Hello,
I have a strange problem. The part is well printed except… some layers ! Do you have any ideas where this problem comes from ?
And I’m quite impressed the printer sucessed to finish the part !
Thank you for your time !
Good prints !
Hi,
Do you see anything in the log area about end stop hits?
If so you should check the solder joints for that end stop.
You should also upgrade the firmware to V2
You could also try setting the reference voltage for the motors to 0.55 instead of 0.425
The end stop ? They are only used at the beginning, they don’t infer at the end of the printing, do they ?
I bought the VM8201, so I’m going to upgrade in few times.
The voltage for the stepper motor is around 0,6V. It’s not the Velleman extruder (I broke the part which you must not break ^^").
EDIT : I measured 61°C for 0,6V. What is the max temperature for the stepper motor driver ?
I set the E-driver to 0,48V and I measured 51°C.
Looks like the spool holder is jammed and less filament is fed to the extruder. Do You use a stock spool holder?
Hi Lmecano,
only in V2 of the firmware the endstops are disabled after the first layer. If you’re still on V1 they will matter all the time.
seems to me that for some reason your extruder output is not constant. Jammed filament might be an issue.
Regards,
BigDee
I’m agree with you, sometimes I heard “clack clack”. I set up the wire tension and add an heatsink on the E stepper driver.
I’m using the original stock spool holder, that one :
I upgraded my firmware to the V2, don’t forget to uncomment the EEPROM chitchat line to get the EEPROM access on Repetier !
I printed some small parts to see if the problem occurs again and I’m trying today to print the K8200 boardcover !
I’ll keep you in touch,
Thank you for your help !
I’m back with some news !
The extruder was guilty ! He asked to much current from the driver and sometimes, he lost some steps !
I fixed the original Velleman extruder and mount it, the printed part are less accurate (wrong setup, I guess) but there is no lack of plastic !
To help the driver to evacuate the energy, I glue with epoxy a heatsink with a thermic pad.
Besides, I find something strange in setup for Velleman extruder, the extrusion multiplier is to 1.15 and with 600step per mm, I don’t extruder the right amount of plastic. I guess the 1.15 factor is here to correct the step per mm and extrude the right amount of wire but… why not enter the right number of step per mm ??
Thank you for your help guys !
Hi,
Are your gears to close together?
Is the Hobbit bolt to tight?
[quote=“Wrong Way”]Hi,
Are your gears to close together?
Is the Hobbit bolt to tight?[/quote]
Yep, there is no angular clearance between gears.
I just turn it 1,5 turns. If less, the wire slips and more, the stepper motor can’t drag the wire.
However, I have another problem, I fixed the original Velleman extruder but I lost the washer and so, some PLA leaked from the hotend…
The 600 steps per mm is based on the theoretical diameter of the feed roller. It’s not a high precision part and the amount of filament fed through the roller depends on the pinch roller pressure because it changes the effective pitch diameter.
Calibrate your extruder;
I try to calibrate the extruder, but thanks to the leakage, all my measures was corrupted…
I just mount the new extruder and will try to calibrate it with ABS. I don’t like ABS 
But which parameter I have to update ? Extrusion multiplier or step per mm ?
In my opinion, the extrusion multiplier should be 1 and we have to update the step per mm…
Either will work, but like you I feel that the multiplier should be set to 1 for normal use and maybe tweaked temporarily if top fill is not satisfactory.
I updated the E step per mm at 645,5 ! And set-up the extrusion multiplier at 1.
This extrusion head is f**** sh***, I’m wondering which kind of engineer design that.
The only thing which avoid the shaft to go away is a tight fit with the cool end. However, the shaft is in steel and the cool end in aluminium. Yeah !
The result is here during an extrusion :
I’m going to glue the shaft… and design myself a new extruder…
Besides, I think I’m going to have a problem with Velleman’s gear, after some parts, the nylon nut unscrewed itself and some radial clearance appears in main gear shaft. I’m going to replace the nut it and see.
The glue hold the extruder, there is some leakage but… I guess it’s ok. I should buy the E3D V6, the coolend and hotend are link together buy a thread, not a tight random clearance.
I printed the K8200 coverboard again and it’s quite good except some oozing, no layers are missing however… What is dat mess ? Why only some layers don’t stick to other ones ??
Amazing problem, I guess ^^
I could be wrong but most of the hot ends I have seen with the cooling fins on them have a fan to dissipate the heat.
Does that one not need it?
[quote=“Wrong Way”]I could be wrong but most of the hot ends I have seen with the cooling fins on them have a fan to dissipate the heat.
Does that one not need it?[/quote]
Do you think the wire is jamming in the cool end ? I had that problem when my first trials and I’m now using the original fan at 30% on the extruder/cool-end like that :
PS : You could see the PLA pool between the cool end and the hot end ! ^^"
I have just printed the VM8201 coverboard and… except oozing, no problems ! I’m thinking about an environmental problem, some vibrations (as I post in another thread, the current is cut in coil when the motor is unused).
The fan that comes with the K8200 is to cool or cure the plastic once it’s the layer is put down.
If you go to thingiverse and search E3D you will find a lot of fan mounts for the cooling fins.
This will not fix the leak though.
Just wondering why you are not using the default hotend that came with the K8200.
[quote=“Wrong Way”]
Just wondering why you are not using the default hotend that came with the K8200.[/quote]
For a simple reason, I have broken the nozzle part with the thread ! And I prefer - mechanic obliged ! - have a full metal hot-end, in particular to work with ABS.
Besides, the original hot-end has a problem, it unscrews itself with vibrations !
I’m back !
Every huges problems are fixed !
The problem was plastic delamination, I followed the triffid hunter guide for nozzle temperature and found 175°C. It was wrong, that PLA needs to be extruded at 185°C and 190°C for the first layer.
Besides, I modified the set-up of wire tension with the screw and so… It changed my E step. I’m now at 703 step/mm for E-motor. I was at 645.5 before.
And, I added an 24V supply for the bed. It’s faster to heat up the bed to 60°C for PLA, but I have to wait around 20min to reach 110°C.
For information, I added lots of ferrite cores and increase driver voltage to 0,6V for X-Y axis or theses axis lost steps.
Moreover, I added an voltage regulator to get 12V for the motherboard fan and cool end fan.
And… I observed the Z axis is wobbling so I update the Z axis with flexible coupler.
Sphere in sphere in sphere !
New Z axis
Electronic
Thank you for the help 