#Printrbot Food Extruder: Some days later I need help from gcode experts…
Now the printer homes nicely (after reflashing the new firmware). Everything seems to be OK. The test object will be a ring (actually it is a disc but I set the “Bottom/Top thickness” and “Infill” to 0).
Before I hit [Print], I set the start position manually.
Then the printer moves very strange. Did I mix up the “start.gcode” part? Some lines are already commented out.
G21 ;metric values
G90 ;absolute positioning
M82 ;set extruder to absolute mode
;M107 ;start with the fan off
;G28 X0 Y0 ;move X/Y to min endstops
;G28 Z0 ;move Z to min endstops
;G29 ;Run the auto bed leveling
G92 X0 Y0 Z0 E0 ; Set current position to zero
G1 Z15.0 F{travel_speed} ;move the platform down 15mm
G92 E0 ;zero the extruded length
G1 F200 E10 ;extrude 10mm of feed stock
G92 E0 ;zero the extruded length again
G1 F{travel_speed}
;Put printing message on LCD screen
M117 Printing…
I’m not able to provide assistance, but have a question. Is this the syringe-based device I’d seen posted elsewhere? I believe what I saw was a brief video regarding filling the barrel and purging the air from it.
Have you had success previous to this project or is this a “first look” of the operations?
Do you have an LCD attached? If not, you should probably remove the last line (“M117 Printing…”). A printer without the LCD SHOULD just ignore it, but I have seen the gcode parser get confused by it before, since the stuff following the M117 is otherwise severely malformed gcode if the parser fails to ignore it. IIRC, in the case I saw, the line also ended up being set without a line number, which is bad.
@foosel G92 with x,y,z=0 comes from Printrbot. In his video @Brook_Drumm set the x,y position manually. In my opinion that would not make sense after homeing. So I commented this out.
Define very strange:
It moves to the start position. OK
It should “draw” a nice circle onto the printbed. But it doesn’t: It moves like a “jerk”.
What do you mean, “it moves like a jerk”? Don you mean it moves way too fast? Does it go in a circle, or does it just move a little and then stop? Also, does it do the initial extruding before it prints properly?
@paul_wallich Hm, it’s difficult to describe because the printer is in the lab and I’m at home. But let me try:
It moves like printing infill between two narrow walls. But no circles!
From that it sounds as if one of the steppers is skipping steps. Unlikely, I know, since you say it’s moving smoothly otherwise. Maybe you could try a bunch of moves and extrusions under manual control.
In order to avoid wasting “useful” food type material or similar material, what could one use for testing a problem of this sort? I read on the web site that wall board compound is a possible component. I would have thought that such material would be extremely viscous and difficult to extrude. Of course, less viscous material has a possibility to be too runny.
@paul_wallich
Thanks for the answer. Even if it chewed the syringe, I’d expect that cost would be pretty small compared to replacing a hot-end nozzle as frequently. I know the stuff is pretty abrasive and would also expect the rubber plunger seal would get chewed up too.
I’ve recently read that someone was extruding chocolate by putting a heater around the syringe and operating the printer inside a freezer! At least the failed prints can be tastefully processed. Wall board compound would not be as healthy.
I very much want to develop a practical use for one of these, so I can convince the family finance officer of the purchase.
The wall compound is powder we mix to desired consistency.
I don’t usually g29 with the paste extruder.
Chocolate will work, it has a heater. The thermal mass of the syringe is enough to keep a constant temp.
If the e-endstop is triggered during print, it freaks… It’s meant only to prevent the machine from destroying itself and to quickly change out syringes- instead of needing to manually watch it as the e rises
A video would help. Travel moves need to be really slow- I use 30mm/sec. The max speed can also be turned down so it doesn’t try to move too quickly on homing or before a print starts.
