Considering Un-cnc Ing

[T Bredehoft]

When I got back into machining, after a 15 year retirement, it was with the hope that I could machine a plotted curve. (the curve I wanted to machine is/was long S shaped.) I soon realized that my old system of bandsaw/file was going to have to do because the cost of the CNC equipment far exceeded the realized benefits of the machine. Yes, I now have a lathe and a mill, and yes, I still bandsaw/file the curves I need, up to 17" long. I can program my computer to draw the curve, and I can cut it out and trace it on aluminum, but I find I have to tweak it after it's cut.

 

[compsurge]

How are you doing the coding now? Are you using any of the conversational programming wizards available in Mach or LinuxCNC? I don't see how manual over these wizards and CNC motion will save a tremendous amount of time based on how quickly you can turn with CNC versus manual movements. What tools do you primarily use?

 

[Transformer]

Thanks for the responses.

Wrat: I hear you. I will move slowly, if at all.

Jim Dawson: A convertible machine would be great but I would not know where to start.

bpratl: So I think the MDI lets you input one line of code at a time and immediately run it. I have never used this approach but for boring involving multiple passes wouldn't you need 4 lines of code -advance tool-cut-retract tool-return to start, repeat, repeat, repeat. I hope I am missing something here.
Also I think an MPG unit only allows you to position the tool and not control it during cuts, or can you use it for more than a replacement for keyboard controlled movement? In general your response gives me hope - sorry for my lack of understanding.\

compsurge: I manually code. I do not use the Wizards although I have used them to help me learn how to code. I do not use any special tools.

A recent job. I had to bore out a piece to take a toonie (Cdn $2 coin), about 1.13". I step drilled a hole to .75" then used a boring bar to widen the hole to full size. I moved the boring bar by turning the stepper motors by hand - they have a small wheel on the projecting unused shaft. It was all done very quickly and I did not need to program or work out in great detail where to start and how many cuts to make. I just did it on the fly, cut is too big, back off and so on. Of course the fact that great precision was not needed made it easier. As a one off job, given my novice programming and nervousness over crashes this was certainly the easiest approach and one which I think even increased experience and confidence would be hard to match.

 

[JimDawson]

Also I think an MPG unit only allows you to position the tool and not control it during cuts, or can you use it for more than a replacement for keyboard controlled movement? In general your response gives me hope - sorry for my lack of understanding.\

The MPG can be used to control the lathe somewhat like using the hand wheels. The down side is that you can only control one axis at a time so it is a bit slower to use than the hand wheels.

Jim Dawson: A convertible machine would be great but I would not know where to start.

Like any engineering project you start by actually defining the need and the goal, then step by step solve each small problem as they come up. In this case it's how do you design a mechanism that will quickly disconnect the lead screw and allow operation with the hand wheel. I don't see a problem with leaving the cross slide connected to the stepper. I would think that you would need some kind of a DRO for manual operation.

 

[bpratl]

Transformer, give the wizards a try, I used the boring wizard to enlarge the ID on 12 bronze bushing and it worked out great. It did it in 4 passes, with automatic retraction and a final skim cut.
It's plug and play and you can save the g code. I am presently in the process of wiring in two MPG's for X and Z which should be done by XMAS I hope. I will report back when working. Bob

 

[maker of things]

I run many programs line at a time with MDI (assuming mach3/4). Up arrow shows you the recent lines you have entered which you can then arrow over and edit. I frequently use this approach when running simple passes. Do you have another way to measure movement without the motors driving the move? i.e DRO or verniers.