Hi guys, I have been lurking for a while after finding Openbuilds while looking at CNC routers. So I need some advice from you awesome people, because I cannot work out what I want/need. Basically I want to do a few things with a router, 3d machine foam cores for composite parts, Machine plywood and other wood to make various things, possibly put into production machining either plywood or foam, so I would like it to be faster than average. I would like at least a 1200x1200 cutting area, that way I can do a sheet of plywood in two operations if needed. Obviously 1500 extrusion would be used. I also want at least 200mm of Z axis working area (more is better) for doing big 3d parts etc. I reaaaalllyy like the idea of C-beam, for the small price increase it seems to be a lot stiffer and stronger than standard extrusion. Do I need 1500mm lead screws? or will I be fine with gt3 belt? I know for foam the belt would be fine but can I get enough stiffness to do plywood kind of fast? I really like the OX and OX metal by Schematix. I would really appreciate any advice, I have a rough idea but I don't want to build a machine that wont do what I need, then have to re design. Cheers guys, Sam!
Belt should be fine and probably the best option for speed. The only real sticking points on what you are wanting would be the gantry span vs. the weight of the router (deflection issues) and 200 mm Z-axis clearance. While materials you are machining are not near as critical regarding minor amounts of deflection, there will still be some and the less the router weighs the better. The bigger issue however is the 200 mm throat. We have repeatedly seen issues with builders setting the gantry up 200mm in the air and then dangling the router back down to the surface on a long z-arm. This leads to a very wobbly z-axis and very poor quality on the cuts. I suggest looking at a vertically articulated gantry beam such that the beam will be running down low and at its stiffest when you are cutting tougher items like plywood and when it is running up higher to cut foam any loss of stiffness is not a big issue. Basically, I'm thinking something along the lines of a cross between C-Beam Big Mouth for its gantry lift and C-Beam Prefab Untitled for the way it mounts the gantry risers (you may wish to rotate them 90 degrees however).
Thanks Rick, So as in the C-Beam prefab, going to 200 would be too much? I don't think I would like to go down the path of having an articulating gantry beam if I can avoid it. I feel like that would open up a can of worms haha. Maybe I need to rethink my Z axis needs...
