[samco]

In kirks defense the novakon's way of rigid tapping is non standard. It turns the spindle into a rotory axis for the purpose of synchronizing the z move with the spindle.

So you have to do a

G 91
A 10, Z-1
A-10, Z 1

to do a 10 tpi.

(obviously works though )

sam

Why do you keep making guesses, when you've been TOLD what the actually hardware is? It IS an AC servo motor. Is is driven by an AC servo drive, NOT a "speed controller". The exact, same make and model AC servo drive used to drive the X, Y, and Z axes. I do not have to guess. I OWN the actual machine, and I am quite familiar with the hardware and electronics.

Regards,
Ray L.

[LeeWay]

Right.
Here is the tapping code that is output by Sheetcam.

N0860 (Operation: Tap, PINHOLES, T21: Rigid tap, 0.161 in x 25.4 TPI, 0.5 in Deep)
N0870 S150 M09 (Coolant off)
N0880 M05
N0890 Z2.5000
N0900 X-2.5000 Y2.5000
N0910 (Rigid tap, 0.161 in x 25.4 TPI)
N0920 T21 M06 G43 H21
N0930 G00 Z1.0000
N0940 M08 (Flood coolant on)
N0950 G04 P1 (delay to ensure breakout switches to A axis)
N0960 X2.2557 Y0.3492
N0970 Z0.0197
N0980 G91
N0990 G01 Z-0.5197 A13.2000 F150.116
N1000 Z0.5197 A-13.2000
N1010 G90
N1020 G00 Z1.0000
N1030 Y1.0492
N1040 Z0.0197
N1050 G91
N1060 G01 Z-0.5197 A13.2000
N1070 Z0.5197 A-13.2000
N1080 G90
N1090 G00 Z1.0000
N1100 Z2.5000
N1110 X-2.5000 Y2.5000
N1120 M09 (Coolant off)
N1130 M05
N1140 M05 M30

[tmarks11]

... ray does make stuff for Novakon he makes there fancy things so if hes says that's how it that is how it is so he does not need to prove a thing at all if you wont to know whats on novakon machine look at the manual its all in there.

Not to mention Ray is an Electrical Engineer, and you are arguing with him about motor theory based upon what wikipedia says. He also owns and uses the machine that you are arguing about. I think you lose this round.

[LeeWay]

In that code I posted reveals the issue with Mach 3 It is not set up correctly to do rigid tapping. Les fudged the numbers and it works great. That post is in every new download of SheetCam. You need some quick and dirty tapping routines. SheetCam will get you there.

[kirk_wallace]

Not to mention Ray is an Electrical Engineer, and you are arguing with him about motor theory based upon what wikipedia says. He also owns and uses the machine that you are arguing about. I think you lose this round.

I'm not trying to be argumentative, but I'd like to clarify that my statements on motor theory are not based on something I read on wikipedia a couple of days ago. I used wikipedia because I agree with what it presents on the subject of servos, that being, a motor with encoder feedback for the purpose of controlling output position, velocity and acceleration. My understanding of motors has been built from studying mechanical engineering nearly four decades ago to studying and putting into practice CNC technology for close to fifteen years. If someone has a better link to a formal definition of a servo in this context, it would be good to post it.

I was hoping that by stating that my comments about the Novakon mill as a guess would be taken as such. In other words I don't mean for them to be taken as fact. Obviously, since I don't own a Novakon or have fully studied all of the Novakon documentation I would expect a reply describing the system and how it works, rather than saying don't make guesses and I should already know all about Novakons and follow all previous threads (by the way there seems to be no schematics or basic description of the spindle servo system or software, I could be wrong, I just didn't find any on their website). Samco did tell me that the Novakon spindle does have a velocity mode for normal machining, then can switch to position mode. His code sample above shows that the angular position can be set, which is something I specifically asked for in order to get a better understanding of the system. My guess that the spindle drive was a speed controller is apparently wrong, since a speed controller can't do position control, but I didn't claim that as fact, but a point that could be cleared up.

My main point, was that the servo spindle and rigid tapping were separate features. Now that some of my guesses are more clear, it seems (not actually fact) that in the case of the Novakon they use the servo(ish) spindle for just that purpose. This frankly didn't occur to me because I didn't believe that the spindle angular position could be controlled to the few degrees that I am guessing are needed to keep from breaking taps (due to following error). One way to clear this up is for someone with a Novakon to command a spindle position and grab the spindle and see how far a moderate twist moves the spindle. If it stays stiff, one can have the satisfaction of telling me I am wrong.

An issue that still bothers me is that the spindle rotary axis (which typically is called C if it is parallel to Z) and the Z feed are keyed to feed rate so are sync'd to a clock. If one axis has a problem the other axis still tries to feed. Also the down motion is one move and the up motion is a separate move. I prefer the system that keys the Z feed not to time but to the spindle encoder pulses, which can take any sort of up and down motion and stay in sync.

I have nothing against Novakon. I actually think that trying to rigid tap with a servo(ish) spindle is kinda clever. The DC, or rather permanent magnet brushless AC motor, might be handy for low end torque. Others may disagree here. I'm not a huge fan of stepper motors so the (true) servos on X Y and Z are a plus. (Though, in my experience, steppers typically work well.) I like the lever draw bar.

The above is just my view. I don't have the time or the energy to reference and crosscheck each item -- if it mattered I might. If you think I'm full of stuffing, but it prompts one to look further at the issue or try to prove me wrong, I don't mind being stuffed. It's not my intention to push anybody's buttons, sometimes it's just an unpleasant byproduct of having an opinion.

[SCzEngrgGroup]

It's very simple. As I've said several times now, the spindle is not "servo(ish)". The spindle is an AC servo motor, with high-resolution optical encoder, exactly like the X, Y and Z axes, and all four are controlled by the exact same AC servo drives, differing only in their parameter settings due to the very different motors used for the spindle and the other axes, and the very different loads. They are all controlled by Step/Dir pulses from Mach3 In normal operation, the spindle is configured as the Mach3 "spindle" axis, and Mach3 sends it a continuous stream of step pulses at a rate proportional to the commanded spindle RPM. Since the spindle motor IS a servo, this means spindle RPM is always precisely as commanded. In rigid tapping mode, Mach3 controls the spindle as a rotary axis, and all spindle motion is coordinated precisely with X, Y and Z axis motion, which is what makes true rigid tapping possible. When the spindle is off, it cannot be turned - it is effectively locked in position by the (very powerful) servo. The spindle neither knows, nor cares, which operating mode Mach3 is operating in. Regardless of mode, the servo drive receives step pulses from Mach3, and it moves the spindle to the position commanded by those step pulses, exactly as any servo would. Rigid tapping is implemented as it is due to limitations in Mach3Mill, not because anyone believes it is the optimal way to do it. It is the only way it can be done in Mach3.

Regards,
Ray L.

[kirk_wallace]

If you say the spindle position is stiff, I'll gladly accept that and drop the 'ish'. The rest I think I have already agreed to except I don't do Mach and didn't know this is was a Mach3-wide thing. Thank you.

[LeeWay]

You can change a tool without needing a second wrench. The spindle is that tight when powered up. Basically it is locked in position.

[iGAK]

Here is a link to the Novakon Pulsar performing rigid tapping at the 2014 Cabin Fever Expo show. The Pulsar peck drills five holes and then uses a 1/2-13 tap to thread five holes in under 15 seconds.

https://www.youtube.com/watch?v=K1Fb...layer_embedded

[philbur]

kirk guessing just gets your arise dragged over the coals

Wikipedia is a don't ref to sight it can be very wrong over hear if you put Wikipedia in a uni paper it gets crossed out

What happens if you reference a hobby forum(chair)

Phil

[daniellyall]

it has more chance of being correct as if someone see`s something wrong they will say so