Edit 11-02-2021: Added the Fusion360 file since I don't have this laser anymore.

This is an adjustable bed for the K40 laser cutter

The stepper controller works on 5 volts

Here is a list of parts;

-Belt 1250mm long 6mm wide aliexpress.com/item/32299384151.html
-Stepper motor controller (dont use speed 8/9 it'll overheat) aliexpress.com/item/32468170000.html
-Pulleys 2x "B 5mm bore no teeth" and aliexpress.com/item/32880405344.html
-Pulleys 4x 8mm bore 10mm width aliexpress.com/item/32878397240.html
-Pulley 1x width 10mm bore depending on the stepper motor that you have aliexpress.com/item/32950329455.html
-608 bearings 8x, buy them from anywhere
-T8 100mm leadscrew 2mm pitch 2mm lead with a matching flange nut 4x, I bought them on amazon
-m8 washer 4x, to be placed between big pulleys and the lower bearings.
-A stepper motor, this design is for any stepper with the same shape as a Nema17

-4x 180mm square tube 20mmx20mm 1.5mm thickness
-4x 280mm square tube 20mmx20mm 1.5mm thickness

-Some m3 nuts and bolts for the leadscrew nuts and attaching the stepper motor.

The tubes are press fit, but holes for bolts are included in the 3d models.

Some sort of sacrificial plate has to be placed on the top tubes. I just attached it with double sided tape.

The motormount goes below the left rail. Attach it to the tubes AFTER placing it there; you can't place the whole assembly in the k40 in one piece