Tormach digitizing probe to find center of a small circle, but bigger than probe tip


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Thread: Tormach digitizing probe to find center of a small circle, but bigger than probe tip

  1. #1

    Default Tormach digitizing probe to find center of a small circle, but bigger than probe tip

    Hello guys,

    I only made about 7 steel part on my Tormach so far, almost all the parts needed to be machining on the other side, so for setting the origin on the flipped part, I used the only element I could use, a 4mm hole I made from the first setup.

    But my problem started when I tried to find the center with the digitizing probe, because it has that "double move" first time quick, than retracts and try again at a slower feed rate. The problem is I couldn't find the a way to set the distance it retracts after findg the margin using the higher feed rate. When it retracts it hits the other side of the hole and I get an error that the probe is already tripped.

    To be able to find the center of the hole I manually jog left untill it touched the margin, than moved right to touch the margin, than moved to the middle and made the same for Y axis .. but this is a little slow.

    Is there any other way to probe small holes, any setting I can make to eliminate the retract, or make it smaller ?

    Thank you.

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    Default Re: Tormach digitizing probe to find center of a small circle, but bigger than probe

    Consider another approach.

    Depending on how good you need the other side to be in register, and how good the hole is (reamed is preferable), I have sometimes used a carbide rod held in an ER20 collet as a locating pin. Put the collet in the spindle; push the part onto the rod; and then reload the part into the vise without moving the table/fixed vise jaw. The fixed jaw gives you an X reference, and the rod centers the part under the spindle. This isn't perfect, and it depends on machining the reamed through hole from side one as well as having a decent side to index against the fixed jaw. IF the stars align, and the part and fixturing are amenable, one can get a thou or a bit more register and repeatability. Not high precision, but sometimes good enough.

    Another option is to gang parts to make multiple copies in one setup, so when you flip the work you're indexing one hole but that single hole provides register for 4 or 8 individual parts. Takes just as long to do the single hole, but now that job is averaged over multiple parts, so it's faster per individual part. Again, not necessarily usable with parts that have much side geometry.

    Third option is to write your own probing code. That was easy in Mach3, don't know how simple it may be in PP.



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    Default Re: Tormach digitizing probe to find center of a small circle, but bigger than probe

    You could also machine a 4mm pin that is a snug but removable fit to the hole and then probe the outside of the pin. I am using Mach 3 with a Renishaw probe on my PCNC 1100, so I cannot offer any assistance with the Tormach probing routines. It is easy in Mach 3 to make custom probing routines, but I have no idea of how to do that with PathPilot.

    I also almost forgot to mention that probe tips down to 1mm or less are also available, although that may not help your situation if the Tormach probe movements are simply too large to begin with.

    You could also try doing manual movements at slow speeds on one axis at a time and watch the indicator light to find the pin or hole location.



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    Default Re: Tormach digitizing probe to find center of a small circle, but bigger than probe

    You don't indicate whether the "7 steel parts" are production parts or one-offs. If one-offs why not do manual positioning with a DTI secured in the spindle? With a small stylus it is easy to find the centre of a 4mm hole; I do such daily. If these are production parts then a locating feature in soft jaws may assist.



  5. #5

    Default Re: Tormach digitizing probe to find center of a small circle, but bigger than probe

    Quote Originally Posted by GLCarlson View Post
    ...Depending on how good you need the other side to be in register, and how good the hole is (reamed is preferable), I have sometimes used a carbide rod held in an ER20 collet as a locating pin. Put the collet in the spindle; push the part onto the rod; and then reload the part into the vise without moving the table/fixed vise jaw. The fixed jaw gives you an X reference, and the rod centers the part under the spindle. This isn't perfect, and it depends on machining the reamed through hole from side one as well as having a decent side to index against the fixed jaw. IF the stars align, and the part and fixturing are amenable, one can get a thou or a bit more register and repeatability. Not high precision, but sometimes good enough.
    So far I don't have any tight tolerances from the clients, an error of 0.1mm is acceptable, it will be visible when milling the exterior contour on side B, but in most of the cases it won't affect the part, if the error appears I have to manually sand the side so it will be smooth as in most cases I also have to make another policarbonate part in which the steel part will slide up and down a few milimeters (3 - 4mm )


    Quote Originally Posted by GLCarlson View Post
    Another option is to gang parts to make multiple copies in one setup, so when you flip the work you're indexing one hole but that single hole provides register for 4 or 8 individual parts. Takes just as long to do the single hole, but now that job is averaged over multiple parts, so it's faster per individual part. Again, not necessarily usable with parts that have much side geometry.

    Third option is to write your own probing code. That was easy in Mach3, don't know how simple it may be in PP.
    Unfortunately I only make one-off, no part in series until now, sometimes I make 2 or 3 parts the same but usually only one of each drawing. And about the third option to write my own code, I want first to learn as much as I can the basic stuff of milling steel, this means also Fusion360, and only after that venture to writing code, hopefully I will find a better/simpler way to do it.

    Quote Originally Posted by Zetopan View Post
    You could also machine a 4mm pin that is a snug but removable fit to the hole and then probe the outside of the pin. I am using Mach 3 with a Renishaw probe on my PCNC 1100, so I cannot offer any assistance with the Tormach probing routines. It is easy in Mach 3 to make custom probing routines, but I have no idea of how to do that with PathPilot.

    I also almost forgot to mention that probe tips down to 1mm or less are also available, although that may not help your situation if the Tormach probe movements are simply too large to begin with.

    You could also try doing manual movements at slow speeds on one axis at a time and watch the indicator light to find the pin or hole location.
    Zetopan, intresting ideea I think I have some 4mm pins I will try to see if they can get in and out without moving the part in vise as the pin needs to be out of the hole before starting milling on Side B, Pathpilot has a routine to measure external diameter, I will see how well it works on small circles.

    On Tormach webshop I couldn't find a smaller tip for the probe, but I found on Renishaw website, I requested a quote now, but I'm afraid the tip will be quite expensive.

    Tormach digitizing probe to find center of a small circle, but bigger than probe tip-renishaw-m4-1mm-tip-jpg



  6. #6

    Default Re: Tormach digitizing probe to find center of a small circle, but bigger than probe

    Quote Originally Posted by kstrauss View Post
    You don't indicate whether the "7 steel parts" are production parts or one-offs. If one-offs why not do manual positioning with a DTI secured in the spindle? With a small stylus it is easy to find the centre of a 4mm hole; I do such daily. If these are production parts then a locating feature in soft jaws may assist.
    One-off unfortunately. What DTI is ? So you too suggest to buy also a smaller tip (I didn't know it's called stylus, I know now ) I believe there is no way to change the default retract distance .. if nobody suggested this, I was thinking there is an option somewhere to change this as it was the easier method.

    About reaming the holes, I don't have any reamer, I just purchased one now from a yard sale just because it was looking quite good, so shiny It's a Mikron tool, but usually in my case the holes made with a drill only are good enough

    Tormach digitizing probe to find center of a small circle, but bigger than probe tip-mikron-tool-reamer-jpg



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    Default Re: Tormach digitizing probe to find center of a small circle, but bigger than probe

    See DTI Holder - The Home Machinist! for some ideas regarding how to mount an indicator for sweeping a circular feature. Indicators are available everywhere for prices from $10 to many hundreds. Some indicators have a swivel built in. Closeups at https://picclick.com/INTERAPIDs-Inte...552095559.html

    See below for a photo of a homebrew holder that I use to secure the indicator in the spindle and another of using it to sweep a hole. The ball at the end of the finger is typically about 1mm diameter so you can centre over quite a small hole.

    Attached Thumbnails Attached Thumbnails Tormach digitizing probe to find center of a small circle, but bigger than probe tip-_dsc0519-jpg   Tormach digitizing probe to find center of a small circle, but bigger than probe tip-_dsc8782-jpg  


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    Default Re: Tormach digitizing probe to find center of a small circle, but bigger than probe

    You could write your own program to find the center of a hole with the probe and specify the back off value.



  9. #9

    Default Re: Tormach digitizing probe to find center of a small circle, but bigger than probe

    Quote Originally Posted by kstrauss View Post
    See DTI Holder - The Home Machinist! for some ideas regarding how to mount an indicator for sweeping a circular feature. Indicators are available everywhere for prices from $10 to many hundreds. Some indicators have a swivel built in. Closeups at https://picclick.com/INTERAPIDs-Inte...552095559.html

    See below for a photo of a homebrew holder that I use to secure the indicator in the spindle and another of using it to sweep a hole. The ball at the end of the finger is typically about 1mm diameter so you can centre over quite a small hole.
    ohh so DTI comes from Dial Test Indicator, I have 2, one for height measuring with a high 1" range and another one similar to yours that I only used foar measuring how parallel I mounted the vise, I haven't used since than. But I noticed a possible issue with mine, it doesn't have a fixed round thing on top , so I can grab using an ER20 collet, but a mobile one, that is sliding about 10mm, so to measure with this I think I will have to mount that part exactly on the center of the tip, right ? Anyway, I will search more about using an DTI to measure the center of the hole, seems interesting and I think it will be quite quick to do it.

    I moved the round part off center as much as I could to make my point, I will have to place that part exactly in the center, right ?

    Tormach digitizing probe to find center of a small circle, but bigger than probe tip-dial-test-indicator-jpg


    Quote Originally Posted by IMT View Post
    You could write your own program to find the center of a hole with the probe and specify the back off value.
    You mean to use GCODE, I don't know why I have though you guys told me to write my own program but meaning to write a plugin or something like DLL file to place inside the controller folder.. but only know I understood you only mean to write a simple program using GCODE commands .. good point .. I started googling and found something, I will have to learn all the GCODE's commands as I know very few, very rarely I needed to input commands by hand but I will definitely print a poster on my workshop wall with a GCODE cheat sheet, but I haven't quite found one to like the design, also I wanted to print another poster with a conversion from inch to millimeters as I'm in Romania, everything is measured in milliliters in here but I purchased a machine from USA, and also a lot of tools from there and they are all in inches I found quite difficult to find the right collet for a 9mm endmill, not visually speaking, but by founding the corresponding inch value that is 11/32 or 23/64.

    A distributor for Renishaw products answered to my email regarding the price of the small stylus, it's just $47 for the small one that has the tip lenght of 4.5mm and 1mm diameter, and around $60 for the one that has the tip lenght of 10mm, and the same 1mm in diameter. But the shipping is almost the cost of another stylus
    Regarding changing this stylus, I didn't seen any option in Path Pilot to change the diameter of the stylus, what can I do to use a smaller stylus with Path Pilot ?



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    Default Re: Tormach digitizing probe to find center of a small circle, but bigger than probe

    The finger is attached using a friction joint so it is easy to move it in one plane (along the axis of the dovetail that you show on top in your photo). Just roughly centre the top rod and then move the finger as required. With a 4mm hole you will probably want it almost vertical. The indicator in the photo that I posted has a heavy swivel at the top which makes it easy to use the indicator on features as large as several inches in diameter.



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    Default Re: Tormach digitizing probe to find center of a small circle, but bigger than probe

    Quote Originally Posted by ovisopa View Post
    You mean to use GCODE, I don't know why I have though you guys told me to write my own program but meaning to write a plugin or something like DLL file to place inside the controller folder.. but only know I understood you only mean to write a simple program using GCODE commands .. good point ..
    Yes I mean write your own GCODE. The machine runs on GCODE so you should learn how to it works, even if you don't think you will hand code anything. It is about the most simple programming language learn and use, just get out the manual and read through the list of G and M codes to understand how each one works. Start with the commonly used ones, then explore the others later.



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    Default Re: Tormach digitizing probe to find center of a small circle, but bigger than probe

    I know this is an old post, but I have been investigating digitizing with pathpilot. The GCODE language used by Lynix (that is the operating system Pathpilot uses) is not the same as G code for CNC programs. Many of the codes are the same but overall the language is more robust, allowing axces to the machine. Here is a brief section of a program to control the probe in GCODE. :

    7 (Configuration section)
    8 G20 (Inches)
    9 F20 (probe speed)
    10

    11 #1=-1 (X start)
    12 #2=.04 (X increment)
    13 #3=51 (X count)
    14

    15 #4=-1
    16 #5=.04
    17 #6=51 (Y count)
    18

    19 #7=1.1 (Z safety)
    20 #8=-.1 (Z probe)
    21 (End configuration section)
    22

    23 (LOGOPEN,probe-results.ngc)
    24 #9=0 #10=0
    25 G0Z#7
    26 O1 while [#9 lt #6]
    27 #10=0
    28 G0 Y[#4+#5*#9]
    29 O2 while [#10 lt #3]
    30 O3 if [[#9/2] - fix[#9/2] eq 0]
    31 #11=[#1+#2*#10]
    32 O3 else
    33 #11=[#1+#2*[#3-#10-1]]
    34 O3 endif
    35 (#11 is X target)
    36 #5070=1
    37 O4 while [#5070 NE 0]
    38 G38.5 z#7
    39 G38.3 x#11
    40 O4 endwhile
    41



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    Default Re: Tormach digitizing probe to find center of a small circle, but bigger than probe

    For anyone who come across this and needs an answer to the original question, all the probing routines have a retract variable. Just go edit whatever routine you need in /operator/subroutines. Look for #<ruff_ret> = [.050 * #<unit_conv>] or similar and modify it.

    Tormach PCNC 1100 Series 3 w/ Rapid Turn, Fusion 360


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    Default Re: Tormach digitizing probe to find center of a small circle, but bigger than probe

    Easiest metod is to use a spindle camera

    Tormach digitizing probe to find center of a small circle, but bigger than probe tip-img_1585-jpg



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    Default Re: Tormach digitizing probe to find center of a small circle, but bigger than probe

    Quote Originally Posted by dannirr View Post
    Easiest metod is to use a spindle camera

    Tormach digitizing probe to find center of a small circle, but bigger than probe tip-img_1585-jpg

    This is cool way to do it. I have used a digital camera microscope and attachment to mill to find dimensions of existing parts and it could be used to find offsets also. I would question how concentric or how accurate I could get it setup to the spindle center. Great for what I used it for. Pretty expensive tool compared to a standard wobble center finder that cost 20$ or less. I use a Hamier probe to find most offsets but I also have a rack of about 10 different tools like center , flat , laser edge finders and a couple z height indicators to use as backups. Also couple dial indicators as shown above.
    Tormach digitizing probe to find center of a small circle, but bigger than probe tip-center-finder-jpg



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    Default Re: Tormach digitizing probe to find center of a small circle, but bigger than probe

    Using an optical center/edge finder is the easiest way to do this. Best of all no more broken probe tips!





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Tormach digitizing probe to find center of a small circle, but bigger than probe tip

Tormach digitizing probe to find center of a small circle, but bigger than probe tip