Extruder feed problem ........ help  

Extruder feed problem ........ help

Ok where I am with my Prusa mk2s adventure, a history of the fun, I had so far.

If you just want to go to the current issue I have, and see if you can help with it, it will be the last part separated by the (underscored Line) _________ line

other wise I am just going to record my journey so far, perhaps other reading this may find it useful

yes I am a noob (new to this the gray hair was there before I order the machine), I have a few personal problems so there are day when I just don't do anything , work on problems with the printer doesn't seem important - funny that pain stop you from caring

original order placed on

Order: 2017244641 Placed on 06/05/2017 18:02:45

Original Prusa i3 MK2S kit - color : Black and orange

Me and family members built the machine over a week end, we took our time to get it right so it was 2x8 hour day assembly

My first problem …..... power up was a shocker, the LCD display was not behaving, time to email for help

my email

“Kit assembled, on power up unit ask for calibration, can select unit status temp etc and menu

but can not scroll through menu on scrolling using the selector and a garbled character/s appears

cant select any option in the menu”

response from Pavel Pelčák Technical support

“Lets try to do one simple trick that might solve that issue. Just unplug the cables, lay them down on a flat surface and gently stretch them. Then just plug them back in and see if there will be any difference.

If that does not help, do not attach the cables to the threatened rods so that they are as little bended as possible.

Please make sure that you have the red cable facing the correct direction as the position of the cables matters!”

I swaped the cables over so cable marked “I” is now in socket “II” and cable marked “II” is in socket “I”

and this cleared the problem on the suggestion of Michele Moramarco from support.

problem/issue2

ok I did not understand what I was doing or saying, the nozzle on the printer was not changed, it was still the .4 nozzle supplied by Prusa I will now add the mails as I got them

my mail

“extruder intermitant, print ok sometime at .2mm, .1mm and .05 fail (Aug 3, 2017 at 05:08 pm)

checked the feed alignment ok

check the 'pinch' roller adjustment ok, bearing is free moving

load filament cmd does not work every time, the display say it heating to 215 but filament dose not flow

checked nozzle for blockage it was clear

on extruder drive to feed filament, when it fails it seams to be driving filament back toward roll, the motor judders and click a lot had some .2 (setting in sli3er) prints print ok .1 and .05 fail it like the extruder is not extruding. i see it following the patteren but nothing is being extruded

support response

please can you check couple of things?

Lets try to clean the possible jam that could be inside the Hotend. There are 2 procedures that we can try to do, before putting the extruder apart.

1st Heat up the nozzle to 295C and wait for 5 minutes. Then press the Load the filament in the LCD. That way we should be able to clear the jammed filament by melting it. Pushing through the extruder with a 1.5mm wire should be the last step to try in this step.

Proceed to the 2nd step only if at least some of the filament is going through the nozzle. If the 1st one did not made any difference. Then check if there is not a broken filament inside of the entrance and check the PTFE tube. (Let me know if you would wanted any help with that).

2nd Heat up the nozzle to 90C and proceed the "cold pull". Simply, waiting for the filament to melt a bit (this way it should attach to it any waste by the sides) and then manually with your hand pull it out of the extruder.

Once you will try any of these. Put the temperature to the normal and try to load the filament. If the filament is doing nice circles, that is what we are looking for.

Also for print on biggest detail, I recommend to use 0,25 nozzle. What brand of filament you are using?

Best Regards

Pavel Pelčák

in trying the higher temperature to clear the blockage we ended up with ooze/PLA over the hotend , the head of the nozzle and the thread of the air cooled filament feed not being tightened properly.

Molten filament was oozing around the hot end, this meant we had to heat up the hot end clean off the filament (support suggested this, we used an earbud and were surprised it worked while the hot end was hot ) and re tighten the nozzle and heat-sink to clear this issue

my email for this issue

“help extruder head pla oosing out by heat sink junction and heating element issue

earlier i had a problem with the filament feeding into the heating head (still awaiting support responce),

we cut a small amount of the white plastic (PTFE I did not know what it was call at the time) that was touching the extruder knurled drive (called the hob drive I did knot know that noob that I am ) and also ground out a small bit off the orange plastic that seem to stop/bind the pinch roller, so the filament seem to feed now and this lead to another issue

pla coming out of the actual heating body,

it was extruding from the nozzle but also some ware in the head, possibility the thread were the actual heat sink is connected to the heating element, the nozzle also unscrewed with pla all over the thread, have i got a faulty extruding head”

At this point going to stop adding actual mails and just describe were and what happened next

we found the bearing that pinches the filament to the hob, was damaged, it would not spin freely

I order new bearing (being budget conscious from aliexpress.com so 30 to 60 day delivery it arrived in 3 weeks). I did not want to pay £10 and get one from the UK (amazon) when I could get 10 from China for £1. I do not know any hardware places that specialise in bearing locally (London) and as I was house bound, this seamed the simplest solution. Being the noob I am I order the wrong bearing I order a 4mm/13mm/5mm and the first one was with a V in the outer diameter, corrected that to a normal bearing then found out I got the wrong bearing it should be 5mm/16mm/5mm and when I reorder the correct bearing, it description match the V bearing , I panicked and got one from Amazon at £10ish, more fool me the 10 incorrect one's I order were correct and now I am swimming in bearing

to add insult to injury I kinked the PTFE cable during my vain attempts to fix the printer so had to order more PTFE. 65p from prusa for 5cm and £8 to ship. 1m from aliexpress at £1 and 30 to 60 day delivery (it was 2 weeks)

so about a month later I had all the bits I needed (also got isopropyl alcohol, asatone and nozzles £1 for 5 etc in the mean time) and now to the issue I current have

Extruder feed problem my current issue

i tried multiple filament all PLA

the funny thing is it loads filament 90+ per cent of the time it just will not print reliably

the original Gray PLA from Prusa fail to print real quick, I checked the diameter with a calipers (it been in my house, though its our lounge so its not cold or to humid. it 1.75 it may go to 1.8 but never less that 1.73

the new White PLA from 3dfilaprint printed well for the first quick/small print 50minutes but failed at 2hour27 on the second print

I tried 2 different nozzles both .4mm no luck

I also put a silicon boot on the hot end hoping that it would helpm it dose not appear to have helped

the LCD show the nozzle head hot at 210c or 215c (tried both) at time of fail

and you and hear the extruder it makes a “tuk tuk” sound

no plastic is visible on the hob, so it not like the hob is striping the filament

at time of failure the filament is being pushed back and forward by the extruder.

I found a older forum post about this

https://shop.prusa3d.com/forum/original-prusa-i3-mk2-f23/extruder-feed-problem-t2892.html

though I tried everything mentioned bar ABS and oiling the filament with no luck

I also been through tightening the spring screws that hold the bearing against the filament and hob from 13mm to 20mm, my first few prints (baby groot 50% scale 5 hour print) seem to work only 2 bad layer and screw were at 20mm, last good print screws were at 13mm

so I 've

change bearing

changed ptfe

hob is tight not spinning on extruder motor

changed filament

change actual nozzle

adjusted tension spring on bearing holding filament to hob

what else should I try???????