Re: [CAD_CAM_EDM_DRO] plastics

Ian,

Our local plastic supplier only recommends cast acrylic for machining
because of the lack of stresses.

It may be possible to stress relieve the plastic by warming it to some
temperature in an oven...BUT...I have been told that many plastics can
emit rather noxious and often toxic fumes as they are heated up...So
sticking with cast acrylic may be the best solution.

FWIW,

Craig

Ian Wright wrote:

>
> Forgive me for raising a question which is not specifically related to CAD
> or CAM but I have a problem which is perplexing me and preventing me from
> finishing my mill !! ;o)
>
> I have been making a new mouthpiece for my euphonium out of acrylic
> (perspex, lucite?) and I have turned it from a solid 2" diameter rod. When I
> finished it and polished it it looked the bees knees and I was delighted
> but, since I have been playing on it for a few days, it has developed a
> network of fine cracks around the narrowest portion of the bore. I am
> assuming that these must be due to vibration from the sweet musical notes
> but, since such plastic mouthpieces are made and sold commercially in the
> US, I assume that they shouldn't be there and are probably due to stresses
> already in the plastic.
> Does anyone know if there is a way to stress relieve plastics after
> machining?
>
> Ian
> --
> Ian W. Wright
> Sheffield UK
> www.iw63.freeserve.co.uk
>
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