Please I need help. We are doing 4 Machining centers with CSMIO ip -A +\- 10V and I need to do the M19 (Spindle Orientation) to be able to change the tool, in addition to being able to have Rigid Taping. As recommended by Cs-Lab, we are using CSMIO-Enc. We have an AC Servo Drive in the Spindel FAGOR, however the CSMIO only gives us an analog output of 0-10V. The spindel runs, I have the visualization of rotation and position and etc, in CSMIO-ENC, but how do we make the M19? So that he is controlling position? Please if anyone can help me with this, even with the M19 and SpOr macros. According to CS-Lab, they need a Mach4 update so they can make a new plugin for Rigid Taping. Is this true? If so, we will have to change our design and change equipment or another CNC. Thanks. I look forward to any help.


– G84.2/G84.3 is rigid tapping for which Mach4 manual says:

“requires the machine to have precise control of spindle speed, axis feed, and precise feedback of spindle RPM.”

It means that for spindle driving, you should use a servo drive that can keep a set position. It can be a step/dir drive (supporting position mode) in the case of CSMIO/IP-S controller or  +/-10V (velocity mode) in the CSMIO/IP-A motion controller.

Further, Mach4 has the “Enable Step/Dir Spindle rigid tapping” option, which you may think should treat a spindle as a rotary axis. It means that even without synchronization provided by a CSMO/IP controller, rigid tapping should be possible because the spindle has become a full-fledged rotary axis. Unfortunately, it’s not like that. ArtSoft informed us (a few months ago) that it would be corrected. (as of 02/16/2022).

Our developers plan to release a plugin update for Mach4 soon that includes the rigid tapping as well if:

we get documentation of newly added functions and changes in Mach4
newly added functions and changes made in Mach4 will work as assumed.
we get explanations for questions we may have.
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As of now, Rigid Tapping is controlled by the motion controller; in this case, CS-Lab.  From what I gather, Mach4 cannot do this internally because Windows is not real time. 
I have not gotten Rigid Tapping to work with the HiCON from Vital Systems even when they claim it has the ability to... I'm not sure why it doesn't work, but we get around it by using floating tap holders.    I am anxious for it to work correctly though; it will be much better than using floating tap holders.

As far as the Spindle Orient, that is something you will have to figure out.  If your spindle is a servo spindle and has the ability to use step and direction for positioning, then you should be able to find a way to set up the spindle as a motor and as a spindle.  I think there are some API calls to achieve this. 
Some servo spindles I have in the shop have their own built in orientation and I just have to give the drive an input and it does it automatically. 
All of the code to do what you want will be put in the m19 macro.

Hi,
I echo what Chas has said. Rigid tapping is a motion control feature not Mach.

Go back to your experience with a manual lathe. With the lead screw lever engaged the saddle is mechanically linked via the gears to the spindle.
If you rotate the spindle in either direction the saddle will move in precise synchronism with the spindle.

To do rigid tapping with a CNC machine requires the same link between axes, say the vertical Z axis and the rotation of the spindle, in the case of a VMC
the C axis.

I am not aware of any Mach4 ready motion control which can do that.

Lets take some hypothetical motion control that could do what we want....what features and properties would it need? In particular lets say that you have
an encoder on the spindle. Any rotation will be reflected in a changing encoder reading. Our hypothetical controller would need to multiply the changing encoder
reading and issue Step/Dir pulses to the Z axis so that the Z axis height faithfully remains in pitch synchronicity with the C axis.

You might say 'but my CSMIO/A is analogue', and that's true....the signal to the servo from the controller is analogue.....but the motion commands issued to the controller
are still Step/Dir.

Neither CSMIO or the Hicon, or in fact any Mach4 motion controller can generate Step/Dir signals for one axis on the basis of encoder input from another.
I may of course be mistaken about that.....I await with baited breath!

Mach is of limited use here because the communication delays both from the encoder back to Mach and then from Mach to the Z axis preclude realtime action.
This is one are where LinuxCNC wins hands down being essentially realtime.

There is another way to do rigid tapping which I have used. It relies on Machs ability to produce a trajectory that is coordinated between axes.
A block of Gcode like:
g1 a3600 z-10 f21600
would cause the C axis to rotate 3600 degrees or 10 revolutions (in 10 seconds) while the Z axis descends by 10mm. This is a helical toolpath with a pitch of 1mm per
revolution. Note that the C axis moves according to the trajectory its given as is the Z axis, the fact that they describe a helical toolpath is because of our choice
of the two trajectories rather than the rotation of one axis 'driving' the other linear axis.

I have a secondary spindle based on a 1.8kW Allen Bradley servo, and I have the possibility of driving it with Step/Dir signals which allow me to use it as a genuine C axis
which in turn allows me to rigid tap.

There is a limitation that you must be aware of however. If I call a move like the above it requires that the C axis rotate at a precise speed despite having to supply the cutting torque of the
tap. If the C axis slows because of that load then the Z axis will get out of sync with the C axis, ie a pitch failure. Thus the spindle must have sufficient torque authority to drive the tap, which in turn
places a restriction on the size of the tap and the material into which it is cutting and the engagement.

My servo is rated at 6.1NM and 18NM overload. I have found that 6mm in mild steel with 65% engagement or 8mm in mild steel with 50% engagement is perfectly doable but is dubious above
those limits. The bottom line is you need mega-torque to rigid tapping, and that I suspect goes for conventional rigid tapping (spindle 'driving' a linear axis) OR coordinated motion between axes
such as I have described.

While I have the ability to do rigid tapping, and I have used it up to 10mm in aluminum, its not a technique I use regularly. It means that I have to load my spindle into the machine,
set up the tap etc, and for the few holes I do I can't be bothered....mostly. In those few situations where I have a run to do, say a whole bunch of bolt hole circles on multiple
pipe flanges, then it becomes worth it.

Craig