7. Z Axis

Bed brackets

L-shape belt clamp base to rear bed bracket

• Bolt M3 x 08 (x2)

• Nut M3 (x2)

Aluminum belt clamp to L-shape belt clamp base

• Bolt M3 x 10 (x4)

• Nut M3 (x4)

Printed bed fixed mount to left front bed bracket

• Round head bolt M5 x 10 (x1)

• Flanged nut M5 (x1)

Actions

Prepare the 3 bed brackets as shown in the picture.

To deal with thermal expansion and possible Z wobbling, a Kelvin kinematic coupler is designed for the bed:

1. The left-front point is fixed in the front bracket

2. The right-front point floats in a slot, allowing the bed to thermally expand in X direction but restrict rotation.

3. The rear point floats on the surface of rear bracket, allowing the bed to thermally expand freely.

Fasten the fixed mount to the front left bracket with an M5 bolt. You can always adjust the position later.

Exam

The printed fixed mount has an 8mm hole for the 8mm steel ball, not for the M5 bolt.

ACM back panel

ACM back panel to frame component M, N

• Round-head bolt M5x10 (x8)

• Flanged nut M5 (x8)

ACM panel to frame component F

• Bolt M3 x 16 (x4)

• Washer M3 x 8 x 0.8 (x4)

• Nut M3 (x4)

Actions

Attach the ACM panel to the frame M, N.

Use the smaller holes in the middle of ACM panel. The larger hols are for the Z rail.

Z rails

Z rail to frame component F, K & L

• MGN12C 450mm rail (x1)

• Bolt M3 x 8 (x3 ~ x5 for each rail)

• Nut M3 (x3 ~ x5 for each rail)

Actions

At the rear side of frame, use the larger holes on the ACM panel for the Z rail. Not all holes should be used. 3~5 bolts for each rail will be enough.

Front Belted-Z

Z rail to frame

• 450mm MGN12 linear guide

• Bolt M3 x 8 (x5)

• Nuts M3 (x5)

Gearbox stepper to frame

• NEMA8 gearbox stepper

• Printed NEMA8 stepper mount

• Pulley GT2 10mm 16T B6

• Bolt M3 x 10 (x4)

• Washer M3 x 8 x 0.8 (x4)

• Nut M3 (x4)

Belt clamp

• Bolt M3 x 10 (x4)

• Washer M3 x 8 x 0.8 (x4)

• Nut M3 (x4)

Front bed bracket to linear block

• Bolt M3 x 6 (x4)

Actions

Attach components as shown in the picture. You can insert a longer M3 bolt in the rail to stop the linear block from falling out of rail.

Front Belted-Z

Top pulley set, also acts as a belt tensioner

• Round head bolts M5 x 30 (x2)

• Flanged nut M5 (x2)

• 2GT belt

Actions

Keep the pulley housing at the lowest position so you can push it up later to tense the belt.

Install the belt

• 2GT belt
  Totally about 8.5 meter belt is needed for two XY and three Z belts. One 9-meter roll or two 5-meter rolls are included so be careful when you cut a preserved section.

Actions

1. Pass the belt around the pulleys and cut 1~2 cm longer than needed.

2. Insert the belt into belt clamp for 50% length of the clamp and pinch/hold the clamp.

3. Insert the other end of belt into the clamp and trim the belt tooth-by-tooth until it is about tensed, and then fasten the bolts at the clamp.

4. Push the top pulley housing upward, tense the belt and fasten the flanged M5 nuts.

Exams

• Make sure the top pulley and bottom pulleys are aligned with the belt clamp. The belt should not make clicking sound in operation.

• Make sure both edges of the belt have the same tension by adjusting pulley positions.

• As long as the belt teeth won't slip when you manually pull the bed bracket, the tension is high enough. Too high tension reduces belt life.

Rear Belted-Z

Gearbox stepper to frame

• NEMA8 gearbox stepper

• Printed NEMA8 stepper mount

• Pulley GT2 10mm 16T B6

• Bolt M3 x 10 (x4)

• Washer M3 x 8 x 0.8 (x4)

• Nut m3 (x4)

Z rail to frame

• Bolt M3 x 08 (x5)

• Nut M3 (x5)

Rear bed bracket to linear block

• Bolt M3 x 6 (x4)

L-shape belt clamp base to rear bed bracket

• Bolt M3 x 08 (x2)

• Nut M3 (x2)

Belt clamp

• Bolt M3 x 10 (x4)

• Washer M3 x 8 x 0.8 (x4)

• Nut M3 (x4)

Actions

The same as assembling front Belted-Z.

Rear Belted-Z

Top pulley set, also acts as belt tensioner

• Round head bolt M5 x 30 (x2)

• Flanged nut M5 (x)

Actions

Assemble the rear part the same as front Belted-Z drives.

Constant Force Spring
(Kits received BEFORE 2021 Oct 31st)

(Note this is a temporary solution for owners who received their kits before 2021/10/31. Once you receive a new longer spring please switch to the more solid way as shown in the next page.)

• Printed template and spring housing (STL here)

• Constant force spring

• Bolt M5 x 45 (x1)

• Bolt M3 x 16 (x2)

• Flanged nut M5 (x1)

• Washer M3 x 8 x 0.8 (x2)

• Nut M3 (x2)

Actions

The spring acts as a counterweight to prevent free fall when the rear Z stepper is not powered.

Drill a hole using the printed template as shown in the picture.

Place the spring in the housing and attach the housing to rear bed carriage. Pull out the spring carefully and fixed it to the back panel.

Constant Force Spring
(Kits received AFTER 2021 Nov 1st)

Spring-side

• Constant force spring

• Bolt M5 x 45 (x1)

• Flanged nut M5 (x1)

• Thin nut M5 (x2)

Rear bed bracket

• Bolt M3 x 08 (x1)

• Washer M3 x 8 x 0.8 (x1)

• Nut M3 (x1)

Actions

The spring acts as a counterweight to prevent free fall when the rear Z stepper is not powered.

Attach the back panel to rear side of the frame as shown in the picture. Clamp the end of spring firmly with a plier, pull it down and attach it to the rear bed bracket. Be careful that spring rebound may hurt people.