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  1. #21
    Join Date
    Aug 2007
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    701

    Re: Renishaw Probe

    Happy Probing!

  2. #22
    Join Date
    Jun 2014
    Posts
    1777

    Re: Renishaw Probe




    Probe adapter with relief for the Tormach collet and polished it up a bit, also the little fitting for the coil cord entry, looks a bit more professional than the tape ha!

    I am trying to figure it out as I know nothing about probing or really how to set it up. I used the probe screen and the ABC settings check out identical with my .0005 indicator that I set initially and both check out.

    The Probe came with a 4" approximately length stylus, I ordered a 20 mm from an outfit in California, 24 dollars delivered.
    I have 1.7 to 1.9 thou discrepancy checking a bored hole against my .0005 indicator and I am wondering if it has to do with the long probe stylus? Is it logical that the long stylus decreases sensitivity of the probe?
    If thats the case then the accuracy should be better with the shorter probe?

    EDIT: Q-Mark manufacturing -stylus

    Any info appreciated.........
    mike sr

  3. #23
    Join Date
    Oct 2005
    Posts
    1145

    Re: Renishaw Probe

    Don't forget you have to Calibrate your probe with each change in stylus tip rad and overall length for it to be accurate. That would also included a calibration for Tip centering to teh spindle.

    (;-) TP

  4. #24
    Join Date
    Aug 2007
    Posts
    701

    Re: Renishaw Probe

    VMAX is right. What I did was used a reamed hole to .35 and probed it in the X and Y direction. Then I adjusted the stylus diameter in the path pilot offsets to get close to a probed value of .175 in ea direction (you can see the vide). Remember - The stylus diameter is not just the tip diameter, you have to add in travel until it triggers (so a 3mm tip may be 3.25mm when you add travel until it triggers). You can see from my video that probing the holes yields .1747 in ea direction - close enough for me!

  5. #25
    Join Date
    Jun 2014
    Posts
    1777

    Re: Renishaw Probe

    Thanks for the info guys.
    So far I havent used it to find a corner as the parts I make I usually indicate centers of bosses or holes. I dont have a good handle on it all yet but hopefully will with some reading, experience and advice from you guys. It is nice that its automatic, I really like that! I have a short probe coming, so probable will have to realign for that one.
    The cord adapter looks better, I just siliconed the lead into it and tapped the holes in the probe transmitter body to 5 mm to attach it.
    mike sr

  6. #26
    Join Date
    Apr 2012
    Posts
    159

    Re: Renishaw Probe

    Do you think it's possible to use a Renishaw probe interface box with Tormach's passive probe to reduce arcing? I assume an inexpensive probe like Tormach's passive probe doesn't have much, if anything for arcing.
    "You can't teach stuff in a school that you would learn in real life unless the real life people are in charge of the school." - Gene Sherman

  7. #27
    Join Date
    Jun 2014
    Posts
    1777

    Re: Renishaw Probe

    Quote Originally Posted by scott216 View Post
    Do you think it's possible to use a Renishaw probe interface box with Tormach's passive probe to reduce arcing? I assume an inexpensive probe like Tormach's passive probe doesn't have much, if anything for arcing.
    I would think it would work at least with the model I have the MP3. It is just a make break type probe, as I understand it the interface senses the resistance across the contacts and as it decreases just before the contact break, it trips the probe on the decrease in resistance thus eliminating the arcing...........

    I am new to probing as well, just my understanding of how the interface box works.

    edit:
    My new 20 mm probe tip is due today, so I can check out how well it works plus I will gain a bunch of Z height clearance. A 100 mm came with the probe and tis a bit long for my machine...
    mike sr

  8. #28
    Join Date
    Jun 2014
    Posts
    1777

    Re: Renishaw Probe

    I have been away from electronics for several years but I would think it could be accomplished with a simple op amp or comparator circuit.

    I could see the value of it in reverse engineering, or in some types of art work where there are thousands of make breaks involved.
    mike sr

  9. #29
    Join Date
    Mar 2008
    Posts
    216

    Re: Renishaw Probe

    Quote Originally Posted by popspipes View Post
    I would think it would work at least with the model I have the MP3. It is just a make break type probe, as I understand it the interface senses the resistance across the contacts and as it decreases just before the contact break, it trips the probe on the decrease in resistance thus eliminating the arcing...........
    That operational description is upside down. The minimal resistance of the contacts occurs when the probe stylus tip is not being displaced by contacting a physical object. As the stylus tip encounters a physical object it starts to lift at least one of the three rods from the pair of balls that it was resting on. The Renishaw Probe Interface box used with contact probes senses the change in rod/ball contact force as a very slight increase in resistance (milliohms or less) and it turns off the current before contact is broken and this obviously reduces the arcing to zero. Since it cannot detect any further changes in stylus tip displacement when the current is off, the current is reapplied after a time interval to further measure future contact resistance. The repeatability of the three TP1S kinematic touch probes that I have purchased over the years when used with a PI-7 interface box is better than 1 micron. The internal electronics in the PI-7 is far more complicated than just a simple comparator since the circuit board has about the same area as your two hands and there are lots of electronic components. Reliably measuring very small resistance changes is significantly more complicated than just a comparator.

    I tried attaching the Renishaw document that describes the operation of kinematic touch probes in detail but CNCZone will not allow uploading a Power Point file. Anyone interested should Google "H-1000-8006-01-B_(Touch-trigger_probing_technology).pptx" to locate that Renishaw document since I cannot upload it from my workstation.

  10. #30
    Join Date
    Jun 2014
    Posts
    1777

    Re: Renishaw Probe

    Quote Originally Posted by Zetopan View Post
    That operational description is upside down. The minimal resistance of the contacts occurs when the probe stylus tip is not being displaced by contacting a physical object. As the stylus tip encounters a physical object it starts to lift at least one of the three rods from the pair of balls that it was resting on. The Renishaw Probe Interface box used with contact probes senses the change in rod/ball contact force as a very slight increase in resistance (milliohms or less) and it turns off the current before contact is broken and this obviously reduces the arcing to zero. Since it cannot detect any further changes in stylus tip displacement when the current is off, the current is reapplied after a time interval to further measure future contact resistance. The repeatability of the three TP1S kinematic touch probes that I have purchased over the years when used with a PI-7 interface box is better than 1 micron. The internal electronics in the PI-7 is far more complicated than just a simple comparator since the circuit board has about the same area as your two hands and there are lots of electronic components. Reliably measuring very small resistance changes is significantly more complicated than just a comparator.

    I tried attaching the Renishaw document that describes the operation of kinematic touch probes in detail but CNCZone will not allow uploading a Power Point file. Anyone interested should Google "H-1000-8006-01-B_(Touch-trigger_probing_technology).pptx" to locate that Renishaw document since I cannot upload it from my workstation.
    Seems I have my increase decrease words in the wrong place, an old guy screw up.
    I am sure its more complicated than just a comparator alone.
    mike sr

  11. #31
    Join Date
    Jun 2014
    Posts
    1777

    Re: Renishaw Probe

    Im beginning to really like this probe! Now that I have figured out the basics of how to use it ha! I have the 100 mm stylus and I thought the accuracy would suffer and maybe it does to a degree, so I bored a hole with a newer sharp 1/2" endmill then moved way off center in x and y then re-probed the hole, then put the half inch cutter back in the machine and rebored the same hole, it went back down the bore with maybe a little fine dust, left no visible mark in the hole, amazing! This may not happen every time but it sure is a confidence builder........

    Thanks again Brian for posting about these probes!!
    mike sr

  12. #32
    Join Date
    Oct 2005
    Posts
    1145

    Re: Renishaw Probe

    A better test is to make a test ring. Take a piece of stock heavy enough that teh probe cannot move it. Bore a precision hole about 1 in in diameter in teh stock . Now place that stock on teh table do not anchor it to teh table. Next insert a blank tool say .500 in teh spindle . Goto teh approx center of teh hole and lower teh tool inside of teh hole . Next write a program to make teh spindle rotate to a circle teh same diameter as teh hole 1.000 accounting for teh Radius of the tool . It can push the stock around a bit . Have the spindle return to center of rotation of the circle When it has completed the move the spindle should be dead in the center of the hole. Change out the tool to the probe and find center of the hole . The 2 locations (Circle,Probed) should be the same. and the probed diameter of the hole should be exact .

    Each time you change the stylus you need to recalibrate and check teh probe against teh Ring Guage. REMEMBER to be repeatable you must always use teh same probing Feedrate as you calibrated it to.

    Just a thought, (;-) TP

  13. #33
    Join Date
    Aug 2007
    Posts
    701

    Re: Renishaw Probe

    Pops - so glad you are as happy as I am!

  14. #34
    Join Date
    Jun 2014
    Posts
    1777

    Re: Renishaw Probe

    Quote Originally Posted by vmax549 View Post
    A better test is to make a test ring. Take a piece of stock heavy enough that teh probe cannot move it. Bore a precision hole about 1 in in diameter in teh stock . Now place that stock on teh table do not anchor it to teh table. Next insert a blank tool say .500 in teh spindle . Goto teh approx center of teh hole and lower teh tool inside of teh hole . Next write a program to make teh spindle rotate to a circle teh same diameter as teh hole 1.000 accounting for teh Radius of the tool . It can push the stock around a bit . Have the spindle return to center of rotation of the circle When it has completed the move the spindle should be dead in the center of the hole. Change out the tool to the probe and find center of the hole . The 2 locations (Circle,Probed) should be the same. and the probed diameter of the hole should be exact .

    Each time you change the stylus you need to recalibrate and check teh probe against teh Ring Guage. REMEMBER to be repeatable you must always use teh same probing Feedrate as you calibrated it to.

    Just a thought, (;-) TP
    Thanks for the info Vmax. I am like a kid with a new toy! Remember this is a Tormach, not a full size VMC, I didnt know about the feedrate, so far I have used 10 and 15 IPM, figuring slower would be more accurate.
    I bought the machine to learn the cnc trade as I never had the time when I worked. I am enjoying the learning process and make a few items, I will snip this info and put it on the desktop so I can try it in the future.

    I figured that about the stylus accuracy, I removed this one and replaced it and it was off less than a tenth or so. I have a new one on order, the first time I ordered the wrong one, so I called them and bought an adapter and a new correct one for the probe but a 20mm length.

    thanks for the info....
    mike sr

  15. #35
    Join Date
    Jun 2014
    Posts
    1777

    Re: Renishaw Probe

    Quote Originally Posted by brianbonedoc View Post
    Pops - so glad you are as happy as I am!
    I am thinking that the probe sequence splits the backlash as well, and gives a more true center?? The dial indicator isnt spindle position dependent but it depends on which way you approach "0" as to the reading you get (plus or minus backlash) and is a bit of a pain to use.
    mike sr

  16. #36
    Join Date
    Aug 2007
    Posts
    701

    Re: Renishaw Probe

    Pops- BTW i always run the probe at 20ipm. On my novakon pulsar this gives quick and consistent results.

  17. #37
    Join Date
    Jun 2014
    Posts
    1777

    Re: Renishaw Probe

    Quote Originally Posted by brianbonedoc View Post
    Pops- BTW i always run the probe at 20ipm. On my novakon pulsar this gives quick and consistent results.
    Thanks Brian, I will set it to 20, it would be a bit quicker than what I am using.
    mike sr

  18. #38
    Join Date
    Oct 2005
    Posts
    1145

    Re: Renishaw Probe

    Hi Brian that is interesting as most probes specifications and performance data is referenced at approx 20 IPM. (;-)

    There is a reason you get different values at different speeds.

    (;-) TP

  19. #39
    Join Date
    Aug 2007
    Posts
    701

    Renishaw Probe

    Vmax- yeah I think I read that somewhere. When I used to use mach3, 20ipm probing would almost break the tip because of the stupid buffered moves causing over travel. Now with pathpilot it is a dream and reveses the microsecond the Led flashes.

  20. #40
    Join Date
    Jun 2014
    Posts
    1777

    Re: Renishaw Probe

    I recieved my short probe tips today 20 mm, after recalibration of the ball I bored a .5 hole, set at x0y0 as before, the results after probing again were off about a thou or so??

    I then tried it again setting the machine to x0y0, by adding half the backlash in each axis back in, then reboring another hole, then reprobed that hole, and then using the same cutter in the same hole and there was no recutting anywhere, I am happy with these results!

    What I learned from this is that the probe was pretty much right on, the error was in the bored hole not being in the true center due to not adding in half the backlash in each axis before boring the hole then setting 0 again.

    I think I have this written up correctly but who knows, one of you knowledgeable guys correct me if I am wrong............
    mike sr

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