molding with electrical pins

[Bowtie1974]

Hi everyone The part we make has 3 brass pins in a socket that a cord plugs into and we have to leak test every one with 10 psi of air and were getting a good amount that are leaking my question is is it possible to get 100 percent seal around pins? We are using rtp 199x and rtp 1005 any help or advice would be appreciated thank you

[iamplwirtz]

Has the number of leaking parts always been consistent, or has it recently gone up? Is there a process in order to clean the pins prior to molding around them? If the pins are clean and free of oil or other contraband, it should mold without leaks.

However, there's a lot of missing pieces. What type of pins? Are they specifically for over molding? Are you drying the material to be sure there's no moisture? Just trying to think of reasons why the bond would be good on some and not others.

[Jendalf]

This is interesting, do you have some pictures whats about?

How the fault looks like, material grade filler %, tool, etc.

J.

[rickbatey]

So you didn’t mention it but I think you’d be better off preheating the inserts too. The inserts can freeze the melt before it can completely flow around the pin. Also ensure you have great venting around the inserts.
Are the inserts treated to ensure bonding to the resin? If not you’ll have to rely on mechanical bonding and that may require several changes to work properly.
Rick.

[Bowtie1974]

422423 picture of the parts

[JeffB]

How does your process compare against the material vendors recommendations? Are you hand loading the pins? Is the mold hot?

[Bowtie1974]

Thank you everyone for the imput . We ended up putting the mold in a different machine and changed the processing a bit we finally got it . We have made these parts for years now and never had this much trouble with leaking. We have tried soaking the pins in acetone and it made no difference. Is there a product that we could soak the pins in that would help the pins are put into hand loads then installed into the mold

[Jendalf]

So Root cause was the machine! :)

Maybe the machine lays in a different temperature area than the previous one. Or You´ve changed the environment around the original one?
I still think that RC is somehow connected with temperature.

thanks for info anyway.
J

[Bowtie1974]

We have four molds that use those pins we have run them in multiple machines and we run them all the time and never had that much of a problem. We were running two of them at the time and having the same problem with both molds the parts looked great but leaked when we tested them we put the one mold in a machine that was a little bigger and with a little adjustment they were good and have been since .