Hi...this is my 1st post to any board on cnczone. I've read about 10 hours worth before posting, so I apologize in advance if these questions have already been answered...I found a LOT of information I needed, but have some lingering questions regarding CAM I'm hoping some folks could help me with:
Question #1:
If you design your own CNC router, how do you "calibrate" the mechanical aspect of the system with the electronics and the control software? In other words, if I design a system using servos driving ballscrews via stepped-down belt-driven gears, how will the servo driver "know" to pulse the motor
x times in order for the ballscrew to move
y inches? Do I have to very carefully match my motor, gearing and screw pitch to the driver and software? Or, do you input this information to the CAM software? Or, is there some sort of calibration routine that you run when setting up the tool?
Question #2:
Is CAM software aware of the tool's bit size and profile? For example, in my CAD program I can round over the edge of a part with a 1/2" round profile. When routing this part, the centerline of my round-over bit might be 1/4" outside the actual part being routed. How do you tell the tool path generator to position the router bit on this vector? I'm hoping that it isn't up to
me to figure out the offsets for the tool!
Question #3:
When doing a CAD drawing, I can show a pocket of material removed from the part I am designing. For example, I might want to start with a block of wood, and hollow out the inside, to make it into a box. In CAD, I'd draw the box already hollowed out. How do you tell the CAM software to actually move the tool back and forth, to hollow out the box? Otherwise I picture the tool simply cutting the outline of the box and leaving a big hunk of material inside.
Question #4:
Same question, but this time regarding cutting depth. In CAD, I can show the outside edge of a part notched out by 3" deep. Of course, I don't want the router to plunge into the edge of the wood 3" deep and try to cut it in one pass. How do you tell the CAM software to take multiple passes and increment the depth each pass?
Question #5:
I'm imagining that I can take my CAD drawing, export it to the CAM software, and then turn on my CNC router and go take a nap. From reading (a lot of) stuff here, I bet my imagination is way off. Say I want to do something like a nice 3-D carving for a fireplace mantle. If it takes me 12 hours on TurboCAD to draw, am I in for another 12 hours setting up the CAM routine? Or is it more of a few minute "tweak" exercise in CAM before going to the router?
Question #6:
Any suggestions (for a hobbyist) of a 'best in class' CAM package to do 2-D and 3-D woodworking?
My game plan is to really understand the software, electronics and math/physics behind the mechanicals before I even think about designing the motion system. I've played quite a bit with TurboCAD, so I'm comfortable doing the up front design work. My goal is to build something very similar to this:
Beezer's CNC machine
Beezer, if you are reading this, awesome job...it's an inspiration to me.
Thanks for your time.
-Chris