PTFE creep/flow
PTFE creep/flow
(OP)
I'm looking at using 30mm thick PTFE as a bearing pad. Plan dimensions are 300 x 170 mm and compressive stress is about 150 - 200 kPa. Will creep/flow be a problem?
John
John
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RE: PTFE creep/flow
Re-enforced composites either dry or lubricated. Some of these rival PTFE for low friction yet can handle significant loads with zero creep.
ORKOT, MARITEX BEARINGS, TUFNOL, TEN MAT are some that can help.
RE: PTFE creep/flow
Regards,
Mike
RE: PTFE creep/flow
As rnd2 states there are other options where creep may be a problem ... and it often is with PTFE.
Mica filled PTFE is available which improves creep resistance - marketed as Flourosint I think, though there may be others. It's also worth checking out other filled polymers which may have PTFE or MOS2 added. Vespel and torlon certainly exist in these forms. You can also try Ketron PEEK HPV which is a bearing grade PEEK composite.
Good luck.
RE: PTFE creep/flow
RE: PTFE creep/flow
i.e., Fluorogold,
http://www.sepbearings.com/index.html
RE: PTFE creep/flow
I should have said but the pads will be supporting bus bars in an aluminium smelter, and are also acting as electrical isolation, hence the thickness.
However, due to the response, we will be looking at alternatives.
John
RE: PTFE creep/flow
RE: PTFE creep/flow
PTFE group are one of very few electrical insulating materials that resist fluorine.
My 2C worth: Position a metal plate that completely covers the PTFE. The plates could be fixed to the busbars and act as load spreaders between busbar and PTFE, thus preventing point loads when the bars move. This wil reduce the risk of the PTFE creep.
RE: PTFE creep/flow
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RE: PTFE creep/flow
RE: PTFE creep/flow
If you get PTFE over 900F you will start to release fluorine type gases which are nasty.
RE: PTFE creep/flow
There is a company on the state line of Bristle, TN and KY that is the largest FRP pultruder in the world by a factor of eight they say. They make the side rails for Warner FRP ladders. They have a complete catalog of FRP shapes that mirrors steel structural shapes. One needs to design by deflection instead of yeild since this product's yield and ultimate are about the same. www.strongwell.com
Look at their pultruded plate material.
If you are looking for just a couple of pices call a company down there called Appalacian Plastics. They buy up Strongwell's scraps and can make you a hell of a deal on the material.
RE: PTFE creep/flow
That is good information for sourcing FRP structural shapes. However, for this thread, if I am correct in assuming apsix's application an aluminium smelter potroom, regular FRP that uses epoxy, polyester or even vinyl ester for the resin matrix will have a (disastrously)short life. Very small concentrations of fluorine gas adsorb into and destroy the resin matrix suprisingly quickly. Fluorine gas is a by-product of producing aluminum metal.
RE: PTFE creep/flow
Upon the advice of a manufacturer we have selected a 12mm thick glass-filled PTFE sandwiched between steel plates, which should cope with the heat (100deg C, higher if the ventilation breaks down) and fumes.
Also at the low compressive stress, thinner size and glass-fill should ensure that creep is not a problem.
John
RE: PTFE creep/flow