I’ve started building a MPCNC machine, great design by the way. I’m printing with a well tuned PrintrBot Simple Metal and getting very good prints. Dimensions are very good and repeatable, and so far I haven’t had to drill any holes. The 5/16" holes are nearly perfect, no appreciable slop, etc.
The initial MPCNC is a 24" x 24" frame size. Starting small until I can verify that everything works. Then maybe will build a slightly larger machine, but this size should be fine for my immediate needs. I already have some steppers and UNO with GRBL controller from an earlier project that I’m going to start with.
I have the corner pieces printed and one set of roller assembly parts. Plus some of the smaller parts, and working on the second set of roller pieces. Then will be printing the feet and finally the center and Z axis parts.
But I have enough to start looking at squaring up the frame and that is where my question comes in.
Following the assembly instructions it looks like I have the frame squared up. That is measurements match at each end of the outside rails as described in the instructions.
But when I roll the cross bar from end to end there is a small gap on the end when moved to the corner blocks. For example with the roller assy with conduit pulled all the way towards me the right roller assy is touching the corner block but the left roller assy is between 1/8 to 1/4" away from the corner block. And if I push the cross bar all the way to the opposite corner pieces then the left roller assy touches the left corner block and the right roller assy has the 1/8 to 1/4" gap.
I am wondering if there is something with the roller assy’s as I printed them that is impacting this since measuring the distance between the corner blocks seems to indicate that things are square as far as the outer frame is concerned, but seeing that gap and having it switch to opposite corners makes me think that I’m either not measuring the correct spot for squaring the frame or that I’m missing something and I’m not really squared.
Has anyone else run into something similar?
I just placed an order for some odds and ends parts from the store. Once I get the CNC machine working I’m thinking about ordering the extruder so I can turn this into a larger format 3D printer when I need it.