How to mount an extruder on a Thing-o-Matic
This isn't easy.
Makerbot Industries does sell alternative toolheads but does not have connectors on any of the toolhead cables nor are the extruder mounting bolts easily accessible. (Or accessible at all.)
Heat up the nozzle, pull out the filament and let it cool down.
Remove the M5 bolts holding the "Dinos" (the arc with the hoolhead).
Take of the toolhead and dinos.
Lower the Z-platform as much as possible.
Turn the toolhead until the stepper points upward. The 4 multing bolts for the extruder should not be level and point to the back of the machine.
Now carefully fiddle your M3 ballhead hex driver through the hotend and unscrew the bolts. Do not remove them. Gravity should keep them just in place as long as you are slow and careful.
Have a Dremel ready in case anything doesn't fit down to the millimeter.
Be sure your cables are not twisted after changing the extruder.
Sailfish - first print
Had to write a "Thing-o-Matic with ABP and Extruder MK6 (Accelerated)" machine profile.
Easy to do by copy&pasting from the HBP+MK7 and the ABP+MK6 profiles in Sailfish/replicatororg-0040-windiws-r003/replicatororg-0/thingomatic*.xmlUsing the jog-controls, I found, I had to reverse X but not Y and the A=stepper.
Heating up and extruding into thin air at 185°C (PLA) worked.
Now on to the first print.
Selected G-Code Generator "Skeinforge (50)".
In generating G-Code a dialog popped up that seems to override many settings of the Skeinforge profile. I don't like that at all. I like having Skeinforge profiles for each machine+material combination. Entering 3mm filament instead if the default 1.85 and 185°C instead of the insane 230°C.
After heating up, the the toolhead stays at maximum Z and prints in thin air instead of the ABP.
I found a G-Code "M132 X Y Z A B (Recall stored home offsets for XYZAB axis)".Maybe I need to set and store the Z-position of the ABP belt somewhere.
The Install Guide and then Setup Guide don't mention anything like this.
OnBoard Preferences have a tab "homing" with "X/Y/Z home offset (mm)".
Z is at 109,4mm. This is the height of my ABP belt. So it looks correct.
The machine thinks it is at X=24,984mm Y=-44,211mm and Z=10.000mm while waiting at the top.
Found out through this issue that there is a calibration script you are supposed to run.
The setup guide didn't tell you to do this.
Generated G-Code again...second print.
Still prints in the air, way above the ABP platform.
Changes the "Z home offset (mm)" from +110 to -110mm.Pressure on the extruder arm is very tight but I can't see any sign of it giving or cracking.
(Tightened it until it extruded as much as it does when I press the extruder arm with my hand.)
No effect. Still prints in mid-air.
Reversed my change.
No mention of this in the troubleshooting guide.
Added some "G92 Z110.3" and "G92 X-57 Y-57" to the end of the homing sequence. (Taken from earlier G-codes I used before the update to Sailfish.)
This issue looked similar. Double checked that I had indeed checked "Use default start/end gcode".
This issue looked similar too but my machines.xml has maxfeedrate=1000 and homingfeedrate=500 aready.
Problem found! It had the wrong machine configuration loaded. They all sound very similar.
next print...
Now it does move down to heat up. But too far left of the nozzle-wiper.It is at command 360 when heating up. I should find and change that command.
Changed the parking positon in start.gcode, didn't help. bed-temperature seems to be overriden by something. My change from 100 to 120°C didn't make it into the final gcode.
That's why I don't like programs overriding setting in other programs.
...found the issue. machines.xml had the HBP instead of my ABP version of start.gcode referenced.
Now my wiper-position and my prefered 120°C ABP temperature are regognized.
G1 X60 Y-60 Z10 F3300.0
M6 T0
G0 X60 Y-57
instead of X25
Some issues with first layer adhesion to the old ABP belt in my very small test object. A raft solves that.
Fist impression: The new extruder seems to fix my extruder-reliability issue with the MK6. (At first glance. Need to test with long running, large prints.)
Faster speeds (still 30mm/s)
Trying: 60mm/s (instead of 30mm/s). Didn't find a setting to change extruder RPM from 1.89 to something higher. Hopefully PrintOMatic scales that correctly. Temperature remains at 185°C for the nozzle and 120mm/s for the bed.It seems that the nozzle doesn't extrude right away and there is a skipping noise once every time the extruder starts up. Maybe it reverses too much. Increase filament pressure slightly doesn't help. Maybe I should increase the temperature.
The extruder RPM was aparently scaled with the doubled feed rate.
200°C
Trying extruder at 200°C (instead of 185°C) and 60mm/s (instead of 30mm/s) now.No skipping noise. Extruding starts right away. The increased temperature seems to do the trick.
I'll have to see if that higher temperature creates warping in large, slender objects.
Hardly a visible difference between the same object printed at 30mm/s(185°C) and 60mm/s(200°C)
The final cooling down and ejection via ABP still needs some work. It seems to cool down and down and down but even after getting below 40°C it still didn't go on to start the belt.
Also I was missing the code to stop heating the belt after a print in my stop.gcode.
Maybe I can change the nozzle wiping in start.gcode to do multiple passes over the wiper.
Just to increase reliability when chaining multiple objects to be printed.
Even faster (120mm/s)
Loosing steps in Y (front/back) but not X at 120mm/s. Doesn't work (yet)Slower (90mm/s)
Trying 90mm/s at 210°C now...This is 3x my original speed that I was limited to for years! It would make 4h prints print in slightly more then 1h.
Still loosing steps in Y.
Back to 60mm/s
...just to make sure it still works.
Keeping the 210°C and my multiple-wiping procedure.
60mm/s works!
- My Extruder Design files on Thingiverse
- Sailfish firmware
- Google+ posting
- First blog posting about designing this extruder
- Photos
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