The Fysetc full metal CNC bed support is a great upgrade

[ChrisA]

The CNC machine bed support was delivered this morning. The printer is not fully built yet. But I did have the Kirigami frame installed but no motor yet and could move it up and down by hand. I swapped parts and put on the CNC frame. What a world of difference it makes. It is dramatically better. Yes, it is stronger but that is not the point. It is so much more accurately made.

The kirigami has to be straightened by bending it into shape and carefully checking with a straight edge. You can never get it perfect. It will always be off by a few 0.01 mm. Then you screw it to the linear rails and the rails force the kirigami to be flat. This loads the bearings with the kirigam sheet metal acting as a spring. It works OK and you can make prints.

But the CNC bed is machined to be 100% dead-on flat and has zero spring. When attached the bearings are still unloaded. With the lead screw unattached you can lift the bed and then let go and it simply falls to the bottom of the rails. There is zero detectable play or spring in the cantilevered bed and almost zero friction. The Kirigami would not fall on it's own but could be moved with finger pressure and had enough friction that it would stay in place if you let go of it. There was also too much pressure on the rails so it felt not smooth, a bit gritty.

Yes the CNC bed is heavy. A lot heavier than the kirigami. But with my Moon's lead screw motor set at 0.5 amps current (it is rated for 0.65) the bed moves at 60 mm per second in both directions. 60mm/s is faster than anyone needs to move in Z (I think)

One problem: Formbot did not ship a printed stock T8 nut block because they shipped a special Kirigami t8 nut block. I had to print one in PLA. I hope it lasts long enough to make an ABS replacement.

 

[Dave32]

Thanks for the information.
Did you have to change out any other printed parts to go along with the bed support?

 

[ChrisA]

The CNC bed support is a drop-in replacement for the Official Voron V0.2 design. However your kit packager might have included only the printed parted needed for the Kiragami build. So the answer to your question is "it depends but likely you will be fine. "

I assume you have some kind of printer, even if it can only print PLA. The worst case is that you have to print a part from the standard design.

For some reason, I had to use quite a lot of sandpaper to make the formbot-supplied Z-nut holder fit. But Forbot did supply a full sheet of sandpaper with the kit. That was the only place I used it.

Notice the Voron assembly manual shows the use of sandpaper in that general area.

The point is that all the z-axis parts have to be perfectly aligned and none of them are forced to align by tightening screws. It has to go together with zero force applied or the bearings bind. In the worst case, they REALLY bind hard.

Now go back and look at the original Voron V0.2 design that uses plastic and 1515 extrusions. People complain it is too flexible and it is, hence the Kiragai and CNC'd third-party parts. But the designer was smart, A very flexible bed support will never bind the bearings and always run smoothly. But it is flexible and people don't like that solution. Flexible support can be built and work with low-precison parts. CNC has to be PERFECT. The Kiragami is a compromise. It is still flexible but not as much as the original design.