Finished my upgrade on my rotary table

[P40Sortie]

Just want to share some pictures with you about my recent modification to my rotary table. I made an adapter block and collar to fit a stepper motor. Dan from Camtronics helped out with a G210 and the motor. Due to the fact that the rotary table is already 90:1 I opted for a direct drive as oppose to belts and pulleys.
I do have a few questions. First, the G210 is set for full steps instead of 10 micro steps as in the G201. I thought this would have made the motor run faster than it does. I cannot set the velocity any faster in MACHIII or the motor will grind. You can see in the mpeg that it does move nicely, I just thought it would be faster. Also, I know there must be a way to have MACHIII display in degrees. I have played with the FORMULAS function under the CONFIG tab but no luck. Currently, a display of 1.000" is equal to 360 degrees. This is convenient in that 180 degrees is equal to 0.50 and 90 degrees is equal to 0.25 etc. But it would still be nice to have the display in degrees.
Anyway, here is the link to my small site. All comments are welcome.

Thanks

http://members.cox.net/caseylorena/

[HuFlungDung]

So what have you got, 200 steps at 90:1? That should give you 18,000 steps per 360 degrees rotation.

That works out to 50 steps per degree.

So perhaps if you define one inch as 50 steps, then you will get a display of 360 for one revolution.

Your maximum command resolution for the table would be .02 degree per step.

[PoppaBear10]

Yes, the way you set angular axis in Mach 3 is:

Go to the Config drop down menu then,

Go and click on Logic settings then,

On that page look over and you will see a box that has the following choices, and cheack the one you want:
1). A axis is angular
2). B axis is Angular
3). C axis is Angular

Which ever one you cheack will make the DRO and the axis read and respond to angular measurements.

G0 A180 will give you 1/2 rotation, etc.

On making your steppers respond faster here is what you need to do, Set your drive to "Micro stepping", when set to micro stepping in can increase the voltage to 2-4X the "rated amount" of the stepper motor, this will give you much more speed, NOTE: Make absolutly sure that you DO NOT exceed the rated amperage max of the motor!!!!! Take the time to calculate the resistor you need for the drive.....Your Gecko literature should have info on doing that, or you can post to Mariss at the Gecko site, and/or Dan.
Relise also that steppers LOSE torque/power as thier speed. So, depending on the Mass of the objects that you will be putting on your A axis, you will want to tune your Acceleration/Deceleration curves, so you don't "overshoot" your mark on deceleration. I would get a "US Digital" 500 count encoder on you A-Axis and run that to the Encoder DRO input in Mach (unless you have another DRO type readout on your machine), to double varify the accuracy of your table.

scott

[P40Sortie]

Got it thanks. I had the Steps per set to 18000. For now I think I will leave it at full steps. Its seems to be fast enough. I milled counter bore slots in my face plate so I could attach my four jaw to the rotary table. Runs like a champ. Thanks for all your help.

Casey

[PoppaBear10]

Hey thats nice, can you post some more pics on how you connected your plate to the 4th axis and how you adapted the 4 jaw to it??

I would appreciate how you did it, it looks very nice indeed.

scott

[P40Sortie]

Thanks, I'll get some more pics after work tomorrow.

[P40Sortie]

Nothing special. I modified the existing face plate that came with the machine from Shoptask to fit the four jaw. I lathed down the face plate to have an extension that centered the four jaw. Then drill and taped four 7/16-14 to mount the chuck. In order to mount the face plate I simple milled a slot to counter bore the mounting bolts.
I wanted to use the four jaw chuck instead of the three jaw for two reasons. First, because I had already modified the face plate to fit the four jaw. I would have to modify it again to fir the three jaw. Second, was not quite sure if the three jaw was going to be as accurate. I'm having trouble centering the face plate to the 4th axis. It always seems to be a few thousandths off. Since the chuck is not going to be spinning at a high RPM I'm not worried about it being off center, only that I can make my material true and centered.
I would certainly like suggestions if anyone has any.

Casey