4th Axis actual capabilities

[toddd]

As many others I am pondering the 4th Axis to add to my AR8 Pro V5 machine.

On the Vectric forum looking at projects people are doing I wonder if they are possible on the Axiom set up as it comes stock. User Randall Newcomb has great tips and videos on a spiral turning method that looks great and I'd like to try.

Has anyone tried this? and with the Magnate bits,

His machine may be better suited to this and also Steve Nelson with his Stinger.

Is it reasonable I can accomplish this, possibly with a slower feed or less pass depth on my Axiom?

thanks for any insight,

Todd

[joeblow]

If you can design it, whether in Aspire or other software, the Axiom rotary is more than capable of cutting it. Albeit slower than what you might expect or see other machines do.

I can verify that the Milo Scott method of continuous rotation does work as designed with the Axiom rotary for both rounding and 3D modeling.  However, I don't use this method.  Having lost steps in the past with continuous rotation/radial toolpaths, I prefer to raster.  This rotary accessory really isn't designed for “lathe-like” operations.  You would need a much more robust system of which I know nothing about.  I do know there are steps you can take to increase the holding power of the Axiom rotary.  I have not done this but another forum member has and perhaps can chime in whether there were gains or not.  

IMO, it is a great addition to the Axiom system and opens up a whole 'nother aspect of CNC machining and design.

[toddd]

Ok thanks for the feedback

[aluomala]

I have been fairly critical of the rotary axis (mainly the lack of holding power due to stepper motor) as well as some QC/build issues. I'll try to keep it toned down.

It is OK, but not great (which sums up most of the accessories for the Axiom line), which might be a bit unfair, considering the price point for the average machines (I have AR4+Pro and AR8+Pro, with a rotary axis for each) in the Axiom line. I think that they should beef up the stepper motor. I bought a 3rd party one a while back, with about 90% increase in holding torque, but I still haven't gotten it working, since it wasn't a plug-play swapout (I have to re-do wiring, and had to bore out the pulley shaft (probably using wrong term) since the stepper shaft on new one bigger than the stock Axiom one). The chuck they supply is junk, and if they removed that from the package, and had a beefier stepper motor, it would likely be cheaper than the attachment is now (I believe it's retailing for $1000US). The headstock/tailstock are VERY rugged, so it's a real shame about the stepper motor. Definitely the weak link.

There is a way to adjust the settings for the stepper motor(s) (the stepper motor for the rotary axis is the same as the other axes I believe), which is set to about 60% at the factory. If you use raster method (I set it to go along the long axis (Y-axis) to minimize stepper skipping, it seems to work better, but you have to be VERY conservative with speeds and depth of cut. VERY conservative. If you can live with that, it works pretty well.

I use mine primarily to make replicas of military tank "bullets" (the projectiles that are launched out of the main gun), and they are 3" - 4.5" in diameter and about 15" long, and they require a lot of machining to get them to the proper shape. Having a full sized (or even bench top) woodworking lathe (plus other standard woodworking tools, like table saw, jointer, band saw, etc) really helps to avoid using only the rotary attachment to get your lumber to working size. There are "gadgets" within Aspire to help you go from a long, square block to a cylinder, but it takes a ridiculous amount of time to do this on the CNC, whereas if you use your table saw to knock off the corners, and then a quick runthrough on the lathe to get it more round (my largest blanks (5.5" diameter) need to be rounded on lathe, otherwise the edges of the octagon shape (after knocking corners off on table saw with blade at 45degrees) still hit the top of the table of the CNC.

Once all of that is accomplished, you can do your carvings, albeit at diminished capacity compared to standard milling. There are many "tricks" to ensuring that your A-axis zero is set properly (I use a small magnetic digital level on a flat spot to ensure that it is level, and then re-check that level after each toolpath. It doesn't take much to make the rotary lose steps, so it helps to have a way to keep your A-0 accurate.

Here is a sample of some of the work I have done with the rotary axis:

[grossmsj]

I mostly agree with the assessments of joeblow and aluomala. The 4th axis is capable, and I can't see a reason something like a crooked walking stick can't be done with a design from Vectric Aspire. The headstock and tailstock are hearty. The chuck is embarrassingly bad junk and will need to be replaced. There are other aspects that are quirky, but it basically works reliably (for me).
I suspect the 'holding power' of the headstock depends on how old the machine is. Aluomala has had issues, as have others. I bought my machine in December 2021 and have never had any slipping. This generation of the AR6 has a 48 volt power supply for the drives that I've been told make a difference (from a dealer in Europe). You might want to check on what your build consists of.
The rotary unit is incredibly, frustratingly slow. It takes forever to make a full 360 degree rotation (like 15 seconds?). When it's doing that all the time to reindex it might make you crazy. But eventually it will get done. The slowness is related to how it is set up with the RichAuto controller. Given all the limitations the RichAuto controller presented, I took it out and replaced it with a different control system that gives the user more control. Now, the rotary unit performs a lot better, a full rotation takes about 2.5 seconds, but works smoothly with no noise or torque loss at ~4 sec for one turn. So it's not the Leadshine DM542 drives or the stepper motor, per se.
If you aren't a production shop and are patient, I suspect it will work for you.

[toddd]

I appreciate all the feed back and nice to see some great projects made with the 4th axis,