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Author Topic: Spindle RPM and Threading Problem  (Read 3560 times)

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Re: Spindle RPM and Threading Problem
« Reply #10 on: October 17, 2017, 01:50:43 PM »
Hi,
Ok, sounds like you have proven the difference between the S commanded speed display and the true rpm display.

May I suggest that you offer the spindle to some load to see if it slows down a wee bit. So using some other Gcode than threading
take a cut in a piece of steel and monitor the true speed, you would expect it to slow a little. The reason I suggest this is that its not impossible
that the sensor is producing pulses for a period of time but then ceasing and Mach is just retaining the true speed display as is rather than
a continuous update.

Craig
My wife left with my best friend...
     and I miss him!
Re: Spindle RPM and Threading Problem
« Reply #11 on: October 18, 2017, 05:37:43 AM »
Okay, but mach has no control on the Spindle speed...i should give it a command every time when i spin it no matter that mach has no control on it?
Re: Spindle RPM and Threading Problem
« Reply #12 on: October 18, 2017, 06:23:37 AM »
Hi,
I don't know. I operated my mill with manual control of the spindle for quite a period of time. For simple handcoded or teach jobs I still operate
that way. Unless your Gcode uses speed, commanded or actual, I don't think it matters. Whether some of the canned cycles in lathe ops rely on
S, commanded or actual, is more than I can say.

I saw something in another thread today which may be related to your problem and may be worth investigating. Config/Ports and Pins/Spindle Setup
in the Special Functions panel check 'Use Spindle Feedback In Sync Mode' and 'Spindle Speed Averaging'. Haven't yet found any documentation about
what those settings mean but they sound promising! May be try them and see what happens.

Craig
My wife left with my best friend...
     and I miss him!
Re: Spindle RPM and Threading Problem
« Reply #13 on: October 18, 2017, 07:13:50 AM »
I have already checked these options. Well, i actually tried giving an S100 command and at the same time rotated the spindle with 100 RPM. There is a bit difference, i mean that the RPM's that Mach counts are 108. Even this way the thread cycle is not working

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Re: Spindle RPM and Threading Problem
« Reply #14 on: October 18, 2017, 07:15:47 AM »
Graig,

Quote
'Use Spindle Feedback In Sync Mode' and 'Spindle Speed Averaging'. Haven't yet found any documentation about what those settings mean
Use Spindle Feedback In Sync Mode - required for lathe  threading as Mach will then use the index to change from G94 to G95 to sync for the multiple threading paths.
The time it takes to read and implement the change can be affected by index debounce and spindle speed averaging.

Spindle Speed Averaging - Used by Mach in threading and averages the rpm
 ( out to 4 decimal places ) over 8 revolutions ( from what I remember when testing ) during a path and uses the result for the the next path. There is more to this and would need find and look at more than 300 pages of notes. This is internal to Mach and you have no access to it. I would just check it and forget about it.

A simple test of the spindle sync would be to use a thin disc and see the scribed
mark made by the tool on the disc's cirmference. It's also a good test to see if ones lathe is capable of doing multiple start threading.  Same old remark, threading only as good as your lathe SYSTEM.

RICH

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Re: Spindle RPM and Threading Problem
« Reply #15 on: October 18, 2017, 08:02:39 AM »
If the index sensor is working and  appropriate for rpm range (  look at the specs of your sensor ) then the real time true rpm shown in the DRO  is more accurate than you will probably be able to measure  ( at least I know that for a fact and use the PP ).

Quote
Something that i'm not sure if it is correct is that i cannot see the index on every single rotation of the spindle.

The LED won't / can't  update fast enough to indicate each time the index is read.
Just consider it a visual that the index is working  since it's blinking randomly.
BUT
You will see the LED change from Waite for Trigger to Threading and Mode indication
from G94 to G95 via LED's every time when threading.

The problem is that the generic screen just sucks both functionally and  if your trying to monitor some things
amd that is why I use  a custom screen set.

RICH
Re: Spindle RPM and Threading Problem
« Reply #16 on: October 21, 2017, 07:10:03 AM »
The LED won't / can't  update fast enough to indicate each time the index is read.
Just consider it a visual that the index is working  since it's blinking randomly.
BUT
You will see the LED change from Waite for Trigger to Threading and Mode indication
from G94 to G95 via LED's every time when threading.

I also tought that the LED can't respond so fast, but i've decided to share that. Yes i see the LED's for G94/G95, and it is changing when i start the G76 cycle. I also see the Wait for trigger LED light up and then it goes down and Threading LED lights up, in that moment the axes start to move and almost immediately stop. The Threading LED is still up. If i stop the Spindle and turn it on again it moves again a bit and stops. Maybe i should upload some of my configuration so u can see better what i did.
« Last Edit: October 21, 2017, 08:19:43 AM by RICH »

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Re: Spindle RPM and Threading Problem
« Reply #17 on: October 21, 2017, 08:19:02 AM »
Have you tried using Mach version 062  as 066 is problematic?

Post the G76 code that you used for your last post. Are you allowing  distance equal to about 3 to 5 dia of the thread
so the  z axis can accelerate to the start of the thread. If you use the threading wizard it will tell you if acceleration is adequate.

Post the xml file that you are using and maybe someone will have a look at it.

RICH

« Last Edit: October 21, 2017, 08:29:06 AM by RICH »
Re: Spindle RPM and Threading Problem
« Reply #18 on: October 24, 2017, 07:25:06 AM »
Yes, i have tried version 062 and it is the same. Anyway i left it with 062.
No matter what code i type it does the same. But let's say that this is it:
Code: [Select]
G76 X-1 Z-10 P1.25 H2 I29 C2I zero the axes where the start of the thread will be and just start the cycle. I do all this in the air, i am still testing the functions, so i can see that everything works fine. Maybe i should really try to move it a little bit fĐ°rther away and try to start it from there, by inputting the start positions of the thread for X and Z.

Here is my XML and my macro for the JoyPad Plugin with wich i input M03/M04 commands. Input 1 and Input 2 come from the contactors that rotate the spindle. After this i engage the solenoids for fast or slow gear from Mach.
 

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Re: Spindle RPM and Threading Problem
« Reply #19 on: October 24, 2017, 08:29:54 AM »
There is a simple answer to your threading problems.

Don't use a PIRATED LICENSE . Purchase a license!

You have nerve to make a fool out of me and others.   >:(

Take Care,

RICH
« Last Edit: October 24, 2017, 08:32:55 AM by RICH »