V carve on columns

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akransom
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V carve on columns

Post by akransom »

Building 4 axis mill to do columns up to 24" by 10' and would like to be able to carve on them. Will v carve wrap around a round surface?
Art Ransom
Lancaster, Texas

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BrianM
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Post by BrianM »

Hi akransom and welcome to the forum,

The current version of VCarve Pro will not wrap the VCarving around a column automatically. However I believe some control systems do allow a 'linear' axis to be wrapped onto a rotary axis within the control system. This will only work for a column of constant diameter.

People have also done this with the rotary axis connected as a normal linear axis and modifying the scaling factors within the control sytem to get a complete rotation for a linear distance equal to the circumference of the column being cut. The toolpaths are then calculated for a rectangular area equal to the length of the column by the circumference of the cylinder.

Hope this helps

Brian

RichardF
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Post by RichardF »

Hi Brian,
what about this idea:

If I have a plane toolpath and want to wrap it around a column, why not just converting the y-values to degrees depending on the given diameter of the column ( y-values because my machine at work has the rotary-axis parallel to x-axis).

Then you can mill it if the circumference is long enough for your path.

I tried this convertion with the OpenSign of VCarve Pro Demo (I still dont have a licence) and used NC-Plot (thank you Scott for this excellent software) to verify the toolpath of the rotary axis..

But since this part was too big for me mill at work (my boss says : "takes too much time") I converted form the Vectorart3d-collection the Praying Hands which I bought last year. I found a piece of aluminium small enough to mill and it took about one hour to mill. I appended some screenshots of NC-Plot and photos of the milling-result.

Regards

Richard
Attachments
The Praying Hands milled in Aluminium
<br />with a 6mm ballnose to rough
<br />and a 4mm ballnose for finishing
The Praying Hands milled in Aluminium
with a 6mm ballnose to rough
and a 4mm ballnose for finishing
the top view
the top view
looking from the right to the toolpath
looking from the right to the toolpath

RichardF
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Post by RichardF »

Hi all,

no replies ?

Did I say something wrong or coz I have no licence?

Richard

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Thkoutsidthebox
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Post by Thkoutsidthebox »

Hey Richard, thats fantastic.....now I just have to figure out your instructions (CAD/CAM not my best subject yet! :) ).....and also buy NC Plots full version and figure out how to do what it is that you seemed to do with so much ease... :oops:

What Im trying to say is.......WOW!!! And kudos to you, that looks great. :) ( PS: No license...tut tut :wink:....only kidding, but you should get one the program is great...me thinks. )

I dont have a rotary axis on anything, but its something Im planning for a future router, so expect some messages asking for detailed instructions in about 18 months. Being able to do this with a router and rotary axis will save me $$$ on a cnc lathe. :)

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dighsx
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Post by dighsx »

Hey Richard it looks great. I read this a while back and laughed. Thought it was funny that Bri says 'nope' and then you come along and say 'yep'. Granted the avg guy might not beable to convert the file like you did.

Nice work and any tips on coverting files. I'm getting ready to convert my lathe over and this might be fun to try out.
Take it easy.
Jay (www.cncjay.com)

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RoutnAbout
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Post by RoutnAbout »

I guess I'm gonna have to get my indexer out of the box and attempt this someday soon
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RichardF
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Post by RichardF »

Hi all,
thank you for your compliments and your kind words.

I think I'll give a bit more explanations:

Let's say you have a column or circle with a diameter of 100mm or a radius of 50mm.
So with the formula to calculate the circumference the length of the circumference here will be :

100 * PI (where PI is 3,14159...) which results in 314,159 mm.
A quarter of this length is 78,54mm which is an angle of 90 degrees of the column/circle.

Now if you have the following NC-code:

G1 X0 Y0
G1 X78.54
G1 Y78.54
G1 X0
G1 Y0

which will be a square in the plane and your rotary axis works parallel to the X-axis, you have to convert all Y-values to degrees.
Using this formula :

angle = length of arc (=Y-value) * 180 / PI / radius

and inserting the values of the example above we have:

angle = 78.54 * 180 / 3.14159 / 50

with the result of 90 (degrees)

Changing the axis-letter and using the calculated angle the NC-code for the square on a 100mm column is:

G1 X0 A0
G1 X78.54
G1 A90
G1 X0
G1 A0

But the manual conversion of a NC-code is of course a huge amount of time (even the PrayingHands of my first post were about 16000 lines).
So with a lot of trial and error ( I am not a software-programmer) I managed to write a little script to do this work for me.
In the attachment you will find the sourcecode written in the free AutoIt-Scripting language (you can find it here: http://www.autoitscript.com/autoit3/)
and the other file is a standalone exe of the script which doesn't need autoit to be installed.

give it a try and report

Richard

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Post by RichardF »

Sorry forgot the attachment.
But here it is

Richard
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Plane2Column.zip
(209.08 KiB) Downloaded 682 times

Andrew
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Post by Andrew »

Hi Richard

Just wanted to say thanks for sharing the conversion utility.
My next machine will have a forth axis. I was wondering how to program large files without 4th axis CAM. Now it looks as though I can use VCarve. It took a while to figure out how to set up a VCarve file suitable for conversion, but it looks as though it will be simple enough.

Thanks again

Andrew

RichardF
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Post by RichardF »

Hi Andrew,

thank you for your kind words.

To the conversion utility I must say it can't handle arcs. I hope somebody (perhaps me) will figure out and tell us how to split arcs into segments.
Up to now you should only convert NC-code without arcs or circles.

Sorry about this :oops:

Richard

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DavidCousins
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Post by DavidCousins »

Richard,
Since your utility can't handle arcs, what do we do? Do we use Vectrics Mach2/3 ATC (inch) Post Processor? Does that solve the problem?
Dave

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Post by RichardF »

Hi Dave,
I think so.

The Mach2/3 ATC (inch) Post Processor breaks arcs into line-segments .

The Mach2/3 ATC Arcs (inch) Post Processor doesn't.

But the result is a much more longer nc-code.

Hope this helps

Richard

cabnet636
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Re: V carve on columns

Post by cabnet636 »

richard has there been any updates and is the conversiuon in metric or can it be done in inches

jim
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http://www.mcgrewwoodwork.com
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johnnydoughey
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Re: V carve on columns

Post by johnnydoughey »

I posted this in the Aspire section so I hope I am not doing something wrong by double posting, but this site might help you guys figure out how to do this with Mach 3..
http://www.wizardsbyrich.embarqspace.com/#

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