Faulty KP3 Probe ?? <Solved, Tighten stylus>

[RJS100]

I recently send my probe in for service. I received the serviced probe and suspected a problem because if I repeatedly probe the same surface... I get different results. I have not had time to do a thoroughly test it, but something caught my attention.

When I just plug the probe in, the led sometimes just stays on when nothing is triggering the probe. See images. Any thoughts. This never happened with my original probe prior to service.

Richard

[tblough]

Are you sure the plug is pushed ALL the way in?

[RJS100]

Yes... Checked it twice.

[centroid467]

If you trip the probe by hand when it is lit up like that, what happens?

Check the PLC Inspector (ALT + I) to see if the Acorn sees the probe as tripped.

Do you store it tip up, tip down, or on its side?

Trying to get an idea of what could be causing this. I can think of a few things but I'd like to narrow it down before I start saying anything.

[Centroid188]

Hello.
The LED on is a sign of a stuck probe? Is the ALT-i showing the probe tripped also? We may need to have it returned for repair.
It was fully tested and fine before shipping to you.

[RJS100]

For what it is worth, the led staying on is an intermittent problem and may not have been apparent before it was returned to me. It happened once and caught my attention. Later in the day, it happened again which is when I took the pictures and posted them. When it was stuck on, I touched the stylus and the led went out.

I have not been able to recreate this problem again. I used the probe quite a bit today. Yes, ALT-I shows the probe tripped when I touch the stylus. Yes, I always store the probe in the holder shown. I am still new at this hobby and certainly not suggesting the probe is faulty, just reporting my findings, and that I never saw this before.

The reason I sent the probe in for service in the first place was because when I repeatedly probed the same surface it looked like I was getting too much variation. Here are the results I posted back in February:

I recently probed the top surface of my vise repeatedly. I set the WCS to zero for the z axis on the first probe cycle. See image. The figures I got were:
-.0003
.0008
.0000
.0004
-.0002

Total variance = .0011


After posting these results and testing the Z-axis for repeatability using some simple G-code provided by Uwe, it was suggested that I send in the probe in for service.

OK, the probe was serviced and the work order noted replaced ball board and pins and that the probe was leaking. Today I repeated the same test with the serviced probe.


Milling Machine Test:
Tests for Z-axis repeatability:
https://www.dropbox.com/scl/fi/63u22p6q ... g2m1k&dl=0
Higher Resolution Z-axis test:
https://www.dropbox.com/scl/fi/2i9nl46r ... nsj42&dl=0

I then probe the z height of my vise, set the Z axis coordinate to zero, and probed 6 times. Here are the results:
0
.0006
-.0001
-.0002
0
-.0002
-.0005

The total variance is .0011. This is the exact same figure I got prior to servicing the probe. Again, I have limited experience here and my goal is simply to establish if my mill and probe are functioning within reason.

With respect to accuracy, please let me know if these numbers make sense based upon what I have demonstrated.
With respect to the LED staying illuminated, please let me know your thoughts.

Best... Richard

[Muzzer]

To me it seems likely that much or most of this variation is due to the machine rather than the probe but you were considering that the probe was the cause, hence you sending it for service.

I'm not sure what this machine is capable of but the figures quoted don't seem silly. What kind of machine is this? I'm not convinced about the effectiveness of backlash compensation myself but you may have better joy if you explore that, rather than focus on the probe.

As well as Uwe's g code, I believe Swissi's probe app measures backlash if you want a second opinion.

[RJS100]

I am not focusing on the probe or machine specifically, just trying to quantitatively understand what I can expect from the system as a whole. Without this understanding, I would never know if there were issues, or what tolerances I can reasonably expect.

I only questioned the probe based on the suggestions made on an earlier post: viewtopic.php?f=60&t=11217

With respect to backlash compensation, I would think if backlash compensation was "off", then the error would be off in the same direction all the time. To simplify this already long post, I did not mention the fact that I get almost identical variances when I tested the x and y axis.

If this amount of variation makes sense for a converted benchtop machine (Precision Matthews PM833), I'm good with that. Just looking for some feedback from folks with experience.

[suntravel]

pls. post a current report.

Uwe

[RJS100]

Sorry, I forgot to post this report.

Just an FYI. This machine has a history of comm errors. Recently, I loaded the most recent manufacturer's ethernet driver. After installing it, the stress test failed. I systematically went through the tech bulletin and changed the ethernet communication setting from half duplex to full duplex. The stress test now passes repeatedly. Since the new drivers and full duplex communication settings have been in place, there has only been one communication error, but this coincided with a power surge (I live in Arizona and this time of year we get strong winds).

I have delayed installing a newer version of CNC12 to keep an eye out for comm errors before making changes. I will upgrade if you want, but I would prefer waiting a bit longer.