CNC + Manual?

[fatal-exception]

In your opinion, if you were to design and build a lathe right now, would you allow for manual operation of the lathe as well as cnc?

I know this depends on alot of factors, but say you were really proficent at operating a cnc mill already, should the lathe be cnc only?

Paul

[Ken_Shea]

Paul,
Do not have a CNC lathe but my CNC mill does have manual operation, it has yet to be used. I am (Still) building a CNC lathe and have no intentions of complicating the build with any manual operation abilities.

If it was a manual conversion to CNC that may be a different story.

CNC jog offers far more precise and easier control that using manual.

Of course others may have entirely different and valid reasons for including it.

Ken

[The Blight]

First of all. I see no real reason to include manual operation on a CNC machine. Unless you have a DRO on the same machine, you wont be able to tell where you are at (well if you keep the dials on the axis that is). Keeping the handles on the machine will also just present one more danger. Spinning handles is never a good idea. And the last, but most important thing. Spinning a stepper motor when it's not powered up is a bad idea. It generates power and this can ruin the driver. So unless you are using some form of clutch to switch between manual operation and CNC, I would not recommend doing this.

If you want some sort of manual operation, get yourself an MPG to jog the machine.

[BrassBuilder]

I have to agree with the other replies.

When I first built my X2 milling machine (I know this thread is about a lathe), one of my concerns was to still have the manual option should I need it. I can say that I have not used the mill manually since CNCing it a couple of months ago. I don't ever forsee using it as a manual mill again. I can jog the head over where I need it with some very simple to input G-code. This is much simpler than trying to move everything manually.
Mike

[cam1]

Hi:
Have a look at the Haas TL series. When last I checked they had a handwheel. Here's why I would say Yes: Every now and then, you may want to do a quick little rework, without having to start the PC, home the machine, setup the tooling, program the toolpath. Sometimes it's nice just to be able to chuck the part and make a cut. A good example of this would be adding a chamfer, or undercutting a diameter.
I am proficient with manual or CNC machines, and sometimes it's just easier to go manual...

regards

[wwendorf]

I have a Syil SX3 mill. I was at first annoyed because all manual controls were removed. Now, it's not a big deal. I just set the mill down to 15% jog speed in Mach3 and jog back and forth using Mach3's DRO display.

I am no longer annoyed by the missing manual controls as they are not necessary.

Wade

[cam1]

Hi wwendorf:
The discussion was centered around a lathe conversion, however if you had to rework a rectandular blind pocket (workpiece was removed from mill table), would it be easier to use the handwheels to move around the walls to remove a few extra thou, or would you jog?
On a lathe, I'd still say yes to manual operation. (just my opinion)

regards

[The Blight]

Well if he can come up with a good way to disconnect the motors then fine. If not he might end up ruining the drivers.

Using the MDI you can move all axis arond fairly easily. If you want some kind of manual operation, you should go for a jog wheel. I have never felt the need to use my CNC lathe as a manual lathe, and I have a jog wheel on it.

[wwendorf]

Yeah, I know it was centered around a lathe conversion, but I was just relating my opinion because of lack of manual controls in general.

If was doing a few thousandths, I would just set the jog control to move only a thousandth at a time, jog to where I need, then go back to normal jog mode and make my x axis move.

The other thing I might do is set a soft limit at the point where my part ends. Then MACH3 simply would not allow me to go any further.

Wade

[fatal-exception]

If I had to remove a few thou from a rectangular pocket, I would definately program a toolpath and do it full cnc. I often use strait jogging or an mpg on my mill for squaring blocks, facing, and other single axis operations, but anywhere there is more than one direction or accurate position is involved, I take the time to create or modify a toolpath to work.

I've never had or used a cnc lathe before, so all my experience is manual. I tend to agree that to do a simple chamfer, or facing off a hacksawed bolt, it might be nice to not have to fire up a computer, and all the other stuff. Possibly just quick disconnect handwheels would do the trick?

For the small amount of manual this lathe may have to do, I don't think I would be worried about blowing up a driver from the voltage created. I suppose if this were a real concern, I could put a switch between the motor and driver.

Is it common practice to use jogging or an mpg on a lathe for cutting?

Paul

[cam1]

Hi: Yes, I use MPG all the time to calibrate tools. Using MPG, take a lick off the OD, back off on the Z, spindle off, measure cut Diameter, enter Diameter into control.....Do the same for establishing Z=0.
Nice to be able to run something without having to think overly hard.

regards