Messages

541

Show"N"Tell ( Your Machines) / Re: Just got a lathe to retrofit

« on: February 19, 2012, 05:59:01 AM »

Yes, using the bolts against the turret would damage it.

You're lucky to have clean air

Dan

542

Show"N"Tell ( Your Machines) / Re: Just got a lathe to retrofit

« on: February 19, 2012, 05:16:10 AM »

Thanks for the description, Hood. It is a nice solution. Just a thought here - looks like it might be better to have the screws' heads touching against the slot wall rather than the tool, as when tightened they would tend to drag the tool out of position.

So you have to use shims for height adjustments?

Interesting.. the sea here is a few kilometers away and everything picks up rust pretty quickly unless it is a good alloyed steel. Think it has to do with the air pollution levels as it's soaring here.

Dan

543

Show"N"Tell ( Your Machines) / Re: Just got a lathe to retrofit

« on: February 19, 2012, 03:51:58 AM »

Hi Hood,

Can you please show how the tool is fixed in the slot?

What steel is it? Aren't you going to have it plated? Your weather is the worst one could imagine for machine tools.

Dan

544

G-Code, CAD, and CAM discussions / Re: Arcs not cutting smoothly

« on: February 16, 2012, 04:36:20 AM »

In any case, this doesn't change anything about the segmented arcs I'm getting on this part. I tried exact stop this afternoon, and it didn't make a difference. Still getting the same behavior.   

I think the answer lies right there, in the numbers of your test. X axis is pretty much obvious, heaving an absolute deviation of 0.002", which is enough for those segments to be seen. I would guess that if you did the test over a longer distance you would see a distinct repetitive nature of the numbers. Entering the numbers in Excel would make it easier to visualize.

Since you're not using a belt drive, you have to start looking elsewhere in the driver mechanism. For instance, what is the motor? Could be a stepper motor with poor accuracy - unevenly spaced poles or magnets on the rotor. Since your Y axis is much better than the X, you could try swapping the motors.

Dan

545

G-Code, CAD, and CAM discussions / Re: Arcs not cutting smoothly

« on: February 15, 2012, 11:42:27 AM »

Sorry I missed this:

The length of the flats are .160" on the outside of the large diameter (0.75") and 0.120" on the outside of the smaller diameter. They're also not flat, now that I take a close look. They're definitely arcs in and of themselves.

Outside of the backlash, the axes are very consistent - example: I make a g0 move from x0 to x-3.7500, then from x-3.7500 to x-3.5000. I now zero the glass DRO, and I can make any move in the positive direction and be pretty much dead on (within a couple of ten thousandths, anyway).

Can you extend this test. Zero Mach3 and glass scales (after taking out any backlash) and then do short moves of 0.01" up to a total of about 0.15" and compare the numbers in Mach3 and the glass scale at each point and see if they correlate. Repeat on both axes.

Dan

546

G-Code, CAD, and CAM discussions / Re: Arcs not cutting smoothly

« on: February 15, 2012, 11:09:43 AM »

Is the arc segmented all around? And segments are absolutely equal in length (both on same arc and different radius arcs)? Can't be seen on the photo.

Mach3 sometimes does do strange things. Have you tried restarting the PC?

Have you successfully cut arcs before?

Dan

547

G-Code, CAD, and CAM discussions / Re: Arcs not cutting smoothly

« on: February 15, 2012, 10:30:18 AM »

Doesn't look like backlash to me. I would, however, guess that it is a mechanical problem in one (or both) of the axes. If you have belt transmission, for instance, a run-out of the pulley could cause something like this.

To make troubleshooting easier you could hold a pencil in the spindle and draw the tool path on a paper.

By the way, the transition points you specified in the above drawing are not all correct. The 2 diagonal lines should be removed as there is no direction change in either axis.

Dan

548

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: February 08, 2012, 03:15:22 AM »

This leopard looks so much more better than the first one. Nice, Greg!

Dan

549

General Mach Discussion / Re: Laser cutting

« on: February 07, 2012, 03:02:30 PM »

Definitely against the rules!

By the way, not sure Tweakie is the address either. He only can cut plastics and woods with his setup. There are many plasma users here though, so may be better asking them to do the job. Not many metal cutting lasers here (if any).

Dan

550

LazyCam (Beta) / Re: LazyCAM Plasma Different Feed per Layer - Is it Possible?

« on: February 07, 2012, 03:58:34 AM »

Thanks, Rich. Looks like there is no provision for this in Plasma mode

Dan