How to make different bed probing patterns

Frederik561

Hey
I am currently working on my project for my bachelors degree and I am due to quarantine unable to test whether my G-code works.

Background:
I am making a cartesian printer for bioprinting similar to this: https://all3dp.com/2/what-is-3d-bioprinting-simply-explained/

I have mounted a FSR on top of the syringe, so that when the needle touches the bed, it will get squeezed and register and can therefor be used for bed probing. The Z-endstop is at the top, so it will only be used for bed probing. The trigger height will be measured once I am allowed access to my university.

The bed is designed to attach either a petridish or different sizes multiwells: https://www.sigmaaldrich.com/catalog/product/sigma/m8562?lang=en&region=DK&gclid=CjwKCAiA17P9BRB2EiwAMvwNyHDWWf2rC0ZpnNOAkNs0A3OEAbc-PecdWQ6XL4AD6bRXAWmXKzU44hoCC8oQAvD_BwE.

Depending on whether a petridish or multiwell (and what size) is mounted, I want to be able to choose different bed probings.

Multiwell bed probing
For the multiwell I have the current setup in the G-code:
---In the config.g file---
M558 P8 C"!^zprobe.in" I1 H30 F50 T200 -; Defining type and speeds + dive height
G31 P500 X0 Y0 Z-3--------------------------------; Guessing trigger height (for now)
M557 X50:80 Y50:80 S15------------------------ ; Arbitrary grid for some multiwell

---In bed.g fil--- (run by G32)
G28-------------------------------------------------; Homing
G30 X62.6 Y41----------------------------------; Single probe in an arbitrary hole for Z=trigger height datum
G29-------------------------------------------------; Probing and mesh bed compensation

Questions for multiwell
1.1: Does this method work in general?
1.2: I have set the dive height to 30 mm. Does it mean that it will raise 30 mm between every probe? I have to make sure it clears the edge of the multiwell between each probe point because it will make a probe in each hole.

Questions for petri dish
I want to make probing at the radius. I just cant figure out how to do this properly and in which files to put the different commands. I was thinking about just making a macro file including all the commands, but I am not sure which ones to use.

2.1: Can I somehow use the M557 R-command to probe in a radius around the middle of the petri dish (middle is placed at X62.6 Y41) and use G29 to execute it?
2.2: If not, can I use M557 P to define a series of points to probe at? And can G29 be used afterwards to execute the probing and enable bed compensation?

Thanks in advance!

Phaedrux

@Frederik561 said in How to make different bed probing patterns:

I have set the dive height to 30 mm. Does it mean that it will raise 30 mm between every probe?

Yes.

@Frederik561 said in How to make different bed probing patterns:

Can I somehow use the M557 R-command to probe in a radius around the middle of the petri dish (middle is placed at X62.6 Y41) and use G29 to execute it?

Yes. That's how it works. https://duet3d.dozuki.com/Wiki/Gcode#Section_M557_Set_Z_probe_point_or_define_probing_grid

Does that get you what you need?

Frederik561

@Phaedrux Thank you for answering! About the probe in a radius, how do I define the point around which the radius is taken (the center)?

Phaedrux

Typically the radius method would be used in a delta printer where the bed shape is round and the 0,0 origin point is the center of the bed. So it may make sense in your case to use a center origin as well.

https://duet3d.dozuki.com/Wiki/Centering_the_bed_or_setting_the_bed_origin