Messages

11

General Mach Discussion / Re: mach3 turn spindle dro not working, spindle speed changing while jogging

« on: December 21, 2020, 03:50:34 AM »

Hello

Please, could you explain to me what difference you mean Diameter mode vs radius mode?
Where/how I can set this modes?
I'm running  R3.043.022

Thanks

12

General Mach Discussion / Re: mach3 turn spindle dro not working, spindle speed changing while jogging

« on: December 21, 2020, 02:07:42 AM »

Dear Graham, RICH

Thank you for your patience

In my previous post I sent the picture of thread cut in multiple passes in a plastic work piece - each pass not more than 0,1mm
I read all the thread cutting instructions, but unfortunately I didn't find the answer to the unusual doing of the machine / Mach3 in my case.

I have tried also with 50 rpm, 100,... it is the same. Spindle is driven by 7,5 kW motor and gearbox. Spindle speed is constant - I have measured it (out of Mach3) also with encoder and digital tachometer. It could not be a reason to slow down feed rate.

Z axis moves smoothly also by 5 times higher feedrate - when not threading. By all other work both axis moves with no problem at much higher feedrate.

I am attaching a picture of the thread - just one pass. Threading in this pictures was started 5mm before workpiece and thread pitch is quite constant, because it was already reduced to 1/2 (before touching workpiece)
If I start treading close to workpiece, thread looks like in my previous photo - pitch is reduced from programmed to 1/2 of programmed.

It is hard to explaine...I have  made a short video...but is too big to upload it.

From my previous post: "I have noticed under Spindle calibration menu one window for index signal "zero if one/rew". There is "1" but I can't change this value." 
Could this creates an issue?

13

General Mach Discussion / Re: mach3 turn spindle dro not working, spindle speed changing while jogging

« on: December 20, 2020, 05:18:53 PM »

Dear Graham

I don't know what your answer is supposed to mean
I just wrote my opinion. If the programmed step (feed rate) is 2mm / rew, and Mach works 1mm / rew, then there are probably some other settings ...
This is the same also without workpiece.

And a scratch test.... the same as pictures in my previous post .... its cut in a piece of plastic, so no (or near zero) cutting force.

14

General Mach Discussion / Re: mach3 turn spindle dro not working, spindle speed changing while jogging

« on: December 18, 2020, 04:17:09 AM »

On my opinion there is something wrong in MACH3 settings.

Mach does not follow the programmed thread pitch.
If programmed pitch is 2mm, treading starts with F= 2mm/rew, but after ~ 2mm of moving this changes to F= 1mm/rew.
Spindle speed is stable and does not change. Feedrate/moving is not smooth but vibrating.
Index signal is one/turn - I tried with short time signal, longer signal, different index debounce settings... nothing change.
I have noticed under Spindle calibration menu one window for index signal "zero if one/rew". There is "1" but I can't change this value.
Could this be a reason for wrong pitch - wrong F/rew?

Thanks

15

General Mach Discussion / Re: mach3 turn spindle dro not working, spindle speed changing while jogging

« on: December 11, 2020, 04:51:17 PM »

Hello

The spindle is driven by a 7.5 kw motor via a gear transmission. Speed is stable, also rpm in Mach3 are stable during threading.
Thread in the pictures was made with multiple passes.
I also can't figure it out why feedrate in Mach3 showes 0,75 mm/turn if programmed pitch is 1,5mm
This feedrate is also not stable despite the fact that the spindle speed is constant.

I’m slowly getting desperate already, as I’ve invested a lot in reworking the machine, and now I can’t cut the thread.

Any advice is welcome ...
Thanks

16

General Mach Discussion / Re: mach3 turn spindle dro not working, spindle speed changing while jogging

« on: December 08, 2020, 02:46:21 PM »

Despite several hours of effort and various attempts, I was unable to find a solution.
The turns of the workpiece are constant, and the pitch of the thread changes ... I am also attaching a photo.
I am also attaching  XML if anyone could help in any way.

17

General Mach Discussion / Re: mach3 turn spindle dro not working, spindle speed changing while jogging

« on: December 02, 2020, 12:48:13 PM »

Thanks for a help, Rich.

1.  There is no warning - only information about threading - I'm attaching print screen...
2.  Both axis are moving smoothly at any feedrate -when jogging, turning,... Also first few mm while treading but then starts to vibrate and
    feed/turn starts to varry (even constant spindre rpm)
3. Rpm is controlled manually - by gearbox. Before threading I start and check rpm in Mach3. Then input this rpm in wizard...
   During threading rpm is stable - motor, and gearbox are quite oversized and therefore very stable.

I will try to find threading manual and try to find reason for not stable feedrate and wrong pitch.

18

General Mach Discussion / Re: mach3 turn spindle dro not working, spindle speed changing while jogging

« on: November 22, 2020, 03:23:01 PM »

Finally succeeded to replace NOVOSUN with traditional LPT breakout board and find older computer with LPT.
Now index works OK and rpm in MACH3 are stable.
So, I have used threading wizard and try to cut threads.
Threading starts, but only few mm moving is smooth and then starts to vibrate. Also return is not smooth.
Next pass starts also smooth, but starts to vibrate after few mm.
It's strange that speed- feed rate in MACH3 shows 0,75mm but programmed pitch is 1,5 mm
Also this feed rate varies from 0,72 - 0,78 - it's not stable - rpm in MACH 3 is stable and doesn’t change during threading.
Also cut thread has ~0,75 pitch.
Pulley ratio is set to 1.

What could be the problem? Any idea?

Thanks

19

General Mach Discussion / Re: Circle not circle but oval - no backlash on the axis, steps per unit set OK,...

« on: November 08, 2020, 01:01:36 PM »

Yeah, that would probably be most likely, but I checked everything and there’s nothing like that.
The beginning and end of the circle are also completely equal - there is no visible transition at all.
I also tried repeating the code:
0.1
-0.1
0.1
.
.
.
on both axes and when measured with a measuring indicator, it shows a movement of 0.17 mm on both axes (only 0.03 mm difference)

Even after prolonged milling, the machine remains in the same position. If I repeat the program, it goes exactly the same path - so even after one hour of milling, nothing slips.
Even if I push the X or Y axis with my hands in one  or another direction while milling the circle , the shape of the circle itself does not change.

Tomorrow I will try to cut a circle programmed from short lines (g1 only). I will report what the result will be ...

20

General Mach Discussion / Re: Circle not circle but oval - no backlash on the axis, steps per unit set OK,...

« on: November 08, 2020, 10:41:52 AM »

It's a simple code with IJ:

M3 S12000
G17
G0 X53 Y0
Z2
G1 Z-2 F800
G3 X-53 I-53 J0
G3 X53 I53 J0
G00 Z20
M5
M30

Also with R I have same issue:

M3 S12000
G17
G0 X24 Y0
Z2
G1 Z-4 F1000
G2 X-24 R24
G2 X24 R24
G00 Z20
M5
M30


Cutter is D6

Thanks