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How to remove Teflon coated onto 0.6 to 0.9 mm thick CRCA strip?

2007

Dear sir,

I am SUDHIR from NRB & my company manufactures bearings that are supplied to automotive manufacturers. Presently all the material having more teflon thickness than specified is scrapped. I would like to avoid the scrap of excess coating material & want to re-work it by removing the applied coat & re-coating it again!

Can you suggest some alkalimetals which can remove this teflon coat? or else suggest something like shot blasting/grit blasting that will not deform by substrate material of CRCA of ~ 0.6 mm to 0.9 mm thick?

SUDHIR KSHIRSAGAR
EMPLOYEE - PUNE, MAHARASHTRA, India

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PTFE is best removed by machining it back. If it is heated, it will melt at about 327C and start to thermally degrade at 350C. One problem with it degrading is that it can cause an illness called PTFE Flu - a lung reaction that gives many of the symptoms of common influenza. It is a quite nasty illness and should be avoided, but I do not think it will kill you. You can heat the bearings up to remove the PTFE, but you run the risk of distorting the bearing shell. The best way of ensuring good production is to avoid errors and faults, so I would recommend more stringent process control and quality assurance -avoiding rejects is better than reworking them,... and a lot cheaper.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2007

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2007

Dear Trevor,

Thanks for the feedback & necessary guidelines. I believe instead of Re-work/Reject, definitely avoid the said the said defect by controlling the teflon coating process.

Is there any alternative method of grit blasting or else as I believe it will be more ctitical to remove the coating from substrate material & will not be uniform.

Pl suggests!

Sudhir J. Kshirsagar
- Pune, Maharashtra, India

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The bearings will be round, so it is easy enough to machine the inernal diameters back to a uniform thickness; this will eliminate the need to grit blast the PTFE off and you may find that remachining eliminates the need to recover the shell and re-coat it.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2007

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2007

Dear Trevor,

Thanks!

Regards
Sudhir

Sudhir Kshirsagar
- Pune, Maharashtra, India

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2007

As a Teflon coater in Spain, I can tell you that there are different polymers under the mark Teflon(R) The PTFE, PFE, PFA and ETFE. If the one you are talking is a one coat PTFE, perhaps you'll have succces with this:
you can try to deep the parts into a solvent called NMP (N-metil-2- Pirrolidone)
Let them few hours and see if the teflon coating starts to disappear...
best regards

Jordi Pujol
- Barcelona, Spain

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Respected sir,
how to remove plastic coated on paper.it may be thermo plastic poly propylene or it may be teflon coated or terylene coated or it may be phonolic resin coated on paper or glypatal resin on paper please give me suitable solvent for me
Thanking you
by,
C.V.Vishwanathan

C.V.Vishwanathan
- Chennai, Tamil Nadu, India
April 30, 2008