Basic Printer Operations
This page will list a set of basic maintenance and troubleshooting processes for operating the M2.
Changing filament
To change filament on the M2, first heat your hotend up to your standard temperature for the current spool of filament, then Retract several hundred mm. Then install the new spool of filament - place it on the spool holder, feed the filament up through the filament guide in the rear, then through the filament guide tube; cut a new tip on the filament, preferably at an angle of 30-60°, and then feed it into the top of the filament drive. If the new filament requires a higher temperature than the old (switching from PLA to ABS, for instance), raise the hotend temperature to the new required temperature; if the temperature is to stay the same (ABS to ABS, or PLA to PLA), or be lowered (ABS to PLA), keep the temperature at the current temperature until after clearing the hotend of the old filament. Once at the proper temperature, Extrude 300-600mm of the new filament, by commanding the Extrude move then inserting the filament further into the filament drive, until the extruder drive gear grips the filament. If the filament misses the bottom filament path, go to "Recovering from a Filament Misfeed" below; otherwise, observe the filament as it extrudes, looking for any remnants of the old filament color. If at the end of the manual extrude the old filament is completely gone, continue with your regular operations - either cool the hotend back down to leave the printer idle, or start a print. If the old filament color was present at the end of the manual extrude, Extrude more filament until the old filament color is completely cleared.
Recovering from a Filament Misfeed
Filament misfeeding occurs when the filament misses the bottom filament path in the filament drive, generally due to the curvature of the filament fighting the curvature of the extruder drive gear. To recover from a filament misfeed, first retract the filament out of the hotend, and cut away the ground-up section of filament; cut a new tip on the filament, again at 30-60°, and then straighten the curve of the filament out. Insert the filament into the filament drive so that the cut angle of the tip creates and arrow pointing Down and Left, Extrude 50mm of filament, and feel the filament as it feeds into the filament drive; if it goes past the drive gear and through the bottom filament path, Extrude more filament until it starts extruding smoothly; if the filament misfeeds again, attempt this process again, or attempt the Simple Unjam (below).
Simple Unjam
The simple unjam method is similar to the simple unclog method (below), but is more concerned with removing filament that has gotten stuck in the filament drive, than removing an obstruction in the nozzle orifice itself. The basic process is to heat your hotend up to your operating temperature, and Retract the filament several hundred mm. If the filament will not retract, grip it just above the filament drive, and apply upward force (basically pull up) on the filament, until the drive gear can bite into the filament and retract it.
If the filament breaks, or will not retract, after the above, you will need to remove the filament drive from the extruder motor. To do this, first layer the hotend cool down to room temperature, then snip the ziptie securing the extruder harness on the right side of the filament drive. Then use your 2.5mm Allen wrench (with the red and black handle) to remove the M3 screw in the top left corner of the 40mm extruder fan (hiding behind the laser cut fan cover), then remove the fan assembly; you will then be able to remove the two M3 screws securing the filament drive to the face of the extruder motor gearbox.
Once the screws securing the filament drive have been removed, you can then remove the filament drive from the extruder motor; if there is filament stuck in the filament drive, you may need to gently rotate the filament drive as you try to remove it from the extruder motor. Once it is free, you can inspect the inside of the filament drive for filament debris; if there is any, remove it with tweezers/pliers/etc. If there is filament debris stuck in the teeth of the extruder drive gear, remove that as well.
If the filament is stuck in the hotend as well, you will need to (carefully) heat the hotend up to your normal extrusion temperature, then again use your tweezers to remove the filament. If you cannot get a grip on the filament, using your 1.5mm Allen wrench (the largest that will fit in the filament path of the filament drive) to push the filament further down into your hotend should help.
Once you have cleared the filament drive and extruder drive gear teeth of filament debris, reattach the filament drive and fans, and attempt extrusion again.
Simple unclog method
The simple unclog method is to first heat your hotend up to your normal operating temperature, Extrude 20mm of filament, and then let it cool down to room temperature. Then send the manual Gcode command "M302" in the communication area of your control program. After sending that, heat the hotend up to 10°C (or 30°C for the V3B hotend with red heater wires) higher than the glass transition temperature of your filament (glass transition is 60°C for PLA, 100°C for ABS - so 70°C and 110°C for a V3A hotend, and 90°C and 130°C for V3B). Once the hotend reaches that temperature, Retract several hundred mm of filament. If done correctly, this will remove all filament from the hotend barrel and even nozzle orifice, taking any possible debris with it.
PID autotune
To perform an automatic tuning of the PID parameters, send the manual gcode command M303. This will start heating the nozzle up to 150°C. Once it reaches 150°C, it will iterate through some changes to the P, I and D values. After several cycles, it will cool down and echo out the values that it found, as P* I* D*. Send the command "M301 P* I* D*", where * is the value echoed earlier. Then set the nozzle temperature to your standard printing temperature, and observe the heating behavior. If the new profile works well for you, you can save those settings to EEPROM with the gcode command M500.
Removing prints from the bed
Removing a print from the bed can at times be difficult, especially when experimenting with different print surfaces, or when printing large objects with very well adhered first layers. The basic idea in all cases, though, is to break the physical connection between the print and bed, at a location where it's easier; this generally means at a corner. A thin sharp chisel or spatula is known to work well for large prints - insert it under a corner and twist/pry up to remove the part.
Smaller parts, or parts with a small bed contact area, can be popped off more easily - often they can be twisted a bit to remove them from the bed.
Applying polyimide tape to the bed
The M2 ships with a roll of polyimide tape intended to be used as a print surface (with the polyimide applied on top of the glass, and the glass heated). To apply the polyimide tape, you'll need a sharp knife, and a credit card or similar to use as a squeegee. It's often helpful to heat the bed up first, to ~60°C, but hot or cold, remove the glass bed from the HBP, and place it on a clean flat surface. Then unroll a piece of tape wide enough to cover the bed, and cut it off the roll. Align it with the front edge of the bed, then angle it down and apply it to the bed on the right side (or left, for Lefties). Then use your squeegee to smooth the tape down across the bed, while holding the tape up at ~30° from the bed. If the tape has a large number of bubbles or is misaligned with the front edge of the bed, peel it up and try again; if the tape is heavily creased, peel it up and discard that piece.
Once the first piece is down, repeat the whole process, aligning the second piece to the first piece. Continue the process until the bed is covered, then use your blade to cut the excess tape off the edges, and reinstall the bed on the printer.
During the whole process, try to avoid touching the polyimide tape with your fingers, as the natural oils on your skin can cause print adhesion trouble.
Temperature tuning
Temperature tuning involves experimenting with a range of temperatures to determine what hotend and bed temperatures work best with a specific source and spool of filament. General starting temperatures for the V3A hotend are 195°C for PLA and 220°C for ABS; for the V3B hotend, 215°C for PLA and 245°C for ABS. For the heated bed, 70°C for PLA and 110°C for ABS.
Temperature tuning can start at the above temperatures; if your prints are completing satisfactorily, you do not need to adjust your temperatures. However, if you have extrusion trouble (the extruder stops extruding filament; or the filament being extruded is lumpy/bumpy, very running, etc.), temperature tuning may help.
To begin, first heat your hotend up to your current operating temperature (or the starting temperatures, above), and extrude 50mm of filament while observing the extruded filament. The extruded filament should come out smoothly and consistently, with no major bumps or surface imperfections, and at a consistent width. If the filament continues to "ooze" out after extrusion has stopped, reduce the hotend temperature by 5°C, let it stabilize, and extrude 50-100mm again. Continue lowering the temperature until the oozing is under control (some small amount is natural and unavoidable, though a long strand in a short period is troublesome), the filament starts to show bumps or other surface imperfections, or the extruder stops feeding filament/starts making clunking/skipping sounds. If you see any of those properties at a temperature, raise the temperature 5°C and test extrude again.
Once you've determined a temperature where the filament extrudes reliably but with minimal ooze, run a test print; the bracelet.g file included on the SD card is a great candidate for this: it's only a single perimeter so will show extrusion issues clearly, and only takes 10 minutes, so you can iterate quickly, and not waste too much time or filament on failed prints.
Once you have a temperature that has been tested and works well with your filament, write it down (on the spool of filament itself works well), and make sure that your slicer is configured to use that temperature.
Filament drive idler tension adjustment
Like the extrusion temperature above, the idler tension of the filament drive has two useful starting points which should work fine, but you may benefit from adjustment. The idler tension is adjusted by the M4 bolt on the top of the filament drive - tightening the bolt increase the idler tension, while loosening it decreases the idler tension. For PLA, the idler tension generally needs to be quite low - a general setting is 1/4 turn looser beyond where the bolt head no longer presses the washer against the filament drive. ABS, however, requires the idler tension to be quite high - a general setting is tightened to the point where there's a 1mm gap between the two sections of the filament drive.
More precise adjustment of the idler tension can be done by setting everything up in your standard printing configuration (same filament you'll use, same hotend temperature, spool location/feed system, etc.), and extruding filament while adjusting the idler tension. Loosen the idler tension adjustment bolt completely, Extrude several hundred mm of filament, then slowly tighten the idler adjustment bolt while observing the extruded filament. If it starts to show bumps, or the extruder motor starts making clunking sounds, loosen the idler a bit and let the extruder run for awhile to confirm the setting.
