Create restricted area on built plate

MacNite

Hey guys,

at the moment I am building a new machine. Due to the design of the z-axis and the Tool head there are 2 corners (marked red in picture) which the print head is not able to reach because it would cause a crash with the z-axis top mount.

Is there any way in RRF3 to restrict movements into this area so the printhead won't move there?

Thanks for your help.
Max

dc42

@macnite, RRF does not provide that facility.

PCR

@macnite

best way would be the slicer i think

@macnite

If it is because of the position of the endstops, because they are mechanically further out then what you would want to print later, then maybe consider to overwrite the homing-"0" in your homing files with for x for example something like:

...
"actual/traditional/real" homing
...
G1 H2 X2.5 F100     ; "free" the endstop (by moving a little bit away)
G90       		    ; set to absolute positioning
G92 X{(move.axes[0].min)}             ; set axis position as "val" (you may want to adjust this) -> in absolut coordinate system (G90)
...
restoffileeventually
...

of course you would restrict your total print area (by the help of also m208 in config.g) to something like this:

You can of course also put it directly into M208 it seems, what might be a bit more elegant:
https://forum.duet3d.com/topic/14414/y-offset-correction/9

But I guess you know that already so this answer might be not really of any help for you.
Anyway - regards

sinned6915

@dc42 can this be added to the feature wishlist?

This feature, definition or modifications of areas, could define and protect things. Like the OP needs "no motion here".
It could be used to isolate motion for things like purge buckets, nozzle wipers, probe docks. These areas once defined could be combined with gcode meta commands to enforce them.

for example- if swithching filaments, allow acess to purge bucket, else do not move into area.

i would not trust any slicer to enforce motion conditions.

fcwilt

@macnite Can you move the build surface back a bit?

OwenD

I would think this is more properly in the domain of the slicer.
It's not an uncommon scenario in cnc routers when clamps are used, but if it's in RRF what happens if you slice something that's in the boundary?
From memory the objects aren't defined until after the first layer, so it would be difficult for RRF to cancel an object completely until it knows it's extent.
This would likely require a simulation before every print.

It's easily done in Prusa Slicer.
Just create an STL of your bed shape by drawing it and paddiing it in a 3d cad system.
Then choose custom bed shape and select your STL
bed 1.png

Here's the result
bed 2.png

Prusa slicer won't show an error unless you're outside of the outer boundary of the bed, but the visual of the modified shape should be enough to stop you putting it in the wrong spot.

MacNite

Thank you for your replies!

@dc42 Thank you for the info.

@Lbi No, it is not because of the endstop position, it is the other way round. I want to "limit" the movements additionally ot the endstop position without decreasing the built volume significantly.

@sinned6915 very nice idea! I think this would be a very helpful feature.

@fcwilt I could move the build surface back, but that would "decrease" my total built volume. ATM I am trying to maximise it.

@OwenD Very nice Idea! I think that will be the way I'll try it!

Greets
Max

sinned6915

@OwenD I am pretty sure there is a bug in PrusaSlicer that only defines the bed from the center, not lower left corner- so EVERYTHING had to be formatted that way.

Slicer level control does not work for general machine control. I can imagine the condition where a move command could path a tool throught a no-no region if its u-shaped as you have drawn. At the firmware level I would think that the same move command would alter the toolpath around it.

OwenD

@sinned6915
Regarding movement through a restricted area, perhaps that could be true.
It would depend on the slicer.
Given Prusa slicer didn't throw an error when placing a part in that area lends credence to your suggestion.
@MacNite should test that by creating a "restricted area" in Prusa Slicer that is in fact safe on the machine.

zapta

This kind of shapes called concave. There down side is that some straight lines between two inside points go through outside points. What would you like the duet to do if it gets such a move, refuse to move? Go around?