SIRIUS - Gantry for QIDI X-Plus / X-Max

What is SIRIUS?

SIRIUS is a new concept gantry for QIDI printers such as X-Plus and X-Max. It is mainly aimed to be used with Igus Drylin RJ4JP-01-10 bearings. SIRIUS is a perfect match for ORION carriage.

After several attempts with Igus Drylin bearings and the classic style gantry (both the original and the one by Humebeam), I decided to design a new solution to solve some issues. I needed to avoid deformation of the bearings that occurs when you snap it in, causing too much friction on the Y movement.

I came up with this design, which have separated housing for the bearings. There are also some other advantages:

1. It is easier to print the parts with the right fits, if the bearings are too stiff or too loose you can only adjust the housing. The same applies if you want to use different bearings
2. The left gantry has pass-through holes for the X rods, making maintenance easier
3. The gantries are more robust and the rods housing is longer
4. You can use slightly different rods length since there is a screw to secure them
5. Thanks to the locking screw, the X belt tension is unloaded on the rods and not on the bearings
6. No stress on the Y rods when mounting/dismounting since every part simply slides into the other

There are also some drawbacks compared to Humebeam's version:

• No belt tensioner, you should use the spring that come with the printer
• Not very recommended for metal ball bearings since it weights a bit more. The weight advantage come from the use of Igus bearings

!!! IMPORTANT !!!

This is a new project and I've tested only on my X-Plus, so it may requires some modifications, be prepared for it. If you have any idea for improvements and want to collaborate, I can provide STEP files privately.

Moreover:
!!! At Y0 there is only 1mm clearance with the frame, ensure there are no collision before making any motion !!!

Printing suggestions

Use 0.4 nozzle and 0.2 layer height, STLs are already aligned to the bed plate. Supports are not needed, but you should enable bridge detection and check your bridge settings. Use a large brim.

Parts are already designed with clearance. I strongly suggest you to calibrate the flow using the visual method by Ellis instead of the classic wall method. The Igus bearings must slide very easily inside their housing. If needed you can adjust internal/external diameter since I included STEP files for the housings.

The suggested materials are PC-CF and PA12-CF. Use good quality filament, avoid cheap PA-CF since they absorb too much moisture.

Assembly suggestions

Pre requisites

If you are going for this mod, please consider first upgrading to 20T metal pulleys and to high quality belts. Be aware that you will need slightly longer Y belts than the original.

I will not going deep into replacing bearings/pulleys/belts since there are other exhaustive guides. This will be limited to SIRIUS gantry instructions

1. Dismount original gantry
2. Install the two M3 brass inserts on the left gantry and the four M3 nuts.
3. Ensure that the rods fits good in their holes. If the they are too narrow, best solution is to use a 10mm reamer, you will get a perfect fit.
4. Loose the Y axis motor shaft joint

Left gantry

1. Pass the bearing housing through the rod, check the orientation
2. Slide bearings and spacer inside the housing
3. Pass the gantry through the rod
4. Slide the housing into the gantry with the correct orientation
5. Check that the gantry moves freely and super smooth. If it get stiffer during assembly, you need to increase clearance between parts. Usually a file or sandpaper is enough, otherwise modify the housing and print it again
6. Install the original spring tensioner on the belt
7. Make a 45° cut on both ends of the belts, this allows an easier insertion
8. Rotate the gantry and insert the screws, do not tighten them yet
9. Insert one end of the belt in the opening, then let it slide towards the inner side to lock it
10. Repeat for the other belt end, but this time use some pliers to hold and extend the belt. You have to keep it in tension while sliding through the teeth.
11. Now you can tighten the screws, don't over do it, just let the screw head touch the top surface. Use Loctite or, better, other two nuts to secure it

Right gantry

1. Repeat the same steps for the right gantry
2. Install the motor and the endstop board as last steps

Rods

1. If the X belt is already installed, relax the tensioner, even if the belt is now loose
2. Slide the X rods inside the left gantry's holes until you get enough space to put them inside the right gantry
3. Push the rods towards the bottom of the right gantry holes
4. Tighten the left rods screws, don't over do it, use Loctite or a longer screw with a locking nut
5. Tighten the X axis belt

Belt sync

1. Move the two gantries to align them
2. Tighten the Y axis motor joint

First power on

1. Check that everything mooves smootly
2. Check for possible collisions
3. Power on, do homing and go VERY SLOW to Y0
4. Turn steppers off and check that you can slightly go at Y<0 by hand, on my X-Plus there is 1mm clearance
5. Carefully check also for all the other MIN/MAX position
6. If there are no collisions, calibrate Z offset and proceed as usual

Version history

• V1.3 - First public release - 2023/03/03

To-Do

Only for the brave - TO BE TESTED - my idea is to cut in a half the Igus bearings, or print two half bearings like this:

If this is going to work, I will probably don't need to disassemble the whole printer again. If you are brave enough you can test it.

Disclaimer

Use these informations and 3d model at your own risk, I am not responsible for any damage