I am looking into building my first CNC router. This will be a purpose built machine in a mild production environment. I want to hang two opposing Bosch 1617EVS's on the Z-axis so they can make a vertical slot on both sides of an LVL (one side at a time). I was hoping someone would know if a NEMA 34 stepper would have enough power to move the Z-axis with 16.6 lbs of routers (plus brackets), or if I should go with a servo. Any additional help or insight would also be appreciated.
Nema 34 is a broad statement. a Nema 34 frame will allow plenty of torque. you should go with a fine pitch ball screw. do not go with the acme thread. My first question is why two routers. if you are only cutting one at a time.
I am new to this and saw the NEMA 34 was the largest stepper motor frame readily available. I know there are NEMA 42, but figured at that point I would just jump to a servo. Since this is for business use, I want the first one to be sized with a hefty safety factor. The two routers are so we don't have to flip the part. These will make a 1-1/2" slot 1/2" deep on each side of an LVL 2x6. We burnt up a Bosch 1617EVS and are at the limits on a 3-1/4 HP Porter Cable with a 1-1/4" slot. Currently, we are checking the budget between dual 4 HP spindles running a 1-1/2" bit or dual routers in a CNC with a 1/2" bit. Another question I should have asked is for a recommendation on a controller? I was leaning toward the 9 axis PlanetCNC because I could see us making some more advanced CNC's in the future and want to standardize on a controller. We want to load the gcode on an SD card and use a Z and X probe to determine the LVL dimensions since there are several widths and heights of LVL lumber that can be loaded. The start button will initiate pneumatic clamps and measure the part. Our tolerances are +/- 1/16" for this part, so it is more important to be repeatable and reliable than accurate.
I would be interested in seeing your design, sounds like a fun project. The stepper motor has plenty of accuracy and is much simpler to put together. As far as the controller you need to ask your self how many inputs and outputs you will need. Homing switches and a couple of outputs for your routers. A simple BOB with a parallel setup would work if you have an old computer. If you have a newer computer and want the cats meow, go with the Ethernet Smooth stepper. there is good local support. I would also go with Mach3 for the software. It is easy to set up, it is very capable, and you have a big pool of knowledge out there to help you. There usually a computer involved unless you use an arduino. (I do not suggest that route.) So you would not need the SD card. a probe sounds sounds really cumbersome. Why not measure it and choose your program. Is this an assembly line running one after another?
