3. X-axis & Extruder assembly

Relevant for:

MINI+

Last updated 6 months ago

Difficulty

Moderate

Steps

Available languages

Step 1 Tools necessary for this chapter

⬢For this chapter please prepare:

⬢1.5mm Allen key

⬢2.0mm Allen key

⬢2.5mm Allen key

⬢Needle-nose pliers

⬢Universal wrench

Step 2 Z-carriage: parts preparation

All the printed parts and fasteners needed for this chapter are included in the box: YZ & X-axis

⬢For the following steps, please prepare:

⬢MINI-Z-carriage-front (1x)

⬢M3nS nut (9x)

⬢M3x12 screw (4x)

⬢Smooth rod (2x) 8 mm diameter

Step 3 Assembling the Z-carriage

⬢Insert the M3nS nut in the MINI-Z-carriage-front part.

⬢Insert four M3nS nuts in the top side of the MINI-Z-carriage-front.

⬢Turn the part upside down and insert four M3nS nuts in the bottom holes.

Always make sure that all M3nS nuts are inserted all the way down into the holes. Use the 2.0mm Allen key to push the nuts fully inside.

Step 4 Assembling the Z-carriage

⬢Carefully slide both smooth rods all the way into the MINI-Z-carriage-front. Before inserting the smooth rods, check if there are no obstructions inside the holes.

⬢Look sideways on the MINI-Z-carriage-front through the inspection hole and check that the smooth rod is fully inserted into the plastic part.

⬢Secure all parts together with four M3x12 screws.

Step 5 X-end: parts preparation

⬢For the following steps, please prepare:

⬢MINI-X-end (1x)

⬢M3nS nut (2x)

⬢M3x12 screw (4x)

⬢M3x20 screw (1x)

⬢M3nN nyloc nut (1x)

⬢Pulley Bearing Idler 623 2Z (1x)

The list continues in the next step.

Step 6 X-end: parts preparation (lubricating)

⬢For the following steps, please prepare:

⬢Linear bearing LM8UU (2x) included in the Rods package

⬢Prusa lubricant aplicator (1x)

⬢Prusa lubricant (1x)

⬢Several paper towels to wipe oil and grease from the bearing surface.

⬢Permanent marker (1x) not included in the kit

Each bearing must be lubricated before mounting on the printer. Follow these instructions carefully.

Step 7 Lubricating the bearings

Use any piece of fabric to protect your working surface from grease.

Make sure the bearing is clean inside.

⬢Wipe the preservative oil off the bearing surface with a paper towel.

⬢It is necessary to lubricate all 4 rows of balls inside the bearing.

Step 8 Lubricating the bearings

⬢Turn the tube and applicator counterclockwise until you feel a slight resistance. This means that the holes in the applicator are aligned with the ball rows.

⬢Gently press the tube to push the lubricant into the ball rows of the bearing.

⬢Look at the front of the bearing. When the applicator pushes the lubricant out (around the black gasket), stop pressing the tube. Hold the bearing with the other hand during the lubricating.

The grease must be spread evenly over all four ball rows inside the bearing. There must not be too much grease, or too little. Take a closer look at the last picture.

⬢Wipe off excess grease on the outside of the bearing with a paper towel.

⬢Use this procedure for both bearings.

Step 9 Marking the bearings

⬢Position the bearing so that you can see two rows of balls. Like in the picture.

⬢Make a mark with a permanent marker on the outer surface of the bearing, in the middle above two rows of balls.

⬢Use the same procedure on the second bearing.

We will use these markings in the upcoming steps to achieve the desired bearing orientation.

Step 10 Assembling the X-end

⬢Insert two M3nS nuts in the X-end.

Always make sure that all M3nS nuts are inserted all the way down into the holes.

⬢Insert the M3nN nut into the X-end.

Use the screw pulling technique.

Step 11 Assembling the X-end

⬢Turn the X-end upside down.

⬢Place the pulley bearing idler into the X-end and align holes on both parts. The orientation of the pulley doesn't matter.

⬢Secure it with M3x20 screw.

⬢Place your finger on the bearing and ensure it can rotate freely. If needed to adjust the screw.

Step 12 Assembling the X-axis

⬢Insert and slightly tighten two M3x12 screws into the X-end.

There is no nut used here. Use more force to tighten the screws into the plastic part. Be careful, not to hurt yourself.

⬢Do not tighten the screws completely. Leave a half of the screw head protruding above the surface of the plastic part.

⬢Slide one bearing on each smooth rod.

Don't forget to wipe off the residue of the grease on the smooth rods with a paper towel.

⬢Push the MINI-X-end all the way on the smooth rods. Before pushing the part on the smooth rods, check if there are no obstructions inside the holes.

⬢Check the correct orientation of the part. The screw holes on the MINI-X-end must face up and the screws on the MINI-Z-carriage-front must face up.

⬢Insert and slightly tighten two M3x12 screws into the X-end. We'll completely tighten them later.

Step 13 Checking the smooth rods: X-end

⬢Look sideways on the MINI-X-end into the inspection hole and ensure that the smooth rod is inserted all the way in the plastic part.

Some early units may be without inspection holes.

If the rod is not fully visible in the groove, try using more force to push MINI-X-end on the rod. Do not use a hammer or similar tools to push the plastic part!

⬢Turn the X-axis and use the same procedure for the second smooth rod.

Step 14 X-carriage: parts preparation

⬢For the following steps, please prepare:

⬢MINI-x-carriage (1x)

⬢M3n nut (1x)

⬢M3nS nut(1x)

Step 15 Assembling the X-carriage

⬢Insert the M3n nut into the MINI-X-carriage from the side.

Use the screw pulling technique.

⬢Locate the hole on the opposite side of the part and insert the M3nS nut all the way down into the hole.

Step 16 Mounting the X-carriage

⬢Align both bearings with the markings facing you.

⬢Place the X-axis with the screw heads in the MINI-Z-carriage facing you.

⬢Take the MINI-X-carriage and place it above the bearings. Make sure the longest side of the part is on the left side.

⬢Align the cutouts in the part against the bearings.

⬢Push the MINI-X-carriage onto the bearings

⬢Ensure the bearings are properly seated and they are centered in the X-carriage.

Step 17 X-axis motor: parts preparation

⬢For the following steps, please prepare:

⬢X-axis motor (1x)

⬢Pulley T16-2GT (1x)

⬢X-axis belt 2GT 561 mm (1x)

⬢M3x12 screw (2x)

Step 18 Assembling the X-axis motor

⬢There is a flat part on the motor shaft. Rotate it similarly to the first picture. See the direction of the arrows.

⬢Place the pulley T16-2GT on the X-axis motor shaft as shown in the picture.

⬢Don't press the pulley against the motor. Leave a gap of 0.7 - 1 mm between both parts.

There is mentioned a 2mm gap in the earlier version of the manual. Please, use the value mentioned in the current manual.

⬢One of the screws must be facing directly against the pad (flat part) on the shaft. Tighten the first screw gently but firm.

⬢Turn the shaft and slightly tighten the second screw.

Ensure you have the correct orientation of the pulley on the shaft. It can be placed both ways, but only one is correct.

Step 19 Mounting the X-axis motor

⬢Place the X-axis motor like in the picture. See the cable direction.

⬢Put the X-axis on the X-axis motor and align the holes on both parts. Make sure that smooth rods are facing to the right.

⬢Fix both parts together with two M3x12 screws.

Step 20 X-axis belt guidance

⬢Place the X-axis like in the picture.

⬢Take the X-axis belt and guide it in the upper position around the pulley in the X-end.

⬢Insert the belt along the entire length of the upper groove in the X-carriage.

⬢Take the second end of the belt and guide it around the pulley in the X-end and through the hole in X-carriage.

Step 21 X-axis belt guidance

⬢Guide the belt around the X-axis motor pulley.

⬢Insert the end of the belt into the lower groove on the X-carriage.

⬢Secure both ends of the belts by squeezing them into the groove with the 1.5mm Allen key.

The belt may seem too loose. We will adjust the correct tension later.

Step 22 X-axis assembly: reward yourself!

⬢You just finished the X-axis assembly. Now, it's time to reward yourself.

⬢Eat the first part of the second row.

Step 23 Z-carriage: parts preparation

⬢For the following steps, please prepare:

Fasteners needed for the following steps are in the Extruder package. Please, prepare this bag.

⬢MINI-Z-carriage-rear (1x)

⬢M3n nut (2x)

⬢M3nS nut (1x)

⬢M3x30 screw (4x)

⬢M3x20 screw (2x)

Step 24 Preparing the Z-carriage

⬢Insert two M3n nuts in the MINI-Z-carriage. Make sure the nuts are properly seated and don't fall out.

Use the screw pulling technique.

⬢Insert the M3nS nut into the hole on the bottom side.

Step 25 Mounting the X-axis

⬢Turn the assembly so that the rear side is facing you.

⬢Place the X-axis on the Z-axis bearings and trapezoidal nut. Hold it by hand all the time during installation.

⬢Place the MINI-Z-carriage-rear on the bearings. See the round recess of the part for better orientation.

⬢Secure it with two M3x30 screws diagonally. You can release your hand from the assembly now.

Step 26 Mounting the X-axis

⬢Insert and tighten two M3x30 screws into the remaining holes.

⬢Look from below and align two holes in the trapezoidal nut against the holes in the plastic parts.

⬢Secure the trapezoidal nut to the X-axis with two M3x20 screws.

Do not overtighten the screws! Otherwise, it can cause issues during printing. Tighten gently, but firmly.

Step 27 Plastic cover: parts preparation

⬢For the following steps, please prepare:

⬢Plastic cover (1x)

⬢Zip tie (1x)

⬢Textile sleeve 5x300 mm (1x)

Step 28 Guiding the X-axis motor cable

⬢Wrap the textile sleeve around the X-axis motor cable.

⬢Secure the textile sleeve with the zip tie a few millimeters from the end. Do not overtighten the zip tie, you might damage the cable.

Cut the remaining part of the zip tie using pliers as closest to its head as possible.

⬢Wrap the entire textile sleeve around the X-axis motor cable and guide it into the extrusion.

⬢Cover the extrusion with the plastic cover.

Step 29 Connecting the X-axis motor

⬢Connect the X-axis motor cable to the Buddy control board. Use the second slot from the left.

Step 30 X-axis belt tensioning

⬢Move the X-carriage all the way to the Z-carriage.

⬢Using a finger on your left hand push the belt down in the center of the X-axis. Some force should be needed for bending the belt, BUT don't try to overstretch the belt as you might damage the printer.

⬢Adjust it by releasing or tightening both screws on the X-end.

⬢Release the screws, bring the X-end closer to rods and thus decrease the overall tension.

⬢Tighten the screws, X-end will move apart, the overall tension will increase.

Step 31 Belt tension check

This step is recommended, but optional. If you don't have a phone at your disposal, continue to the next step. You can do this check later on.

⬢To verify or fine-tune the X or Y-axis belt tension on your printer, visit prusa.io/belt-tuner and open up the webpage on your mobile device. Or using your phone, scan the QR code in the picture.

⬢Follow the on-screen instructions to fine-tune the belt tension.

The belt tuner app was tested on multiple phones and should work across all most common phone manufacturers. However, in some rare cases it might not work as expected. Please state your brand and model in the comments below the step.

Step 32 Securing the X-end

⬢Look at the X-axis from the side. Align the X-end parallel to the Z-axis smooth rods by twisting the plastic part. Do not use too much force to twist, you may damage the X-axis.

⬢Securing the X-end by tightening both screws on the front side of the plastic part.

After tightening, check once more the X-end is parallel with the Z-axis.

Step 33 Extruder motor: parts preparation

⬢For the following steps, please prepare:

⬢Extruder motor (1x)

⬢Motor pinion (1x)

Step 34 Assembling the Extruder motor

⬢There is a flat part on the motor shaft. Rotate it similarly to the first picture. See the direction of the arrows.

⬢Place the Extruder pinion on the Extruder motor shaft as shown in the picture.

⬢Don't press the pinion against the motor. Leave a 1.5 millimeters gap between both parts. You can use the 1.5mm Allen key to set the gap.

⬢The set screw must be facing directly against the pad (flat part) on the shaft. Tighten the screw with the longest part of the Allen key. Be careful, not to strip the screw.

Ensure you have the correct orientation of the pulley on the shaft. It can be placed both ways, but only one is correct.

Step 35 Extruder-front: parts preparation

⬢For the following steps, please prepare:

⬢MINI-Extruder-front (1x)

⬢M3n nut (3x)

⬢Bearing 625 2Z (1x)

Step 36 Assembling the Extruder-front

⬢Place the MINI-Extruder-front like in the picture and insert three M3n nuts to the holes.

Use the screw pulling technique.

⬢Turn the part upside down and insert the bearing into the part.

Step 37 Extruder-rear: parts preparation

⬢For the following steps, please prepare:

⬢MINI-Extruder-rear (1x)

⬢M3n nut (1x)

⬢M3nN nyloc nut (1x)

⬢Bearing 625 2Z (1x)

Step 38 Assembling the Extruder-rear

⬢Place the MINI-Extruder-rear like in the picture and insert the M3n nut into the hole.

Use the screw pulling technique.

⬢Turn the part upside down.

⬢Insert the M3nN nut into the MINI-Extruder-rear from the opposite side.

Use the screw pulling technique.

⬢Insert the bearing into the part.

⬢Make sure the bearing is aligned with the top surface of the printed part.

Step 39 Extruder-idler: parts preparation

⬢For the following steps, please prepare:

⬢MINI-Extruder-idler (1x)

⬢Bearing 625 2Z (1x)

⬢Shaft 5x12 mm (1x)

⬢M3nS nut (1x)

Step 40 Assembling the Extruder-idler

⬢Insert the M3nS nut into the MINI-Extruder-idler.

⬢Place the bearing into the part.

⬢Align the holes and secure the bearing with shaft. Make sure the shaft is aligned with the surface of the plastic part.

Step 41 Extruder assembly: parts preparation

⬢For the following steps, please prepare:

⬢Spring 5x15 mm (1x)

⬢M3x12 screw (3x)

⬢M3x25 screw (4x)

⬢M3x40 screw (1x)

⬢Filament Spur (1x)

⬢PTFE tube 4x2x150 mm (1x)

Step 42 Assembling the Extruder

⬢Place the Extruder motor like in the picture. See the cable direction.

⬢Put the MINI-Extruder-front on the motor and align the holes on both parts.

⬢Secure both parts with two M3x12 screws.

Step 43 Assembling the Extruder

⬢Place the filament spur into the bearing. The longer part with the jagged groove must face up. See the picture.

⬢Make sure that both gears fit together.

⬢Rotate with one pulley to ensure the second is moving as well.

Step 44 Assembling the Extruder

⬢Place the MINI-Extruder-rear on the MINI-Extruder-front. See the orientation of both parts.

⬢Make sure the cable from the motor is oriented in the same way as in the picture.

⬢Secure parts together with three M3x25 screws.

Step 45 Mounting the MINI-Extruder-idler

⬢Insert the assembled MINI-Extruder-idler to the Extruder.

⬢Align the holes on both parts and secure it with the M3x25 screw. Do not overtighten. Make sure the idler can move freely.

⬢Place the spring on the M3x40 screw.

⬢Hold the extruder and idler with your hand.

⬢Insert and tighten the screw with the spring into the Extruder. Stop tightening when the screw head is aligned with the edge of the plastic part.

Step 46 Inserting the PTFE tube

⬢It's recommended to mark the distance of 2.5 cm (0.98 inches) from the end of the PTFE tube before the insertion to the extruder. Both ends are symmetrical.

⬢Locate the hole for the PTFE tube on the side of the extruder assembly and insert the marked end of the tube all the way to the extruder. Check the correct insertion according to the marking on the tube.

⬢Secure the tube with the M3x12 screw.