Messages

6241

Mach SDK plugin questions and answers. / Re: XBox360 Controller Plugin Update Available

« on: May 13, 2009, 05:31:02 PM »

Dave,
Is this what you wanted?
RICH

6242

Mach SDK plugin questions and answers. / Re: XBox360 Controller Plugin Update Available

« on: May 13, 2009, 01:52:29 PM »

Lee,
Thanks for the upgrade. The ref all, disable diagonal movemet , and especially the time out fix are really
good upgrades and appreciated.
RICH

6243

Members Docs / HOMING A LATHE ( WITHOUT LIMIT SWITCHES )

« on: May 12, 2009, 09:52:28 AM »

This is a quick overview of homing and  setting up a lathe without switches.
RICH

6244

General Mach Discussion / Re: Accuracy Problem

« on: May 11, 2009, 07:46:09 AM »

Just a few comments Kevin,
1. A paper disc with a single fine reference line attached to the motor shaft can provide for comparing
actual steps to commanded steps. Poor mans mechanical encoder for checking if steps are lost ( your trying to isolate the commanded steps to physical movements delivered ).

2. No backlash implemented in your xml. The closer you try to get to perfect the harder it is to find the
what is causing the out of tolerance. AT .05mm ( .002" ) your in the area that a number of things can be
adding up to the tolerance call it the "system influence" . Lead screw tolerance, backlash, your measurements, etc.

Just thinking out of the box FWIW,
RICH

  

6245

General Mach Discussion / Re: Strange motor speed on reversing....

« on: May 09, 2009, 04:18:23 PM »

 
RICH

6246

General Mach Discussion / Re: Strange motor speed on reversing....

« on: May 09, 2009, 10:20:24 AM »

thedude,
Suggest the following:
Create a new xml file for the lathe. One that has no homing, tool offsets, etc. because
you should start all over again, as if you were just setting up the lathe for the first time.
I think, and could be wrong, that the iddle current reduction caused you missed steps
which screws up your setup.

1. Disable the iddle current reduction
2. Set your steps / unit at the calculated values
3. Disable backlash
4. Check your x & z movements based on calculated values, if required, change accordingly
5. Check backlash to find values, then set at 50%
6. Retune your motors, find where they start to skip using an acceleration value of 3, then use a
   use a value of 50% of were they skipped for the velocity, and also use a shuttle acceleration .05.
   ( You can tweek the system later on )   
7. Enable backlash
8. Run some repetative gcode programs to confirm that the movements are repeatable
   and tweek the backlash if necessary.
9. Test some actual cutting.
10. Tweek the system based on your experience.

Hope this solves your problem,
RICH

6247

General Mach Discussion / Re: Strange motor speed on reversing....

« on: May 09, 2009, 09:06:20 AM »

thedude,
You sent me xml info for the MILL and we are working with the lathe.
That's all right for now.
Can you call me?

RICH

6248

Show"N"Tell ( What you have made with your CNC machine.) / Re: complex turnings

« on: May 08, 2009, 07:50:20 PM »

Hi All,
This thread is certainly interesting and echo that what Marcel is doing is great.
I thought all of you guys had a robot in the shop. 

Enjoyed, Thanks Marcel for the post.
RICH

6249

General Mach Discussion / Re: Strange motor speed on reversing....

« on: May 08, 2009, 01:03:29 PM »

thedude,
- Your steps per unit: Use the calculated values Z=32000  X=38400
   Yes, you can use a different value, don't want to confuse  ( only when you know why you are doing it ).
   When you checked your steps / unit you were jogging in small incremenntal steps. It would be much better to
    jog a longer distance ( at least an inch ) and use that to confirm settings. Once the steps / unit are confirmed
    then find the backlash setting.

   Reading this post you said you had .0135" backlash in the X and then somewhere else it was .0012" so i am  
   confused.

 - What settings for the pulse & dir time in motor tuning are appropriate for your drives?

   I could not find any recomendations on the Hobbycnc Site and additionaly no instruction sheet for your driver.
   That sucks HOBBYCNC!  
   So if the steppers are working fine with the 0 value, use it . By increasing the value your giving        
   more time for the computer pulse to be seem by your drives.
  
- Your driver has an idle current setting such that it will reduce the current 50% after 10 seconds.
  I could not find how you change that setting on your driver board. Is there a jumper or something
  on the driver board to change that setting ? I couldn't tell from the pictures of your drives posted on the
  Hobbycnc site but it does say it can be changed.
  
  Some time ago, someone else had a problem with that driver and changing it such that there was no current
  reduction solved a backlash and or missed step problem. Just don't remember. It was in the last year or so.

  Can you post your xml file? It's located in the subdirectory where you installed Mach3. Change the file extension to
     .thedude   for posting.


RICH

  

6250

General Mach Discussion / Re: Muti-start threading....

« on: May 08, 2009, 09:08:32 AM »

Andy,

This M76 threading code is a two start thread using a Z offset for the start of the threads and keeping end of the thread passes the same. ( first pass starts at Z=0 and second pass starts at 1/2 the pitch ) but both end at the same point.  Looking at the where the threading started on the end of the piece you can see they are 180 degrees out as expected. Looking where the threading finished for both passes you can see that they ended along the thread at the same point.
 

G00 Z0.0
G76 X0.33 Z-0.600 Q1 P0.0591 J0.004 L0 H0.005 I30 C0.01 B0.0002 T0
G00 Z.02955
G76 X0.33 Z-0.62955 Q1 P0.0591 J0.004 L0 H0.005 I30 C0.01 B0.0002 T0

Now as far as using the angle setting, you can get some intersting results but that is
a different story.

RICH