Hi I am very new to CnC , in fact have only had the machine for about a week.  I hooked it up and ran the mach 3 driver test and got HUGE sppikes and the number would go from 25000 down to to 4500 and all over , needless to say the motors could not be tuned, i looked for the optimize file that was talked about in the video, to help with this problem and have not been able to find it (probably right in front of me) .

   I hooked up the controller to a computer i have (the wifes) and the driver test was great i got the motors runnning fine......  BUT....  when i loaded a gcode into it it cut the item waaaay smaller than it was drawn in BobCadv22  i have made sure all the settings in BobCad are correct all in inches  then drew a 1 inch cube and posted it . then proceded to cut a cube that was so small i couldnt see it  again i have looked every where in mach for a place to set it to inches other than the place to set units for tuning motors (even that is in inches) and on the settings page its set to inches.  so what am i missing?  oh ya i am using the mach3 post processore form Bobcad




  Running in circles
  Rich

There are several things that could cause this. Scaleing, G-code, Motor tuning, ect. I would guess it is your steps per in motor tunning right now. I have pasted in something I hope will help.

Here is how you do the math. I will give you mine as an example. What we need to know is, How many pulses from Mach will it take to move the machine 1 of your units? (inch,mm) Mine is in inches. 1 inch = 10,000 pulses on mine. This is how I came up with the number.
My steppers have 200 pulses per revolution. ( 360 degrees divided by 1.8 degrees = 200 )
Micro stepping = 10. So 200 X 10=2,000
Motor to screw gearing is 1-1. So 2,000 X 1=2,000
Screw lead is .200 of an inch. My screw will have to turn 5 rounds to move the nut 1". 1.0 divided by 0.200=5. So 2,000 X 5=10,000.


Brett

sounds like you have not set your steps per unit up correctly. Look in the Support section of this for the Mach manual. It goes into great detail on how to calculate and set up the steps per unit.

ok thanks i got the steps set and that seems ok but i still need help getting the pother puter to run the program the wifes gonna shoot me if i keep the mini mill in the living room lol

The optimisation steps can be found on the download page (link at the top of the forum) If that fails to improve things then the SmoothStepper would sort you out but its more expense for you if you have to go that route, well worth it IMO but depends on your budget.
Hood

The first place to look for information is always the Support and Downloads section. The Windows XP Optimization document can be found about 1/2 way down this page: http://www.machsupport.com/downloads.php

Some computers will just not run the Mach LPT driver correctly. Video cards/chipsets, power settings and other items can wreak havoc. Laptops are generally not good candidates either. I just got my hands on a SmoothStepper. I had Mach III and the SmoothStepper turning stepper motors on my laptop (with Vista) in under 30 min. I would HIGHLY recommend the SmoothStepper if you can't get you PC to work with the optimizations.