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Boss cracking after insert welding
10 August, 2005 - 01:49 — alban
For mobile handset ,we weld nut insert to the plastic panel for assembling the top and bottom panels.The OD of the insert is 2.45 mm and the boss ID is 2.2 mm.The machine used is of 20 khz (2000 W).after welding the bosses are developing horizontal cracks(across the boss) inside.Can somebody give advice?
Forums:
Re: Boss cracking after insert welding
Hi Alban,
You really need a plastic welding expert for this one - can you ask your equipment supplier?
With my limited knowledge of the subject two thoughts come to mind:
1. If the direction of the cracks is always consistent, this could be caused by distortion of the panel during welding (so that returning to its old shape it stresses the boss). How well does your support match the shape of the panel - could you improve this?
2. The parts seem quite small for a 20kHz system - you might get more control over the weld process at a higher frequency.
Hope that helps.
Chris
Re: Boss cracking after insert welding
Hi Chris,
Thank you for the advice.We are also on the same line of changing the machine to 40k.Pleas give some info on the testing of the welding strength of nutinserts and some benchmarks..
Thanks,
Alban
Re: Boss cracking after insert welding
Alban,
Sorry, can't help you with strength figures - as I said it's not really my field. But for that kind of application I would think the geometry of both the insert and the hole would be critical. Can't your suppliers (either equipment or insert suppliers) give you any example data?
Regards
Chris