I bought a K8400 and build it in the weekend. The instructions were clear on the website and followed, however I have some issues with moving the printhead…
[ul]
[]The printhead can’t move when it’s in his home position, there’s to much pressure between the rods and the printhead. The steppermotors can’t handle this and lose their steps[/]
[]I alligned the rods like in the manual[/]
[]The belts are really tight, I don’t have any idea to make them less thight. I think this a part of the problem[/]
[/ul]
Is there an easy way to allign them totally perfect? I saw something here on the forum however I don’t have acces to a 3D printer at the moment.
Like stated in the manual, you can try this : [quote]If the resistance increases in any way when you get close to the any of the panels with the
printhead, it is possible that the distance between 2 of the XY CARRIAGE CLAMPS is not
correct. You can try to fix this by pushing or pulling these together a bit and seeing if the
problem improves.[/quote]
[quote=“minitreintje”]
The belts are really tight, I don’t have any idea to make them less tight. I think this a part of the problem
[/quote]Just loosen the bolts on the ‘V’ clamps on the belts and wiggle them a little. The harder you tighten the clamp, the lower the V goes, the tighter the belt.
So I realligned everything again and it’s much better now! The axes move smoothly.
I have only 2 problems left now:
[ul]
[]I lose steps on the X axe when changing direction. The belt on the motor seems to be the cause?[/]
[]The Y-axe blocks when it is very close to the endstop. If I extend the carrige endstop trigger by ± 1cm the problem is away. Is that the right solution?[/]
[/ul]
[quote=“minitreintje”]Thank you all! It’s now working perfect!
Cheers,
Dylan[/quote]
However, when I started printing, the X-axe sometimes lose his steps. I fixed the X-axis motor again and it’s better but the problem only appears now during printing.
[quote=“minitreintje”]
However, when I started printing, the X-axe sometimes lose his steps. I fixed the X-axis motor again and it’s better but the problem only appears now during printing.
[/quote] Did you loosen your belts? That’s the first thing to try when you miss steps. Loosen the bolts on the little ‘V’ clamps. You might have to wiggle them a bit to get the belts to loosen. Get them as loose as you dare but so that the clamp still holds and try that. If you still miss steps during a print, then the motor may be at fault.
Try again to modify the distance between the carriage clamps (usually they’re to close from each other).[/quote]
In my case they were way to far from each other. The clamps really have to be aligned very thoroughly and I think the manual is a little too vague on this point.
With a transparent ruler I aligned the belts with their pulleys, so that’s alright.
The X-axis still have the problem of shifting layers. I tried everything in the section ‘Troubleshooting - Shifted layers’ but the problem still exist.
I tried your tip and it’s still the same. I am trying to print the 8mm help rod from thingiverse to align the XY of the K8400.
The slip occurs after he printed the initial layer.
Yes I did. I also realligned again the rods to be sure and I moved the fan for cooling the electronics near the motherboard to achieve a higher cooling rate.
The shifting problem now happens on the Y-axis also.
The Gcode has been made with Cura 14.12.1, printed from SD-card at 50 mm/s print speed and 100 mm/s travel speed.
Filament flow 90%, motion settings in the Vertex menu in the printer are the one from Velleman/factory.
Repetier doesn’t do well on Linux (I don’t have a Windows PC) since the problem is worse with Repetier
I don’t know anymore how to fix it, I tried so much without any result.
Next thing you could try : lower the acceleration data from 10000 to 5000 and from 6000 to 3000 (in the EEPROM settings - sorry you’ll need Repieter to do this or you’ll have to modify them in the firmware - in that case once the firmware uploaded, don’t forget to go into the LCD Menu : load defaults/save).
Sorry Raby but I would not recommend this. Minitreintje, you clearly have a mechanical problem which needs to be solved. Default parameters work and you first need to get a correct print with them before even thinking of changing them.
I have also had quite a few issues with getting the X and Y axis to work smoothly. I think that the instructions are not very clear on the amount of effort it should take to move them manually. Let’s make it very clear: when the belts are not attached, both X and Y axis shall move very smoothly with almost NO resistance. While you don’t get that it is useless to continue..
There’s only one parameter that shall be adjusted and that is the distance between the carriage clamps, because the distance between the rods is given by the holes for the bearings in the printer walls so this is a fixed value. The parallelism is also good and cannot be adjusted. The only reason something could not be right there is if the frame has not been properly adjusted (such as gaps between the Plexiglas pieces).
If you push the printing head rods fully in the clamps you will end up with something that matches the measures that are given in the instructions. For most people according to what I read in this forum this is a bit too short and doesn’t allow the axis to move freely, but it is difficult to get (or know) the exact required value as there’s some imprecision in measuring with a measuring tape. So here’s what worked for me:
Loosen all the pulleys on the rods, pull the rods on two sides so that you can remove the printing head assembly with its two rods.
Make sure that the clamps are fully inserted on each side
check that you get something really close from the distance values in the instructions
Reassemble everything but do not tight any pulley
make sure the printing head moves freely on the X and Y axis
if it doesn’t (it blocks near on end or the other), it should be because the distance between the clamps is too short. The best way to adjust it is to hit the clamp with a small hammer (to the ouside of the printer). Be careful, I do not take any responsibilities! I did put a piece of cloth on the rod to make sure that it will not be damaged by the hammer. We are talking about a couple of 1/10th of millimeter.
Once again, no need to do any other adjustments until you get the printing head moving smoothly with almost no resistance.
jf2020 all this has already been said many times in the previous posts so I had to suppose he did check everything and his axis are moving smoothly.
Lowering the acceleration is a last resort action but can’t do any harm.
I successfully printed the 2 aligning pieces now but after that the K8400 had again the shifting problem.
I realigned the K8400 again for the 4th time (!) but now with the 2 aligning pieces from Thingiverse. The axes are now running without ANY resistance even when I attach the motors.
I also found out that 1 pulley wasn’t fixed anymore but I fixed him yesterday… I repaired him like someone in the pulley topic.
Maybe that pulley was the cause…
I am now printing the Z-axis stabilizer from Thingiverse for the K8400. I hope he will finish it without any problem, the print job will take about 3 hours, if there aren’t any problems.
When building the Vertex, my xy-rods didn’t move that well either. That is when I discovered that lowering the acceleration helped quite a bit but immediately the prints started to show a lot of unwanted stringing. That is when I decided to build the alignment rods AND re-define the length between the xy-clamps.
I mounted the xy-rods without the printhead attached and figured out the correct distance between the clamps. I don’t know for sure anymore but it was something like 0.2-0.4mm wider then what the manual says. After making sure the xy-rods moved as smooth as possible, I measured the distance precisely, took it all apart and mounted the print head based on the newly found distances. Then, aligning with the calibration clamps was very easy and since then I do not have any movement/shifting issues anymore.
The distance between the clamps if extremely important, although I remember the manual states it should be ‘about 32.8cm’, which is incorrect and not precise enough.
