Melinex alternatives 1

[MEDarren]

Forum:

First, I'm not sure if this is the right forum to post this in, but I figured I'd give it a shot.

I'm working on a product right now that has a Melinex 515(1000 gauge) backing with felt stuck to it, using a double sided tape. The part slides back and forth over a metal shaft, lubing it as is travels back and forth.

The current process to make them is we cut the three layered part to size(35x35mm, about 1 3/8"x 1 3/8"), roll them over a mandrel and insert them into a drilled out hole, resulting in a tight fit. We then heat them up to 160C(320F) in an oven for 15 minutes and after they cool we remove them from the jig.

The result is a tubular shaped part, that holds it's shape pretty well.

Working temp and stresses are unknown since this is the early stages of design. This is the next thing I need to look into.

What we're looking for are Melinex 515 alternatives. Cost is an issure here, so cheaper=better. Using heat to form the part is fine but again, lower temps and shorter times would be nice. Or would baking the part for a shorter time work?

The part needs to hold it's tubular shape, and from the few of the people I have called it seems like Melinex 515 might be the best way to go.

I appreciate any help, and look forward to reading your responses.

Darren

 

[patprimmer]

I am not familiar wit the 515 grade, but my knowledge of Melinex is that it was a biaxially oriented PET film.

Melinex used to be an ICI trade name, and Mylar is the Dupont equivalent. I am sure there will be others.

The 515 designation might indicate variations on raw material used, colour, surface finish, or things like flame retardant or anti-static.

From you description of the application, it sounds like straight biaxially oriented PET would do the job.

If you do a google search for Mylar and foe biaxially oriented PET, you should find another source.

Oriented PET is very crystalline for a semi crystalline thermoplastic, and the temperature of 160°C will be quite critical to thermo-form it.

PET does absorb moisture from the atmosphere, and does hydrolyse if heated while containing water. If heated above 100°C, out-gassing can also result in a pimpled surface with a feature like a microscopic volcano.

If this is a problem, you might need to dry it according to the manufacturers recommendations, which I don't presently have at hand, but of which I am sure you can obtain on request from your supplier or the manufacturer.



Regards
pat pprimmer@acay.com.au
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[MEDarren]

Thank you.

 

[sreid]

Would it be possible to use just a tublar felt bushing (perhaps made from a stack of felt washers)?