Heidenhain

[Archie]

A question for the machinists out there. Has anyone any ideas as to why a hitherto perfectly functioning Heidenhain linear encoder on my mill should suddenly start skipping segments. It works fine for parts of the travel and then does nada for the rest. My first thoughts ran to dirt but I'd rather not have to take it apart. Does anyone know of this and/or a cure?

Secondly, and related to the first, I tried using the manual dials on the mill (Bridgeport) which I've never had to use (at least not the horizontal ones). However, only the coarse ring moves. Taking the dials apart it would appear that there is a missing gear of about 5mm dia. but it seems strange that I should be missing all three of them from all the dials! Am I missing a gear or something else and if it's the former any ideas where I might get a replacement?

Ta.

 

[slim_boy_fat]

Can't help with the missing(?) gears, but you could try HPC Gears for replacements if you need them.

www.hpcgears.com, I've used them and found their service to be excellent.

 

[MrFluffy]

Any of this lot any use?
http://bridgeport.askmisterscience.com/bridgeportlit.htm

 

[Luke]

What is it? optical? magnetic? The glass type optical encoders do seem to wear/degrade over time.

If you end up looking at replacing it, I'd recommend talking to IED.

 

[Highway_Star]

Optical ones suffer from oil getting onto the glasses. The markings are etched onto the glass, pretty much microscopic, so it doesn't take much oil to clog them up.

Place I worked at 20 years ago did optical repairs amongst other things, we had a nice wee number going with Rosyth Dockyards toolroom, Lammond & Murray gearcutters up the road and the TK Valve plant locally. For the simple reason we had chemical cleaning baths for lenses that would make the encoders work again. A local gunsmith was another regular for our services on them, as well as telescopic sights & spotting scopes.

Them were the days!

 

[Archie]

It's an optical type. I suspect you're right and it's got oil in it. So, this being the case, what's the best way to go about cleaning it?

Or... should I just be buying a new setup? This one's pretty old and has other problems too. If I were to look for another are there any particular makes or types (optical or magnetic for instance) that I should look at?

 

[Highway_Star]

Strip it down, carefully to find the two glass plates, they are usually about an inch long.

We used to clean them in stuff called 'Micro', as used in labs to clean glassware to, very very very clean. Combined with warm water in an ultrasonic tank.

http://sciencekit.com/micro-liquid-laboratory-cleaner/p/IG0026343/
is the stuff, should be able to get it locally from a lab suppliers. It's useful for cleaning much more than glass. My dad used it for years to clean fired cartridge cases before reloading.

 

[Archie]

Last time I had a peek there was just the one glass strip and it was about 12" long but I guess the theory stands - just strip it down and bathe in something like the above. Got to be worth a go if I can find a sensible quantity of the cleaner. Cheers.

 

[Highway_Star]

AYe, some of them have one graduated glass, the other half is on the lens of either the pickup or the emitter.

Another thought, depends on the type of emitter really, perhaps the LED or bulb has aged? Some of them you can adjust the drive current, but you really need to know what you're fiddling with.

 

[graffian]

If I were to look for another are there any particular makes or types (optical or magnetic for instance) that I should look at?

If you have to replace look at Newall systems. No worries about dirt or breaking them.
My DRO died, 30 year old unit needed some TLC, I was amazed how long it took me to do stuff without it.