Can I specify when to use extruder resets (G92 E0)?

[jaded 1]

I am creating a multi-color print with a single extruder machine.  To accomplish this design, I have four  "TYPE:SKIN" sections that I need to print in a second color.  Because I have only one extruder, I am making the color changes by manually inserting M600 codes in the G code. To reduce the number of manual changes from 8 to 2, I am manually moving blocks of G code to place all four TYPE:SKIN sections together.

Because the extruder values are not reset, I have to insert custom G92 E####.#### codes at the start of each moved section.  If there is an option to insert G92 E0 commands to reset the extruder axis at the start of each TYPE: section, then each section becomes portable and I won't have any extra work when moving them.

Is there an option to have Cura insert these extruder reset commands at the start of each section?

Edited December 5, 2017 by Guest

[gr5 2,172]

I don't think so but that's a cool idea.

[burtoogle 513]

You can't do that but the recent versions of Cura (3 onwards?) support relative extrusion for those printers that can use it. It's in the special modes section. The Ultimaker people can confirm this but, unfortunately, I do not think that their printers can cope with relative extrusion so if that's what you have it probably won't help.

[gr5 2,172]

What makes you think UM printers can't do relative extrusion? I have no idea if it can or not but it seems a pretty trivial feature and it's in the gcode definitions so I would expect it to work? Oh - but I think it's all or nothing. ALL movements have to be relative (x,y,z and e) when you switch to relative mode. Does cura support that?

[burtoogle 513]

What makes you think UM printers can't do relative extrusion?

The Ultimaker people reported problems with various printers when the relative extrusion mode was added, they will be able to give you more info.

 

ALL movements have to be relative (x,y,z and e) when you switch to relative mode.

I don't think so, I am happily using absolute zyz coordinates with relative e values.

[jaded 1]

You can't do that but the recent versions of Cura (3 onwards?) support relative extrusion for those printers that can use it. It's in the special modes section. The Ultimaker people can confirm this but, unfortunately, I do not think that their printers can cope with relative extrusion so if that's what you have it probably won't help.

 

Well that's perfect! I've been using 2.6.3, so I installed 3.1 and ticked the box for relative extrusion. Just what I needed, thank you!

[gr5 2,172]

I see it now.

G90 sets all axes to absolute mode

G91 sets all axes to relative mode

M82 sets extruder (only) to absolute mode

M83 sets extruder only to relative mode

More here:

http://reprap.org/wiki/G-code#G91:_Set_to_Relative_Positioning

Well this is great. So that combined with cura lets you do all relative motions in gcode and lets you cut and paste gcode around with less issues.