John, how did you come up with the g-code to make the leg? I'm close to finishing the rotary I had posted ideas on making. Once it's done I'll create a thread showing what i did in case you are interested. Since the rotary isn't controlled by the CNC controller what bit did you use and what did you set the feed and speed rates at?
My plan was to (I use Fusion 360 at the moment) create a 1/4" thick board with the profile I want. I was going to use a 1/4" downcut bit to do the work. This way the G-code wouldn't move the Y axis. I would manually set the speed of the rotary. The speed would need to be slow enough so the rotary could make a full revolution while removing all the wood. Too slow will take too much time and have too light of a chip load on the bit. Too fast and it's not going to remove all of the wood. It'll change depending on the diameter of the wood as well. If it's a tapered leg that's a 4x4 going down to 2" there's obviously more wood to remove at the 4" end than the 2".
Hi Alex. I didn't have enough Z axis height to put the bit above the centerline of the leg, so I had to work from the side. My milling path was a tapered box on X and Y, the taper being the same as what I wanted on the leg. I used a pocket toolpath, and that allowed me to use the stepover feature, which worked well with the high rpm I used on the 4th axis.
I think you're going to need a toolpath strategy that machines in steps. Trying to remove 1" of material in one pass seems far too aggressive, no matter how slowly X moves.
John
One way of doing this is to create the finished profile offset from a zero plane. Zero on the centerline of the axis of rotation.
Then the Vcarve file use 'offset' to create a number of passes - each one offset a distance from the prior (say, .15") - which defines depth of cut. Trim these at some outer limit. When you create the toolpath, group them all sequentially to create a series of passes, each one an increment closer to the final profile.
That makes perfect sense, Carl. But what toolpath strategy do you use to create a taper, for example, when the bit is centered above the centerline?
John
My plan is to try and do this.
top.jpgside.jpg
I'm just going to remove the white section inside the dashed lines. I'll move the spindle slowly and set the code multiple depths using .2" (using a 1/4" upcut endmill) as a step size. The rotary will be spinning at a speed to be determined by trial and error. The G code will think it's just very slowly making a cut on the end of a long but very narrow board.
That is what I was imagining - and can take multiple passes to get to the final profile? (I may be missing something)
https://www.shopbottools.com/ShopBot...xerasLathe.pdf