Same master probe for multiple machines?

[Douglas]

Maybe I'm overlooking something but is there any reason one master probe build cannot be used on multiple machines just simply to save on the number of modules needed on my machines?
I have shared regular probe builds between them with no issues, I just keep probe files local on the PC for each install so they can be calibrated on each machine and for each machine. Until recently there has never been a master probe in this building but my better machine has one in the rack now and I'm thinking it could just be used on both and the third machine when it is purchased... ?


EDIT: Holy debate... anyway yes I physically build a master probe, give it a probe file 'MASTER' and use it for nothing other than to set the sphere location when it is moved. Mine is a 4mm x 10mm and it always gives me a result of less than .0000 std dev when locating the ball.
It can do this because it never gets bumped/crashed... never any wear on the ruby from parts... the geometry of my master probe is pretty much guaranteed to never change and because of this my probes will relate to each other better. That is really the advantage to having an actual master probe... I think everybody understands that any probe previously calibrated at A0B0 can be used to set the sphere location... it is what others have done to that probe in the meantime that you have no idea. If that probe got bent a bit in use then you go set a sphere location with it you have error now in how that probe relates to others.

I'm going to stick to having a physical master probe... those of you saying use any odd probe to say yes the ball has moved... you risk introducing levels of error into your probe calibrations... yes the software can do it but it is not ideal.

Maybe it changes the game for me that there is no possible way to leave the ball on the table, it must be located for each probe calibration I do then removed... there is just no room for the part and sphere to be on the table at the same time.

[andrewb91]

That should work.

[KIRBSTER269]

Not sure why people speak of "Master Probe" I have no special Probe that is necessary to be a "Master Probe" I relocate my Calibration Ball sometimes. Sometimes I start Calibration with my 1X20X20. Has Calibration Ball moved? Yes, Then I take a hit on top and it starts calibrating. Sometimes I start with my 2x20x20. Same again. I guess if PC-DMIS asked "Have you dropped your Calibration Ball? Would you like to use a "Master Probe", to see if it's ok? Then I guess you need a "Master Probe".

[andrewb91]

The master probe is "supposed" to be a 5x20 that isn't used for anything else according to the Hexagon training. I've had good results picking up the sphere location with a T1A0B0 with the main probe from the program and calibrating everything else back to that.

[Ego Murphy]

The master probe is "supposed" to be a 5x20 that isn't used for anything else according to the Hexagon training. I've had good results picking up the sphere location with a T1A0B0 with the main probe from the program and calibrating everything else back to that.

The master probe is supposed to be a short-length & medium/large diameter stylus that isn't used for anything else according to industry super-ultra-precision best practice.

In a certain popular and highly effective Germanic software that rhymes with Schmalypso and makes lots of decisions for the user, you actually can't use the master probe for inspection and you can't locate the qual sphere with any other probe. And the master probe costs 10x as much as a regular one, LOL.

However keeping a rack slot reserved for a probe that isn't making the company any money by making beeps on parts is also not best practice. At my current gig we have a ton of CMMs on the shop floor, and the probe in the #1 rack slot on each of them is used for qual sphere location and roughly 50 to 75% of part inspection all day every day. We see no downside but we're not chasing sub-micron tolerances, plus we have keen operators who know to replace styli when issues arise - and a fully automated calibration system.

[KIRBSTER269]

Well Let me try to break this down, When you home your machine, The bottom of the "Z" rail is 0,0,0.(somewhat) When you create a probe build, Lets say you create a new program, first thing that pops up is LoadProbe. So you choose your probe build and at that point at the middle of that Ruby becomes the new 0,0,0 (somewhat) remember the builds are perfect in PC-DMIS the actual hardware is not. So know you have a perfect sphere you created in DMIS Then you have an actual Calibration sphere that isn't perfect either, then when you calibrate the Probe and the Calibration ball it calculates the error between the 2. It doesn't say "well according to this 5 mm probe" So if you wish to continue with a "Master Probe" deal go ahead. Look in your Help file and Locate the words "Master Probe" there's no such thing.

[Matthew D. Hoedeman]

Well Let me try to break this down, When you home your machine, The bottom of the "Z" rail is 0,0,0.(somewhat) When you create a probe build, Lets say you create a new program, first thing that pops up is LoadProbe. So you choose your probe build and at that point at the middle of that Ruby becomes the new 0,0,0 (somewhat) remember the builds are perfect in PC-DMIS the actual hardware is not. So know you have a perfect sphere you created in DMIS Then you have an actual Calibration sphere that isn't perfect either, then when you calibrate the Probe and the Calibration ball it calculates the error between the 2. It doesn't say "well according to this 5 mm probe" So if you wish to continue with a "Master Probe" deal go ahead. Look in your Help file and Locate the words "Master Probe" there's no such thing.

the "master probe" is the probe that measures the qual-tool when you say "YES IT MOVED". That's it, that's all it is. Be it slot1, slot3, or slot2395 in your probe rack(s), or the probe you just screwed into the head. If you tell it "YES THE TOOL MOVED", the probe you 'find' it with is the 'master probe'.

[KIRBSTER269]

well ok maybe misworded that, but to actually say it is one particular probe, then no

[KIRBSTER269]

but you got the jist of it from my first post. knitpicker

[KIRBSTER269]

Location,Location,Location.................. Maybe we should call it the Location Probe

[Matthew D. Hoedeman]

Alfonso Ribeiro was the nit pickter (ok, ok, TICK picker)

[Mike Ruff]

I don't use a master probe at all. I only calibrate the relevant angles for the tip/program that I'm using. The qual sphere is not fastened to the granite on either of our CMMs (due to lack of workspace) and we don't have enough modules to have one dedicated to do nothing except locate the qual sphere. I don't need every angle of every tip to relate to each other, and I highly doubt anyone else does either. We only have a handful of programs that use more than one tip, and when I calibrate those, just answer yes the sphere has moved for the first and No, the sphere has not moved for the second and that's all that's necessary. IMO, using a master tip is the easiest way to make sure all your tips are good to each other, but if you understand how the calibration works, it is completely unnecessary

[NinjaBadger]

True, but it wouldn't work in my situation.

We have a library of over 400 programs, 12 probes with multiple angles and some star probes.

We have maybe six or seven different parts running at once and we can't be re-calibrating all the time. Full calibration takes over half a shift. If we were to re-calibrate tips for one job using any old probe as master we'd loose correlation with all the other tips.

[A-machine-insp]

Here's my $.02. Every machine we have (5 total) have a "Master" probe. It's a 4MM10 and they are all on standard force TP20 modules. The exception is the one machine that has the SP25 so it is on a scanning module. I calibrate with the master first every time then go on to calibrate the needed angles for what ever program I'm running. I also do this religiously because I am primarily on the CMM with the scanning head and I work with the tightest tolerance parts in the shop (routinely .0000 true position with less than .001 bonus, ect...) so I do it to eliminate that variable. This is also the way it was taught to me when I first got into this field so it's become a habit.