Strange probing behavior - UGS


(mikep) #1

I’ve got some strange behavior when probing sometimes with UGS - maybe 10-15% of the time, when pulling off the probe after successfully probing the axis goes down instead of up. It being already in contact with the probe, this really stinks as it crams the endmill hard into the probe and just keeps doing so until you turn it off/hit stop. The odd part is that it only happens sometimes, not every time, and of course, at the worst possible time in the middle of a project.

Sigh.

Anyone else seen this?


(Luke) #2

Is it touching off twice? Or just once?


(mikep) #3

It touches twice (Z only) - first the “fast” seek, then the short, slow one, then instead of retract from there as set in the probe dialog (for me, 50mm) it crams into the probe.


(Neil Ferreri) #4

You’re sure the probe had completed and that what you’re seeing is the retraction move?


(mikep) #5

I’m pretty sure. The timing is about right, but I can’t be sure without actually starting up a debugger, which I’m loath to do on this machine.

Should be fast touch, slow touch, then retract. I see the fast touch, the slow touch does touch, the only thing after that that should happen is the retract but instead, suddenly Z down.


(Neil Ferreri) #6

Are you using a custom macro or a built-in probe tool?

You should be able to see what is sent in the console.

What version of UGS?


(mikep) #7

It’s the “stock” probe plugin. Will check the log next time it freaks out.


(Luke) #8

I had some issues with z probing on its own where it would give the wrong offset. Never a plunge issue as you describe… Usually I restaeted ugcs. Are you regularly updating the nightly platform build?


(mikep) #9

I’m on the July 21 nightly right now. The “stable” beta from right about the same time was a disaster. I’ve seen this behavior for at least a month though. It recently seems to have gotten worse, but I’ve also been using the machine a lot more in the past couple weeks than I usually do.


(Neil Ferreri) #10

I gave up on UGS a while ago because of issues related to the grbl 0.9 to 1.1 upgrade. I’ve seen so many issues that have been resolved by using a different gui that I don’t bother with UGS anymore. Try something else.


(Stephen Taylor) #11

I’ve had some issues too. Works great with the xyz probe but if I just do the Z probe probes as normal gets it’s spot and then doesn’t retract at all. Just have to move the z up a little and pull it out but it’s annoying.

Tried a quick cut with cncj and it worked well but not sure if they have an xyz probe, and I don’t know a macro for it.


(mikep) #12

After a particular version, you need to set the pull off amount, and it defaults to zero. I have mine set to -50mm, which is about 2 inches back up.


(Stephen Taylor) #13

Yea it pulls off when I do xyz together but just the z it doesn’t . I’ll check it again tonight


(Luke) #14

That’s interesting. If I just z probe I have issues too, I just gave up on it and use 3 axis probing now.


(mikep) #15

I got annoyed enough with this I reimplemented Z probing with some macros. Someone is going to find this post and respond that there is a plugin in UGS for this…I know. It doesn’t work “as well as one would hope” and doesn’t do everything I want…and I’m not feeling like fixing it in the “native” java and installing all the “stuff” that requires.

First, here’s some background on how this works

Set Probe Position (Make sure there is enough room here for any endmill you will use)
G92.1; G30.1 . -> Cancels temporary offset, then store current position.

Go To Probe, seek toward Z0 first, then through WCS XY zero, then to directly over probe and then down.
G90;G92.1;G53G0Z-5;G30 X0Y0; G30

Go to probe, and probe Thick
G90;G92.1;G53G0Z-5;G30 X0Y0; G30;g91;g21;g38.2z-100f300;g1z5f150;g38.2z-100f50;G92Z24.98;G0Z20;g90;G53G0Z-5

Go To Probe, and probe Thin
G90;G92.1;G53G0Z-5;G30 X0Y0; G30 ;g91;g21;g38.2z-100f300;g1z5f150;g38.2z-100f50;G92Z21.96;G0Z20;g90;G53G0Z-5

Probe Thick from current position -> Goes straight down from current position! (24.98mm thick Z probe)
g91;g21;g38.2z-100f300;g1z5f150;g38.2z-100f50;G92 Z24.98 ;G0Z20;g90;G53G0Z-5

Probe Thin from current position -> Goes straight down from current position! (21.95mm thick Z probe)
g91;g21;g38.2z-100f300;g1z5f150;g38.2z-100f50;G92 Z21.96 ;G0Z20;g90;G53G0Z-5

Example for custom probe thickness (a piece of 6.44mm aluminum on my desk)
g91;g21;g38.2z-100f300;g1z5f150;g38.2z-100f50;G92 Z6.44;G0Z20;g90;G53G0Z-5

In this macro set are the following:
Go XYZ Zero . -> Goes to the XYZ Zero for the current WCS (because UGS Return to Zero isn’t what I want)

Go XY zero + 24mm -> Goes to the XY Zero, and 24mm above it in Z, like CM does.

ReadyChange -> Brings carriage straight up, then almost all the way forward, like CM does. It DOES NOT change the spindle on/off state.

SetProbe -> Sets the position of the probe so you can go back to it easily.

GoProbe -> Goes back to the probe position you last stored.

Changetool-Thick -> Goes straight up from the current position to near top, goes through the current WCS zero (XY), and then over to the probe, straight down, and probes, assuming you’re using my carbide 3d probe, and the “thick part”.

Changetool-Thin -> Goes straight up from the current position to near top, goes through the current WCS zero (XY), and then over to the probe, straight down, and probes, assuming you’re using my carbide 3d probe, and the “thin part”.

Workflow would be something like:

  1. Install your tool
  2. Set your XY Zero
  3. Jog over to where you want to have your probe, and move down so there is still enough room for any longer tools you’re going to use.
  4. “SetProbe”
  5. “ChangeTool-Thick” (sets your Z zero using the probe)
  6. Run your program. NOTE: this assumes your program doesn’t mess with G92.x or G30.x

When your program is done and you want to change tools…

7)“ReadyChange” to bring the carriage someplace convenient
8)“ChangeTool-Thick” (go set the tool length)
And you can run your next program.

All the old constraints on how you do tool changes on SO3 are still there - it doesn’t support T commands, so you want to generate your gcode as a file per tool. This isn’t a perfect solution obviously, but it works and is easier than jogging all over to get back to your probe and the hassles involved with that. If you always have your probe in the same place (don’t know why you would, but you could) you don’t need to reset the probe position between power cycles, it is stored in eeprom. It will be wiped out on some firmware upgrades though.

You could certainly use this same methodology to do x and y probing on the sides of the probe, but I don’t need it, so didn’t do it.

Macros.zip (1.3 KB)

Zip file contains a text file (contents pasted above) and a XML file that should be importable to UGS. It will add all the macros to your UGS install even if they already exist, which isn’t the best, but it could probably be worse.


(system) #16

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