Delta printer calibration procedure

Phaedrux

@ArekRucki said in Delta printer calibration procedure:

I still not sure which one.

I suggested a detachable probe, something like this.

https://www.amazon.ca/Printer-Precision-Z-Probe-Leveling-nozzles/dp/B07V6GR72Q

dc42

@ArekRucki said in Delta printer calibration procedure:

But yes, I need to change the plates every print so they can differ in few milimeters

If the plates are flat but the thickness varies then I suggest the following:

Calibrate the printer just once (without a probe) to establish the delta radius and endstop corrections. Save the result.
Before each print, after homing command the nozzle to a few mm above bed centre and execute G30. This will account for the bed thickness having changed.
Ensure that your slicer start GCode does not home the printer at the start.

ArekRucki

@dc42 OK. Thank you.
But now I've examined one of my build plates by touching it with the nozzle in different points and get values from 14,30 to 15,15. I guess the whole bed is a bit tilted. It gives 0,85 mm difference. I don't know it it is big... So when I go with G32 for the very first time with 6-factor calibration and save the results will it eliminate these differences? Or somwhere in higher parts the nozzle will hit the bed?

dc42

@ArekRucki if the bed is tilted wrt the towers then running 6 factor calibration once and saving the result will correct for it. OTOH if the problem is that the bed plates vary in thickness from one side to the other, you will need to recalibrate every time you change the bed plate.

nikscha

@dc42 @ArekRucki or if reuse the same bed plate but rotate it*

nikscha

@ArekRucki said in Delta printer calibration procedure:

@nikscha Thanks for your time. I was not very clear. I'd have normal print bed e.g. plywood or plaster board. I think both of it have fairly even sufrace. The material I'd print with is clay.
But yes, I need to change the plates every print so they can differ in few milimeters each other.
So I will buy a z probe as @Phaedrux suggests. I still not sure which one. As I wrote few post above it could easily get dirty with clay. For now I'd bet on BL Touch.

I see, that makes more sense now thanks for clarifying!
Yeah, BLtouch seems like a good option then! Is it also possible to print on a metal surface with clay? If so, then an inductive probe could be used which prevents inaccuracies from the clay residue on the printbed.

dc42

@nikscha for delta printers, nozzle contact probes are highly recommended. This is because an XY offset of the probe from the nozzle means that if the effector tilt varies even slightly with effector XY position, the effective trigger height of the probe will vary and mess up calibration.

ArekRucki

@dc42
I've just bought BL Touch.
There is in Duet3d manual: Adding trigger height corrections to the bed.g file
What is this actually for? I'd guess one need to do those corrections when there are
any points on bed surface that falls out of probe effective trigger height?
For BL Touch it is from 2,3 to 4,3 mm. So when all the bed is in this range I don't need to do it?

nikscha

@dc42 right, good point!

@ArekRucki (assuming you don't use the nozzle for probing,) the nozzle and the probe aren't the same thing. What you want to know is the distance between the nozzle and the bed, but what you get from probing is the distance between the probe and the bed (obviously ^^). Now most of the time the two are the same (well not the same maybe but they're consistent). But there are some circumstances where (depending on the XY location) the difference differs. One prominent example is effector tilt, mentioned by dc42 earlier. This means that the "plane" on which the arms attach and the hotend and probe is located can have a slight tilt depending on XY location.

If your delta is well build, then you shouldn't have to worry about it.

ArekRucki

@dc42 @nikscha
Many thanks for your help.
Heading for next step of calibration...