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chrisr

Cura 15.01 release. Oddity with other slicers?

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I've recently been using Simpify3D for slicing with this default Gcode for startup

G28 ; home all axes

G1 X20 Y20 F3000 ; bring extruder to the front

G92 E0 ; zero the extruded length

G1 Z0.3 ; lower

G1 X35 E30 F225 ; purge nozzle with 30mm of filament

G1 X45 Y20 F2100

G92 E0 ; zero the extruded length again

When first turning my UM2 on and starting a print, this code will try and home the bed (it already is)

That's all fine. The bed will then raise (once everythings up to temperature) and the print will begin.

But subsequent prints (with my UM2 remaining switched on) cause the bed to re-home twice before

printing. i.e the bed will raise up, lower and then raise back up again before the print begins.

It's not particulary problematic, just unnecessary and I'm wondering what's the cause of it?

The ending Gcode is this:

G28 X0 ; home the X-axis

M104 S0 ; turn off heaters

M140 S0 ; turn off bed

M84 ; disable motors

 

Any pointers? :-)

 

Daid?

 

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...

It's not particulary problematic, just unnecessary and I'm wondering what's the cause of it?

...

 

 

The root for this "might" also be in the firmware.

...

 

Yep. It is...

After selecting the file from sd-card the buildplate is raised up to the priming height (20mm) before it even starts reading the gcode.

This behavior is not related to the GCode-flavor - although priming takes place only for UltiGCode.

The fact that this will not happen directly after turning on - is more or less "by accident"...

The firmware has just no clue about the current position of the z-axis before the first "homing"... and runs into the "soft-endstop control".

Conclusion: i think this has to be fixed in the firmware.

 

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After selecting the file from sd-card the buildplate is raised up to the priming height (20mm) before it even starts reading the gcode.

This behavior is not related to the GCode-flavor - although priming takes place only for UltiGCode.

 

Ah! That's the reason then... I wonder if modifying the start Gcode to "G28 (just_the_head_please_and_not_the_bed)"

would fix it... I'm tempted to try but I'm wondering what then controls raising the bed to the nozzle to start the print? Is that the firmware again?

 

Conclusion: i think this has to be fixed in the firmware.

 

That would be ideal, I guess the Gcode which controlled that raising/priming sequence could always be added to the generated prints Gcode by Cura instead of having it in the UM2's firmware.... or am I missing something very fundamental? :smile: (which is very possible!)

(Edited for a bit more clarity)

 

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That would be ideal, I guess the Gcode which controlled that raising/priming sequence could always be added to the generated prints Gcode by Cura instead of having it in the UM2's firmware.... or am I missing something very fundamental? :smile: (which is very possible!)

...

 

Nothing fundamental.... only a penny:

The "firmware priming" (and heatup - using UltiGcode) uses the target temperatures of the current material preset. IMHO this is the major (respectively the only...) benefit of UltiGcode - one can print the same gcode file with different materials. This is very convenient (in my opinion) - i frequently switch between PLA and XT for example.

With those start code generated into the gcode - you would have to reslice for every material (or at least: edit the temperature settings in the file)...

 

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