Has anyone done accuracy tests on an optical style touch probe versus a mechanical? I've been told there is a small difference which usually shows up in form, but looking for real world numbers. I currently use an HP-THD (now an HP-THe), which is a tp200 I believe. But after replacing 2 probe bodies in the last year and 2 months at over $3k a piece, I'm searching other more robust options. Like the older tp20. Is it worth the switch? am I losing that much accuracy? Occasionally I do get jobs with a +.0005/-0" tolerance which I think may be affected, but could be worked around with deltronics pins. Does anyone else here use tp200 or the newer and have problems? I know the first module may have gone bad due to the previous cmm programmer. I was told when I started my job here that he crashed it a lot. But this new one I've had on for the last year has never been crashed, dropped, even looked at wrong. TIA
actually, the TP2 (IMO) is better than the TP20. Yeah, TP2 is useless if you are a rack user, unless you use the rack that swaps the whole things out from the quick-change adapter. BUT, the TP2 could have the tension adjusted so you could use a 100mm long probe. Yeah, not the best, but depending on the tolerance you needed to hold, and not good at angles, but straight up and down, worked fine.
I generally don't use any extensions. The machine is a global advantage 555. Most everything I measure is the size of a hand down to a pinky nail. Half mm probes half the time and 1mm probes the rest. I can back up what is said about the tp2(tp20) as far as indestructible. after using them for the first 18 years of cmm life, I've seen them go through a lot.
About the same size as the SP25, but can handle up to 225mm extensions (straight) or 100mm (cranked i.e. star probe) but without the ball ache of the SM25-1, SM25-2 etc 'modules' and then the SH25-1,SH25-2 stylus holders. Which makes probe changing a much simple and quicker affair.
On a small machine (much like with the SP25) you can struggle for space, but a lot of this can be overcome by using Star/L/T probe configs so you're not indexing the head all the time.
Also worth considering what probe head you have. Does it have the adapter between the head and the TP-THD or is it simply a direct M8 thread?
mostly +/- .002 but occasionally i get a +.0005 - nothing or vise versa. so optical accuracy is always better. Just wondering what the difference is between that and the older tp20s. is it microns? is it more? Even to have as a back up until a new module comes in for the HP-THe.
I have the HH-AS6-T5 head with HA-TM-31 attached to that, then the HP-THDe-B body, then HP-THD module. I'm definitely limited on space with a global 555. But then again, I measure some small parts. I also doubt my company wants to buy a whole new set up. That would probably cancel out my garage for all the modules as well I'm assuming.
