Dynomotion

Group: DynoMotion Message: 11644 From: cnc_machines Date: 6/5/2015
Subject: Lathe Setup

Greetings,


I am building a small lathe with the KStep, and have some questions on how to configure it. Basically I will be using 2 small NEMA 17 steppers to drive the to run the X and the Z axises, and and a NEMA34 stepper to actually turn the spindle (I Know torque wont be good at high RPM). The reason for the stepper driving the spindle is so I can stop and index the spindle at different positions. I have never done this before and am hoping to get some guidance.


KMotion Questions:

  1. How do I define the coordinate System in my INIT program to set X,Z, and C-Axis around Z.
    2.     DefineCoordSystem(0,-1,1,-1,-1,2);

  2. Anything in KMotionCNC - Just need to click on degrees for the C axis under trajectory planner?


So the "C" axis is also the lathe spindle of rotation. Does anyone know how to write a G-Code program that stops the spindle and then starts using C as a rotary axis? Maybe something like this?


M03 S2000 - Sets the axis to turn like a spindle at 2000 RPM

M05 - Stops the spindle

G00 - C 90 - Moves the spindle to 90 Degrees from home?


Can you simply stop the spindle, and then call a position for C and have it move there? Is there anything else that would need to be configured (special .C programs to execute) to get it working?


Thanks,


Scott
Group: DynoMotion Message: 11646 From: Tom Kerekes Date: 6/5/2015
Subject: Re: Lathe Setup
Hi Scott,

You can't have a KFLOP Axis configured to be part of the Coordinated Motion System (C Axis) and as a Spindle at the same time as there will be a conflict (one may tell the axis to move and the other may tell the axis to stop).

But you should be able to use a custom M Code to include/exclude the KFLOP Axis from the Coodinated Motion System.

Note also to define the B or C axis you must use the DefineCoordSystem6 function to define all 6 axes.

To include as C Axis do:

    DefineCoordSystem6(0,-1,1,-1,-1,2);

To exclude and operate as a Spindle do:

    DefineCoordSystem6(0,-1,1,-1,-1,-1);


HTH
Regards
TK
Group: DynoMotion Message: 11648 From: cnc_machines Date: 6/5/2015
Subject: Re: Lathe Setup
Excellent! That makes sense. Maybe I can do something like this:

  • M03 to exclude the spindle (DefineCoordSystem6(0,-1,1,-1,-1,-1);)
  • Spindle - "S" to jog the axis at the speed passed in by S (Jog(2,Speed)) 
  • M05 would stop jogging and re include the axis to coordinated motion (Jog(2,0))(DefineCoordSystem6(0,-1,1,-1,-1,2);)

Does this seem reasonable? Maybe the push buttons in KMotionCNC wouldn't work to start and stop the spindle, but that should be okay (On CW, On CCW and Off).


Thanks,


Scott
Group: DynoMotion Message: 11654 From: Tom Kerekes Date: 6/6/2015
Subject: Re: Lathe Setup
Hi Scott,

I'm not sure it would work well having the same MCodes M3/M5 switch modes.  It isn't clear to me you should switch modes every time the Spindle is turned on and off.  You might start off with separate MCodes such as M100, M101 to switch modes and prove everything works.  Then see if you can simplify by combining them.

Regards
TK

Group: DynoMotion Message: 11657 From: Tapio Larikka Date: 6/7/2015
Subject: Re: Lathe Setup

Hi Steve!
 
I don't know how this would work under KMotionCNC, but this works for me under Mach3
 
-Init file includes the spindle axis to coordinate system on startup
-M3/M4 excludes/detaches the axis and starts jog at commanded speed
-M5 stops jog and re-includes/attaches the axis back to coordinate system
 
Mach specific parts propably need some modding.
Use the below example at your own risk and with caution.
 
Rgds,
Tapio
 
#define SPINDLE_AXIS 3  // axis set up as Spindle, possibly Step/Dir or Servo
#define FACTOR 240000 // Converts fractional pulley speed to counts/sec (may be negative)
 
main()
{
 int message = persist.UserData[0];  // Mach3 message ID
 int Direction = persist.UserData[1];  // Mach3 Spindle Direction
 float speed = *(float *)&persist.UserData[2];  // value stored is actually a float
 int *On = &persist.UserData[3];  // value stored is actually a float
 int DirFactor = 0;
 
 //if (Direction==0) DirFactor=-1; // change Direcion 0 or 1 to DirFactor -1 or +1
 if (Direction==0)
   {
    DirFactor=1;
   }
   else if (Direction==1)
   {
    DirFactor=-1;
   }
 

 switch (message)
 {
  case EX_SPINSPEED:
       DefineCoordSystem6(0,1,2,-1,-1,-1);
   speed = *(float *)&persist.UserData[2];  // value stored is actually a float
   printf("Mach3 Notify Message=%d, Direction=%2d, Spindle Set to %f, Run=%3d\n",message,Direction,speed,*On);
   Jog(SPINDLE_AXIS,speed*FACTOR*DirFactor);
   while (!CheckDone(SPINDLE_AXIS));
   break;
 
  case EX_SPINON:
   *On = TRUE;
       DefineCoordSystem6(0,1,2,-1,-1,-1);
   printf("Mach3 Notify Message=%d, Direction=%2d, Spindle Set to %f, Run=%3d\n",message,Direction,speed,*On);
   Jog(SPINDLE_AXIS,speed*FACTOR*DirFactor);
   while (!CheckDone(SPINDLE_AXIS));
   break;
 
  case EX_SPINOFF:
   *On = FALSE;
   printf("Mach3 Notify Message=%d, Direction=%2d, Spindle Set to %f, Run=%3d\n",message,Direction,speed,*On);
   Jog(SPINDLE_AXIS,0.0);
   while(!CheckDone(SPINDLE_AXIS));
       DefineCoordSystem6(0,1,2,3,-1,-1);
   break;
 }
  //Jog(SPINDLE_AXIS,speed*FACTOR*DirFactor);
  //while(!CheckDone(SPINDLE_AXIS));
 
}
----- Original Message -----
Sent: Sunday, June 07, 2015 12:49 AM
Subject: Re: [DynoMotion] Lathe Setup

 

Hi Scott,

I'm not sure it would work well having the same MCodes M3/M5 switch modes.  It isn't clear to me you should switch modes every time the Spindle is turned on and off.  You might start off with separate MCodes such as M100, M101 to switch modes and prove everything works.  Then see if you can simplify by combining them.

Regards
TK

Group: DynoMotion Message: 11660 From: Tom Kerekes Date: 6/7/2015
Subject: Re: Lathe Setup
Hi Tapio,

Thanks for sharing we really appreciate it.

But I see one issue.  (It might have been from one of our examples).  A continuous Jog at some speed will never indicate "Done".  For a Jog the "Done" condition will only go true when a Jog Speed of zero (stop) is commanded and then after completely stopped.

So the:

   while (!CheckDone(SPINDLE_AXIS));

should probably be removed from the

  case EX_SPINSPEED:

and

  case EX_SPINON:

It may work ok because the program will simply never complete and be killed by the next Spindle command.

Regards
TK


Group: DynoMotion Message: 11661 From: Tapio Larikka Date: 6/7/2015
Subject: Re: Lathe Setup

Hi Tom,
 
I think you are right with them checkdones being unnecessary. I just haven't removed them as I haven't found them disturbing. 
If I remember right (its over two years since i wrote that) I added them for some reason that had to do with mach starting with
EX_Spin On as first message after startup. I have a vague memory that after startup setting the spindle speed to a speed DRO started spindle unless the spindle was first toggled on and off.
 
This is why anyone trying this code under mach should use extra caution. KMotion console is useful help in tracing the messages and figuring out what happens.
 
If you ever get a moment that you have nothing better to do ( ;-) ) you might take a look at this to see if there is something that you can do  in plug in to prevent this.
 
Rgds,
 
Tapio
 
----- Original Message -----
Sent: Sunday, June 07, 2015 10:13 PM
Subject: Re: [DynoMotion] Lathe Setup

 

Hi Tapio,

Thanks for sharing we really appreciate it.

But I see one issue.  (It might have been from one of our examples).  A continuous Jog at some speed will never indicate "Done".  For a Jog the "Done" condition will only go true when a Jog Speed of zero (stop) is commanded and then after completely stopped.

So the:

   while (!CheckDone(SPINDLE_AXIS));

should probably be removed from the

  case EX_SPINSPEED:

and

  case EX_SPINON:

It may work ok because the program will simply never complete and be killed by the next Spindle command.

Regards
TK