# 5-axis jobs on a Probotix CNC.



## 4DThinker (Feb 16, 2014)

I've been using an adjustable angle clamping jig on my Probotix CNC(s) for a few years now. This summer I've been toying with a way to automatically set the angle of that jig with a stepper motor. I see no real need for the PC/controller to do the adjustment if I don't need to move the jig while a cut is in progress. Truthfully I can't think of any job where dynamically changing the jig angle would be useful. 

Today the idea popped into my head to add a stepper controlled turntable to the center of my angle jig. If both the angle and the rotation of a clamped down part were CNC controlled then I'd have true 5-axis capability. If the turntable could be moved down or up the angle jig, then projects of different sizes could spin under the 5" of Z travel available. Hell, if the turntable position was also dynamically controlled during a cut then all sorts of projects could have extremely complex cuts under the "conventional" 3 axes of a simple CNC. I can think of many past carved furniture parts that might have become easily reproducible if we'd had such a 5 axis machine.

So @probotix if you are listening, can a 5th axis be added to your Unity controller? Does linuxCNC support 5 axis control?

I believe Fusion 360 can create 5 axis toolpaths. I'm not sure if there is a linuxCNC post processor for it though. 

Many ideas have an existing solution out there. There are 5 axis machines out there. They generally appear to start with a complex spindle head that points the bit at any angle/rotation under the gantry. My idea uses the down pointing bit of a conventional CNC over work that tilts and rotates beneath it. 

I occasionally do true 4 axis work (X/Y/Z and A) using the rotary axis on my Meteor. Very complex spiralling spindles can be cut with relatively simple moves of both the A axis and simultaneous X/Y/Z movement. Aspire can't make the needed toolpaths so I generally add A axis lines to my X/Y/Z g-code. I'm trying to see if fusion 360 could handle this work too. 

Am I crazy? 

4D


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## BalloonEngineer (Mar 27, 2009)

I don’t know if you’ve seen the pocket CNC Kickstarter. It is a 3 + 2 axis CNC (essentially what you are building).
They are using Fusion 360.

https://www.kickstarter.com/projects/1090944145/pocket-nc-the-first-5-axis-cnc-mill-for-your-deskt


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## honesttjohn (Feb 17, 2015)

4D,

You lost me at "adjustable angle clamping jig". I got the rotary axis with my Nebula. It's still in the box under the table. Don't know if I'll ever use it.


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## 4DThinker (Feb 16, 2014)

BalloonEngineer said:


> I don’t know if you’ve seen the pocket CNC Kickstarter. It is a 3 + 2 axis CNC (essentially what you are building).
> They are using Fusion 360.


Yep, I've seen that. Relatively small working area, and relatively high price or I'd already own one. The main advantage of adding 2 more axes to a Probotix Comet (25" x 25") is that those two axes can be removed (or covered) and you'll still have a useful 3-axis CNC. You've got potentially a 24" x 24" x 24" spheric volume that you can carve 5" into from any side. Pivoting the work around down below the frame.

4D


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## 4DThinker (Feb 16, 2014)

honesttjohn said:


> 4D,
> 
> You lost me at "adjustable angle clamping jig". I got the rotary axis with my Nebula. It's still in the box under the table. Don't know if I'll ever use it.


We most often cut simple tapered legs on our 4th axis John. They are quick to draw up and make a nice leg for little tables or stands. 

You could take any circular sign you made and put 3 tapered legs on it. 

4D


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## 4DThinker (Feb 16, 2014)

honesttjohn said:


> 4D,
> You lost me at "adjustable angle clamping jig".


This is what I'm talking about: 4D Furniture Thoughts: Advanced Compound Angle CNC Clamping Fixture.

Very handy for cutting furniture joinery. I'm adding a stepper motor with some sort of input pad so you can enter the angle you want the jig to be at, and the jig will move to that position. 

4D


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