After some initial problems I have produced several good quality prints with this upgrade. But now the extruder motor fails to feed the filament. It clicks and I can feel the filament being pushed up on each click… Pushing the filament in against the click will get some extruded. It started with the occasional click and now is almost continuous
I have tried temperatures between 190 and 220 and stepper board reference voltages 0.8 to 1.1 with no noticeable differences in performance.
I have disassembled the top end (above the barrel) and found no fault.
The fact that some extrusion is taking place suggests to me that the hot end is clear, although I suppose it could be partially blocked
With the K8200 I could disassemble and drill out the PTFE barrel, The seal between the nozzle and the heater was separate. In the 8203 the nozzle screws directly on to the barrel and presumably will be full of solid polymer and effectively glued on.
Any suggestions as to cause and remedy
Added later
Is Nozzle cleaning filament any use? Anyone has experience of using it?
I have not tried to use cleaning filament, but I have had problems with smooth feed through the 8203. Here are a few things that seem to have helped:
When changing filament, always heat the extruder and then extrude a couple cm of material before you try to reverse direction. This will melt away the thick end of the filament and avoid jamming the extruder guides. The old filament will usually leave behind a small thread of melted plastic which could be part of the problem as well - try to pull this thread out of the extruder.
I have had to remove the hot end and clear it out on occasion. Just pop the heater block off and then remove the two bolts and it will come right off. I have replaced the section of PTFE tubing and also had to clean the nozzle this way when it has gotten clogged.
I also found that the small black plastic (hexagonal - cone shaped) filament guide that goes between the extruder and the hot end can easily get jammed, either when printing or when changing filament. I removed this small part and the extruder seems to work a little better - fewer jams and fewer feed problems.
Even so, I do sometimes have a slight clicking sound during print jobs, especially with ABS. Higher extruder temperature did not really help, and neither did boosting the extruder driver current. The motor gets fairly hot during a print job. When this happens, I have to reduce my print speed to about 50% to avoid clicking feed problems and low output.
TL;DR - This extruder takes a little practice to operate without trouble. Better documentation from Velleman might help reduce the learning curve.
I presume you mean you operate without the little hexagonal tube. I certainly have had this block up. But it isn’t the source of the problem at present. Just checked - it is clear. Did you get the nozzle of the end of the feed tube?
Dismantled, cleaned and reassembled hot end. Extruded cleanly. Started print of 100mm disc at 197 C. 8 minutes in started clicking and feed became erratic abandoned
Increased extruder reference voltage from 0.8 to1.05 Started print again at 197 - clicking after 8 mins - increased temp to 203 Clicking stopped first layer finished OK.
On second layer clicking started after perimeter. Increased temp to 205. clicking became continuous - feed stopped completely.
Yes, I operate two 8203 extruders with the small hexagonal guide removed. These were a constant source of jams when changing filament. Removing them didn’t make much difference with the feed problems, though.
[quote=“Dr. Vegetable”]Yes, I operate two 8203 extruders with the small hexagonal guide removed. These were a constant source of jams when changing filament. Removing them didn’t make much difference with the feed problems, though.
Is your extruder motor getting hot to the touch?
No barely warm. Planning to check again for blockages
Dismantled hot end again. On restart the clicking/jumping back still occured even on free extrusion. Diameter of the extrudate when flowing freely (no jumping) is about 0.26mm with a fall of about 100mm. Is there any idea if this is normal?
Do Vellemann have a view on this problem? If I hadn’t ordered several Kg of 1.75mm filament I would revert to the old 3mm and the big wheel extruder and enjoy printing again.
this problem can occur when the small ptfe tube inside the extruder has not been cut to the exacting specifications stated in the manual. You can check this by dismantling the extruder and checking if hot plastic has leaked besides the tube. Clean all parts and cut a new ptfe tube before assembling.
You may also want to check your extrusion settings if these are wrong youwill also experience these problems.
The PTFE tube was cut exactly as specified in the manual. Nevertheless I will dismantle and attempt to remove and replace it. Will report back later.
Which extrusion settings are these?
Replaced PTFE tube. (Ends of removed one were clean) On restart fault still exists. When extruding manually clicking start occaisonal then becomes continuous.
What program are you using to slice? The clicking sound shows that your extruding is trying to extrude to much material.
It is also possible that your nozzle is clogged, If the extruder is trying to extrude but no plastic is coming from the nozzle. Pleas follow the steps described in the K8400 manual to fix this issue.
Previously mentioned that the solidified extruded filament diameter was 0.26mm. If this is low would suggest a blocked nozzle. Have you got a figure for this?
Do Velleman answer? Asked me to provide information, which I did, but no reply. Rebuilt the hot end with new parts. Extruded at 0.36mm so not blocked.
Printing 100 mm disc. Started on first layer OK for 8 minutes, then started the clicking again and filament jumpimg back became more frequent till almost no polymer being laid down. Changed filament - old came out OK New went in without problem and extruded. Laid down very little. On second layer (faster) nothing laid down at all. Changed feedrate and temperature - no effect.
Have checked and reassembled motor part several times including checking pulley for tightness and position. In any event I doubt if a loose pulley wouldn’t show the same symptoms.
The pulley grips the filament but cannot reliably feed it forward against the back pressure of the extruder. As if the motor is deficient in power/torque. It tries, feeds forward, cannot complete the step and gives up, pushing back with a click and a jerk upwards.
The extruder is clear. Extruding manually gives a filament 0.36mm diameter. Tried to get that value from Velleman - silence. Asked another contributer to check for me.
How high can the reference voltage be set? The motor runs cool at 1 volt - assuming I am checking correctly
Increased extruder reference voltage to 3.6 versus recommended 0.9. Printer worked without previously noted symptoms of dodgy feed. Motor only warm after 1 hour. Is this likely to damage the motor?
