Extruder problems

I have a delta i buily myself.

Nema 17 1.5A
Extruder MK8 with Nema 17 2.5A
Hotend E3D V6, 0.4mm for 1.75mm filament
Arduino + Ramps 1.4 + LCD
DRV8825 Stepper drivers (1.3A set current for xyz and 2A for extruder)
PSU 12v 15A (180W)
Traxxas 5347 with carbon fiber tubes
220mm heated alu bed, isulated with cardboard and aluminium tape. The electronics are under the bed. I have them cooled with 2x 40mm fans, the steppers drivers and mosfets stay at about 35-40 degrees when printing.

After 30-40 mins of print, extruder start skipping, because it can't no longer push the filament in the PTFE tube. I attached a picture of how the filament looks when it gets jammed. As it can no longer go in the PTFE tube, the extruder keeps pushing until the filament snaps, then it just extrudes it outside, wasting it.

I thought it would be a problem with the heater cartridge. swapped it with a new one, the problem is the same. Then i though it would be something strange with the hotend. Swapped it with another hotend that works on another printer, but it's same problem. I changed the Arduino + ramps + steppers, uploaded software and calibrated the printer, but it still happens, with both PLA and ABS. Printing PLA at 210 degrees and ABS at 245 degrees. The extruder motor reaches 45 degrees after 30 min of printing, but i guess that's normal. It's also calibrated.

I attached a few pics with the printer.

I'm lost, does anybody have an idea?

Edited 3 time(s). Last edit at 05/22/2016 07:44PM by CrisCG.

You have a crappy HE3D extruder (or at least one from the same source), buy a E3D titan and your problems will disappear, they did for me!, at least you have a genuine E3D hot end already.

Also it looks like your drive gear is biting too deep into your filament, this can cause debris to build up in the bowden and increase friction.

next time you look at a jam inspect the filament between the extruder and hot end, disconnect your bowden from the hot end and extruder and try and push that piece of filament through it, compare this with a virgin piece of filament, is there more friction

measure the filament with a calipers, and look at it very closely, can you see any points where the filament appears to haev bubbles in it or the filament has expanded?

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RepRapPro Mendel 3 Tricolour
RepRapPro Fisher
-Carbon Arms
-Easy adjust Carriage+effector
-axis stiffness mods
HE3D -600 delta
-Duet 0.8.5
-PanelDue
-DC42 Height probe
-RobotDigg metal components
Simplyfy3D
RS Design Spark CAD

Did you calibrate the thermistor ? Are you sure the reading you got is right ? Use a multimeter with a thermocouple and put the sensor IN the nozzle and check the temps.

I had the same thing happen to me it was the thermistor reading way too low , I was reading 200 when in reality it was more in the 160-170 range, enough to print slowly but end up grinding the filament because of the extra pressure needed to push the filament at that low temp.

Also looking at your filament , it look to me the mark on the filament are way too deep ( maybe its the picture) ,try release the pressure a little bit there so it wont grind the filament but skip, I use a MK8 drive gear and it not deep like that

Thank you for the replies. I understand it's a crappy chineze clone, but it prints perfectly on another printer. So switching to a e3d titan, may will solve some things, but surely not this one. The filament is spot on, 1.75mm and no moisture. Also it happens with diferent brands of filament.

I will measure the thermistor temps and return with an answer.

Edited 1 time(s). Last edit at 05/23/2016 01:41AM by CrisCG.

Quote
CrisCG
Thank you for the replies. I understand it's a crappy chineze clone, but it prints perfectly on another printer. So switching to a e3d titan, may will solve some things, but surely not this one. The filament is spot on, 1.75mm and no moisture. Also it happens with diferent brands of filament.

I will measure the thermistor temps and return with an answer.

Yeah I too was sure this extruder was good with its nice shiney aliuminium body etc, thats why it was the last thing I changed, always worth checking the calibration of the thermister and if you don''t mind excessive stringing printing at a higher temp helps but I went through all of that plus trying some expensive brand filament, tried reducing the bowden length with a flying extruder design but like I said, as soon as I shitcanned the extruder and used the titan my problems disappeared, and Im back using a full length bowden and getting excellent 'minimal string prints, plus have ordered two more titans for my Mendel refit.

your other printer a Delta with a long Bowden tube?

---

RepRapPro Mendel 3 Tricolour
RepRapPro Fisher
-Carbon Arms
-Easy adjust Carriage+effector
-axis stiffness mods
HE3D -600 delta
-Duet 0.8.5
-PanelDue
-DC42 Height probe
-RobotDigg metal components
Simplyfy3D
RS Design Spark CAD

Yes, both printer have about 65cm bowden tube.

I checked the reading with the multimeter with thermocouple, and the reading is 165 degrees, when set at 210. So that is the source of the problem. I was sure i was going to find a lower value, everything else works fine.

Edited 1 time(s). Last edit at 05/23/2016 06:49AM by CrisCG.

I searched online, found a few things, but i have no idea what to change in the firmware, to have an accurate temp reading.

I'm using repetier firmware.

How do you calibrate it?

Edited 1 time(s). Last edit at 05/23/2016 09:36AM by CrisCG.

It seems that the thermistor type in the firmware wasn't coresponding with the actual thermistor i have. Changed it and now temp is ok, but i still have the same problem.

Edited 1 time(s). Last edit at 05/23/2016 11:59AM by CrisCG.

What are your retraction settings?
I've had trouble before where my retraction was too agressive, and the wad of melted plastic would pull up into the PTFE tube, jamming it.

You might try turning retraction down, or even off, just to see if the problem continues.

i have a 8mm retraction, but i had the same setting when the printer was printing just fine.

I have solved the riddle. I changed the extruder, with the one from the other printer. It's a mk8, like the one i was using, but this one is smaller, 1.2A. I adjusted the current to about 1A. Completed a 1:30 h print with no problems.