[Arbo]

To not fill up C1's thread... I appear to be having a problem with my machine. I am getting times where the X just loses steps this way or that way.

My X is driven on both sides by the R&P drives. At first I thought it was the steppers overheating, but I managed to get fans on them and keep the temperatures down, so I don't think it's that.

I tightened up the bearing blocks where there was a little slack (some bearings not hitting and spinning as it moved). With power off I have moved the X back and forth and feel nothing catching.

With power on, I can't move the X, no play at all that I can tell.

So what else might it be? Controller? Mach 3 settings? Not sure where to progress on this one.

Most of the stuff I have been cutting in the past has been 3D gcode that just moves the y back and forth, and the x slowly increasing as it moves over the part, so perahaps I have always had the problem and just never cut much to notice it, or maybe it's a newer issue.

Any suggestions on what to check or look at would be appreciated.

[ahren]

I would check the set screws on the motor pulleys -- pulleys slipping on motor shafts are one of the primary reasons for lost motion. Tighten them up, and I recommend putting loctite on them as well one you do. Might not be your issue, but it's definitely worth checking.

Best regards,

Ahren
CNCRouterParts

[Arbo]

Will go out and check that now. Just made a g code file with a bunch of rounded corner rectangles to run over and over with a vbit in some scrap wood to look at the start and end point.. it is most often a bit off, so I can tighten and tweak until those two points line up.

Thanks for the input.

[Arbo]

Well, that might have been it, the drive on the other side was pretty much free wheeling, the set screw not even in it. So only one side was driving the whole thing. I amazingly found the set screw, cleaned up both R&P's, used some loctight, ran some tests and it seems to be working ok.

Will now try the C1 3d Myan haab and see if it cuts the whole thing without screwing up.

Thanks

[Arbo]

Had a request from someone for a litho. I couldn't get the detail needed to do it justice. So I went from a 1/16 BN, to a 30 degree v bit with a .005 flat end. Now my step over is .004. It means it takes a bit longer to cut (a 5x7 seems to be about 5 hours) but the detail possible is far better than with the old bit.

Here's an example of a test cut I did. The machine messed up on the Z on the left hand side, you can see the line.. but other than that, I am pretty blown away by the quality that can be achieved with the new setup.

[CarveOne]

You can get even finer details if you use a sharp pointed V-bit, but at the less than 0.005" dimensions, 0.001" less step-over really ramps up the cut time. All you can do then is to increase the feed rate. Then you run into chip load issues because of almost no flutes at the tip.

What size is the litho?

[Arbo]

I'm not sure it's realistic to use a sharp point and less step over, the cut time ramps up so much the time/quality benefit just isn't worth it.

[CarveOne]

I'm not sure it's realistic to use a sharp point and less step over, the cut time ramps up so much the time/quality benefit just isn't worth it.

Definitely not worth it. That was my point. What you and I are doing is already beyond where most people would want to go. I haven't made any lithos yet, but I know I don't like an all day cut job.

[Arbo]

I've only ever had one greater than 20 hr cut... that was a 12" x 24" litho.

I have loads of nice new 60 degree bits now btw, my CMT showed up while I was out of town, and I bough some other one that flattens out at the bottom, says it's for 'sign lettering'... so much stuff to do, so little time.

[Arbo]

Here is the final cut. Only lit up by a dim morning sky.

[harryn]

That is a great picture. Is that Crater Lake in OR ?

[Arbo]

I believe so. I just finished another one for a customer, detail is simply stunning, but unfortunately can't show it off here.

[ecurb5]

Harryn, Yes, it is Crater Lake. Awesome place.


Sent from my DROID2 using Tapatalk 2

[Arbo]

Going down in size of images to see how fine of detail I can get. This one is only 2.5 inches across. Pretty stellar detail IMO for such a small litho.

[harryn]

You are really motivating me to get my act together and get my router built. I have been hesitating, because I was unsure if I would have enough resolution.

So you are doing all of this with:
- Rack and pinion on all axis
- 1 in dia pinion
- 3:1 reduction
- Other fairly conventional setup
- 10x micro stepping
- 0.004 in step overs ?

If so, my confidence is rising.

Great work BTW.

Take care

Harry

[Arbo]

I don't actually remember the specifics, but it's the CNCrouterparts R&P nema 23 drive units, one on each side. I believe that is 3:1.

Y and Z are whatever I said long long ago in the thread. Man I have spent far too much time not using the machine.

Yeah, .004 step overs on the bit that has a .005 'flat' end. It actually cuts faster than I would have thought, but at that, it's still a couple hours for the cut.

I don't even recall settings for micro stepping... it might be in the thread long ago. I suppose I should re-familiarize myself with all these things as I am getting back up to speed.

Even with a 1/16" ball nose, you can get some really nice images, but if you plan to do smaller sizes, it seem necessary to shift to the 30 deg v bit with a flat tip to really get some of the finer detail.

[Arbo]

Another test, a 2.5 x 3.3 inch litho. I think I've got the detailing down. This one just blows me away...

[Arbo]

In other cool news, I met a neighbor (who I should have met years ago), who is working on two CNC routers. Very cool, good to meet him, and good to have others around interested in the same stuff.

[Arbo]

Another litho, this one 5x5" ...

[CarveOne]

I bought some cutting boards from Wal-mart that are 5/16" thick with the intent to carve the 3D Haab calendar into if I can invert the tool paths and cut it from the rear. It has a slightly textured surface on both sides and I want a smooth outer surface. Haven't had time to do anything with it so far.

Think it will work ok when backlit?