Starts perfect, then Layer offset on y axis

Hi

I recently bought at Reprappro Mendel, and just started to print with a decent result.
But sometimes when i print comes a big problem. As you can se on the first picture , it starts perfect, but then suddenly the layer gets an offset on the Y axis? it moves with the same amount in every layer.

The belt are tight and the speed is slow, could it be a g-code fault? you can se the printset.pdfprint settings in the attachments.

Hope you can help

Regards Morten

It looks like you are missing steps on the Y axis. Does it do this on every print, or just "complicated prints" (if you print a calibration cube, does it work?)

In any case, you may want to try increasing the current to your Y stepper motor, and check that the table moves freely.

If it is happening on complicated prints, try turning down your acceleration and xy jerk setting. If you are using RAMPS, Marlin and have the eeprom enabled, you can do this using the following G codes (even doing it mid-print works):

M503 : show current settings

Here is an example of mine
PC>M503
SENDING:M503
PC>echoteps per unit:
PC>echo: M92 X22.22 Y22.22 Z200.00 E685.00
PC>echo:Maximum feedrates (mm/s):
PC>echo: M203 X5000.00 Y5000.00 Z8.00 E1200.00
PC>echo:Maximum Acceleration (mm/s2):
PC>echo: M201 X5000 Y5000 Z8 E1500
PC>echo:Acceleration: S=acceleration, T=retract acceleration
PC>echo: M204 S1500.00 T1500.00
PC>echo:Advanced variables: S=Min feedrate (mm/s), T=Min travel feedrate (mm/s), B=minimum segment time (ms), X=maximum xY jerk (mm/s), Z=maximum Z jerk (mm/s)
PC>echo: M205 S0.00 T0.00 B20000 X10.00 Z0.30 E5.00
PC>echoID settings:
PC>echo: M301 P22.20 I1.08 D114.00

If you want to change the value, let's say I wanted to turn my acceleration down from 5000 to 1000 (yours may differ!), I would do
M201 X1000 Y1000

Don't forget to save the settings once they are working (M500). You may also want to change them in your Configuration.h so if you ever do a "restore to factory default"(M502), they will get decent values.

If you are not using Marlin, your firmware may do this too

I had this problem. Tried changuing g-code, motor drivers, acceleration etc etc etc. It actually turned out to be a faulty y-axis stepper motor. Your problem looks the same, you can test it by swapping the y and x axis motors.

Hey mitchese and busyman

Thanks for your fast answer and sorry my late reply, but i had some water damage i my flat.. took all my time

I turned my acceleration down to 1000 and now it works perfect!

Busyman, I too experience this problem, and will first be trying acceleration as I can painless edit it with marlin, but are you suggesting I could swap the x and y motors, or simply plug them the x into the y socket, and the y into the x socket?