I’ve been planning a V2 build as a first-CNC project, however I’m interested in some possible modifications to the stock design and wanted to get some input.
First and foremost: I’m building towards handling a full 4x8 sheet, but want to build a more accurate/stable y-axis guide system. To this end I’m considering using an alternative roller system. I’ve considered linear rod and bearing (difficult to get rail that long), aluminum X extrusions (same), aluminum profiles with bearings, or conduit rails, such as used on the X axis. I’m strongly leaning towards conduit or iron piping, as it is relatively easy to support it using off the shelf connectors or 3D printed parts and with 608’s, you get pretty decent kinematics without relying on the table to be perfectly smooth - in fact it is possible to surface/tram the whole table once the guides are straight and parallel. Further, the axis attachment to the machine can be made quite stable
The y axis drive system is the next consideration. The longer belt lenght has some backlash to it due to the length of travel. Even with PU steel core belts, there can be a not insignificant stretch over 9-ish feet of belt. The idea here would be to use a piece of flat stock or ply cut to the right thickness to allow a second belt, contact cemented to the face to intermesh with the drive belt along the whole length, similar to modifications I’ve come across for the MPCNC. This would help limit stretch and could improve overall accuracy.
The latter is the concept I think will actually be the most difficult, likely requiring a lot of adjustment to get the pressure right over the whole length of travel. There are a variety of ways to do this, so I think it’s more of a “What is the best way” as opposed to “How” and I’m quite open to suggestions - or to be told it’s a waste of time.
Last, I very much plan on running this on a 5-driver board. Likely an SKR 1.3 with DRV chips, two axis self-squaring and possibly an auto-home for the Z (there are several options open with this board type). Definitely 24V for the better torque.
Thanks for taking the time to read!