4 Axis CNC?

[Mark J]

I am looking for some more information on 4 axis CNC machines, software and their capabilities.  

I have a project idea that could make use of one, so at this point my questions are just academic, but this could end up going somewhere.

I saw some 4 axis machines at this year's International Woodworking Fair, but they were industrial scale and industrially priced.  Do any companies make machines more within the hobby realm?  Size and cost are both issues, but something the size and cost of a deluxe SawStop is within my reasoning.

Is the software something a mere mortal can manage?

As an alternative to purchasing are there companies out there with 4 axis machines that would make one or a few pieces for a customer?

[Mick S]

I'm going to assume you're talking about a rotary axis. Many of the machines in your budget can be equipped with a rotary axis as long as the controller is set up for it. We ordered our FineLine Automation router with CNC Router Parts control prewired for a 4th axis. The rotary unit itself can then be installed or removed as necessary. We have not done it yet, but hope to over the holidays when we have a little more time. The rotary indexers usually run ~ $400 - $600 for the setup (Amazon).

Vectric, EnRoute and lots of other products support rotary indexers with ease. Programming is usually done just as 3 axis is, then one axis, either X or Y is "wrapped" around the rotary axis which is then output to it's corresponding drive through the 4 axis post processor. In some cases, a 3 axis controller can be used to power the "wrapped" axis.

[Mark J]

@Mick S do have any idea how large a diameter these units will turn?  I did a little Google Fu and found an Axiom unit that would turn a 3 inch piece.  But the project I'm thinking of would need to turn 9 to 12 inch diameters.  I did find a Laguna with 10 inch capacity for a mere $28,000.

And yes the 4th axis is rotation.

[Mick S]

One issue you'll run up against with that diameter is the Z axis clearance. If the rotary axis is mounted to the surface of the table you'd have to have a very high Z axis which (especially in this price range) can be pretty unstable for general routing with the unit. The higher the Z clearance, the less stable and more inclination to vertical error. 

What's the length of the parts?

That's why most of the table "lathe" attachments are limited in diameter. It's also the reason for the difference in cost. CAMaster offers a side mounted rotary axis with a cantilevered gantry that extends over the attachment. Not $28k, but probably out of your price range. You might try going to CNCZone.com/CNC Router Parts forum and asking around. There's a guy named Gary Campbell that modifies smallish Chinese routers. He may be able to help.

[Mark J]

Thanks Mick!  Not sure how far I'll pursue this given the cost and complexity, but I will follow your leads another couple of steps at least.  

To answer your question maybe 4 to 12 inches in length.  I am actually trying to make up a twisted block as a turning blank that would then go on the lathe.  If you want to see, I posted in the Digital Design section last week when I was just trying to "see" the shape.  

So as much as I would like to venture into the adventure of CNC and do this and a lot of other things maybe what I should do for now is look for a company that already has a big CNC and would make me up some blanks for a fee?  Any ideas where I might find, or how I would search for, such a company?

[Catco]

We just received a 4 axis CNC at my work. I can turn up to a 48" diameter and 96" long blank on it..... Granted it is for foam, but I may have used it for a few table legs already... I believe you said a 6"x6" square 4" high with the two face rotated 45 degrees with respect to each other correct?

[Mick S]

2 hours ago, Catco said:

We just received a 4 axis CNC at my work. I can turn up to a 48" diameter and 96" long blank on it..... Granted it is for foam, but I may have used it for a few table legs already... I believe you said a 6"x6" square 4" high with the two face rotated 45 degrees with respect to each other correct?

What kind did they get?

[Catco]

3D Cutting

We got the FrogMill, the FrogWire, and the FrogSpray, along with the handheld 3D scanner.

Needless to say, I've been having fun with it.

*Edit* while technically it is a 4 axis machine, it only has the ability to run 3 at once, unlike a 4 independent axis machine which I would drool over.

[Mark J]

On 12/5/2018 at 7:31 AM, Catco said:

We just received a 4 axis CNC at my work. I can turn up to a 48" diameter and 96" long blank on it..... Granted it is for foam, but I may have used it for a few table legs already... I believe you said a 6"x6" square 4" high with the two face rotated 45 degrees with respect to each other correct?

That sounds like a very cool machine.  I found a company out this way that has a 7 axis machine?!  No idea how that works.  That's more dimensions than I have in my universe.

A 6x6x4 block twisted 45 degrees was what I was trying to draw in Sketchup just to try and understand the shape better.  But as I have continued to ponder this potential project I am thinking that a larger blank with more twist would be better.  I have to spend more quality time with graph paper and Sketchup studying this, but let's say for discussion 8x8 and 5 or 6 inches thick and 90 to 135 degrees of twist.  

As I work out the geometry that means I'd have to start with a dry board 20/4 or 24/4 and 11 1/2" wide.  Not the sort of thing that grows on trees .  

I was able able to get two round blanks nominally 5x10 and 5x11.  I had to go to two different Rocklers to find them, and don't ask what I paid, I didn't look.  I've never seen wood that thick for retail sale before.  So in theory I could make twisted blocks 7 and 7 1/2 inches x 5.