Redesigned Z-stage support for Vertex K8400

thingiverse

There are two major issues with the original K8400 Z-stage design. The entire Z-stage rests on a coupler that connects the motor to the leadscrew, which acts as a spring and can be compressed by approximately 0.5mm just by applying pressure to the leadscrew with a finger. This is an extremely common problem in 3D-printers, and it's simply bad practice. The coupler exists solely to compensate for any misalignment between the leadscrew and motor axle; it should never bear any axial load. Because individual holders are used for the linear bearings, it's incredibly easy to misalign them, resulting in high friction and potentially choppy movement with low-quality bearings. This problem is exacerbated by the springiness of the motor coupler, which causes the bearing to become stuck while the coupler stretches and then snaps back into place, leading to uneven layer heights. My Solution: I designed a new motor mount for the Z-stage that incorporates a pillow bearing (such as Miniatur Flanschlager 8mm). There is still ample space underneath the motor, and three of the original mounting holes can be utilized. I drilled two additional holes to enhance stability. The entire Z-stage now rests on the pillow bearing, which exhibits zero flex, resulting in remarkably even layer heights. I simply connected two of the original bearing clamps in a vertical direction to prevent any misalignment from occurring. Additionally, high-quality linear bearings (Misumi) were used as the originals are subpar. Required Hardware: 1. A countersunk M5x10 screw with nut (length not critical) 2. 2 M5x12 screws + nuts for the pillow bearing 3. Pillow bearing for 8mm rods/leadscrews Preparing the Pillow Bearing: The cheap pillow bearings come stuck in their housings, but they are designed to swivel and compensate for misalignment. To loosen them, force must be applied; then remove them and polish the mating surfaces by adding metal polish, reinsert the bearing, and move it around until smooth. Repeat this process until the bearing moves freely, then apply grease. Assembly: Mount the motor to the motor mount. Attach it to the Vertex rear panel. The top screw on the right must be the countersunk screw. Add the coupler. Pillow bearing (you will curse a lot). Add the leadscrew. Drink a beer. Print Settings Printer: Vertex K8400 Rafts: Yes Supports: Yes Resolution: 0.1 Infill: 100% Notes: The linear bearing mounts should be printed with 100% infill, as I attempted 50% and they cracked due to the significant stress exerted on these parts when compressing around the linear bearings. The motor mount could be printed in 50%, but it's not recommended as the entire Z-stage rests on this part; therefore, I printed it with 100% infill.