V-carving on slightly curved surface

[steveibe]

I love the V-carve feature and use it most often when working with wood. I am trying to v-carve text on the outside of wine barrel staves, obviously, there is nothing flat about them and when v-carving most text the slightest variation in Z shows up big time. I have tried creating a model with the approximate shape and using the 'project toolpath' feature with limited success, I believe if I knew how to make a more accurate model it would probably work. I am only carving about 8 inch lengths but still, the X and Y radius comes into play ( i will attach a photo). The ends of most barrels have a 22 to 23 inch diameter I think would be close enough to figure the x radius. If one of the experts out there have any ideas to share I would sure appreciate hearing from you.
Thanks in advance, Steve

https://imgur.com/a/n8Cfn

[highpockets]

You might try Code Ripper http://www.scorchworks.com/Gcoderipper/gcoderipper.html, Free application.

Using a very simple DIY probe Code Ripper will map the surface allowing the g-code file to follow the contour of the barrel stay.

Do a Google search for videos on how it works.

Here's one of my favorite videos of how simple your probe setup can be.

[Phil]

A few months ago I had a project where I had to V-Carve on a curved surface. See this thread http://forum.vectric.com/viewtopic.php? ... ur#p193517
The contour was done in Aspire. If you could take the measurements as shown in my post I would be willing to create the component for you.

Phil

[steveibe]

Thank you both for your reply. I certainly appreciate your offer Phil to work up a model for me to use but the underside of the barrel staves, or inside of barrel, are very irregular so the carving surface would be different for each one. Probing and g-ripper would do the job but it is above my current limited skill level! I wish there was a G-ripper for dummies tutorial!
Steve

[Phil]

Would it be OK to use your CNC to flatten the area of the stave? Then you could simply V-Carve on the flat surface.

[Phil]

Thank you both for your reply. I certainly appreciate your offer Phil to work up a model for me to use but the underside of the barrel staves, or inside of barrel, are very irregular so the carving surface would be different for each one. Probing and g-ripper would do the job but it is above my current limited skill level! I wish there was a G-ripper for dummies tutorial!
Steve

The underside of the stave really does not matter. The measurement are taken while the stave is setting on a flat surface, that's how it will be setting when it is clamped to the CNC table.
The reference for the measurements is the table top, not the underside of the stave.

Phil

[fizzygas]

I could be way off track here but Gravograph and Roland us a floating weighted Z axis for engraving on uneven surfaces it's a simple idea. The router slides up and down a dovetail as it moves across the piece with pre loaded pressure on the router/cutter

[steveibe]

Thanks again Phil, but this will be more than a one-time job and the barrel staves vary in width and thickness, I doubt your kind offer meant you would work up as many as I needed!
I am curious as to fizzygas's reply, I can't quite picture it. Is there somewhere I can see that
setup?

[steveibe]

P.S. Phil, I thought about flattening the surface but as a last resort.

[fizzygas]

Have a look on YouTube at Roland's engravers the cutter assembly has approx half an inch of weighted float.
Any unevenness allows the cutter to follow.
Depending on the size of the cutter also have a look at spring loaded cutter holders

[Phil]

Hi Steve,

If you'd like, I'd be willing to make a model of one of the staves. I'd suggest you select one that would be the best representative sample, take the measurements and send them to me.
In any event I am very curious as to how you will finally decide on the way you will deal with this problem. Please let us know and post pics.

Good luck,

Phil

[FixitMike]

I would suggest cutting the text by using a pocket toolpath that is projected onto a 3D model of a typical stave. If you pocket the letters with a 1/16" dia end mill, any distortion resulting from variation between the Z of the model and the actual stave will be minimal.

The challenge will be how to set the Z0. I would suggest importing the model so Z0 corresponds to the highest point.

[steveibe]

Thanks fixitmike, I also thought of that but would like to if posable keep the sharp corners and depth variance you get with v-carving.
I am going to try to give you those measurements Phil and will add a couple of photos to help visualize things. If you haven't figured out already, what I'm making are balancing wine bottle holders. They will all be the same length with the same hole placement, the width of the pieces can vary altho the piece I used is as big as I will ever use. I am using a Handibot as you can see. I built this jig for this operation, when I tighten the screw the rubber cork works quite well for securing the piece. I apologize for my sloppy penmanship, I hope you can make sense of my measurements. Thanks again everyone!
Steve

https://ibb.co/mwvD9Q
https://ibb.co/ekNt9Q
https://ibb.co/myE6UQ
https://preview.ibb.co/hk9vOk/barrel_st ... Medium.jpg

[Phil]

Hi Steve,

you have a private message.

[steveibe]

I don't know how to view private messages?