bed center adjustment

A Former User

A Former User

@sgk
I am 0.5cm from the edge of the bed

jay_s_uk

@sgk that offset is your probe offset and not a homing offset. you should make sure your G31 values on config reflect that

A Former User

@jay_s_uk sorry I don't know how to make the adjustment I won't have how can you help me to do this?

MintyTrebor

@sgk Assuming the carriage physically travel any further left then that photo indicates you should set your config initially to:

M208 X0 Y0 Z0 S1 ; Set axis minima
M208 X350 Y350 Z350 S0 ; Set axis maxima

you can then make fine adjustments to these values to get perfect center position.

A Former User

@mintytrebor ok thank you but is it where I have to change the values so that it is in the center?

A Former User

@sgk M671 X-30.0:364.0 Y175.0:175.0 S5.0 ;bed compensation
G30 P1 X5 Y150 Z-99999
G30 P0 X300 Y150 Z-99999 S2

here?

mrehorstdmd

@sgk It seems to me you're confusing the home position and the origin. Home is where the endstops are located. When you home the machine, the motors should drive the extruder carriage toward the endstops. The location of origin is entirely up to you and is determined by the values you use for axis minima and maxima, not by the endstop locations.

Slicers put prints at the center of the bed. One advantage to putting the origin at the center of the bed is that it's super easy to set up in different slicers without resorting to custom gcode.

If the maximum length of the movement of the X axis is 400 mm and the bed is 350 mm wide, the difference between the X min and X max vales should be 400. If you want the origin at the center of the bed, measure the distance from the center of the bed to the minima or maxima and put the appropriate values in the M208 statements. For example, if the left edge of the 350 mm wide bed is at X min, then the center of the bed will be 175 mm away from the left edge. So set Xmin to -175 and set Xmax at 225. Do the same for the Y axis.

A Former User

@mrehorstdmd thank you for your explanation, it's true that it's not easy when you've done it like me.
I'm going to try in m208 I must put the minimum and the maximum in relation to the center that's good.
if as you say the bed is 350x350 then half is 175 for the x and -175 y

A Former User

@mrehorstdmd but which line determines the center?

engikeneer

@sgk when you home an axis (with a G1 H1 homing move), what happens is:

the axis moves (in the direction set in your homing file) until the endstop is triggered
at that point, the axis position is set to the value from M208. If you have low-end endstops (like on your printer in the x direction), it sets the axis position to be the axis minimum. If you have high-end endstops configured, it sets it to the maximum (like on your y-axis).

This means that you can put the origin (0,0) anywhere you like. I have mine at the front left of the bed. Some people put theirs at the centre of the bed (like you are now trying)

So you need to set your axis minimum and maximum values so that 0,0 ends up at the center of the bed.

My guess is that you want someone like:

M208 X**-170** Y-175 Z0 S1 ; Set axis minima
M208 X175 Y**175** Z350 S0 ; Set axis maxima

But you will need to modify the x-min and y-max values a bit to get 0,0 dead in the centre of the bed.

When you've done that, you'll need to update your slicer to have 0,0 in the centre.

A Former User

@engikeneer Ok thank you for the explanation I will modify to see what it gives

mrehorstdmd

@sgk The center is the physical center of the bed. Use a permanent marker to draw lines on the bed across diagonal corners. The center is where the lines cross.

The easiest way to think about it is draw the lines as described and think of that point as the origin. Setting up min and max for each axis is simply measuring from that point to the min and max travel positions of each axis. Those values go into the M208 statements.

In the slicer, the printer's min and max limits don't matter, only the dimensions of the printable area of the bed. PrusaSlicer assumes the origin is at the front left corner. You use offsets to move it to the center of the bed like this:

alt text

In Cura, just give it the bed dimensions and check the box that says "origin at center".

I wrote an explanation of this stuff here: https://drmrehorst.blogspot.com/2018/07/ummd-better-way-to-set-up-origin-and.html

A Former User

@mrehorstdmd look

dc42

@sgk perhaps you just need to tab the cursor away from the Y origin box?

A Former User

@dc42
if the right side moves away the nozzle comes out of the bed