CNC Shark Forum

I'm curious is any of you are using the 4th axis as a positioning axis for the 4 faces of a rectangular part? Rather like on a 5-axis machine, where the 4 and 5 axis move the workpiece and work holding tool? Obviously this 4th axis isn't going to hold a vise or a spoilboard, but I've got a couple cases where I'd like to machine holes and slots on three faces of a piece approximately 4" long by 1" x 1/2". Sounds like it might take some custom GCode to move the part. Or, something like carving/drilling/engraving on the six faces of a hexagonal rod?

Thanks in advance,

Thom

I don't have Nextwave's rotary axis, but I do have one to use on a CNC where I work. In the controller they provided for those who bought the RA is there an input box where you can enter g-codes to send directly to the Shark? If so, g-code commands of G0A90, G0A180, G0A270, and G0A360 could be sent to rotate the stock 90 degrees between each side of your 4 sided stock. Then run 2D/2.5D X/Y/Z toolpaths using the non-rotary post processor.

If you can't enter g-codes directly, then you could edit your toolpaths to include them. The rotary post processors are changing X (or Y) codes to A codes when wrapping jobs are done. To make the router move in true X and Y directions without rotating the stock you'll need to save your toolpaths with that non-rotary pp.

I have an indexing jig I use on my Shark, and do exactly what you are asking to do only with no CNC control to rotate the work. I simply pull a pin, rotate manually to a new side, then put the pin back in.

Look on the Vectric site for the tutorial Rotary Machining 3D. It has some parts about machining on the flats.

Thanks to both of you! 4DThinker, would be so kind as to post a photo of the jig? RCrick, thanks, I'll take a look!

You could mill your holes, slots on the top face, jog A 90 degrees, mill next face, etc.
I have squared my stock to the table and then "0"ed the A axis to get started
Jim

My jig: http://www.cncsharktalk.com/viewtopic.p ... t=Indexing

4D

4DThinker wrote:My jig: http://www.cncsharktalk.com/viewtopic.p ... t=Indexing

4D

That's PERFECT for what I need, though smaller. Thanks!

To answer your question, No.

The vectric software will not create 4 axis code, only 3 axis where one of the axes is use to rotate the model.

There are software packages the will do true 4 axis work but they will cost you. One of the less expensive I've seen it DeskPro at about $2500.

Im not exactly sure about your question however it is similar to what I am trying to use the 4th axis for. I am using Aspire and there is much more flexibility with this than V-carve. Once the work space is laid out using the wrap Gadgets>Wrapping>Wrapped Job setup I go to the material size and put reference vectors (that will never be cut) and then position the artwork, carving, profiles etc. where I want it within the reference vectors. Tip - when ever you remove material the size of the wrap will be smaller so I find it easier to recreate a wrapped job setup.

My flutes have straight cylinders, tapers and other irregular shapes. And I think what I need to learn and what you may be interested in is importing an stl file. The touch probe creates an stl file. It is extremely slow and I have not found anyone who has used it with 4th axis. Vectric shows making a knife handle in their videos. They import a stl file, but fail to tell you how they got it. Then they create a center axis like a dowel rod running the the center of the project, which will be cutoff later from the finish part.

My plan now is to cut a complex shape on the lathe, sand it well, mount it in the 4th axis and measure it with the touch probe to create the stl file. To speed up the process I will set touch probe parameters very coarsely and see what happens and then adjust the vectors in the software using node editing (another slow process for me).

Thanks, grazinghorse. I long ago moved from Vectric to BobCAD which has quite good multi-axis capabilities.

My need actually requires a bit more hardware than the Shark's 4th axis has, since there really needs to be a way to lock the position of the 4th axis.

This is what I'm trying to do. First, I work with Aluminum, not wood. Several of the parts in my product start from 2" square aluminum bar, and require machining on all six surfaces. What I'd like is to be able to clamp the end of the bar into a chuck, and then have the machine mill out each of the four faces in succession. That would mean:

- rotate to 0-degrees orientation and lock position
- machine out first face
- unlock position, rotate to 90-degree orientation and lock position again
- machine out second face...

through to the fourth face. I would machine the features on one end, a large hexagonal boss (post), and use that as the chuck-held part. After the other faces are done, I'd move the part to a vise or fixture to machine out the last surface, the "far end" of the bar.

Make sense? I've seen and heard of these capabilities on (far) more-expensive machines, but it's just not feasible on the Shark. If for no other reason that the controller doesn't have any outputs to control the 4th axis position lock.

Oh well, not a big deal. For now I just do the part rotation manually, and live with it.

Regards,

Thom