Weird pocket

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Juzwuz
Posts: 21
Joined: Sat Mar 03, 2007 12:10 am

Weird pocket

Post by Juzwuz »

Hi! I was testing out the new cnc router and I was cutting some square pockets in Corian with the attached crv file. It's just a 1 inch square. I thought I would do an external radius on the corners and I'm cutting with a 1/8 carbide endmill. Anyway, I output G-Code Arcs (inch) and if you take a look at the g-code at line 67, it starts to "peck" at the corners. Is it supposed to do that? I've actually gone back to square corners and it works as expected but I was just curious about the radius corner and the pecking.

I forgot to add that I'm using the latest VCarve Pro 4.5.
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square.zip
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square.crv
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TReischl
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Post by TReischl »

Yup, pretty darn strange alright.

I think this is going to be one for the Vectric Team.

Sorry I could not help you. :(
"If you see a good fight, get in it." Dr. Vernon Johns

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js11110
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Post by js11110 »

I'm on my way out the door right now, but I'll guess its because your using a .125 cutter trying to cut a .0625 radius. try making the corners .063 or your cutter size .1245 and try it. I'll check it out later tonight.


Jason
The Official Vectric Cartographer


You are limited only by your imagination

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Tony Mac
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Post by Tony Mac »

Hi Juzwuz,

Sorry to see your file seems to be doing a 'jig' in the one corner, but the good news is that I've tested your file in the latest development build and this has been fixed :)

We will post more details in the next couple of weeks.

Thanks for the files,

Tony

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js11110
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Post by js11110 »

I changed the corner radii to .063, posted it and can't see anything weird in the gcode. Try doing the same and let us know. Sometimes VCP gets confused when trying to cut corners with the same size tool.


Jason
The Official Vectric Cartographer


You are limited only by your imagination

Juzwuz
Posts: 21
Joined: Sat Mar 03, 2007 12:10 am

Post by Juzwuz »

Thanks for the help! I always get nervous when the machine does something unexpected in the middle of the run, especially since I'm testing out a new machine. I actually went back to square corners and the corners just are naturally rounded due to the diameter of the tool. I did notice that while playing with the feed rate and acceleration parameters for the machine with a low acceleration value, the corners would be quite rounded. When I turn up the acceleration, the rounding becomes smaller. Does this make sense? Anyway, I think this is an issue with tuning the machine and not with the gcode.

ger21
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Post by ger21 »

Juzwuz wrote: I did notice that while playing with the feed rate and acceleration parameters for the machine with a low acceleration value, the corners would be quite rounded. When I turn up the acceleration, the rounding becomes smaller. Does this make sense?
Are you using Mach3 in Constant Velocity mode? In order to maintain that constant velocity when changing directions, one axis needs to start accelerating before it gets to the corner, while the other axis starts to decelerate. This results in a rounded corner. The higher your acceleration is set, the farther into the corner it can get before the accel/decel occurs, giving you less rounding.
Gerry - http://www.thecncwoodworker.com

Juzwuz
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Joined: Sat Mar 03, 2007 12:10 am

Post by Juzwuz »

Hmmm...I think that makes sense even though I'm using EMC2. Kinda bummed out though that the machine x-axis crashed while I was out. It ran fine for 8 hours straight so I left it to go to dinner. When I came back the x-axis all the way to one side and the spindle crashed into the side of the machine. Luckily all that was damaged was the spindle holder and the helical coupler tore itself apart. The motor was still happily stepping away even though the leadscrew was not connected anymore. I guess I should hook up some limit switches. I tried troubleshooting to find the reason why it crashed but everything seemed to be working except the computer seemed slower than normal. Anyway, I'll probably post this to cnczone since the gcode didn't cause the machine to crash. Thanks!

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