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Old 04-01-2018, 01:18 PM
Wolff Wolff is offline
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Default Cutting depth issue

Hi,
I work for a company that has a Cammaster Cobra ATC, CR510, and we use Vcarve Pro and the software that came with the machine, it's been running fine and I got past the learning curve on this enough to do my own setups and drawings.
Recently though I've run into an issue I cant figure out, neither can our "guru" the issue is I set up a profile tool path outside cut on 3/4" MDF, and then an identical profile path, same tool etc to cut out two roughly 8" square holes in the middle of the 2 foot by 4 foot piece, I set the depth cut to "z" on both. It cuts the outside perimeter perfectly, right to the very top of the spoil board, however, on that inside cut the cutter is leaving almost 1/8" of material at the bottom.

I've tried zeroing the machine with the tool we use for doing that in T5, and measuring the 3/8" rough compression cutter I used in T2, no difference, the only think I can think of is maybe a bug/corruption in the software and it needs to be reinstalled. We've had the machine about 2 years but it doesnt get a lot of use and can sit for a few weeks at a time not used, so wear etc is not likely an issue here.

If I open up the TAP file showing all of the cut information, it shows the Z cut in both paths is where I had it set to; 00000000, so that information is correctly being saved to the TAP file, yet the inside cut is like z -1/8"

We keep pretty good on resurfacing the spoilboard to maintain flatness, it was done about 10 days to 2 weeks ago, it's one more of the things we'll probably do shortly again just to rule out, out of flatness as a possible cause, but I actually measured the table in about six different places with the bit we use in T5 and monitored the WinCNC window where it shows the Z of the bit, it was zero at x1y1 and it didn't vary more than from that to -0.023" at the far right corner- a very small amount- nothing like the 1/8" we are seeing on these cutouts!
Here are some photos which will make it a lot clearer, while table warp is always a possibility, it would have to be warped by 1/8" across 2" to do this!

One photo is one of the panels with two cutouts, it's about 48" by about 24", keep in mind the perimeter using T2 with a 3/8" rough compression cutter was set to cut to "z" for the depth, it cut right thru the MDF and it's bottom veneer and the part was easily removed from the waste edge frame left over. Using the exact same tool in T2 it cut those two squares out, same tool, same profile path, same spindle speed, same cut thru to "z" in the tool path, the only difference is it was cutting inside the lines instead of outside the lines, yet instead of cutting to "z" as it did all the way around the perimeter, it left almost 1/8" at the bottom (second photo of one of the cutout scraps.

It seems to be confined as best as I can tell right now- to just inside cutting.

One other thing I noticed too is, I usually like to cut the 3/4" stuff in two passes, so I usually set up two passes, and click "OK" and the machine makes two passes, but this time I noticed when I went back to that in the tool path that it was displaying ONE pass full depth, so I set it again, saved, and went back to look and it was again back at one pass full depth. So I said "screw it" and ran the part and the machine ran TWO passes as I wanted despite the toolpath apparently reverting back to one pass.

The two issues have been happening on several pieces of late, I've gone over everything in the vcarve and WinCNC and it's baffling.

Also typically I like to run rough climb cut in two passes and keep the depth of those two cuts to 0.70" and the offset to 0.01" and then follow up with a finish 3/8" bit in T3 conventional cut to cut the remaining material to "z" and to offset to 0.0", but with this almost 1/8" material being left I thought I'd troubleshoot and leave off doing that finial finish pass with T3 because it was like it was being skipped over somehow, and I set the rough cut to do the whole cutting down to "z" to eliminate that step of changing tools and so on, keeping it all on one tool, but like I indicated- the same tool and everything was still causing this.

I set the T5 tool to x1y1 and into a piece of paper just dragging the paper and set that to z=0 and measured T5, T2 and T3 which is what I was using, I did that at least twice or three times, it didn't make any difference. I even tried setting that inside cut to z=+010 and it of course put up a warning about cutting into the spoil board, so I left it at "z"

As this is, I had to take a jigsaw and cut the rest of the material out around both of those cutouts, and the hand route the openings to clean them up.

https://imgur.com/a/KW7tq

https://imgur.com/a/iQWaj

https://imgur.com/a/qZaQL

Last edited by Wolff; 04-01-2018 at 01:23 PM.
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  #2  
Old 04-01-2018, 02:13 PM
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When you ran the spoil board did you re calibrate and reset Z ? the measure all tools
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Old 04-01-2018, 02:16 PM
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Gary Campbell Gary Campbell is offline
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4 steps to success.. Post back here if you do not know how to do this.

Make sure that any erroneous user offsets on the Z are removed by typing in "G92.1 Z0" and press enter

Calibrate switch to spoilboard using any tool, make sure it is picked up by typing in "T#"

Press "Measure all tools"

Set the Z datum in VCarve Pro at the bottom of material, toolpath and cut.

That's all there is to it.
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Old 04-01-2018, 03:45 PM
Wolff Wolff is offline
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Quote:
When you ran the spoil board did you re calibrate and reset Z ? the measure all tools
I personally did not resurface the spoilboard, our guru does this and he's good about checking procedures etc., He did it about 10-14 days ago, the spoilboard was recently replaced too. I'd have to ask him.

Quote:
4 steps to success.. Post back here if you do not know how to do this.

1) Make sure that any erroneous user offsets on the Z are removed by typing in "G92.1 Z0" and press enter

2) Calibrate switch to spoilboard using any tool, make sure it is picked up by typing in "T#"

3) Press "Measure all tools"

4) Set the Z datum in VCarve Pro at the bottom of material, toolpath and cut.

That's all there is to it.
The machine is used by myself, our "guru" who has learned the most on it from day one, and one other guy who uses it maybe once in 6 months, and there have been instances where the Z and the x1y1 have been changed to accomodate moving the x1y1 to say x12x12 and the z to accomodate much thicker material or material that was small and needed to have a 3/4" thick backer board screwed to it, but I've always checked to see that those are reverted back to the normal x1y1 location and z at the top of the spoil board.

We did have one instance where the "guru" sent me a file he said was ready to just to cut, when he was away, he forgot to set his cut for the bottom of the material and when the cutter was up in the air cutting nothing I caught that error in his drawing.

I have not learned item #1 with the G92.1 Z0 or how to calibrate the switch to the spoilboard yet, or to resurface the spoil board, I have only set the bit to the z=zero at the top of the spoil board and measured the tools I was using when I had this issue the thread is about, I figured someone changed the setup for thicker material and zeroing the cutter and measuring it would fix that but it didn't.

Still, I would think that is any of these were off, I would get either ALL the cuts to the z=zero level, or ALL the cuts leaving 1/8" of uncut material on the bottom of the workpiece, not the perimeter cut being correct and the inside cut being off using the exact same tool, specs and everything else, the only difference being on is cutting around the outside of the drawing's lines and the other is cutting on the inside of the lines.

I will see what our "guru" says if he is in to-morrow, thanks Gary.
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Old 04-01-2018, 04:19 PM
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Gary Campbell Gary Campbell is offline
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My guess is that with multiple users and not all of them fully understanding the procedures and order that they must be performed in is what is causing the issue.


"Still, I would think that is any of these were off, I would get either ALL the cuts to the z=zero level, or ALL the cuts leaving 1/8" of uncut material on the bottom of the workpiece, not the perimeter cut being correct and the inside cut being off using the exact same tool, specs and everything else, the only difference being on is cutting around the outside of the drawing's lines and the other is cutting on the inside of the lines."


This is most assuredly a user error. The same tool will not return different results unless told to
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Old 04-01-2018, 04:36 PM
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I caught the same sentence this alone will cause this error, sounds like a board surfaces but not recalibrated
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The principle of Measure twice cut once has not been replaced by a CNC

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Old 04-01-2018, 06:04 PM
Wolff Wolff is offline
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Quote:
Originally Posted by james mcgrew View Post
I caught the same sentence this alone will cause this error, sounds like a board surfaces but not recalibrated
We'll see what we find to-morrow if the "guru" is there to check that. This issue wasn't just on the one file or one board with the two cutouts, it's probably been doing this on the last dozen or more workpieces over different days, different drawings and setting up toolpaths for each.

Almost everything I do make on the machine is not a dozen or two dozen of the same part from the same setup, with few exceptions everything we do is a "one-off", we very rarely make more than one piece the same, though we will usually try to cut multiple items out of a sheet, none of them are the same and each sheet of MDF pretty much gets it's own drawing and toolpaths set up for that.

This means each drawing and eact setup is done for each piece, in other words if there was an error in the toolpath or something entered in Vcarve before saving as a TAP file, it would only affect that one piece, I don't copy/paste or reuse previous paths because each is a unique workpiece.

A recent cutting involved cutting these 4 pieces from 3/4 apple ply.

https://imgur.com/a/aOgjz

We also use 1/2" MDF and others.


Last edited by Wolff; 04-01-2018 at 06:07 PM.
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Old 04-01-2018, 06:27 PM
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We do cut cabinet parts daily yet custom parts radiuses mostly and a lot of handicap frames, i have the same machine

if you need my cell is 803 518 207four
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CAMaster ATC 508
The principle of Measure twice cut once has not been replaced by a CNC

www.mcgrewwoodwork.com

https://www.facebook.com/pg/Mcgrew-W...=page_internal

Camera 1 ATC Closeup !
https://video.nest.com/live/esNTrZ
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Old 04-01-2018, 07:28 PM
Wolff Wolff is offline
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Quote:
Originally Posted by james mcgrew View Post
We do cut cabinet parts daily yet custom parts radiuses mostly and a lot of handicap frames, i have the same machine

if you need my cell is 803 518 207four
Thanks James, we'll get to the bottom of this, if you don't think it's a software corruption or bug, or machine fault then there must be something I'm missing, as you know, something like that can be starring you right in the face and you look at it and don't "see" it and then suddenly it hits you!

If I start changing more than one thing at a time, the issue may vanish and I'll never know what the actual cause was!

I'm not new NEW at this but there's a lot I haven't done yet, but cutting the many pieces of 3/4 and 1/2" apple ply for this assembly on the machine was one I did early on when learning, it turned out fine, including cutting out the tight joint slots, and the 4" square recesses- those were done with the pocketpath. The real challenge was laying the sheets out so the good sides would face out and less nice sides of each piece faced in where the glue goes to laminate the layers up.

https://imgur.com/a/zicQQ

Last edited by Wolff; 04-01-2018 at 07:37 PM.
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Old 04-01-2018, 07:34 PM
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this type of overlook is common I have worked thru it with plenty of owners (mostly new ones) !
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The principle of Measure twice cut once has not been replaced by a CNC

www.mcgrewwoodwork.com

https://www.facebook.com/pg/Mcgrew-W...=page_internal

Camera 1 ATC Closeup !
https://video.nest.com/live/esNTrZ
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