Quote Originally Posted by canyonsam View Post
I am attempting to build a 8'x4' CNC router specifically designed for rough cut wood slabs. I have launched the project on kickstarter.com. Any feedback, positive and negative is welcome and needed. Support is always welcome!

Here is the link:



I have been in the CNC Machining business for 12 years or so, mostly metals and plastics. I would say that one of your hurdles is flatness, the definition of rough cut is not flat, at least it is to me. CNC's hate "not flat". Looking at your initial table design I would guess that your table looks a bit flimsy, the spans between the legs are too far for a large heavy work piece. I can do a study on the design and make suggestions for reinforcement. Any flex in the table will be transfered to the workpiece and to the spindle head.

I've installed several CNC's as well and I dont think your going to have issues in certain places if the right steps are taken.

You posted "Vibration of the table must be kept to a minimum and additional bracing may be necessary to address vibration issues." first, I think your table should be lower, is there any reason not to have the work piece top surface at about 24"? Lower the center of gravity will help eliminate vibration, also mounting it directly to the concrete slap ould help, and don't forget about adding dampners or shocks. "Matching motor power and speed to the material to be machined will be a real challenge due to the nature of rough cut wood slabs." I think your over thinking this, speed and feed for years was a single value based on what material your cutting, its only recently and for economic reasons, that variable speed/feed heads have made an impact on the market. In my experience with wood (which is limited) speed and feed can be narrowed down to 1 constant, or possibly 2. There are plenty of programs and equipment that can do this automatically based on load, but I dont think that necessary. The area that I would be more concerned with here is Flute design and helix degree of the cutter. Down cut vs upcut vs compression. An issue with the carvewright is its difficult to control a climb vs conventional cut, being able to control that would help eliminate clean up and aid in chip ejection, but the cost, time programing and design time would be way out of the average hobbyists realm, also it wouldnt be realistic for 1 or 2 projects. Now if you plan on production, keep that in mind because there may be benefits to having control over that.

Well thats my quick .02