counterbore/countersink Plastic Injection
counterbore/countersink Plastic Injection
(OP)
Does anybody have any experience/direction with this question. Regarding DFM, design for manufacturing, would a plastic injection operation w/ glass nylon have an easier time spitting out widgets with counterbores or countersinks if it otherwise made no difference. Are the holding power between comparable holes the same between c-sink and c-bore? i would guess c-bore as the tool won't require the sloped surface but I haven't the experience/education to tell me the answer. any help would be greatly appreciated!! thnks!!





RE: counterbore/countersink Plastic Injection
If you use counterbore make sure the contact area between the bottom screw head and the lip of hole is large enough not to yield the material. This is mostly a problem when using SHCS and oversized holes.
If you use countersink ensure your tolerance stack is close enough not to allow unwanted loading when screws are torqued.
It really depends on the part and what the part connects to. You might need counterbore with room for steel washers.
Barry1961
RE: counterbore/countersink Plastic Injection
RE: counterbore/countersink Plastic Injection
Assuming you have done that, and must have screws for political reasons ....
Counterbores and countersinks are both produced by core pins, and it is usually a simple matter to modify or replace core pins in a given mold, so you can try it both ways if you wish.
Mike Halloran
NOT speaking for
DeAngelo Marine Exhaust Inc.
Ft. Lauderdale, FL, USA