Y-axis off -4,4%

[supermange 0]

Hello again,

i have a slight problem with my pre-owned UM.

It seams that the Y-axis is of a bit.

I modeled a reference object (20x20x20mm cube) in sketchup and exported to stl and then printed with cura.

The object came out: 20,00 x 19,12 x 20,46.

(Yes, there is a chanse of error as i have a cheap vernier caliper.)

Can someone please tell me on what "knob" to tinker?

(Yes the previous owner have installed belt tension clips).

Is there any easy way of adjusting this in like firmware?

br

Magnus

[joergen 2]

I make precision parts/prints with my UM, and I did work on the XY calibration long time ago.

Usually, a small object like this, seeing a 0.5mm error is somehow normal, and doesn't necessarily have anything to do with the XY steps/mm calibration that is ruling the general scaling and calibration of the XY.

if you print a 100mm object, you get a much clearer measurement how much error you are getting (which will most likely stay at the 0.5mm range, and not a percentile error as you indicate.

the 0.5mm error can be a couple of things:

- belts that are not tight enough, or too tight

- set screws for the pinion gears have some wobble

- the XY rods in the sliding blocks have play/slack

- over or under extrusion

- filament printed too hot and not cooled fast enough (you should see a difference between the fan side and the side away from the fan)

but in general, the nature of dealing with liquid plastic pushed through a tiny hole and cooling it always involves some error, no matter how precise the machine is (and the UM is pretty precise), but it is usually an absolute error, not a relative error.

[Daid 303]

I think you have some backlash on the Y axis, with something as simple as a cube this would show as a smaller print. Is the small belt on the Y motor tight?

[supermange 0]

I will check the small belt on the y-motor.

I will also print a 100mm "y-long" part. 5x5x100?

I have been trying to print a extruder drive upgrade, but all small parts especially round come out oblique.

I do print at a high temp (around 245 c) i dont get usable objects at lower temps...

[joergen 2]

I will check the small belt on the y-motor.

I will also print a 100mm "y-long" part. 5x5x100?

I have been trying to print a extruder drive upgrade, but all small parts especially round come out oblique.

I do print at a high temp (around 245 c) i dont get usable objects at lower temps...

you seem to have plenty of more fundamental problems: printing temp (for PLA) should be around 210C.

go back to the assembly wiki and check some more fundamentals, and read around on this forum, and on the google group for tips.