Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: BOHICAMAN on August 02, 2010, 06:26:52 PM

Title: Sizing seems to be a problem!!
Post by: BOHICAMAN on August 02, 2010, 06:26:52 PM

I have MACH3 (demo) version 3.042.029 installed with a HobbyCNC Pro board hooked to a Sherline 2000 CNC Mill. I also have LazyCam Pro V3.00.2. Here's the problem. I downloaded the LazyCam tutorial drawing (LCRO_HCIR.dxf) used in tutorial #1. After EXACTLY following the tutorial, I posted the G-code to MACH. It appears to run fine - except in minature! The entire machined piece is only about an inch long! This happened before with another drawing. I was meticulous in setting up MACH3 and LazyCam, but obviously I missed something ???. The are both set for "inches" . Anyone have any suggestions? Thanks!
Bob

Title: Re: Sizing seems to be a problem!!
Post by: Hood on August 02, 2010, 06:35:45 PM

If you command a move via MDI does it travel that distance. Example, if you zero the X axis then command G0X1 does the X travel one inch?
Hood

Title: Re: Sizing seems to be a problem!!
Post by: BOHICAMAN on August 02, 2010, 07:21:07 PM

Hood,
It moved 1/8th inch

Title: Re: Sizing seems to be a problem!!
Post by: Hood on August 03, 2010, 02:13:12 AM

Sounds like you need to set your steps per unit correctly.
What pitch ballscrews do you have?
Any gearing between motors and ballscrews?
What microstepping do your drives have?

Hood

Title: Re: Sizing seems to be a problem!!
Post by: BOHICAMAN on August 03, 2010, 02:23:35 PM

Hood,
Ballscrew 20 tpi, single start. No gearing between motors and ballscrew. Microstepping setup on board at 1/4inch, motors are #23-305-DS8A 425oz-in bipolar rating, 305oz-unipolar rating, 4.2v, 3A, 200 S/R, 3.2mH, Size #23, Dual Shaft, 8 wire. Hope that provides info you requested.

Title: Re: Sizing seems to be a problem!!
Post by: Hood on August 03, 2010, 02:34:11 PM

Ok so
your steppers are 200 steps per rev, Microstepping is 1/4 so you will need 200 x 4 = 800 steps to turn the motor one revolution.
You need 20 turns of the screw to move one inch so steps per unit in motor tuning will be 800 x 20 = 16,000.
Hood

Title: Re: Sizing seems to be a problem!!
Post by: BOHICAMAN on August 03, 2010, 02:37:59 PM

Thanks!! Will elt you know how I make out.

Title: Re: Sizing seems to be a problem!!
Post by: BOHICAMAN on August 03, 2010, 02:57:45 PM

Hood,
That seemed to fix it! Thanks for the help!!
Bob

Title: Re: Sizing seems to be a problem!!
Post by: Hood on August 03, 2010, 02:59:27 PM

No problem :)