Finish quality on starboard

[DMcDonald]

I am making some parts for a customer out of .75 starboard and when the cnc gets to the points where the arcs stop and start it kind of chatters the edge of the part. I am going to get a picture tomorrow of the cut part. It seems to happen where the points are if you go into node editing on the attached file. At each one of those points the machine hesitates for a second. Is this something I can fix by doing the drawing differently?

forum.crv

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[IslaWW]

What control software does your machine run? In most cases, this can be eliminated using control parameter settings.

[tomgardiner]

C R Onsrud has a pdf of recommendations for successful cnc routing on their website. One thing they recommend is to draw small radii at sharp corners even if they are only a few thousandths of an inch. I have tried this with mixed success. V Carve seems to have a lower limit to radii application in filleting. But the strategy eases the cnc movement around the corners for me. I have been unwilling to go into my Fagor controller to mess with acceleration settings.

[martin54]

Have Laguna got their own forum ? If they have then that would be the best place to ask this question, can't look at the file on this machine but from Gary's reply it is probably to do with your CV settings for the control software you are using so the best people to ask are other Laguna users

[Adrian]

I agree that it's really a control software issue but something that might be worth doing to see if it makes a difference is to use the Fit Curves to Selected vectors tool to change the arcs to beziers. If that stops it happening then you know it's the way your control software is dealing with the arc commands rather than a problem with curves in general.

[Leo]

I will add another vote for the control settings

I looked at the CRV file. Nice smooth vectors - clean, clear and nicely flowing.
Nothing in there to cause an issue.

[DMcDonald]

I got busy and didn't get the pics up. I am going to try changing to beziers and run it again on Monday. I tried finding a Laguna forum but didn't find one doing a quick search. Not sure on the control software will have to check Monday. Thanks for the replies hope to figure this out. Will make the finished parts look much better.

[martin54]

If Leo says the vectors are good then I doubt making any changes will make a difference, have you tried decreasing your feed rate ? May be you are cutting to fast for this particular material, I don't run production machinery myself but I would have thought with your machine your DOC is far to conservative for this type of material with a 1/2" bit. Maybe try reducing the feedrate but increase your DOC so you do fewer passes.
If there isn't a forum then might be worth speaking with Laguna technical department.

[printmaned]

I have found that when cutting parts that are close together in starboard, it works best to not cut all the way through but to leave a skin of material that is cut with a second toolpath.

[DMcDonald]

Yes I leave a skin when cutting on the machine. Just took it out to try and see anything in the preview. Sent the program to Laguna lets see what they say in the morning. I did a little work changing things on the drawing. It would appear our machine doesn't like cutting arcs. When I convert to bezier it cuts the profile a lot better. Thanks for all the help. Will post what they say for anyone interested.

[ryadia]

I'm no wizard with Vectric stuff but I do know when I create a drawing in Corel Draw, I have to change it from vector images to biezer curves before I can get clean routing from it. This suggests to me that if you change to use biezer curves, there is a strong possibility you'll get a clean cut. It worked for me but like I said, I'm no expert with this stuff.

Ryadia