Messages

1

Mach4 General Discussion / Re: New people welcome !! Come in here and introduce your self!

« on: December 26, 2009, 04:28:36 PM »

Hello, my name is Dan.  I'm new to CNC.  I converted a Seig X2 mini-mill and am now in the process of "fine tuning" it.  I'm new to G-Code but not to programming.  In a former life I was a Microsoft Certified Developer.  I hope to shorten my learning curve by glean some knowledge from the more experienced members of this group.  Hopefully, in time, I'll be able to contribute as well.  This is currently a hobby for me although I've done a little prototyping work for a friend and would like to do some more.  I'm also planning to convert my mini-lathe to cnc in the near future (once I've got the mill figured out).  I also have an interest in air rifles that I modify and make custom parts for.  That's it for now.

Dan 

2

General Mach Discussion / Re: First Post - Help with setup issue?

« on: May 27, 2009, 05:40:57 AM »

Thanks for the note.  Once I'm satisfied with the mechanical setup of each axis I plan to set the backlash compensation for each in Mach.  I've played with it a little but haven't really figured out how it works yet (noob curiosity). 

Dan

3

General Mach Discussion / Re: First Post - Help with setup issue?

« on: May 26, 2009, 08:33:58 PM »

Yes, I've installed Nook ball screws.  I disassembled the table and found the X axis ball nut mount set screw wasn't tightened down.  I'm still working on getting it properly positioned.  My first try cut the backlash down to 0.003" but I still think it can be improved.  I'm going to have to look into oversized balls.  I can tell there's some slop in the nut.

Thanks,

Dan

4

General Mach Discussion / Re: First Post - Help with setup issue?

« on: May 25, 2009, 07:52:12 PM »

Thanks for the input Ray.  I'm going to take it apart and see if I missed something.  If not, I guess I'm going to figure out how Mach3 handles backlash.

Thanks,

Dan

5

General Mach Discussion / Re: First Post - Help with setup issue?

« on: May 25, 2009, 06:34:49 PM »

Looks like it's backlash.  I'm surprised to see that much backlash in a ball screw.  I've got the lower cost Nook ball screws.  I've checked the table mount and the ball nut is screwed into a bracket.  I guess I'll have to tear into the table and see if the bracket is secure.

6

General Mach Discussion / First Post - Help with setup issue?

« on: May 25, 2009, 04:46:41 PM »

Hello Everyone,

I'm new here and could use some help.  I've been working on an X2 CNC conversion for some time now.  I have no prior CNC experience.  I have some machining experience so I'm comfortable using a manual mill or lathe.  I'm just starting to learn Mach3 and g-code.  

My X2 CNC conversion is almost operational however, I discovered a problem while testing this afternoon.  While checking position repeatability I discovered the X axis is traveling .006" short of what Mach3 is reporting on the DRO.    

My test setup is simple.  I've clamped blocks a fixed distance apart, 2.000".  The DTI has a 0.099" diameter ball end.  The indicator is set to read 0" at the starting block.  It travels 0.001" after contact to get to a 0" reading.  I wrote some simple g-code to move the X axis from 0.000 at the starting block to the end block (2.000" away).  By changing the distance little by little until the DTI reads 0.000" (at the end block) I found that distance needed to be 1.906".  I put a dwell in so I can read the DTI at the end block before it returns the table to the original position.  The repeatability is fine. It returns to within 0.0005"  on both ends repeatedly.  

Here's my breakdown.

Start = 0"
Reported distance traveled = 1.906"
+ DTI travel to 0" = 0.001"
+ indicator ball dia. 0.099"
Actual Distance traveled = 2.006"

Over travel of 0.006" per the Mach3 DRO

I've also tried the above test with blocks set 3.000" apart with the same 0.006" over travel reported by the Mach3 DRO.

By using my Shuttle Express to jog at 0.001" per click I found that the DTI doesn't move til about 0.006" of reported travel when changing directions.  

So, would this be the backlash on the X axis?

Thanks for the help,

Dan