I bought a K8400 printer and assembled it, small prints are fine but when I try to print something bigger layer shift happens randomly.
When I start the print sometimes after 10 minute layer shift, other times after 4 hours layer shift.
I checked the distance between the clamps seems ok, when I move the print head by hand It feels smooth enough not much resistance.
I used the printable tool (XY-Carriage Alignment Helper) to check the rods and adjusted them.
I checked the panel, multimeter shows around 0.91 V for all three boards.
I reassembled the print head carriage rods hoping to find the problem but nothing so far. (I also use oil on the rods)
I have no other problems circles are fine , sometimes I can print a small enough object without shifting.
The shift only happens on the Y axis.
Edit:
Modified the Vxy-JERK value from 10 to 5 then 2 , no improvement.
If anyone has any Idea whats going on or something I can try to solve the problem please help. Thank you!
You can measure the reference voltage on the steppermotor drivers to make sure they are calibrated ok from the factory but see this as a last resort because this problem is mostly due to calibration and lubrication.
That was the first thing I tried to solve. I noticed that some air was stuck between the rod and the clamp and It pushed the rod out. (I drilled a small hole)
I reassembled the case and the printhead rods, pulleys twice but the Y axis is still shifting randomly.
The Wiki shows some basic information about this but nothing specific my Y axis can shift because " a lot of reason" but thank you for the advice.
It’s just sad to see what is this machine capable of when It’s working, but mine is just dead weight for now.
If the problem still persists, swap the X and Y drivers on the controller board. If itś a faulty driver, you should now get a shifting problem on the X Axis instead. Remember to power off the printer before attempting this.
Swapped the drivers the problem still persists.
I made a wooden gauge to check the distance between the rods of the Y axis the distance seems good enough.
I also measured all four sides of the case and measured it diagonally, found no significant difference.
When I slowly move the Y axis I barely hear the sound of grinding but I can’t find the source of the noise. (very silent noise)
When I move (only when I move it slow enough) the printhead diagonally I also feel some twitch like resistance (like rubbing against something) while the rod or the stepper motor is rotating.
Layer shifting is nearly always down to the head meeting resistance as it moves. That’s really only explanation.
So what are your options? First undo the belt clamps and take off the belts. Check the head moves with zero resistance (I mean zero) in all directions, the full length of travel. If there is any resistance whatsoever with the belts removed, then your rods are not parallel. Fix.
Then place the belts in their clamps and tighten them to the absolute minimum that will stop them falling out. Is there any resistance at the end of the rods? Generally as you tighten one belt, it pulls those rods towards each other, making it harder for the head to travel towards them on the opposite axis. Have you made absolutely sure your belts are parallel and not rubbing anywhere (look for black dust underneath)? Finally, check the belts on the stepper motors. Make sure they are mounted normal to the drive wheel on the motor and not too tight.
It’s basically a methodical process of eliminating all the possible areas that could cause any resistance to the head movement. Layer shifting often happens after a period of time. When I suffered from it, it would often take an hour or so to happen. It’s extremely frustrating, but I can promise you that the cause is nearly always mechanical. Usually the belts are simply over tightened in their clamps, which is a simple fix.
Yes I agree with you that the problem is mechanical, but It is a very frustrating one indeed. I need to check every component multiple times, reassemle the kit a half a dozen times. I am a bit disappointed.
I print a different type of clamp top which I found on the forum to check if the belts are too tight with the vertex one.
I’m thinking about printing two new clamps with 10mm inside diameter for the rod and use copper bearing in them.
I also have some suspicion about a slight misalignment in the plastic XY Carriage component with the bearings in the print head, I will check It out.
Today I noticed a scratch on the front panel the screw ends in the clamp are rubbing against the plastic case.
It did not solved the shifting but one less problem left. kepfeltoltes.hu/view/150618/ … es.hu_.jpg
“Edit”
I reassembled the XY carriage of the print head and my shifting problems are gone. I think there’s a small gap between the plastic parts wich makes it possible to misalign the bearings while the rods are parallel giving the same error as misaligned rods.
I would like to know if I can buy a spare nozzle (just the Nozzle) somewhere?
