Slic3r?

[@CiDG]

I'm having a problem lately with gcode produced by slic3r in any version. I am printing with Mach.
My problem is that at the start of EVERY layer and also the skirt, my extruder is commanded to advance 3.5 beyond it's current location (even at 0 at the beginning of a print.) and then at the end of the layer it will retract 3.5 from the current location (backing all the filament out of the extruder. Between the puddles and gaps the printer is doing everything properly.

What gives? I can't find a setting responsible for this problem. The funny thing is that I was printing just fine and then I came back to start another print and this happened.

Thanks and have a great holiday weekend!

Gabe

[Polygonhell]

The setting that controls that is under retraction.
Mines set to
Length=1.5
Lift Z=0
Speed =15
Extra length =0
Min travel =2

If you don't want any retraction at all, set length to 0, but you'll get long strings on head moves.

[johnoly99]

Double check your extra length on restart setting. That would cause it to do what you described.

[@CiDG]

John,

I think I got it, thanks to your post, but I will not know until I can print it tomorrow. The gcode looks better. I had loaded your ABS_oly_Slic3r config file and noticed that the retraction was set to 3.5mm. I had looked at it just before updating slic3r the other day. I never changed this file or printed from it, but when I loaded the new slic3r 0.7.2b it seemed to hold some of the settings from that config file permanently. My config is set for 1, but slic3r seemed to ignore it and used the 3.5 figure instead. I sliced an stl from my own config on a different computer and it looks right. I also scrapped the slic3r folder on my print computer and replaced it and tried slicing from my own config and it worked again great.

This problem occurred after opening a slicer config and then updating slicer without a reboot. might be an isolated case, but I would suggest updating from a fresh reboot and not loading a config until after the updated program is run once. Or run it from a USB stick like I'm going to start doing.

Gabe

[@CiDG]

So that wasn't it... I'm stumped. It's as if the units are off or ??? Instead of moving one mm retraction it moves the extruder much farther. The coordinates in mach are mm from 0 correct? My mach units are mm, my model is drawn in mm, exported to STL in mm, and sliced. Result is x, y and z all moving as they should, but the A is haywire. My .28mm tip is extruding a 3mm bead of plastic. Impressive, but wrong.

Any help would be deeply appreciated. I'm getting nowhere with this. Email me directly at [email protected] if you like and we can chat or even talk on the phone.

Thanks!

Gabe

[Polygonhell]

Most people configure mach in inches, that's the global units setting in the options, and it is used for the steps per settings in the motor tuning etc.
The GCode then sends a G21 which tells Mach to interpret distances as mm, so subsequent moves are in mm.