Firmware / WebControl suggestion

Hello everyone.

SItuation:
I have a one nozzle Ormerod. When printing with PLA or ABS, I change the fillament color during printing, for design reason.
It works very well: Pause the print, retract the current filament and extrude the new filament until it arrives, then resume.
DIsadvantage: I have to wait during print until a certain layer has been reached to pause manually, to avoid the missing the layer I'D like to exchange filament.

(I also tried to continue with different plastic PLA->ABS / ABS->PLA, but layers do not stick together after print)


Suggestion:
To make it easier, a function to pause the print automatically when a certain layer number has been reached would be great (maybe multiple numbers when to stop). To resume printing continue command must be performed by user action.
Beside firmware, this could also be a feature of the web interface.. When the defined layer number has been started, sending pause command automatically.

Maybe this also has potential for test printing...




What do you think?


Regards
Stephan

Edited 1 time(s). Last edit at 10/30/2015 08:01AM by gazoox.

Your alternative is to edit the gcode file using e.g. Notepad++, look for the G1 Z command that moves to the layer where you want to change the filament, and insert a M226 command there.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I was considering to add layer actions to the web interface, but OTOH everything necessary can be done in the G-code files already. In fact this is even the better solution, because you can only roughly predict at which move the print will pause once you've sent M26. As dc42 already said, you can insert M226 in your G-code file to pause the print after a certain move and I've done this multiple times to make parts with embedded threads (by inserting nuts coated with a thin layer of glue stick so the filament of the next layer will stick properly, at least when printing ABS). I've been quite happy with the results I got, but I'd advise you to put that M226 code somewhere in an infill region so you don't get blobs on the perimeters when the print is resumed.

The M226 cmd in the code is a good solution. Thx for the hint. Even though, over web interface as a "on the fly" feature would be more dynamic...

I modified the resume command, not to extrude a lot of filament when continue. The blobs are very minimized. I start with inner perimeter. The minimal blob is only visible in the inside and only little bit visible with transparent filament.