New Tridex build questions

[Marine6680]

I am in the process of building a Tridex.

While I am familiar enough with klipper that I can follow guides and even figure out some things on my own, and also Linux console command work, enough that I can follow guides without issues...

I am in no means proficient. I am great with mechanical things and electronics and electrical work. I am an Avionics Tech by profession... But code work is not a strong suit at all.

Currently I have the printer built and mostly running properly. Had a few hiccups with the Y axis homing after redoing the config. (The build is a kit provided by an enthusiast and the config files were included on a drive. I decided to switch to community sourced configs located at this git page https://github.com/joseph-greiner Some of the original included configs seemed off, even though things seemed to be working okay, hence the switch, but while transferring the pin info I got the Y switches mixed)

My three biggest questions currently.

Is there a way to have klipper automatically determine the Z offset between the two toolheads, by using two nozzle probes?

I have two PZ Probes from E3D, not the integrated Revo hotend version, but the standalone version.

If it can be setup in klipper, I would like to use them to make the Z offset automatic. Or at least partially automatic. Even a macro that would take a probe reading from T0 and then T1 and provide the offset amount for me to manually enter into config would be great. I am not very concerned with copy or mirror mode, so the doubletap setup isn't as appealing, but I could switch to it if the PZ probes don't work out.

Next, does anyone have any experience with the PZ Probe and how/well it works?

Edit: The bit about the PZ Probe may be solved now. At least the sensitivity. The accuracy, I needed to do some testing.

Currently I am having a frustrating time with the system being both too sensitive and not sensitive enough at the same time.

I often get false positive triggers during movement as the bed is coming up but not near the nozzle, and I also occasionally get delayed activation where the nozzle hits the bed but doesn't activate until the pressure builds to the point of flexing the mount.

I tried faster movement but lower motor torque, but that actually increased false triggers. Seems like the reduction in motor torque means they need to struggle more, which causes vibrations that then cause false triggering. (My hypothesis anyway) Decreasing sensitivity of the Probe always results in poor performance with delayed activation, but false triggers are reduced or eliminated. I am using default 7 most sensitive setting with vibration filtering. It is the only one that is somewhat consistently working.

Now I began the testing before putting on all the panels and securing the toolhead harnesses with support and chafe wrap with frustrating results. After putting on the rear panel and securing the harnesses false triggers seem reduced but still present. Still frustrating but at least progress.

Accuracy is also an issue, with my Probe consistency sometimes reaching 0.02 deviations.

I am going to attempt a lower motor torque and higher Probe speed again, to see if the panels have helped there.

Being the standalone probes, I am not sure my mounting is correct. I used a metal washer to sandwich the peizo element between the mount and heatsink, then tightened that down snug. It could be that less initial load pressure is required for the Probe to work well. E3D does not provide guidance, and I have found no pictures that show how the prebuilt probe heatsink is assembled in enough detail to gleam any insight.

Any guidance on the PZ Probe would be helpful.

Edit: I found this setting and have it corrected now.
Lastly... Safe Z home position for homing is not centered on the bed. Using the config files outlined above. I have searched through the files for a section that defines this position, but I have not found it. I perhaps overlooked it.

I uncommented all of the 250mm bed sections properly I believe, but a mistake there might possibly be an underlying cause?

Sorry for the wall of text and several questions.

Thanks in advance for any help.

 

[Marine6680]

Well, I believe I am giving up on the PZ Probe.

While I do not have all of the panels in place, I did add some foam fill into the channels of several of the extrusions to reduce some vibrations.

After much experimentation, I settled on a probe movement speed of 5mm/s and a stepper power setting of 0.2A as any lower would tank repeatability accuracy. Higher would work well enough, but risked crashing the bed. Higher Probe speed and higher stepper power would both effect repeatability in a undesirable way, combining them would of course compound the issue.

I was able to get the Probe repeatability down to 0.005 variance over ten readings.

To do that I had the sensitivity set to 1 (most sensitive) with no vibration filtering. I also had to disable the reactivation gcode so that it did not re-enable full stepper power and immediately reduce power and do a short pause between every probe attempt.

With the standard behavior, doing the deactivation and reactivation for every probe attempt, it was not as good but close. 0.006 to 0.01 variance. Good enough considering that is 6-10% of a 0.1mm layer height, and I rarely print with layers that thin.

The problem with the first solution was that it would give a false trigger when the toolhead had to move between probe points. If there was a way to add a measurement wait/pause after a movement for things to settle it would not be an issue.

I could live with the slower and slightly less accurate default behavior, if it wasn't for the fact that when attempting to probe with the hotend fan running is either impossible due to false triggers, or with the vibration filtering enabled, the accuracy drops significantly. If I am lucky the accuracy is about 0.02 variance, but it frequently fails to trigger with bed contact and I get some flex. It eventually triggers but with increased deviation, resulting in out of variance range fails.

Enabling vibration filtering always had a negative effect on the probe accuracy, even when no fans are running.

So after much testing and frustration, I am just going to install Tap.

But if anyone has any insight before I get that started, I am willing to give it a shot.

 

[Marine6680]

Swapped to TAP and that is working well.

I am not sure if the magnets are actually doing anything though. I do not feel resistance when lifting the toolhead.

Had some inconsistent extrusion. It would be fine and then under extrude for a bit and then be fine again. It was consistent as well, with areas of solid infill like the bottom and top layers showing a regular pattern to the under extrusion. This is new behavior, as it was working fine prior to swapping to TAP.

Adjusting the gear meshing on the extruder stepper seems to have fixed it mostly. There was still some brief times of under extrusion, but they seem to be improving over the very short test print I did.