Mat
RRCRat Rig Community [Unofficial]
•Created by Mat on 4/17/2025 in #fix-my-printer
Beacon probe Z-offset is consistently too far from build plate
I am going to order a SuperPINDA and compare results when that comes in to see if I have something else going on or if is Beacon related
26 replies
RRCRat Rig Community [Unofficial]
•Created by Mat on 4/17/2025 in #fix-my-printer
Beacon probe Z-offset is consistently too far from build plate
Further testing notes from today:
My problem now is variance in first layer hieght now that I've been setting model_offset. Recreating a beacon model from scratch using the Beacon3d docs yielded very similar results to RatOS's calibration. The variance I am experiencing now is enough to take a dialed in first layer to over-squish ribboning or visible gaps in lines in subsequent prints.
I set variable_beacon_contact_expansion_compensation to False to see if this was causing any additional variances. This did not seem to have any noticeable impact on layer consistency.
I did notice on my lasty few test prints today that the Z-offset in the toolhead window is being set to strange values during the start print process. Sometimes its 0.0, sometimes its 0.3, other times its somewhere in-between. But none of these values are the model_offset value. I have no idea where or how this number is being calculated, maybe in the auto-contact calibration does in the pre-print process. But I believe this to be the leading cause of my variance issues now. The large variance in this number, typically +/- 0.15mm, is about the amount I need to correct back to a good layer height.
26 replies
RRCRat Rig Community [Unofficial]
•Created by Mat on 4/17/2025 in #fix-my-printer
Beacon probe Z-offset is consistently too far from build plate
I will read through this thread. Right now all of my first layer test prints have been ~5 minutes. Once I start getting consistent results at the start of a print ill bump it up to plate size first layers to see where im at.
26 replies
RRCRat Rig Community [Unofficial]
•Created by Mat on 4/17/2025 in #fix-my-printer
Beacon probe Z-offset is consistently too far from build plate
This has me thinking now, if a basic error like this exist for simple adjustments, could there be the same mistake in regards to the nozzle thermal expansion compensation or one of the other calibrations the RatOS macros handles for us? I think my next step is to do a few more first layer pritns to really quantify any variance in repeatability of the first layer offset accuracy and then create a beacon model using the procedure outlined on the Beacon3d offical docs to see if I get different results
26 replies
RRCRat Rig Community [Unofficial]
•Created by Mat on 4/17/2025 in #fix-my-printer
Beacon probe Z-offset is consistently too far from build plate
I've made some interesting finds after some ad hoc testing tonight. It appears that the variable controlling z-offset for the beacon model is "model_offset =" under [beacon model] and using SAVE_Z_OFFSET as stated by the RatOS docs is incorrect and doesnt update the beacon model offset. The correct command to use is Z_OFFSET_APPLY_PROBE as stated in the docs from Beacon3d. Coincidentally, this is what the "SAVE" button does in the toolhead babystepping window, the button the RatOS docs specifically tell you not to use for Beacon. My guess is that those docs were written in a time when the Beacon integration wasn't fully complete and then not updated later? Don't know, maybe someone else can confirm my findings.
Next discovery was with the values that were saved using "Z_OFFSET_APPLY_PROBE". I had to adjust the nozzle to be about 0.100mm closer to the print bed to get a good first layer. This resulted in a model_offset of 0.100 being saved. Started the next print and the nozzle was even further away than before. Stopped the print and on a whim manually set the model_offset to -0.1mm. This brought the nozzle to nearly the same spot I had it on the print prior. Made a few babysteps to get back to perfect which was another 0.03mm closer to the print bed. Used Z_OFFSET_APPLY_PROBE to save the value and restarted the printer. Except now the model_offset was set to 0.0300mm. It looks like I may have found a bug. Of course this resulted in a first layer too far from the print bed. So I stopped that print, went in and manually set model_offset to -0.130mm and started a new print. The first layer was perfect.
So:
-It appears the correct command to save beacon offset values is Z_OFFSET_APPLY_PROBE BUT any values saved using this method will be in the incorrect sign
-Using babysteps to dial in the nozzle a second time after setting model_offset will result in that value being overwritten with the sum of your current print's microsteps adjustments
26 replies