Hi folks
In the past the forum helped me solving some problems, thanks therefore.
Today I´ve another problem calibrating my Kossel XL.
The plan was to adjust the extruder height in the positions immediately in front of each pillar. Theoretically I define an even layer, which provides all the same height at each XY position over the heat bed. But that was just theory. Real life teaches me, that the even layer is more or less bowl shaped, so the center touches the heat bed.
I´m sure, there is a special command which is used to make a correction and I´m also very sure, many of you know this command, well I don´t.
So please could you help me?

Thanks
Nik

Hey there,
I’ve a question concerning the extruder. When I extrude manually 100mm of filament by using the function at the web interface the extruder spends round about 148mm in real life. I suspect that the printer uses too much filament while printing, because the slicer doesn’t know anything about the device. The G-Code just tells the printer to use a specific amount of filament and the printer think he’s right. So far so good. I watched out for reducing the extruder values, but I didn’t find it in the config. After consulting the chapter “Choosing an extruder drive” I’ve learned that somewhere the gear of the extruder is defined. My extruder is equipped with a gear of 5 2/11:1. (What an unaesthetic value, but that’s it)
My question is where to set this value.

Thanks
Nik

Hey folks, thanks a lot for your great hints, but I think I had a break through tonight.
To say it with monty python: and now for something completely different!
While tinkering at the Kossel, swapping the motor assignment, trying this and that suddenly the stepper at the suspicious pillar made a real bad sound. Great, finally there was something I could track.
To make a long story short: it was the gardener . OK, no. What my problem was, is the tube, which leads the filament from the extruder motor to the hot end. The extruder motor is mounted at the “tricky” pillar as recommended in the manual. A PTFE tube act as a Bowden guide. Although this tube is installed in a gentle arch it acts as a spring, especially when filament is pushed through. This push impulse has influence on the balance of the Kossel print head.
As the last test this night I printed my cube while relieving this “spring” by holding the tube so it going in the print head relaxed.
And … surprise: the cube is really a cube. All the other actions and theories was just ghost-hunting.
Now I have to think about installing the Bowden tube in a relaxed way.
Nik

That idea sounded just too simple, don’t you think?
Increasing the current leads to …. nothing.
The test cube is still shifted.
What I’ll try next is changing the motor (pillar) assignment on the board. Due to the symmetric setup of the Kossel type printer that seems to be possible without any risk. Thereby I can encircle the source of my problem. If it’s a problem with the board, the shifting direction of the print also will move to the new assignment, if there is a problem with the mechanical setup (incl. motor) the failure won`t move.

Yes, there are flats on the motor shafts and surely all grub screws are tight and aligned.
Let me see if the real world follows the theory or has its own physics…
I`ll report later…
Greetings
Nik

What do you mean with movement system?
The printer is a KosselXL. Obviously there is nothing the print head or the slider could be catching on. All Belts are tight, the motors can be moved freely and sound like they expected to.
In the mean time I discussed the problem with a friend of mine and we have the idea to turn up the current a bit. The idea is based on the following fact: the shifting direction leads always to one of the pillar so the consideration was, that there might be something with the motor in this corner. Well, the failure and its symmetry points out a systematic error. If, theoretically, this stepper is losing some steps while going to the next layer (z-movement) the slider wouldn’t reach the correct height and the diagonal rod takes care that each layer is pushed in the opposite direction. So far the theory.
What I try next is increasing the limitation of current for the motors (60% to approx. 70%) to insure the correct behavior of all motors.
Thanks

Hallo,
Have anybody ever had problems with a shift of the layers while printing?
OK, let me explain the problem.
I constructed a calibration cube 20mm edge length. After slicing, using Kisslicer, I started to print. The print went well without any warning. The result: a test cube with shifted layer. Each layer shows the values 20 x 20mm, but every layer is shifted about approx. 0.5mm to the prior one, all in the same direction.
What I did next was checking the g-code from Kisslicer, but the data seems unremarkable to me. For cross-checking I unload the filament and fix a pen at the printer head instead. The sketch shows the explained behavior.
Have you ever seen a printing behavior like that?
Or is it a problem with Kisslicer after all?

Greetings from Germany
Nik

Oh wow, this was it! Thank you so much. After updating the driver everything works well.

Hey,
Maybe there is already a thread concerning my problem, well I didn´t find it. In feb. 2017 I ordered a Kossel-XL from a distributor from the Netherlands with a Duet Wifi board (343/500).
Well, first the board did its job very well although the board just was configured for a Kossel-Mini. First I changed this configuration which worked well more or less.
Then I found a config.g in the download space on the page of the printer distributor for the KosselXL / Duet combi.
I made an upload of this config via the web interface on the board. Well, what can I say: what a stupid idea. After that nothing works anymore. No web interface, no connection to pronterface, nothing.
OK, I said to myself, it’s time for a firmware update. The usual procedure doesn’t work cause there was no web interface. Fallback procedure #1 and #2 doesn’t work either for some reason. The Windows-PC didn’t see the Duet board. But… option #3 seems to work. With the SAM-BA 2.16 the PC sees the DuetWifi (Yippeeeeee!).
After sending the fresh downloaded DuetWIFIFirmware.bin (1.18.1) and proceeding the other recommended steps I pressed the Reset bottom at the board followed by the typical “pling-pong” sound when a USB-device is disconnected, also the “Diag-LED” turns off.
Connecting the board via pronterface was still not possible.
After spending quite a couple of nights trying to fix the problem by myself now I´m desperate.
How can I fix the problem, what was my mistake? Is it possible to get back the state of delivering at least?
The distributor in the Netherlands is: http://builda3dprinter.eu/ There you also can find the config.g where the trouble began with.
Greetings from Germany
Nik