I'm designing a helical turning lath and I'm wondering what approach to take with the software.
It's a relatively simple thing for turning wooden spindle spindles with barley twists, rope twists, hollow spirals and so on - left hand and right hand. Work size max 2" diameter by 10"It's similar in function to a small metalworking lathe with the ability to cut threads. I'm not using a metal lathe partly because of the cost, partly because i don't need the extra functionality and partly because the changes needed (to the spindle drive and gearing) are proving impractical for me.
It's basically a 3-axis machine. X axis for moving the tool (a dremel-type tool) along the length of the spindle in the chuck, a Y axis to advance the tool into the wooden spindle and a z axis which is the rotation of the chuck (slow speeds for positioning not fast for cutting). There will be a 4 th axis for minor adjustments to the height of the cutting tool.
The x and y axes are a small x-y milling table,the rotation z axis is a small rotary table, mounted vertically, and 4-jaw chuck. The 4th tool-height adjustment axis will be a small scissor lift lab table.
.All axes will be stepper-motor driven, probably nema 17 bipolar. I'm still learning about driver boards so I haven't decided on them yet.
So for the front end software, I don't need anything too sophisticated. I'm not sculpting in 3D. I just need to:
rotate the spindle slowly and continuously
move the tool along the spindle at a specific speed
sync those two movement to cut a helix
advance the tool into the work slightly on each pass
I will also need to:
take into account end stops
rotate the spindle c/w and cc/w for right and left hand threads
vary the speed of the x movement during a cut to vary the pitch of the helix in a spindle.(excited about that one.)
A preview of the result would be good bit I think I basically need to enter an x to z ratio (where x might be variable and z might be negative, a depth, a start and end position and an overall cutting speed.
As you can probably tell i'm new to all this so any advice or observation offered will be gratefully received....
I've uploaded an early drawing to give a rough idea. The bed and tail stock arent included at the moment and the xy table is actually cheap xy milling table used inverted.