. The gate on the TPE portion seems to be large - I assume this is because it has a viscous melt. Can a TPE patch go to a feather edge? How thin can it be? How thick?
Is a tunnel gate possible for better appearance?
Lastly, what are the pitfalls that I haven't yet even considered?
