Glass Scale Cleaning

[Roger]

Hi All,
I'm having trouble finding information on cleaning glass scales. Do reader
heads need cleaning also? Is there non-residue contact cleaner used on the
scales/heads? Certain cloth? Any info would be greatly appreciated. I'm on a
friends computer and don't have email but can access this newsgroup for
replies.
Thanks in advance,
Roger

[Jeff Lowe]

Post by Roger
Hi All,
I'm having trouble finding information on cleaning glass scales. Do reader
heads need cleaning also? Is there non-residue contact cleaner used on the
scales/heads? Certain cloth? Any info would be greatly appreciated. I'm on a
friends computer and don't have email but can access this newsgroup for
replies.

Nothing caustic i.e. window cleaners.
Renishaw scales can be cleaned with acetone, but alcohol will dissolve them.
Sony laser scales can be cleaned with alcohol, but acetone will dissolve
them.
Most Heidenhain scales can be cleaned with either, but can't take a lot of
rubbing.
I would stay away from the read head as whatever cleaning fluid you use
tends to wick into them.

When in doubt RTFM.

[Bhagwan]

Dear Jeff,
Experts caution against using cotton swabs because stray cotton
threads left behind could cause damage if they reach the Sensing head,
for example. There are low- or no-lint foam tipped cleaning swabs sold
by A/V stores, Radio Shack etc. which would be safer to use.
For instance Radio Shack #44-1001 ultrathin foam cleaning swabs. RS
#44-1113 A/V head cleaning solvent "leaves no residue behind"
according to the catalog.

we suggest lint-free cloth, chamois swabs and 99% isopropyl alcohol,
among other things. Rubbing alcohol contains some fraction of water
which may leave more residue. The service manual for this tape scale
specifies "super fine applicator" (NIPPON APPLICATOR P752D) and
"cleaning fluid" (Y-2031-001-0) for cleaning the scale path, for what
it's worth. (After disassembling the unit, the sensor Index plate is
cleaned with a special cleaning cloth . It can be damaged easily, and
I don't suggest touching it.)

Also you can refer to RS catalouge for lint free cloth and Isopropyl
Alchohal in it's pure form.

Best Regards,
Bhagwan

Post by Roger

Post by Roger
Hi All,
I'm having trouble finding information on cleaning glass scales. Do

reader

Post by Roger
heads need cleaning also? Is there non-residue contact cleaner used on the
scales/heads? Certain cloth? Any info would be greatly appreciated. I'm on

a

Post by Roger
friends computer and don't have email but can access this newsgroup for
replies.

Nothing caustic i.e. window cleaners.
Renishaw scales can be cleaned with acetone, but alcohol will dissolve them.
Sony laser scales can be cleaned with alcohol, but acetone will dissolve
them.
Most Heidenhain scales can be cleaned with either, but can't take a lot of
rubbing.
I would stay away from the read head as whatever cleaning fluid you use
tends to wick into them.
When in doubt RTFM.

[Jon Elson]

Post by Roger
Hi All,
I'm having trouble finding information on cleaning glass scales. Do reader
heads need cleaning also? Is there non-residue contact cleaner used on the
scales/heads? Certain cloth? Any info would be greatly appreciated. I'm on a
friends computer and don't have email but can access this newsgroup for
replies.
Thanks in advance,
Roger

If it is a glass scale with chrome or nichrome vacuum deposited on the
glass, then a pure alcohol would be a good thing to try. it may take
several very gentle cleanings to get all the oil, etc. off the scale.

If the scale is dirty, the read head will be, too. But, these can be
damaged very easily on some models. The cheap scales are designed
to self-destruct. The head rides against the scale on teflon sliders,
and when they wear out, the grating of the head crashes into the scale,
scraping the chrome pattern off. That can't be repaired once it
happens. So, check if the teflon pads are worn, and see if you can fix
that before disaster strikes. The gratings on the read head still needs
to be real close to the scale, though. Typical gaps are around .020".
If your scale has tiny ball bearings that run agaisnt the housing
(some even run them on the glass) check to see that all of them turn
freely.

Also, when cleaning the read head gratings, I'd use a cloth very lightly
wetted with the solvent, so it doesn't wick into the works.

Check the wires for fraying. Many of these heads are driven across
the scale by a spring wire or strip. Check for kinks, bends or
cracks developing in that. The wires, especially, should be straight,
not bowed. If the wire has a bow in it, there will be backlash before
enough force develops to make the head move.

Most of these are pretty simple, self-aligning mechanisms, but you have
to be EXTREMELY careful getting the head off the track and back on.
it is real easy to crunch the read head gratings against the scale.

The sliding seal mechanisms are very different from scale to scale,
probably due to patents. Some of them work well and are easy to
clean, some of them are insane and end up dragging tons of junk
inside the scale.

Jon

[Cliff]

Post by Jon Elson
If your scale has tiny ball bearings that run agaisnt the housing
(some even run them on the glass) check to see that all of them turn
freely.

What would they be lubricated with, if anything?
Would not many solvents remove any such lubrication?

[Jon Elson]

Post by Cliff

Post by Jon Elson
If your scale has tiny ball bearings that run agaisnt the housing
(some even run them on the glass) check to see that all of them turn
freely.

What would they be lubricated with, if anything?
Would not many solvents remove any such lubrication?

Some scales (Mitutoyo slimline, for instance) have 6 (I think) very
small ball bearings on a little frame that rides in the housing.
I think they are standard shielded bearings about 3/16" OD, I think.
I wouldn't do anything to them, certainly not douse them with solvent!
My general procedure would be to do what is required to unload the
tension on the bearings and then remove the read head and carriage.
You want to release the tension on the carriage if possible to avoid
having an accident that chips the scale or the read head.

Once you have the head out, you can use Q-tips, cloth, or even paper
towels and be fairly liberal with solvent. Most scales have the
glass epoxied into the housing. But, there are some that have the scale
held in by double-stick foam tape. I'd be more careful with solvent
with the tape versions. Obviously, you want to use only the softest
things on the side of the scale that has the metal pattern on it.

If you need to clean the bearings, I suppose you could drip solvent
through the shield, and then put some lube back in it. but, I think
it would be tricky to not cause contamination to get out of the
bearing and cause problems later.

And, as I and others have said, you want to be real careful with getting
solvents into the head itself.

Jon

[toolsntoys4u]

What brand of scales do you have? I fix and install Mitutoyo and some
Heidenhain scales and could help you out if thats the brand you have.

tools

Post by Roger
Hi All,
I'm having trouble finding information on cleaning glass scales. Do reader
heads need cleaning also? Is there non-residue contact cleaner used on the
scales/heads? Certain cloth? Any info would be greatly appreciated. I'm on a
friends computer and don't have email but can access this newsgroup for
replies.
Thanks in advance,
Roger

[Buddy]

Post by Roger
Hi All,
I'm having trouble finding information on cleaning glass scales. Do reader
heads need cleaning also? Is there non-residue contact cleaner used on the
scales/heads? Certain cloth? Any info would be greatly appreciated. I'm on a
friends computer and don't have email but can access this newsgroup for
replies.
Thanks in advance,
Roger

Be sure that if you find the scales damaged and un-repairable that you
replace them with magnetic scales.

Buddy

[Tim]

Post by Buddy

Post by Roger
Hi All,
I'm having trouble finding information on cleaning glass scales. Do reader
heads need cleaning also? Is there non-residue contact cleaner used on the
scales/heads? Certain cloth? Any info would be greatly appreciated. I'm on a
friends computer and don't have email but can access this newsgroup for
replies.
Thanks in advance,
Roger

Be sure that if you find the scales damaged and un-repairable that you
replace them with magnetic scales.
Buddy

If you have allot of money then that is one option.

Tim

[toolsntoys4u]

Actually scales with magnetic pick up, like in case of Mitutoyo, are half
the price of glass. To be exact 40%. It is not as precise as a glass scale
but in most cases magnetic pick up scale will do a very good job.

tools

Post by Tim

Post by Buddy

Post by Roger
Hi All,
I'm having trouble finding information on cleaning glass scales. Do reader
heads need cleaning also? Is there non-residue contact cleaner used on the
scales/heads? Certain cloth? Any info would be greatly appreciated. I'm

on

Post by Tim

Post by Buddy

Post by Roger
a
friends computer and don't have email but can access this newsgroup for
replies.
Thanks in advance,
Roger

Be sure that if you find the scales damaged and un-repairable that you
replace them with magnetic scales.
Buddy

If you have allot of money then that is one option.
Tim

[hamei]

Post by Tim

Post by Buddy
Be sure that if you find the scales damaged and un-repairable that

you

Post by Buddy
replace them with magnetic scales.

If you have allot of money then that is one option.

Nah. If you have a lot of money you replace them with
renishaw lasers :-)

[Jeff Lowe]

Post by hamei

Post by Tim

Post by Buddy
Be sure that if you find the scales damaged and un-repairable that

you

Post by Buddy
replace them with magnetic scales.

If you have allot of money then that is one option.

Nah. If you have a lot of money you replace them with
renishaw lasers :-)

Laser will certainly give you a lot of resolution, but there is the whole
environmental compensation thing to worry about and the data rate can kill
your speed. Many of the older Moore machines that used laser feedback
isolated the beam path in a tube filled with helium to reduce the effects of
temperature and air pressure. With interpolation, a diffraction type glass
scale like the Sony Laserscale or the Heidenhain LIP-382 can easily reach
the same resolution as a laser and typically has better position stability.

[Cliff]

Post by Jeff Lowe
Laser will certainly give you a lot of resolution, but there is the whole
environmental compensation thing to worry about and the data rate can kill
your speed.

I suspect that if you can manage the data rate you then only need
to worry about "environmental compensation" to get the finest
accuracy.

[hamei]

Post by Jeff Lowe

Post by hamei

Post by Tim
If you have allot of money then that is one option.

Nah. If you have a lot of money you replace them with
renishaw lasers :-)

With interpolation, a diffraction type
glass
scale like the Sony Laserscale or the Heidenhain LIP-382 can easily reach
the same resolution as a laser and typically has better position stability.

I'm sure as hell not gonna argue with *you* about that,
but the point was "if you have a lot of money." Isn't
the renishaw still a better money-gobbler ? $10,000 an
axis seemed pretty spendy to me :-)

[Jeff Lowe]

Post by hamei

Post by Jeff Lowe

Post by hamei

Post by Tim
If you have allot of money then that is one option.

Nah. If you have a lot of money you replace them with
renishaw lasers :-)

With interpolation, a diffraction type
glass
scale like the Sony Laserscale or the Heidenhain LIP-382 can easily reach
the same resolution as a laser and typically has better position stability.

I'm sure as hell not gonna argue with *you* about that,
but the point was "if you have a lot of money." Isn't
the renishaw still a better money-gobbler ? $10,000 an
axis seemed pretty spendy to me :-)

They are spendy, but they are wicked cool. I had one of the new fiber feed
modular ones set up on a super invar bar at minimum deadpath for testing.
Put the whole thing into a beer cooler and watched it for about a week. At
about the same resolution a glass scale is a bit more stable, but you have
to map the scale.