Re: [CAD_CAM_EDM_DRO] Jerry K, Was: Ultrasonic cleaners for delicate parts?

motoproto wrote:

> You are absolutely right, it's a Baumer! I looked at the Baumer
> website, and found the exact switch, the only question is what
> activation pressure the switch is.

The Newark Catalog I have lists three switches but doesn't note
that they are Baumer. One is type 748310-005 and takes 50 grams
activating force with a sapphire stylus. Operating voltage is
24vAC/15vDC max and is an N.C (normally closed) output. The next
one is type 748520-007 and has a ruby stylus taking 75 grams of
activating force. Other characteristics are the same. The third
is type 748321-107 and has a sapphire stylus taking 75 grams of
activating force and has an operating voltage of 5-34vDC and the
output function is NPN, N.O. With this in mind, maybe you can
find more information from Baumer, if these numbers and
characteristics belong to Baumer, or find a substitute via Newark
electronics as required.

> So, what do you
> think about ultrasonic cleaning of the Baumer switch? I thought I
> could clean the switches in a water soluable cleaner(in the
> ultrasonic bath), then rinse them in straight water(in the ultrasonic
> bath), then gently warm them on a heating pad of some sort to dry
> them out. Then perhaps attempt to get a drop of very light oil past
> the plunger.

Those plungers may not be glass now that I think of it. They
could be sapphire if clear like glass or ruby if redish cast.
May be why they cost so much. I doubt the oil should be used.
Most of us think oil works but in this case with crystalline
material it may do nothing more than gum up the works. So I
would be reluctant to use oil on sapphire/ruby (both same thing -
aluminum oxide crystal). In fact, your problem right now may be
stiction due to oil and dust on the plunger.

My ideal solvent for these sorts of small items would be freon
113, but that is really hard to get these days. Alternatively, I
would probably try DMSO (dimethyl sulfoxide) or methylene
chloride. You may not actually need an ultrasonic bath.
Methylene chloride has a boiling point of 38 deg C so would dry
out at armpit temperature. DMSO is higher. Maybe electrical
contact cleaner will take care of the external parts. I think
I'd stay away from anything that is water based as evaporating it
might leave a residue of much higher boiling point. Electronics
usually have an upper operating or storage temperature and I
think I'd choose a degreasing solvent with a much lower boiling
point.

In any case, you might want to try some methyl or isopropyl
alcohol, or methylene chloride on the glue part to see if the
glue gets soft. If so, you don't want to use that solvent and
need to try something else. As you say, it may take some
diddling around but worth the effort if these switches can be
cleaned out successfully.

Good luck with this. I've done similar things so I'm counting on
you having success.

JerryK