Itty Bitty Double FLEX Extruder

**jasay** · 04-14-2015, 10:53 AM

Originally Posted by clough42

Which hot end and nozzle size are you using?

Hexagon Ø0.4mm hotend, Ø3mm PLA at 205ºC. The hexagon heatsinks/fans seem to be working well as I can touch them right above the fiber/kapton insulation and they are quite cool.
I have Pololu 1209 NEMA14 motors. Voltage on the A4988 drivers is 0.32-0.325VDC which if my math is correct is ~0.8A. When it skips the entire belt path rotates backwards including the metal gear and motor shaft (presumably under the force of the filament pushing back on the hobbed bolt) so I don't believe there is a belt or gear anchoring issue.

**clough42** · 04-14-2015, 10:10 PM

Originally Posted by jasay

Hexagon Ø0.4mm hotend, Ø3mm PLA at 205ºC. The hexagon heatsinks/fans seem to be working well as I can touch them right above the fiber/kapton insulation and they are quite cool.
I have Pololu 1209 NEMA14 motors. Voltage on the A4988 drivers is 0.32-0.325VDC which if my math is correct is ~0.8A. When it skips the entire belt path rotates backwards including the metal gear and motor shaft (presumably under the force of the filament pushing back on the hobbed bolt) so I don't believe there is a belt or gear anchoring issue.

You might try a little higher temperature. I typically run PLA at 225C in the .4mm hexagon. There's something about the hexagon (and some other all-metal hot ends) that requires a little higher temperature.

My firmware fork is also using the standard Type 1 thermistor tables instead of the Makerfarm-modified type 6 tables. This could make small differences at some temperatures.

**jasay** · 04-15-2015, 10:18 AM

That did seem to help. Had a print in progress so bumped up the temp on the LCD and was even able to push the speed up to 150% (90mm/s infill) without any skips. Perimeters look good at an effective 75mm/s. Will have to play more with the faster speeds, would be nice . . ..

I've run PLA at 190ºC for years, but you're right it's a different hotend. Funny that hexagon worked just fine at 190-200ºC on the Makerfarm stock extruder though.

**voodoo28** · 04-15-2015, 07:23 PM

I think my printer has become possessed...!!

ABL was working perfectly 2 days ago...i turn it on today for the first time since and..the G28 and G29 commands make the z carriage move up instead of towards the bed..BUT...if i press the negative Z in Simplify3D controller it moves in the correct direction. So ,that means the wires are not inverted nor is the direction of the steppers in Marlin. Ive reloaded Marlin several times from a fresh download and NADA!

What can it be???

**clough42** · 04-15-2015, 08:38 PM

The NEMA17 motor is much, much stronger (at least 3X) compared to the NEMA14. Probably 4X once you count the gear ratio. This allows the extruder to force the filament through the nozzle against a much higher back pressure.

The MakerFarm default Slic3r configs for the Hexagon 3mm/.40 all have the PLA temp at 225C.

James

Originally Posted by jasay

That did seem to help. Had a print in progress so bumped up the temp on the LCD and was even able to push the speed up to 150% (90mm/s infill) without any skips. Perimeters look good at an effective 75mm/s. Will have to play more with the faster speeds, would be nice . . ..

I've run PLA at 190ºC for years, but you're right it's a different hotend. Funny that hexagon worked just fine at 190-200ºC on the Makerfarm stock extruder though.

**clough42** · 04-15-2015, 08:59 PM

Originally Posted by voodoo28

I think my printer has become possessed...!!

ABL was working perfectly 2 days ago...i turn it on today for the first time since and..the G28 and G29 commands make the z carriage move up instead of towards the bed..BUT...if i press the negative Z in Simplify3D controller it moves in the correct direction. So ,that means the wires are not inverted nor is the direction of the steppers in Marlin. Ive reloaded Marlin several times from a fresh download and NADA!

What can it be???

Hmm...that is odd.

I have never used S3D, but I have the Google, so I won't let that stop me...

First off, when you move the Z axis, does the LCD agree? When you move up 10mm in S3D and the carriage moves up 10mm, does the LCD Z position increase by 10mm? If the LCD number goes the wrong way, then you have both the motor and S3D reversed. Flip your motor connector (or invert the Z direction in the firmware) and flip the Z axis in S3d. There's an option to flip the Z direction in Tools->Options->Machine to flip the build table axis.

If you've been messing with the Configuration.h file, you might also check to be sure your Z_HOME_DIR is still set to -1.

My recommended start GCODE lifts the bed a bit before deploying the probe. If the printer thinks it's at a negative position, this could cause it to go up a lot. This video shows my carriage raising a little before probing:

If none of this helps, share your Configuration.h file and I'll take a look.

**voodoo28** · 04-16-2015, 10:14 AM

after further testing M119 code...z endstop was always triggered no matter what i did..Finally i decided to check the terminals on the switch and sure enough one of the terminals were broken off...GEEZ!!

**kablahz** · 04-16-2015, 03:17 PM

Unrelated to the double extruder(btw awesome work cant wait to upgrade to the double extruder once I have some more experience under my belt), what feedrates are you running for homing/between probings? I have the 12" model and a g29 n3 probing takes forever, especially the z homing if the last print was tall. Thanks!

**clough42** · 04-16-2015, 10:07 PM

I believe I'm just uisng the defaults. You can always just download the firmware and look at the Configuration.h file to see exactly how it's set up.

**voodoo28** · 04-21-2015, 07:16 AM

Finally got all the firmware and slicer settings squared away...here is the first dual color print with ABL. Next, need to fine tune slicer for ooze and retraction.

PLA Temp 200
Bed Temp 70
Layer Height .1500
Speed 60 mm/s
10% infill
4 hrs to print

I think she's hot...