K40 Laser Z Table

thingiverse

My take on a motorized Z table for the ubiquitous K40 Chinese laser is a low-profile design that takes advantage of the confined space in the laser. Min/Max heights (as built) are 1.5 inches and 4 inches, respectively. This allows for easy removal to switch out to a rotary Z axis if desired. Two 608ZZ skateboard bearings or similar are pressed into each corner. A small arbor press or drill press is needed to seat the bearings. The bottom end of the lead screw is tapped for 8-32 low-profile Phillips head screws to retain the shaft/sprocket assembly in the bearings. Preload removes any play, preventing side-to-side movement in the table. Drive sprockets are 20 and 40 tooth GT2, and the belt is a 1350mm long, 6mm wide 675 tooth. An 8mm lead screw and matching brass nuts are used. The stepper motor is the standard issue 90oz torque NEMA 17 bipolar model. I designed the corner parts mounting holes to be helicoiled with 8-32 x .188" inserts for added fastener strength. Nuts and bolts can also be used. A setscrew will be used in the center of the three holes to level the device in the cabinet, as the sheet metal has more waves than Lake Michigan on a calm day. A 2.5 to 3-inch hole must be cut in the bottom of the cabinet for the stepper motor. The cabinet will need to be boosted about 2 to 2.5 inches above the table it is sitting on. I opted out of leveling screws and used some shim washers to set the unit level instead. Four .750 cup magnets are screwed to the underside, allowing easy removal and installation of the table. Additionally, I have designed, built, and tested a limit switch for this Z table. Hopefully, I will get time to post the details soon. It's cool to turn on Smoothie, hit home, and then go into Light Burn, specifying material thickness and having it self-adjust.