TP-20 worn out?

[Octopussjump]

Hey all,

I have 3 different Renishaw STD Force TP-20 modules all used on different machines that have been failing to trigger on occasion or won't re-arm.

2 of them are set up on DCC machines with 2mmX20mm styli on 20mm extensions. One is 5 or 6 years old, the other is maybe only 2 or 3.

The other is a 2mmx40mm on a 10mm adapter and is used only on an old manual machine. This module is possibly 10 years old or more - the machine dates back to the early 80's.

I know the other guys who worked here before me used to crash the CMM's a lot and really abused the **** out of our equipment. The manual machine takes some heavy abuse because it's use is completely unrestricted. (IE: people taking fast and heavy hits in every direction - like say minus Z)


I proposed replacing these modules either with new ones or on an RBE - the big boss man actually wants to go with new ones, but he won't give me the go ahead until I can provide proof of mechanical failure or give them some kind of stats on life expectancy for these modules.

Honestly, I don't really know much about the mechanics of these things, but I'd assume even with normal wear and tear, eventually they'd get a little tired. Taking into consideration the crashes, the fast and hard hits, dropping them, sticking them to the side of the machine before I worked here, etc... I'd bet they're begging to be rebuilt.

Frankly all I know is they just don't work that well all the time anymore and eventually it's going to lead to a more expensive problem.

I just don't have any hard evidence that these things can wear out... any proof or documentation from Renishaw or anyone, so for all my boss knows, I'm just not doing something right or I need to clean them better.

Anybody have any help for me on this one?

[craiger_ny]

Man you're lucky. Normally I'd say 2 years is doing well for me. I run 24/7 though. The fact that you are having issues reseating is an indication it is taking a crap on you. 10 years, wow!

Buy new, don't bother with RBE.

[Bill **********]

Renishaw themselves state that they are only good for a half million hits. If they're six years old then they are well past that, at least the way I run them. When they quit resetting thats all the proof you need that they're worn out. Call renishaw and talk to them for documented proof that they're worn out. Also, there is NO advantage to spending the extra $$ for new.. Repair exchange is all I ever use.

Bill

[Matthew D. Hoedeman]

Man you're lucky. Normally I'd say 2 years is doing well for me. I run 24/7 though. The fact that you are having issues reseating is an indication it is taking a crap on you. 10 years, wow!

Buy new, don't bother with RBE.

I was told, once, that the BRE for the TP2 was not really an RBE, but a new TP2 that put in an old case, they gut out the ones coming in and put all new guts in them, that is the BRE of the TP2. As for yours, yeah, boogerboy is right. Hey, wait until your head wears out as well. Those also have an expected life of so many seat/un-seat cycles. Nothing lasts forever.

[John Kingston]

Time to replace them. I think you can find life expectancy on Renishaw's site. The half million hits is a number I recall hearing too. As Matt said;

Now, don't hang on
Nothing lasts forever but the earth and sky
It slips away
And all your money won't another minute buy
Dust in the wind
All we are is dust in the wind
All we are is dust in the wind
Dust in the wind
Everything is dust in the wind
Everything is dust in the wind
The wind

(Kansas)

[Matthew D. Hoedeman]

Time to replace them. I think you can find life expectancy on Renishaw's site. The half million hits is a number I recall hearing too. As Matt said;

Good tune, dude, good tune.

Hey, right now I am listening to "No Anchovies, Please"

[dwade]

Do an RBE. Renishaw will check them out before replacing them and if they do not need replaced you only pay for the shipping plus you have the knowledge that the module is good. I keep 1/2 dozen or so of the std force modules on hand as spares and keep at least 2 ext force or spares. Could save you a few dollars now and then doing the RBE.

[AJHVW93]

I was told, once, that the BRE for the TP2 was not really an RBE, but a new TP2 that put in an old case, they gut out the ones coming in and put all new guts in them, that is the BRE of the TP2. As for yours, yeah, boogerboy is right. Hey, wait until your head wears out as well. Those also have an expected life of so many seat/un-seat cycles. Nothing lasts forever.

Matt, I was told the same thing as well.

[Octopussjump]

Just incase anyone is interested, I found a .PPT file of technical data on the trigger probes by renishaw on their website.

It stated 2 times that the life expectancy of the modules is greater than 10 million hits!

We run these things almost 24 hours a day for 6 days a week, but it would still take a long time to reach 10 million hits - if that is in fact true.

Could be a line of BS from the company, but there you have it.

[#2#]

Hey all,

I have 3 different Renishaw STD Force TP-20 modules all used on different machines that have been failing to trigger on occasion or won't re-arm.

First, I'm not disagreeing with anyone else. If yours it 10 years old, it's probably time for a new one.

Second, a few things that may help.

1) Do you clean them regularly? You can buy some stuff that is like poster putty (some say just use poster putty) to clean the modules and the probe ends. Dirty contacts could cause your problems. Dirty magnets could cause them to not seat properly and allow them to wobble.

2) A bent tp20 body right where the module connects could cause the module to not seat properly on the probe. Do a visual check that the probe body isn't out of round.

4) I have noticed after a particularly hard z-minus hit (oops )that the electrical contacts on the back of the module got pushed out a little. This allowed the module to rock on the tp20. I pushed them back in by pushing the module down on the surface plate until they were flush. This restored the function of the module and seems to have not affected its accuracy. In fact it was the module used for the last calibration.

5) You didn't start measuring magnetic parts did you? The regular TP20 doesn't play well in magnetic fields. You can buy a special TP20 that isn't affected by magnetic fields.

HTH

[Don Henger]

Here is the link to Renishaw

RENISHAW