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Upper Management is looking for answers/Justification on probe breakage

SMace
Hello ALL GURU's:
Here's a great post for a lot of input on WWGD (What would Gurus Do)?
Lets start by saying there are NOT an excessive amount of probes being broken yearly. I would estimate less that $500.00 - $700.00 yearly max, if that.
However, The uppers want justification.
Now, it has been suggested to slow the rapid in the machine settings, which would cause more cycle time on check parts that are in a Pallet setting.
There is a CRASH attachment from Renishaw. Anyone currently use these?. And do they work. Say on a .7x20mm probe or a 1mmx27mm probe?.
In our shop, we have 4 Cmm's that all have touch probes and 2 have vision as well. What would a normal (realistic) probe consumption be expected
at your place?. Mind you that the specific probes that we have in question are 1.5x30mm. 1mmx27.5 and .7x20mm. Sometimes it may just be human error (can't help that).
Maybe a slight misload, part has been machined or molded not into spec. Other times, maybe doing a manual align and you forget the rapid is on and "Snap". It happens.
I was asked to figure the FORCE in which a probe breaks. Well, honestly what other factors go into that one?. Are you rapiding, your prehit/retract too close and you touch the part and snap?.
Seeing as we are a high volume molding/machine shop with multiple parts at any given time to inspect via DCC. What is the best course of action to go ZERO probe breakage a year?.
This would not include Set ups, Prove Outs as well.
I am just looking for some insight on this issue from a lot of people who know way more than me!. Hence, picking the brains of the Guru's. ANY input would be greatly appreciated and if you want to keep it short and sweet. great. I don't want to consume too much of your time writing.
Thank You All Slight smile

  • Seems like the cost of doing business to a certain extent.

    Maybe start a log of broken probe instances so you can identify root cause or if someone needs to be more careful.

    My favorite way to break a probe is: post calibration, probe moves from directly above the cal sphere to the part's clearance plane (which is lower in Z than the sphere) and slams at full move speed directly down into the sphere, sending shards of broken probe at your eyes.

    Zeiss O-inspect machine probe racks are held in place lightly by magnets - brush against it and the rack falls to the floor, breaking your star probes. Needs a tether . . .

    Proving the program initially should eliminate any issues - after that it's probably a mis-mount or operator error like starting a program with the probe over the sphere.
  • -instruct your programmers to never run a program full speed until it has 100% been vetted
    -once your programs are vetted, save them in a certain folder where only "Approved" Programs go. train people they can ONLY file/open from the approved folder
    -when OPERATORS are using the cmm, you can prevent them from "accidentally" editing the program by running the CMM in PROTECTED MODE or purchasing & using OPERATOR MODE
    -train the operators to ONLY take manual touch points with TURTLE MODE ENGAGED
    -get a probe rack, minimize the amount of handling being done to your probes

    if you are lucky enough to have decent fixturing, you can set up your programs where the operators NEVER have to do manual alignments & everything is handled in CNC mode. the less an operator touches the jogbox the less things will go wrong.

    we have a room with 5 cmms & three full time cmm operators. none of those machines have probe racks. they build probe tips by hand, they hand load as the machine asks for different probes, and EVERY program has a manual alignment prompt... they crash every so often & spend ~$300/month replacing broken probe tips. My 7107 that has ZERO manual alignments & a probe rack & an approved program system hasn't broken a probe in 2 years hitting the budget for literally $0 in replacement stuff
  • I honestly don't have a lot of probes break on me. I have three CMMs and maybe spent a couple hundred a year on probes, if even that. But you should have a budget built in case you do have a crash or malfunction, ie: module goes out.

    What is your probing system? TP20?

    What is your current prehit and retract set at? What is your touchspeed at? Movespeed?

    Do you have enough prehit and retracts for your rough DCC alignment in order to find the part so the rest of the program can fly through?

    If you have problem areas, try creating a dummy point/feature by using a larger prehit and retract to find an edge or feature of size, then align or use variables to that dummy feature to key into the feature you need to measure.
  • To be honest in nearly 20 years I've probably only broken maybe three or four probe tips, make that five if you count the 0.5mm tip which just evaporated during the calibration cycle on an SP25 whilst scanning the reference sphere.

    But I'm aware that's uncommon, perhaps I'm just unusually cautious when running the machine myself and good at writing 'safe' programs.

    The problem with the fine tips is that they're both expensive and fragile - it's just what it is. Probably cost more in your time for you to look in to it that the cost of the tips.
  • in reply to bfire85
    We have Tp 20, TP200 and Global 9-12-18 scanning.
    The pre/retract varies per part. Usually touchspeed is at 2 and move speed would be 100% absolute.
  • Seems like the cost of doing business to a certain extent.

    Maybe start a log of broken probe instances so you can identify root cause or if someone needs to be more careful.



    I agree. I don't think you will ever reach zero broken probes, especially if you are using those really small tips - they just break so easy.

    I like the idea of creating a log. It is difficult to improve a process if you don't measure and monitor it. Then you can generate annual reports with pareto charts and such to show the higher ups. You can then implement solutions for the worst offenders and monitor the progress. I don't think you will ever completely eliminate the problem, but you can at least show that you are working towards solutions. If they want to play blame games, it allows you to point a finger to something that is likely out of your control.

    Unfortunately, I think has it right in saying: "Probably cost more in your time for you to look in to it that the cost of the tips."
  • 1) Operator mode. This was a huge upgrade and cannot begin to explain how this saved programs not be " accidentally " altered.
    2) Slow the move speed down untill the DCC is completed, then speed it up
    3) The zoo keepers never let the monkeys into the employee lunch room..... keep them off the CMM....
    4) Program from CAD, You will break less probes at proveout with the collision detection and being able to look at PATHLINES.
    5) The moment you idiot proof anything , and better idiot will evolve.......
  • THNAK YOU ALL FOR THE INPUT!!!.
    Really Appreciate it!
  • I put this together, feel free to steal/use as you see fit.

    NOTE-- Rename *.PDF to *.XLSX before opening. --We are restricted from uploading xlsx files apparently.

    Probe breakage is inevitable, no matter how much you implement to isolate it.
    You are better offf tracking the frequency, and producing a spares inventory. I have gotten to the point that i can safely say we burn through about 9 1x27.5's on average each year. Boom in the budget for next year, and we have a full set of production spares at the ready for each year.
    I'm also tracking bigger ticket items like probe modules, bodies and heads, as well as maintenance activities to log all unscheduled maintenance and costs including HMA / "MyCare" current bullhonkey.
    I manually insert the mycare/HMA costs in the analysis tab.
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