Snapmaker 2 X-Axis Reinforcement

This non-destructive modification is most usefull when using the 200W CNC spindle and when running aggressive CNC operations. During these the unmodified machine toolhead tends to rock up and down during cutting and you are forced to slow down cutting speeds or reduce the stepdown. The machine is capable of more engaging feedrates, but in stock configuration it is lacking stiffness.
This enhancement of the X-axis carriage should also help with the stock CNC spindle.

I only used this together with the mod of linear rail guide for securing the bed of the Snapmaker. 

After installing the bracing kit my Snapmaker 2 A350T still has had some significant flex along the X axis at the toolhead carriage.

The two other axis are built with two linear actuators, where each pair blocks out the rotation on the respective axis.

This modification to the Snapmaker can be installed without modifying the machine itself and only adds two additional printed parts. The two identical parts need to be installed on top and below the X-axis.

The modification has only been tested with the bracing kit and the quick swap kit installed.
It should be possible to fit this without the bracing kit or the quick swap kit, but then shorter screws must be choosen and this has not been tested!

Reasoning and Theory

My theory for the majority of the noticed flex is showcased in the following simplified model of the Snapmaker 2, that is only showing the linear actuators.

The blue ring shows the direction of the noticable flex of the toolhead carriage. This flex is in the rotation around the single actuator of the X axis.
With very little visual contrast (against the white background) you can see the green rings that are drawn around both dual actuator axis. Here the placement of two parallel actuators is blocking the possible movement around one single actuator.

Print Settings

The printed part can be printed in PLA, but should be printed with 100% infill. If you need high temperature resistance you might print them in ABS or ASA. Try to avoid PETG due to the materials lower stiffness.

For the print orientation it should stand on the side that is facing the cariage. A brim around the print helps to keep the print on the plate, since 100% infill PLA prints tend to warp as well.

Organic support helps to print a cleaner overhang for the slot that is supposed to hold the bearing.

Layer height is neglectible in my oppinion and you can simply choose any structural sound printing profile. Avoid any speed optiomized print profiles for printing these small parts.

Additional Parts Needed

In addition to the two prints you need to replace the eight screws that are used to fix the bracing and quick-swap kit to the carriage of the X-axis. The shorter screws are replaced with the new shorter ones.
One special ball bearing with a POM tire is secured inside each of the printed parts. These are riding along the outside of the linear actuator in one groove as shown in one of the fotos. They are the key part of this mod that brings the needed stability against the direction of the rotation.

This is the complete list of additional hardware needed:

• 4x screw M4 30mm
• 4x screw M4 35mm
• 2x screw M3 25mm  
• 2x ball bearing with POM tire (15mm outer diameter, 3mm inner diameter and 4mm wide; these seem to be furniture replacement parts). 

Sadly the POM bearing can not be one of the usual V-groove-riding POM bearings of older 3d printers, due to size constraints. The groove width on the actuator is only 5mm wide and those are usually thicker. Using bigger bearings would make this mod a lot bulkier.