Ender 5 Plus Linear Rail Conversion by GiulianoM

Last crawled date: 3 years, 3 months ago

Summary
THIS DESIGN IS NOW COMPLETE
This is a conversion kit for the Ender 5 Plus to MGN12 Linear Rails, 450mm long x 3 and 3 x MGN12H linear blocks.
I highly recommend these MGN12 rails from RobotDigg:
https://www.robotdigg.com/product/766/Quality-440C-SUS-MGN12-linear-rail-with-carriage
3 x SS_MGN12-1H-450
You will also need M3 T-nuts, I recommend slide-in 20-series M3 nuts like these:
https://www.ebay.com/itm/100X-M3-M4-M5-M6-T-Block-Square-nuts-T-Sliding-Hammer-Nut-Aluminum-Profile/274057650436
Get a pack of 100, you will need a bunch of them.
You will also need a bunch of M3 12mm long screws, button head or normal socket head cap screw.
Each rail has 18 mounting holes, so you will need 54 screws and 54 T-nuts.
The adapter plate for the MicroSwiss Direct Drive extruder adapts the back of the plate to join to the MGN12H block.
This adapter plate requires modifications to the back of the MicroSwiss plate!
You will need to take a 3/8" or 9.5mm drill bit and drill out the two wheel mounting studs on the back of the plate, but only drill until the surface is flat, don't drill through the plate.
The stock Ender 5 Adapter plate shouldn't need any modifications.
There is a printable drilling rig part in the parts list to attach to the front of the MicroSwiss extruder to provide a flat surface to drill against.
This design uses "OpenBuilds" style M5 low-profile screws of various lengths:
https://openbuildspartstore.com/low-profile-screws-m5-10-pack/
They're somewhat expensive, but if you search eBay for "M5 Low Profile hex screw" you can find less expensive ones:
https://www.ebay.com/itm/Precision-M5-Low-Profile-Hex-Screws-Black-3D-6-8-10-12-15-20-25-30-35-40mm/133296439988
I also used M3 button head socket cap screws, which have a shorter head than the normal socket head cap screw.
I recommend Albany County Fasteners:
https://www.albanycountyfasteners.com/metric-socket-cap-screws/693.htm
Parts List
The following is the printed parts list and hardware bits required.
X-Carriage
Print:

1 x X-Carriage MGN12 Block.stl
1 x X-Carriage_Microswiss_DD_Adapter.stl
OR
1 x Stock_Ender5+_Hotend_Adapter.stl
Suggested infill of 50-75%.

Hardware:

3 x M5 30mm Low-Profile screws.
2 x M5 8mm Low-Profile screws.
1 x M5 12mm Low-Profile screw.
4 x M5 Hex Nuts
4 x M3 12mm button head cap screws, for the MGN12H mounting block.

Y-Axis Blocks
Print:

1 x Y-Axis Idler Horizontal Block.stl
1 x Y-Axis Motor Horizontal Block.stl
2 x Y-Axis Vertical Block.stl
Suggested infill of 50-75%.

Hardware:

4 x M5 30mm Low-Profile screws.
4 x M5 Hex Nuts
4 x M5 10mm Low-Profile screws.

Idler Bearing Blocks

The Idler Bearing blocks are designed to hold the Gates 2GT 20T toothed 6mm idlers, the ones 15mm in diameter, 6mm wide for 6mm belts.
https://www.filastruder.com/collections/hardware/products/gates-2gt-idler
The design requires 6 of them.

I also highly recommend getting Gates 2GT belt as well - I ordered 4 meters and had about 2 feet left over.
Print:

6 x Idler Bearing.stl

Hardware:

6 x M5 20mm Low-Profile screws.

Alignment Blocks

These parts are used for aligning the MGN12 rails to the aluminum extrusion during assembly, and they are removed after.

Print:

6 x Y-Axis_Alignment_Block.stl
6 x X-Axis_Alignment_Block.stl

Hardware:

12 x M5 10mm Low-Profile screws.
12 x M5 T-Nut

X-Axis Motor Standoffs

The design of the Y-axis bearing blocks interferes with the normal position of the X-axis stepper motor, so you must flip it upside down on top of the gantry with these standoffs.
Note that flipping the stepper motor also requires that you flip the X-axis stepper direction in your firmware, or swap the motor wiring pins around to flip the direction.
The pulley on the stepper motor must also be flipped upside down, with the grub screw portion of the pulley facing down.

Print:

4 x Motor Standoff.stl
Infill: 100%

Hardware:

4 x M3 25mm screws.

Limit Switch Holder

The Limit Switch for the X axis will need to be relocated on top of the extrusion.
It should be installed at the end of the linear rail, to prevent the MGN12 linear block from sliding off the end.
You may have to adjust the position of the linear rail to get the X-axis endstop location correct. I would suggest taking a sharpie and marking where the factory switch is located.
The Y-axis Endstop Switch should be able to remain in the factory location.

Print:

1 x Limit Switch Holder.stl

Hardware:

1 x M5 10mm Low-Profile screw.
1 x M5 T-Nut

Assembly Guide
X-Axis Motor

You will also need to flip the direction of your X-axis in firmware, or re-wire the stepper motor wires to flip the direction.

Remove the X-Axis Motor and the cover.
Remove the pulley from the X-Axis Motor and reinstall it upside down.
Place 4 x Motor Standoff parts on top of the plate, and place the motor on top of the standoffs, with the shaft and pulley facing down.
Insert 4 x M3 25mm screws through the motor mounting holes in the bottom of the plate, up through the standoffs, and into the motor.
Y-Axis Blocks

The Y-Axis blocks mount to the underside of the X-Axis ends, where the wheels would normally go.
Make note of the difference between the Motor End and Idler End Horizontal blocks, they are different and not interchangeable. The vertical blocks are the same.

Remove the wheels and hardware from the X-Axis ends.
Assemble each horizontal block with a vertical block, using 2 x M5 30mm low-profile screws and 2 x M5 Hex Nuts.
Insert the peg on the horizontal blocks into the bottom side of the X-Axis metal plates. The vertical blocks should be on the outside.
Screw 2 x M5 10mm screws in through the top side of each metal plate into the plastic of the horizontal block.
X-Axis Linear Rail

The X-Axis linear rail mounts to the top side of the rail, with the MGN12 bearing block facing up.
Be very careful with handling the rails, and make sure that the bearing block does not slide off!

Remove the belt idler bearing assembly from the end of the X-axis extrusion.
Slide in 18 x M3 T-Nuts, if you got the slide-in kind. If you got the twist-lock kind nuts, skip this.
Insert 18 x M3 12mm screws into the holes in the rails.
Drive the screws into the T-Nuts in the extrusion, but do not tighten them fully.
Attach the X-Axis Alignment Blocks to the front and back of the rail so that the lip on the part presses up against the linear rail to center it.
Tighten the screws in the linear rail.
Remove the Alignment Blocks.
Y-Axis Linear Rails

The Y-Axis Linear Rails are installed on the outside of the 2040 extrusion on the left and right sides, in the top slot, with the linear block facing outside to the left and right.
The Y-Axis Linear rails do not go on top of the 2040 extrusion.

Remove the Y-axis Idler pulley assemblies from the front of the printer.
Slide in 18 x M3 T-Nuts in the side of the 2040 extrusion, in the top slot - facing right/left.
Insert 18 x M3 12mm screws into the holes in the linear rail.
Drive the screws into the T-Nuts in the extrusion, but do not tighten them fully.
Attach 3 x Y-Axis Alignment Blocks in the slot underneath the T-Nuts, with the arrow on the alignment blocks facing up. Put one at each end of the rail, and one in the middle. The edge of the blocks should be supporting the rail above it.
Tighten the screws in the linear rail.
Remove the Alignment Blocks.
Attaching the X-Axis to the Y-Axis

At this point, you will take the entire assembled X-Axis with their adapter blocks, and drop them on top of the MGN12 blocks on the outside of the printer.
You will adjust the tension on the rails by tightening the screws on the Motor End fully, and tightening the screws on the Idler End.. less fully.

Take the assembled X-Axis, and slide the vertical mounting blocks over the MGN12 blocks on the Y-Axis rails. It should be a be a tight fit.
On the Motor End of the X-Axis, insert 4 x M3 12mm screws through the vertical mounting block into the threaded holes in the MGN12 block.
On the Motor End of the X-Axis, tighten the screws in an X-fashion until they are tight with roughly the same tension on all 4 screws.
On the Idler End of the X-Axis, insert 4 x M3 12mm screws.
On the Idler End of the X-Axis, tighten the screws in an X-fashion - but NOT too tight!
Move the Y-axis back and forth on the rails, pushing from the center of the rail.
The rail should move with very little friction or noise.
If there's too much friction or noise, loosen the screws on the Idler End a bit until the friction goes away.
X-Carriage Assembly
If you're using the MicroSwiss Extruder, print out the drilling jig part first and drill off the top two wheel studs on the back of the extruder plate until the surface is flat. Use a small needle file or sandpaper to flatten any edges.
Remove all the wheels and hardware from the hotend.
Cut out the holes in the adapter block.
Insert the 2 x M5 8mm Low-Profile screws into the top two holes in the back of the adapter plate, where the top two wheels would go.
Insert 1 x M5 Nut in the adapter plate where the bottom wheel would go.
Attach the X-Carriage MGN12 Block to the X-Carriage_Microswiss_DD_Adapter block using the 3 x M5 30mm Low-Profile screws and 3 x M5 Hex Nuts.
Attach the front of the adapter block to the back of the MicroSwiss extruder plate, using the 2 x M5 8mm screws threading into the upper wheel mounts.
Insert the M5 12mm screw in through the front of the MicroSwiss Extruder plate where the bottom wheel would go, and tighten into the nut in the back.
Mount the assembly to the linear rail block using the 4 x M3 12mm button head screws. The top of the screws must be flush with the top of the block, they shouldn't protrude or they'll interfere with the extruder stepper motor.
Alignment Calibration
Once the printer is fully re-assembled with the linear rails, you may find that the X-axis may not be perfectly perpendicular (square) to the Y-axis. This is also called "skew".
The first part you should print is a calibration square, I recommend this one:
YACS (Yet Another Calibration Square)https://www.thingiverse.com/thing:2563185
Print it out, and use a digital caliper to measure the distance across the diagonal flats.
They should measure the same, within a few tenths of a mm.
If they do not measure the same, then your X-axis is not square with the Y-axis.
You can correct this by either:
Physically adjust one of the pulleys on the Y-axis motor end to move one end of the X-Axis end farther or closer.
Enable "Skew Compensation" in your printer's firmware to correct for the physical alignment.
For Marlin firmware, you will need to update your configuration.h file to enable Skew Compensation.
Video to watch: https://www.youtube.com/watch?v=YfAb5IaHDSo
I would recommend these steps:
Print off an YACS X/Y calibration part.
Measure the diagonal distances.
If the differences are ~2mm or less, then set up the Skew Compensation in firmware.
If the differences are more than 3-5mm, then adjust the pulleys on the Y-axis to compensate, then print another YACS X/Y calibration part.
Repeat above until satisfied.