1 Topic by BlueNalgene

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Topic: Very slow extrusion on a new unit

I'm a new user, just got the unit this month and I finished the build today.  I'm running the sample ABS, and I am extruding at a painfully slow rate (<1"/min).  My suspicion is that there is an electrical issue.  The stall board reads a current of 0.6A, about half the expected value according to info I've found.  The in and out voltage are both 12V.  The screw is turning, but it does not appear to be progressing the polymer beads which suggests a torque failure to generate pressure in the barrel.  Checking with an external multimeter, the values reported by the stall board are correct.  I adjusted the CC/CV pots according to the instructions, and it gave this value.  After that, I fiddled with the knobs in just about every combination. 

So what gives?  Is there a voltage divider I can check on the stall board to verify nothing is messed up? Did I miss some obvious part of the instructions?  Do I need to provide a blood sacrifice for the machine?

TL;DR: The numbers:
V_in = 12 V
V_out = 12 V
I = 0.6 A
T = 180 C

2 Reply by genesat1

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Re: Very slow extrusion on a new unit

180C is very low for ABS.  Try a higher temperature, 195-200C to start.

3 Reply by BlueNalgene

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Re: Very slow extrusion on a new unit

genesat1 wrote:

180C is very low for ABS.  Try a higher temperature, 195-200C to start.

To quote the operations manual: "Set PID to 180 degC if using included ABS. Wait 10 minutes beyond the PID achieving 180C.  During this time, please confirm the PID settings match the factory settings described in the included PID controller"

I'm not saying you're necessarily wrong, but I am being critical by necessity.  What is your basis for the suggestion that I increase the temperature contra to the suggested operation in the manual?  How would a change in head temperature fix the low supply current issue?

4 Reply by Kronikabuse

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Re: Very slow extrusion on a new unit

I extrude ABS @ 186c

Sd4 #9080 with a glass bed. E3d chimera duel extruder. Paste extruder , duet wifi.
Lawsy carriages. linear bearings. Y axis direct drive, Kinect scanner
SD4#8188 glass bed, lawsly carriages, E3d v6, octoprint http://www.ustream.tv/channel/hotrod96z28
Filastruder/filawinder, Custom Delta 300mm x 600mm

5 Reply by genesat1 (edited by genesat1 2018-05-21 21:04:31)

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Re: Very slow extrusion on a new unit

BlueNalgene wrote:
genesat1 wrote:

180C is very low for ABS.  Try a higher temperature, 195-200C to start.

To quote the operations manual: "Set PID to 180 degC if using included ABS. Wait 10 minutes beyond the PID achieving 180C.  During this time, please confirm the PID settings match the factory settings described in the included PID controller"

I'm not saying you're necessarily wrong, but I am being critical by necessity.  What is your basis for the suggestion that I increase the temperature contra to the suggested operation in the manual?  How would a change in head temperature fix the low supply current issue?

The stall board is showing you how much current the motor is drawing, it's not going to show you what potential current could be supplied  - the motor is not going to draw more than it needs to turn the augur.  Assuming the pellets are feeding in correctly (not jammed in your hopper), and that the augur is turning the right direction - pressure should be building up, and increasing the motor current needed to continue turning the augur as more plastic is getting added. 

You can also try taking the cooling fan off, and seeing if plastic starts coming out.  If your fan is off angle and hitting the nozzle sometimes that can bring things to a halt.

6 Reply by BlueNalgene

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Re: Very slow extrusion on a new unit

Per recommendations, I have adjusted the temperature.  I am currently running at 190C.  This is still extruding poorly.  I measured 1.17"/min (29.8 mm/min) as the extrusion rate.  I checked to make sure the temperature readings are correct, and I was able to confirm that the head 180-200C with a thermal scope.

I will try bumping up the temperature again and report back.  If there are other suggestions in the meantime, I would be happy to hear them.

7 Reply by elmoret

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Re: Very slow extrusion on a new unit

Could you post a photo of where/how you've mounted the thermocouple?

Is the melt filter nozzle clean?

What is the RPM of the output shaft of the gearmotor?

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8 Reply by BlueNalgene

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Re: Very slow extrusion on a new unit

BlueNalgene wrote:

Per recommendations, I have adjusted the temperature.  I am currently running at 190C.  This is still extruding poorly.  I measured 1.17"/min (29.8 mm/min) as the extrusion rate.  I checked to make sure the temperature readings are correct, and I was able to confirm that the head 180-200C with a thermal scope.

I will try bumping up the temperature again and report back.  If there are other suggestions in the meantime, I would be happy to hear them.

@200C - 3.04"/min

@210C - 3.94"/min

9 Reply by BlueNalgene

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Re: Very slow extrusion on a new unit

elmoret wrote:

Could you post a photo of where/how you've mounted the thermocouple?

See attached photos.  One photo shows the complete setup.  The second photo is looking at the hot end.  Due to the lighting, it is difficult to see inside of the insulated sheath, so I have illuminated the tip of the thermocouple with a laser.  The wires are positioned against the metal of the pipe and the heating mantle. 

elmoret wrote:

Is the melt filter nozzle clean?

The entire setup is new.  There was no observable debris when I inspected the items during install and put in the wire mesh.

elmoret wrote:

What is the RPM of the output shaft of the gearmotor?

7.09 rpm according to the highly accurate "watching the sharpie dot" method.

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10 Reply by elmoret

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Re: Very slow extrusion on a new unit

Looks like you have the thermocouple mounted in the heater, not the nozzle. The instructions call for mounting it in the nozzle. The heater always runs hotter than the nozzle. That is why you're starting to see reasonable output rates as you increase temperature.

Also, looks like you're extruding 3mm filament? Typical rates for that are 1/3rd the rates you see posted for 1.75mm filament, as 3mm filament has a crossectional area ~3x that of 1.75mm filament.

7RPM is fine, as is watching the sharpie dot.

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend

11 Reply by elmoret

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Re: Very slow extrusion on a new unit

Also you might want to put the PTFE tubing into the filament guide.

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12 Reply by BlueNalgene

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Re: Very slow extrusion on a new unit

elmoret wrote:

Looks like you have the thermocouple mounted in the heater, not the nozzle. The instructions call for mounting it in the nozzle. The heater always runs hotter than the nozzle. That is why you're starting to see reasonable output rates as you increase temperature.

Also, looks like you're extruding 3mm filament? Typical rates for that are 1/3rd the rates you see posted for 1.75mm filament, as 3mm filament has a crossectional area ~3x that of 1.75mm filament.

7RPM is fine, as is watching the sharpie dot.

Ah, that can be remounted once I get my polyimide tape in from Amazon.

I assumed that the 3mm nozzle would have the speed decreased by area from the 1.75mm, but the rates I was getting earlier were crud.  What I have now is much more reasonable.

I may not use the PTFE guide.  I'm planning to make a different guide and a DIY filawinder with some stuff I have laying around the house.

I would recommend in future iterations of the guide to include text which clarifies that the 180C is a suggested starting point temperature, the current wording makes it sound set-in-stone.


----------------------------------------------

genesat1, Kronikabuse, and elmoret: thank you for your assistance.  I think this can be considered solved.  You folks are lovely, and I am sure you will be hearing more from me as I move forward.