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Author Topic: V Carving Quality - possible problem on entry and exit points?  (Read 1926 times)

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Hi, I am new to the forum, but not new to my CNC.  I have a Legacy Arty 18 x 36 that I have owned for about 6 years.  The machine/software seems to work fine when making parts, but when I try to make signs the letter quality is not good and it seems the problem is in the entry and exit points of the letters for the most part. 

I have done everything I know to do to make sure it is not mechanical on my machine.  Everything is tight, travel is smooth and seems fine to me.  The problems with the letters is very consistent so they are always the same so starting to wonder if it is a Mach 3 adjustment or problem.  I have VCarve 7.5 that I use to design and generate the G Code for the machine.  The previews always look great, but the end result does not match.

I have attached a couple of pictures to show the problem and would appreciate any help and ideas you have.  The pictures show the problems with the letters. I believe the letter style is Times New Roman.

Thank you, Steve

Offline Tweakie.CNC

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Re: V Carving Quality - possible problem on entry and exit points?
« Reply #1 on: July 27, 2017, 01:42:56 AM »
Steve,

Check that you are actually using the same angle of V-Bit that you are specifying in VCarve.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: V Carving Quality - possible problem on entry and exit points?
« Reply #2 on: July 27, 2017, 09:02:11 AM »
Tweakie

Thank you for your reply, I am using the same bit that I programmed in VCarve that generated the G Code.  60 degree V Carve bit from Magnate.

Any other ideas, I just cant figure this out.

Steve

Offline ger21

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Re: V Carving Quality - possible problem on entry and exit points?
« Reply #3 on: July 27, 2017, 06:47:38 PM »
What he means, is to check if your 60° bit is indeed 60°.
It's hard to tell from your pictures, but this is a common problem.
Watch this video.
https://www.youtube.com/watch?v=NugdOnwnnPY
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: V Carving Quality - possible problem on entry and exit points?
« Reply #4 on: July 27, 2017, 08:40:28 PM »
Got it that makes sense, I have down loaded these V bit test files and will try it tomorrow.  I will report back with results.  Thank you!!!  Steve
Re: V Carving Quality - possible problem on entry and exit points?
« Reply #5 on: July 29, 2017, 09:54:43 AM »
Well I made myself geometry test files for 45, 60 and 90 V Carve bits.  Of course ran the my 60 degree bit with the 60 degree program.  I would say the 60 degree section is the best, so it doesn't appear that the geometry of my bit is the problem.

I did notice a little bump on the top side of the triangle, but this little bump is in ALL of the test cuts 55 through 65. 

Any ideas where to look next?  This is surely frustrating.

Thank you, Steve

Offline ger21

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Re: V Carving Quality - possible problem on entry and exit points?
« Reply #6 on: July 29, 2017, 10:02:05 AM »
Probably a machine rigidity, or backlash issue? Make sure everything is tight.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: V Carving Quality - possible problem on entry and exit points?
« Reply #7 on: July 29, 2017, 06:12:04 PM »
Yes to my best ability, the machine is tight, but smooth in motion in all directions.

I have a ticket out with Legacy CNC Woodworking Machines, but so far they have no solution.

Back to a software issue of some sort?  I am not very good with the software pieces!

Steve

Offline ger21

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Re: V Carving Quality - possible problem on entry and exit points?
« Reply #8 on: July 29, 2017, 08:38:16 PM »
It's highly unlikely to be a software issue.
Does the issue shop up in the preview in V Carve Pro? If not, it's not a software issue.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: V Carving Quality - possible problem on entry and exit points?
« Reply #9 on: July 29, 2017, 08:49:30 PM »
Nope, the previews looks good in the software. 

The errors are consistent every time I run the program on the machine.  If it were mechanical, wouldn't the error change.  I guess that is why I was going down the software road.  And it is not just this project, it happens anytime I V Carve letters.

Any other ideas?  Oh and I have also tried different feed rates and it always comes out the same.