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PVC compound

 

Hi,

I'm in sales. We are wire harness and cable assembly manufacturers. Cable uses UL2464 5 cores molded on 8 Pin mini din plug. During evaluation stage our assembly was put together with the end product with plastic casing (Computer) with packing, put into chamber test for 5 days under temp.62°C and the result was our cable assembly left a deep dent or grove on the casing and our cable is okay (UL 2464 standard 80°C and 300V)

Question : what could be the actual cause.

Please advise.

Regards,

EC Koh
- Singapore

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Hi EC Koh,

I know zilch about cables and little bit about plastics... so I'm going to assume that the cable material, the cladding, is PVC and not a softer material like Polyethylene (which burns easily unlike PVC).

Seeing that you are testing to 60 degr. C, well, that is the max. upper limit for RIGID PVC (in pipe corrosion pressure applications, for example) ... but you say it's not a cable problem but the computer casing .... and many computer casings are made of, I believe, thermoplastics like hi.impact PVC or ABS.

The ONLY thing I can surmise is that a) you gave us the wrong temperature b) the computer casing is made of Polyethene (highly doubtful!) or c) that the cable itself was being severely forced onto the casing.

Failure in thermoplastics is time/pressure/temperature orientated. The 60 degree temp. is not THAT high. The time of 5 days is a good test time. That leaves us with pressure or undue pressure.

Sorry, but I can't fathom your problem too well.

Cheers

Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).

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I think the question you mentioned is the migration of PVC to ABS, Please contact your supplier of PVC compound, ask them to change the plasticizer in the PVC compound to Polyester.

Hankel Kang
- Shenzhen, Guangdong, China