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Jog Lock A-Axis while Program Runs?

Andrew Preisler

Plastic
Joined
Jan 8, 2024
Is there a way to jog lock the A-axis while I have a program running in the background? I'm having difficulty doing it in CAM.

Maybe I could set up a custom M or G code to accomplish this?

I basically have a lens that I want my rotary to spin continuously while a grinding pin cuts out a curve.
 
Here's a great thread on that topic:

 
It is simplest if your A axis has a brush motor, apply DC power to the motor leads. Adjust the voltage to get the speed you want. As stated in DH's link, a brushless motor requires three phase power. You can get three phase controllers from hobby suppliers. Most all hobby electric airplane motors are three phase. Far cheaper than a commercial VFD.
The problem is timing the rotation to the grinding pin movement. It sounds more like a cam grinding problem. Make a master an spin it with the blank with the grinding pin slaved to the master.
You mentioned grinding a "curve". Circular arc? The motion does not need to be continuous, just program the XYZ axis within the angle of the arc. Join multiple arcs together if needed.
 
Hint: that was his thread, asking the same question a week ago. :D
In that thread (which was posted in a different category), the suggestions provided were to "throw an A on each line" or to spend hundreds of dollars on electrical components to literally hotwire my company's machine.

I tried programing with G91 and G93 as suggested and could not achieve a continuous motion without the rotary stopping between lines of code. So no, that is not really a great thread on this issue. But I really appreciate you being a wise guy about it.

I have done extensive research on the Haas website, manuals, and other forums and there is some information out there but it apparently does not work for my machine. They even have a G33 code for it that pulls an error on my machine that not even my machine tool supplier could answer why. (See attachment). The rotary could only possibly serve two purposes, to index and to spin continuously. It makes ZERO sense why Haas would brick the latter function. So sue me for trying to ask somewhere else.
 

Attachments

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In that thread (which was posted in a different category), the suggestions provided were to "throw an A on each line" or to spend hundreds of dollars on electrical components to literally hotwire my company's machine.
Because that's the only way it's going to do what you want. Lots of owners and small shops here who would do exactly that if that's what was needed. In your post you said I, me, my super mini mill. That sounds like it's your machine. No snark involved. Also: this isn't facebook. You posting it under a different sub topic is like moving over three feet and shouting in a different direction. We're the same people.

I tried programing with G91 and G93 as suggested and could not achieve a continuous motion without the rotary stopping between lines of code. So no, that is not really a great thread on this issue. But I really appreciate you being a wise guy about it.
Not being a wise guy. That's the way it works. It's a commanded axis, not a spindle.

I have done extensive research on the Haas website, manuals, and other forums and there is some information out there but it apparently does not work for my machine. They even have a G33 code for it that pulls an error on my machine that not even my machine tool supplier could answer why. (See attachment). The rotary could only possibly serve two purposes, to index and to spin continuously. It makes ZERO sense why Haas would brick the latter function. So sue me for trying to ask somewhere else.
It's not a spindle. It's that simple. What you want to do is for a lathe with live tooling. You're asking for a lathe operation on a milling machine. Take it one step further: why can't my spindle stop and hold a lathe tool stationary while spinning the part in the rotary?

So back to what you do have and what it can do: a rotary command on every line should execute as fluidly as any other axis move in X, Y or Z. Are you still trying to do a standalone rotary command line and then resuming XYZ? Or are you doing all four axes at once?

Also: are you in Inverse Time Feed mode (G93)? If you aren't, the rotary is calculating linear feed based on the 'diameter' set in the control. Time Feed mode gives the machine a time value for all four axes to reach their destination. If you want smooth motion, you will probably need to use that:

 
As I mentioned in the other thread, you could program an arc in the XZ plane and throw an A move in there and the endpoint of your XZA move would all end at the same time. You’re only limited by the number of revolutions the A will move before “wrapping up”

Picture the grooves on an old record album.

If you’re using a lollipop style tool and it’s a substantial percentage of the radius you’re trying to cut, you may get away with relatively few A axis revolutions to cut your surface with minimal cusp height.
 
In that thread (which was posted in a different category), the suggestions provided were to "throw an A on each line" or to spend hundreds of dollars on electrical components to literally hotwire my company's machine.
It's an axis like others have said. If you go to another category it is still going to be an axis. It is not going to magically change to a spindle. Thats why you have to put an A command on each line. Making multiple posts on the same subject in different categories is not going to change the functionality of the machine.
 
OP took his ball and went home. In case you come back, this is what you want:

 








 
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