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CNC 4th Axis

Alexander

Alexander

Ultra Member
Administrator
I want to start a build thread for my stepper controlled rotary table. This will be a copy of the @Johnwa rotary indexer project. I have attached a photo so you can see what i am talking about.
I could definitely use some pointers on the design.
 

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This is the block i will use to make the body.
15492240042212149912953122300445.jpg
This is the chuck I will use. It is a 6 inch 4 jaw self centering chuck from aliexpress.
15492240312154067652467413647825.jpg
 
It will be independently controlled for the first tests but if i am able to get it to work with the milltronics ill control it with that. I did start a foot stock already. Just need to finish it
 
Thanks for the links guys ill go in the house and read those after i get done roughing this chunk to size. I think this will push my setup to the limit. There is allot of material to remove here.
 
Hogging out! wow. You have a big mill Alex. very nice. You seemed to shim the block?

Do you anticipate being able to turn the table under power while milling? What kind of parts do you anticipate? Turbine Blades? Custom Scooter turbos? Only tongue in cheek a little. I think that could be really interesting.

Will Fusion 360 support 4th axis CAM?
 
I used shims under the block to get the side perpendicular to the bottom. I also used a shim on the movable jaw because the front and back are not parallel, yet. I really didn't want the block to shift during milling. Those were some heavy cuts.
 
Yes i belive fusion 360 cam allows for 4th axis. I actually plan on using the 4 jaw chuck to machine 4 sides of my parts without reaching inside the machine. Why you ask? If you machine the 5 sides without removing the block from the chuck then everything will be square and you won't need to dial anything in.
 
@PeterT as for the idea of attaching the stepper motor to a rotary table i thought about it. I do have an 8 inch rotary table. But it is not what i would call fast, or accurate. I know allot of people would disagree. I think the design of cnc lathes with live tooling could be copied. They use the spindle motor as a servo. It is basically an electric motor when turning, an accurate servo for continuous machining and an electric brake when indexing. I am sort of experimenting here with a very large stepper motor and hopefully it can replicate those capabilities.
 
I'm an old fart engineer here. What the heck is the 4th axis? X, Y, Z is my norm?
 
Mount a rotary table on its side on the mill - attach a chuck, and a stepper motor for automated control and you’ve got a 4th axis. You can now mill 4 sides of a square part without taking it out of a vise etc.

Alex if you put the rotary table down flat is it still called 4th axis?
 
Janger said:
Mount a rotary table on its side on the mill - attach a chuck, and a stepper motor for automated control and you’ve got a 4th axis. You can now mill 4 sides of a square part without taking it out of a vise etc.

Alex if you put the rotary table down flat is it still called 4th axis?

This will be really interesting keep posting Alex as you progress.
Click to expand...
 
If you assign a letter to the 4th axis is called C axis. When axis of the C is parallel to the spindle you have a rotary table not a 4th axis. Most big VMC machines use a rotary table because it is hard to rotate big parts on there side.
 
I always thought 4th axis meant about a rotational axis over & above the 3 normal linear axis. But I think there is a more robust definition like below. I found this definition on the internet, so it must be true LOL. I guess you could have a machine with no rotary component but some other 'direction the cutting tool could move' and that might also be a 4th axis? (Although I cant think of one off hand).

The term “5-axis” refers to the number of directions in which the cutting tool can move. On a 5-axis machining center, the cutting tool moves across the X, Y and Z linear axes as well as rotates on the A and B axes to approach the workpiece from any direction.
 
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