Has anyone had an intermittent extruder issue that only happens are certain places on the build plate?
I have a weird problem. been printing like a champ for weeks and now all of a sudden I get the symptom of a clogged but only in certain places on the build plate. I can feel the filament and when it gets to certain places I can feel a chunking or clunking movement of the extruder. I am thinking I am getting an intermittent connection and have a broken wire in the extruder wiring. Has anyone else had this issue. It seems to happen on the far right and the far left of the extruder plate. Center still extrudes ok. Below is what I am seeing.
Re: Has anyone had an intermittent extruder issue that only happens are certain places on the build plate?
Forum won't let me edit my post? I found the problem. The motor has a broken wire somewhere near the extruder. If I flex the wire at different places the extruder motor turns off and on when it is running. This is the 3 time I have had to cut and splice wires into the harness. I have have the Thermister on the plate, The fan on the extruder and now the motor on the extruder. I work with flex harnesses all the time and never have failures like this with equipment. I may have to redesign the flex harness or use wires meant for flexing. This is getting to be a pain in the butt to troubleshoot and fix every 4 months.
Re: Has anyone had an intermittent extruder issue that only happens are certain places on the build plate?
That does seem quite a frequent wire break.
How many km of filament does the printer "odometer" say it has processed?
Re: Has anyone had an intermittent extruder issue that only happens are certain places on the build plate?
That does seem quite a frequent wire break.
How many km of filament does the printer "odometer" say it has processed?
A little over 3552km and 91days of print time. I worked in the computer chip and medical industries and we have harnesses that run 24/7 for years without failing. I don't think Prusa understands the strain flexing wire repeatedly. 30 years ago in the computer chip industry we used regular wire which is what I think they are using. Once they started shipping hundreds and thousands of systems the cabling got a lot better. I will have to do some research and see if I can start fitting cables that are meant to be repeatably flexed into the instrument.
Re: Has anyone had an intermittent extruder issue that only happens are certain places on the build plate?
That does seem quite a frequent wire break.
How many km of filament does the printer "odometer" say it has processed?
A little over 3552km and 91days of print time. I worked in the computer chip and medical industries and we have harnesses that run 24/7 for years without failing. I don't think Prusa understands the strain flexing wire repeatedly. 30 years ago in the computer chip industry we used regular wire which is what I think they are using. Once they started shipping hundreds and thousands of systems the cabling got a lot better. I will have to do some research and see if I can start fitting cables that are meant to be repeatably flexed into the instrument.
Hi Richard, I would be interested in the results of your research,
I know that the wire used on Mk3 heatbed power cables now (Last time I destroyed one 😀 (about 27 individual filaments in each conductor) is better than that used on my Mk1 and early Mk2 heat beds (7 filaments per conductor IIRC)
personally I don't use the spiral wrap for the moving cable looms, whilst it is better than no cable management, spiral wrap does tend to concentrate bending moments into smaller areas than necessary... I have been using braided sleeving for quite some time...
for the heatbed I fitted 16 AWG flexible silicone wires with 252 individual copper filaments in each wire, the wire is rated at 22 amps which should be satisfactory (over 250 watts capability at 12 volts (which is more than the PSU is rated for) and over 500watts at 24 volts ( WAY more than the PSU is rated for)) I have some thinner flexible silicone wire (24 AWG I think) in numerous colours ready in the event that more cables flex fracture...)
hope you can come up with a smart solution
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: Has anyone had an intermittent extruder issue that only happens are certain places on the build plate?
Basically just 3 months of continual printing and you got all those breaks. Wow.
Might have to stock up on some more silicone wire myself.
BTW 3552 meters right?
If that is 3552 km, it would be 11,000 spools in 90 days. 122 spools/day is a lot faster than my mk3. 
Re: Has anyone had an intermittent extruder issue that only happens are certain places on the build plate?
Forum won't let me edit my post? I found the problem. The motor has a broken wire somewhere near the extruder. If I flex the wire at different places the extruder motor turns off and on when it is running. This is the 3 time I have had to cut and splice wires into the harness. I have have the Thermister on the plate, The fan on the extruder and now the motor on the extruder. I work with flex harnesses all the time and never have failures like this with equipment. I may have to redesign the flex harness or use wires meant for flexing. This is getting to be a pain in the butt to troubleshoot and fix every 4 months.
Maybe post a picture of your wiring setup and see if anyone has any input. That's sounds like a very rapid and uncommon failure rate.
Re: Has anyone had an intermittent extruder issue that only happens are certain places on the build plate?
That does seem quite a frequent wire break.
How many km of filament does the printer "odometer" say it has processed?
A little over 3552km and 91days of print time. I worked in the computer chip and medical industries and we have harnesses that run 24/7 for years without failing. I don't think Prusa understands the strain flexing wire repeatedly. 30 years ago in the computer chip industry we used regular wire which is what I think they are using. Once they started shipping hundreds and thousands of systems the cabling got a lot better. I will have to do some research and see if I can start fitting cables that are meant to be repeatably flexed into the instrument.
Hi Richard, I would be interested in the results of your research,
I know that the wire used on Mk3 heatbed power cables now (Last time I destroyed one 😀 (about 27 individual filaments in each conductor) is better than that used on my Mk1 and early Mk2 heat beds (7 filaments per conductor IIRC)
personally I don't use the spiral wrap for the moving cable looms, whilst it is better than no cable management, spiral wrap does tend to concentrate bending moments into smaller areas than necessary... I have been using braided sleeving for quite some time...
Flexible Sillicone wire table.JPG
for the heatbed I fitted 16 AWG flexible silicone wires with 252 individual copper filaments in each wire, the wire is rated at 22 amps which should be satisfactory (over 250 watts capability at 12 volts (which is more than the PSU is rated for) and over 500watts at 24 volts ( WAY more than the PSU is rated for)) I have some thinner flexible silicone wire (24 AWG I think) in numerous colours ready in the event that more cables flex fracture...)
hope you can come up with a smart solution
regards Joan
My company uses those spiral wraps but an outside consultant company just came in and suggested we use Energy Chains instead.
I think that is what has happened to me. I have isolated the break each time and they are close to the back of the extruder after the extension and tie wraps.
There is an nice Energy Chain on Thingaverse for the Prusa's MK2 and MK3 so I might print that. I looked at the wire that we use in our stage harnesses at work and we use Cicoil but that is around $3-$5 a foot 😯 for 4 conductor 20awg cable. I think I will take my chances with some 100 strand 20awg silicon wire I found on Amazon. Most of the Flexible wire and cables are found online from professional places have high minimum orders. 3552m not km.
I am going to do a temporary fix for now and after Valentines day I will do something something more.
Thank you for the wire guide Joan.
Unfortunately to the person who asked for a picture I have already cut the tie wraps and troubleshoot the where the break is so it is a rats nest so I think a picture won't be of much use. I should know better to take pictures before I do any work to post if I am asking for help. I am Product Support and New Product Development Engineer for my company for Serviceability so I often deal with Field Service and I always ask the for "As Found" information before they tear into things and I have a list of 6 "Must Have" pictures before they do anything so I can work up a POA (Plan Of Action).
Thanks Everyone
Re: Has anyone had an intermittent extruder issue that only happens are certain places on the build plate?
my mk3 has had minor reparative 'field' surgery to restore service for my Pinda,,, (not pretty)
the cable went faulty at an inconvenient time, when I couldn't access soldering iron etc.
so I did a temporary repair using the wire off an old usb micro cable, and bodge tape...
with twisted connections... and it's still working...
I was going yo change it when I did the mmu2 upgrade with R3 parts, but laziness overcame me in the rush to install the mmu upgrade on new year's eve... so I just cut the grill out of the original parts on the right of the cold end chamber and left it at that...
I have flex silicone on hand for the next time
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: Has anyone had an intermittent extruder issue that only happens are certain places on the build plate?
my mk3 has had minor reparative 'field' surgery to restore service for my Pinda,,, (not pretty)
the cable went faulty at an inconvenient time, when I couldn't access soldering iron etc.
so I did a temporary repair using the wire off an old usb micro cable, and bodge tape...
with twisted connections... and it's still working...
I was going yo change it when I did the mmu2 upgrade with R3 parts, but laziness overcame me in the rush to install the mmu upgrade on new year's eve... so I just cut the grill out of the original parts on the right of the cold end chamber and left it at that...
I have flex silicone on hand for the next time
Too Funny. I cut up a charging cable from an old BlackBerry. 20 strands of copper. I needed a quick fix because I am printing Valentine Hearts for my kids for school. It is actually really good wire. I had a few charges and cut the wire off and they all seem similar with good copper wire. The Stepper motor from Prusa seems to have aluminum wire.