Rubber Industry

ARPM Rubber Manufacturing Blog

The ARPM Rubber Manufacturing Blog allows members to rapidly communicate with each other. Post both questions and answers to questions that other ARPM members have about any industry topic from material and process issues to R&E Tax Credits and other business issues.

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Rubber Manufacturing Blog / Equipment / Thread gaging on metal inserts
Posted:  05 Jun 2013 20:50
This isn't necessarily an "equipment" question but here goes:
We have a customer who supplies aluminum, female threaded inserts.  We use loose-fitting male threaded steel mold mandrels to locate the inserts in our mold and we bond silicone to the outside of the inserts.
The ongoing issue we're having is that our customer is using a very, very tight-fitting male thread gage as a go/no-go tool and we are getting repeat failures.
We don't know enough about thread cutting and aluminum to know/argue that the gage is too tight.
I'm in need of a thread expert who can help me document a repeatable go/no-go test that isn't affected by slight aluminum powder/dust buildup on the gage.
Hoping someone can help...

Charlie Braun
Posted:  05 Jun 2013 21:24
Ok, I'm allowed to ask dumb questions: can you change your process to begin using the higher/tighter threads on your mandrils?
And if the customer supplied you the inserts in the first place, is it being implied that your current process of 'loose-fit male steel mold mandrels' are causing a non-conformance?
And/Or, it's not that you have over-molded silicone creeping into the threaded area of threads (that you could chase-out?)?
I'm unable to comment on alum vs. steel.
I have a job of molded alum. inserts and I use steel bolts to register the job during transfer, and reduces the thread chasing clean out later.

Good Luck.
Rick/R&R Rubber

Rick Norman/R&R Rubber
Posted:  05 Jun 2013 21:57
Rather than get into a long discussion, I would suggest that you reference a copy of Industrial Fasteners published by the Industrial Fastener Institute.

Dave Bayne/Jason Ind.
Posted:  06 Jun 2013 13:32

For these type of issues we typically work with our machine shop / toolmaker.  We have found these guys to be very creative at making jigs or solving metallic issues.  Regan