4. Z-axis assembly | Prusa Knowledge Base (2024)

⬢For this chapter, please prepare:

⬢2.5mm Allen key

⬢Needle-nose pliers

⬢For the following steps, please prepare:

⬢Z-bottom left (1x)

⬢Z-bottom right (1x)

⬢M3x10 screw (6x)

WARNING: Printed parts aren't the same! There are left and right pieces. See the protrusion (tooth) on each part. For the right side of the frame, there is a protrusion on the right side of the plastic part and vice versa.

⬢Attach both Z-bottoms to the frame and secure each part with three M3x10 screws.

⬢Tip: you can turn the printer on its back side for better access to the Z-bottom installation. It is recommended to place a cardboard pad under the printer to protect your workbench and the printer against scratches.

In case of increased resistance during tightening, try to run the screws through the threaded hole first without the printed part. Then remove the screws and attach the printed part.

⬢For the following step, please prepare:

⬢Z motor left (labeled Z-axis left, shorter cable)

⬢Z motor right (labeled Z-axis right, longer cable)

⬢M3x10 screw (8x)

⬢Rubber pad 42x42x2 mm (2x)

⬢To avoid accidentally discarding parts, prepare the trapezoid nuts from the motor box and keep them in a safe place. You will need them in a few steps.

⬢Place both rubber pads onto the motor surface. Make sure the holes in the pads are aligned with the holes in the motors.

⬢Place the Z motor left (short cable) next to the left Z-bottom.

⬢Place the Z motor right (long cable) next to the right Z-bottom.

⬢The motor cables must guide under the frame to the PSU (right) and xBuddy Box (left).

⬢Push each motor through the Z-bottom and secure it with four M3x10 screws. Do not tighten them completely at the moment.

⬢Guide both the Z motor cables under the frame towards the xBuddy Box.

⬢Connect the cables to the third and fourth slots on top of the xBuddy Board. Motor cable labeled ZL connect into the left slot, ZR into the right.

⬢For the following steps, please prepare:

⬢Trapezoidal nut (2x)

The trapezoidal nuts are included in the Motor kit box.

⬢M3x10 screw (4x)

⬢Smooth rod 10 x 325 mm (2x)

⬢X-holder (1x)

⬢Gently insert the smooth rods into Z-bottoms. Do not apply too much force and do not tilt the rod!

If the smooth rods are dirty or have too much preservative oil on them, wipe them with a paper towel.

Through the inspection hole in both Z-bottoms, check if the rod is completely inserted. There must be no gap between the smooth rod and the bottom of the hole.

⬢Carefully slide the X-axis assembly onto the Z-axis smooth rods.

⬢Secure the position of the X-axis to the frame. Engage the X-holder IN THE CENTER of the X-axis by the top smooth rod and then by the printer frame.

It is important to place the X-holder at the center of the frame and the X-axis. If not, the centering results could be inaccurate.

Centering the threaded rods of the Z motors is important. However, it doesn't have to be perfect. See the following instructions for more:

⬢Start with the right Z motor.

Take a look at the threaded rod from the top. The threaded rods should be close to the center of the X-end-idler hole as much as possible. The threaded rod shouldn't touch the surface of the printed part. See the third picture.

⬢PROCEED THE SAME WITH THE LEFT Z MOTOR.

⬢Screw the trapezoidal nut onto the right threaded rod. Note the correct orientation of the nut. The smaller diameter of the nut must fit into the hole in the X-end. If it does not, the threaded rod is incorrectly centered.

⬢Secure the trapezoidal nut with two M3x10 screws. It does not matter which holes in the nut you use.

There may be a small gap between the trapezoidal nut and the printed part. Tightening the two screws will cling the nut completely to the part.

⬢In the same way, install the second trapezoidal nut on the X-end-motor (left threaded rod).

⬢For the following steps, please prepare:

⬢Z-top-left (1x)

⬢Z-top-right (1x)

⬢M3x10 screw (4x)

⬢Place the Z-top-left on the rods and align it with the frame, and align the holes in the plastic parts with the holes in the frame.

⬢Use two M3x10 screws to attach the Z-top-left.

Don't use excessive force during tightening. In case of increased resistance, try to run the screws in from the other side of the frame first to "clean up" the threaded hole. Then return to the front side.

Tip: move the X-axis a few centimeters down for make some space if you can't reach the screw behind the rod.

⬢Repeat this step on the other side of the frame with Z-top-right printed part.

⬢Rotate both threaded rods in parallel to move the X-axis assembly a few centimeters higher to release the X-holder.

⬢Remove the X-holder from the printer.

⬢For the following steps, please prepare:

⬢LoveBoard (1x) included in the ELECTRONIX BOX

⬢M3x6 screw (1x)

⬢Move the X-axis assembly to the center of the Z-axis height.

Do not push on the X-axis assembly! Turn the threaded rods to move the axis.

⬢Move the X-carriage approximately to the center of the X-axis.

⬢Take the end of the extruder main cable without the white label.

⬢From the back of the printer, guide the extruder main cable to the front of the printer through the gap between the belt and the upper rod.

⬢Divide the twisted wires and straight cables from each other.

⬢First, guide the straight cables through the channel in the X-carriage.

⬢Then guide the twisted cables through the channel.

⬢Connect the extruder main cable to the LoveBoard. Leave the extruder main cable extended approximately 2 centimeters (0.8 inches).

⬢Attach the LoveBoard to the back of the X-carriage and secure it with the M3x6 screw.

⬢Very gently pull on the extruder main cable bundle to reduce the bundle on the connector side. There must be a minimal loop. Otherwise, the cable will interfere with other parts in the next chapter.

⬢The cables must not interfere with the extruder motor compartment.

⬢For the following steps, please prepare:

⬢X-carriage-cable-holder (1x) with the screw hole

⬢M3x40 screw (1x)

⬢Push the M3x40 screw through the X-carriage-cable-holder.

⬢Attach the X-carriage-cable-holder to the X-carriage underneath the extruder main cable and tighten the M3x40 screw.

Do not pinch any wire of the extruder main cable!

⬢For the following steps, please prepare:

⬢X-carriage-back (1x)

⬢Rubber pad 20x10x1 (1x)

The rubber pad 20x10x1 can be found in the Z-AXIS bag.

⬢M3x18 screw (2x)

⬢M3x10 screw (1x)

⬢Nylon 3x555 mm (1x)

⬢Place the rubber pad into the rectangular pocket in the X-carriage-back.

⬢Insert one of the bent ends of the nylon filament into the hole located on the left side of the extruder main cable channel in the X-carriage.

The nylon filament must CURVE UPWARDS. Not down, not to sides. See the detail.

⬢After the nylon filament holds in the X-carriage, check that it inclines upwards as seen in the picture. If it is pointing down instead, re-install the nylon filament into the X-carriage by the other bent end and check again.

⬢Before we cover the back of the X-carriage, make sure that:

⬢the upper bearing is in the pocket inside the X-carriage and the marking is facing you

⬢the nylon filament is pointing upwards

⬢Place the X-carriage-back on the X-carriage and arrange the main cable wires like in the picture.

Be careful, no wire must be pinched!

⬢Secure the X-carriage-back with two M3x18 screws.

⬢Insert and tighten the M3x10 screw into the upper hole in the X-carriage-back.

⬢For the following steps, please prepare:

⬢Textile sleeve 8x520 (1x)

There are three different textile sleeve sizes in your kit package. You can always make sure by comparing their lengths.

The ends of the textile sleeves are heat-sealed at the factory to prevent ripping. To open them, the sealed end joints must be cut or torn.

⬢Zip tie (2x)

⬢X-carriage-cable-holder-cover (1x)

⬢Push two zip ties through the X-carriage-cable-holder. See the correct orientation of the zip ties.

⬢Wrap the extruder main cable and the nylon filament near the X-carriage with the textile sleeve. Keep a 1 cm (0.39 inches) gap between the sleeve and the X-carriage. Wrap just this part near the joint, for now, we will continue wrapping the bundle in the next step.

⬢Cover it with X-carriage-cable-holder-cover.

⬢Tighten both zip ties so that the "heads" fit into the pockets in the plastic part. Cut off the excess zip tie.

It is important that the heads of the zip ties are seated in the pockets. Otherwise, they may collide with the printer frame during X-axis calibration and the calibration could fail.

⬢Wrap the textile sleeve around the extruder main cable and nylon filament.

⬢Proceed in a spiral motion around the bundle so that it is tightly bound together.

⬢For the following steps, please prepare:

⬢Ext-cable-holder-b (1x)

⬢Ext-cable-holder-a (1x)

⬢Zip-tie (1x)

⬢M3x18 screw (2x)

⬢M3x10 screw (2x)

⬢M3nS nut (2x)

⬢Textile sleeve 5x300 mm (1x)

⬢Wrap the X motor cable to the textile sleeve.

It's alright that the textile sleeve doesn't go over the full length of the motor cable.

⬢Insert two M3nS nuts all the way into the Ext-cable-holder-a.

⬢Take the bent end of the nylon filament. And locate the hole in the Ext-cable-holder-a.

⬢Push the bent part of the nylon filament into the hole in the Ext-cable-holder-a.

⬢Guide the extruder main cable freely from the printer. Do not twist or rotate it.

⬢Guide the X motor cable freely from the printer.

⬢Insert the extruder main cable in the cable channel in the Extr-cable-holder-a.

⬢Take the X motor cable and guide it over the extruder main cable through the left channel in the Ext-cable-holder-a.

Guiding the X motor cable behind the main cable could cause problems with axis travel when printing.

⬢Cover the cables with the Ext-cable-holder-b and secure it with two M3x18 screws.

⬢Secure the Ext-cable-holder together with the zip tie in the groove. Tighten up the zip tie and cut off the excess of the zip tie.

⬢Push the X-axis motor cable and the extruder main cable through the hole in the xBuddy box to the electronics.

Double-check that the X motor cable does not guide behind the extruder main cable. Compare it with the picture.

⬢Attach the Ext-cable-holder onto the xBuddy box with the two M3x10 screws.

⬢Leave the cables free in the xBuddy box for now. We will connect them later on.

⬢According to the third picture, compare the guiding of the extruder main cable. Note the curve of the cable guide.

⬢Compare the guiding of the X motor cable.

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⬢Compare your build with the picture.

⬢Everything is right? Congratulations! You have successfully assembled the Z-axis with some other small things.

⬢So, let's continue with the next chapter: 5. Nextruder assembly