Using mill table manually,, mach3 DRO readout

[TheDude]

Another few questions.
Hobby cnc 4 axis kit.
-How reliable is the readout in the mach3 software for using it as the DRO?
-Does the mach 3 software have a backlash setting like in kcam?
-Do the motors turn fairly free for manual machining?

Thanks again

Steve

[LeeWay]

The Dro's in Mach are as accurate as you set them up to be and as your machine can handle.
They won't actually work in the typical sense for manual milling. Say with the handwheels.
The motors are easy to turn with no power applied. They lock up to their holding torque when you apply power.

To use Mach 3 with a semi manual mode is easy to do using the MDI page. Type in where you want which axis to go and hit enter. In this case, the DRO's are accurate again as close as you have them set. Use the keyboard for manual milling instead of the handwheels.

Mach 3 does have backlash compensation, but I am unaware if it actually works when using the MDI screen or when using the jogging tab. I do know you can set it and it will work when running a program.

[TheDude]

So there is no way to have the steppers run free while manually milling with the handwheels while watching the position on the screen?
Sounds like I'll soon learn that manually typing position and feed rate would be easier?
But why do they advertize that "You can still use your handwheels with these motors"

[ger21]

The DRO's correspond to the steps sent to the parallel port. It's possible to use encoders and create DRO's to display the encoder's positions. You'll need to modify the screens.

[LeeWay]

As Gerry said, encoder's attached on the motor or handwheel should make the DRO's work, but then I'm not sure about how they would work when still under power. Seems it would still be tough tyo turn them unless it was only the encoder's that were powered.
You can use handwheels for manual milling, you just won't have the Mach 3 DRO's with the typical stepper setup.

I do a small amount of manual milling with my mill. It doesn't have handwheels, so not really manual milling in that sense. I use the keys to jog and mill. I leave the jog set at about 5% and run the X and Y axes like that. If I need to make a faster move, I hold down the Shift key and use the jog arrow. This lets it run full speed.
I typically use the MDI screen for more precise depth settings on the Z when I am doing this.
Most guys find they never touch manual handwheels after you sink your teeth into Mach 3 a little more.
I had them on my router, but removed them as they seemed a safety hazzard and were redundant with Mach.
They are useful before you get a machine powered up though. Setting limit switches, finding travel extremes and things, but these can also easily be done with Mach in charge.

[ger21]

Originally Posted by LeeWay As Gerry said, encoder's attached on the motor or handwheel should make the DRO's work, but then I'm not sure about how they would work when still under power.

You'd need a different set of DRO's on a custom screen. The regular ones only work with outgoing step signals.

[TheDude]

Sounds like it would eventually be better to use the MDI to locate for my next feature as I get more comfortable with the software.
I was hoping to avoid buying a DRO kit and it sounds like I would only need one if I wanted to operate the mill manually.
So when you are finding an edge with an edge finder. Can you manually jog each axis by .001" then zero the location in the mach? Then jog half the dia of your edge finder, rezero and you have your origin?

I'm sure these are questions I would soon learn when operating the mach. I'm just curious to the level of "manual" control I have with the jogging controls.

Thanks again guys, very helpfull.

[ger21]

Originally Posted by TheDude Can you manually jog each axis by .001" then zero the location in the mach?

Yes.

Originally Posted by TheDude Then jog half the dia of your edge finder, rezero and you have your origin?

You don't have to do that. Just click the button on the offsets page and Mach will set it for you.

[TheDude]

Thanks again guys. Look forward to sinking my teeth into this facet of the machining hobby..