Wrapping 4th axel does not work - HELP

Topics related to wrapped rotary machining in Aspire or VCarve Pro
Idefixer
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Re: Wrapping 4th axel does not work - HELP

Post by Idefixer »

Hello again.

I made a discover! If In Vectric Desktop sets the zeropoint for X and Y different, the output is completely different.
IMG_1023.JPG


If I set the XY Datum position as the Picture shows, the outcome is very bad. Like the lower engraving in the Picture added to this mail. You can see that the capital letter ”C” is missformed and all characters bottom line is not straight.
IMG_1022.JPG
If I choose to set the XY Datum Position like this instead
IMG_1024.JPG


Then the outcome is like the upper engraving in the Picture added to this mail. Still the Characters do not stand straight but they are fully engraved.

So what do we Think about this?

Is it a problem for Vectric? Do they not have a correct PostScript? And if so, can all the errors with missformed engraving and the tillted basline, be explained?

Hopefully one or two steps nearer a solution

Best regards

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TReischl
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Re: Wrapping 4th axel does not work - HELP

Post by TReischl »

As others have said, you have a machine issue, not a software problem.

Something to think about: Literally thousands of users are creating thousands of programs everyday using the software. The post processor you are using is used by hundreds of folks. It is highly doubtful you are the only one who has used it. The preview is showing the correct motion, so you know that at that point everything is correct.

There is one more step, post processing. But as I mentioned above, hundreds, if not thousands of people use that post processor.

So what does that leave you? The machine and how it is set up.

It is very easy to want to blame something you cannot see, like software. The benefit is that your problem then becomes someone else's problem. The downside is that if those people do not agree they have a problem they need to fix then you will never get your problem resolved.

99.99% of the folks who have suspected there is a problem in the software have discovered that it was not the software. Vectric software has been around a long time, 14 years, so the software is quite stable by any standard.

Some wisdom I learned long ago: When there is a problem that is not shown in the preview, start looking at the machine and the machine control setup FIRST. I have saved a lot of time not chasing software bugs that do not exist.

Edit: One other thing, it is REALLY handy to be able to read gcode. If a person can read gcode then they can actually see and understand what the machine is being told to do. If you cannot read it then you will remain in the dark and always suspect that the software is creating the wrong gcode.
"If you see a good fight, get in it." Dr. Vernon Jones

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Rcnewcomb
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Re: Wrapping 4th axel does not work - HELP

Post by Rcnewcomb »

You are not dealing with a software issue.

Is your material really only 20mm long and 24mm in diameter? That is really quite small.

Debugging your setup:
You need to round the material on your rotary axis so that the material is aligned and a consistent distance from the axis. Having material that is slightly out of alignment or varying slightly in thickness will make the results inconsistent.
Where you set the XY datum position is a personal preference. Just be consistent.
Do NOT set your Z-zero to the cylinder surface. Set it to the cylinder axis. It will make debugging much easier.

Use a simple test file. I've attached and example. Note how it uses squares to check alignment and consistency.
I encourage you to learn to use the Snipping Tool in Windows to take screen shots. It is much better than taking photos of your computer monitor with your phone.
Attachments
RotaryTest.crv
(424 KiB) Downloaded 42 times
RotaryTest.png
RotaryTest02.png
- Randall Newcomb
10 fingers in, 10 fingers out
another good day in the shop

Idefixer
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Re: Wrapping 4th axel does not work - HELP

Post by Idefixer »

Hi TReischl

I am not trying to blame vectric, I am trying to find out where the problem can be. I am just now directing questions to GOCNC who I bought the machine from. Also WINPC-NC that is controlling the stearing of the machine from the G-code from Vectrics postscript.

And ofcourse, reading G-code is a thing that I am learning but not fully can read as a normal book. But every step is a step forward.

Thanks Rcnewcomb for your answer.

No it was just a way to focus the engraving to a specific part of a longer rod.

I have really tried to mount the rod as exactly as possible, so I think this is not the problem. But I understand what You are saying :-)

I will try the attached file.

I have also tried the snipping tool, but I did not achive to paste it in this forum. I tried to save as jpg, but the attachment-function refused to import any image.
Do You have some qlue?

Best regards all who tries to help me
Claus

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TReischl
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Re: Wrapping 4th axel does not work - HELP

Post by TReischl »

Hi Claus,

It would help if you told us your feed rates when attempting these cuts.

In the meantime, have you tried slowing your feed rate down? Way down?

If you slow way down and the problem goes away then you will know that you are missing steps in the motor.

If it does not go away then it could be an issue involving the number of steps per degree.

Keep us posted!

PS, I wrote the above because quite often people new to this stuff are baffled by the gcode and software in general, so it is natural for them to be suspicious of things they do not understand.
"If you see a good fight, get in it." Dr. Vernon Jones

Idefixer
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Re: Wrapping 4th axel does not work - HELP

Post by Idefixer »

Hi TReischl

I have tried with very slow speed. Feedrate 0,02 in/sec. And there is no change :-(

I will try getting some answers from GoCNC in Germany, if they have any experience with there 4th axel and motor. Its control-card sits on there main-controlboard for the CNC.
The mainboard has a setting of 1/2 step resolution. And I have set the same on the controller-card of the 4th axel.

I will keep You posted and I hope there will be some light at the end of the tunnel

Brg
Claus

Idefixer
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Re: Wrapping 4th axel does not work - HELP

Post by Idefixer »

And the setting of the 4th axel in WinPC-NC is:
Skärmklipp.PNG

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Rcnewcomb
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Re: Wrapping 4th axel does not work - HELP

Post by Rcnewcomb »

I will try getting some answers from GoCNC in Germany
Claus,
Sind Sie Deutsch?
- Randall Newcomb
10 fingers in, 10 fingers out
another good day in the shop

Idefixer
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Re: Wrapping 4th axel does not work - HELP

Post by Idefixer »

Nein, Ich bin Schwede aber Ich kann Deutch sprechen und schreiben. Meine Mutter kam von Deutschland :-)

Idefixer
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Re: Wrapping 4th axel does not work - HELP

Post by Idefixer »

Hello again.

I have done a test and really tried to logg everything.

If someone has a chance to take a look and give me some hints on what can be wrong.
Is it really a mechanical problem with the 4th axel? I have tried to get in contact with the dealer of the motor but so far no answer.

Flat jobs is great. But rotating jobs does not work.

I have attached both pictures and configurationsfiles as well as the NC-file.



Best regards
Test with rotary engraving 8 may 2019.pdf
(625.86 KiB) Downloaded 44 times
Lasertest Rotary axel 24 mm.nc.txt
(43.4 KiB) Downloaded 50 times
Lasertest rotary 24 mm.crv
(130 KiB) Downloaded 39 times
Laser 6W GoCNC PWR 4-axel.WMS.txt
(9.43 KiB) Downloaded 53 times
Claus

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Rcnewcomb
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Re: Wrapping 4th axel does not work - HELP

Post by Rcnewcomb »

I noticed the G code does not use arcs for the circles: no G02 or G03 moves.

It will take more time to read through it.
- Randall Newcomb
10 fingers in, 10 fingers out
another good day in the shop

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TReischl
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Re: Wrapping 4th axel does not work - HELP

Post by TReischl »

Hello Claus,

I have read through your G code.

The circles look fine:

N40 G00 X14.968 A95.759 M09 'Starting Point
.
.
.
.
N207 G01 X14.968 A95.759 'Ending Point

There is nothing wrong with your G code.

What mystifies me is that your post is producing the correct code. The squares look pretty good, if you had the steps set wrong they would be just as bad as the circles, but they are not. Same thing with the letters.

It is almost like there is a rounding error with all the small moves in the circles. I also use a post that does NOT produce circular motion (G2/G3) when cutting circles on the rotary. I do not see the problem you are seeing. Hopefully someone using WinPC will spot the issue with your setup.
"If you see a good fight, get in it." Dr. Vernon Jones

Idefixer
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Re: Wrapping 4th axel does not work - HELP

Post by Idefixer »

Thanks both for your help. I will talk to WinPC-NC and ask if it can be a rounding error.

I will give full feedback as soon that I will have some facts

Best regards
Claus

Idefixer
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Re: Wrapping 4th axel does not work - HELP

Post by Idefixer »

Regarding G02/G03.

I think that the software Vcarve does the choice not to use G02/G03 when making cirkels on rotating axels. I let the job be flattened and then it used G02/G03.

Or is it really only depending on the postprocessor-file?

Idefixer
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Re: Wrapping 4th axel does not work - HELP

Post by Idefixer »

And is it even possible to user ARC-command G02/G03 when engraving on a rotating workpiece. Isn´t G02/G03 movements both x and y? And then y has to stand still and the axel is instead rotating.

My knowledge in this matter is really limited but I am willing to learn :)

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