skidude

iTrader: (3)

I have a circuit board I'm mounting on a molded piece of ABS. It's currently mounted on molded bosses with holes that I put screws in, but the screws strip and pull out, and pulling out is bad. Stripping is bad in this case.

I want to replace the screws with pins that would be molded to the boss, so the mounting hole in the board would fit over the pin, then I'd melt the pin down to act sort of like a rivet.

It's sort of like the pins outlined in this document (pg. 2 Mounting Instructions).

I have searched google for every combination of plastic, welding, rivets, mounting, pins, PCB, and tools I can think of and I'm not turning up quite what I am looking for.

Can anybody help me out? I want both the tool that would melt the pin, as well as a little info on how to do it right. My company hasn't ever worked with plastic before, so I'll have to give the assembly people some instruction.

BTW, this is the actual board and piece in question. I need to have them modify the mold before I approve the prototype.

deezums

iTrader: (3)

I used to make "egg roll flipper" conveyor parts for the food industry. We used blue and white nylon rod as pins to hold UHMW flaps down on the stainless base.

To get the heads of the pins rounded out like rivits, we used a soldering iron with a custom turned tip. It was really that easy, wish I saved some pictures.

gesso

iTrader: (1)

Soldering iron with a custom tip seems like your best bet if you're going to be doing manual assembly. Just make sure you've a good fume extractor.

Also I assume this is for cost savings over press in brass nuts? And you don't plan on ever having to replace the board?

rleete

iTrader: (21)

How about just limiting the torque you put on the screws? Self tapping and/or thread cutting screws have been used in this application countless times with success.

Make sure you've got the right sized screws for the bosses. Too small and they'll strip out too easily. Too large and they can split the boss.

Leafy

iTrader: (1)

This seems like the answer if you wanted to stick with screws.