Hello Guest it is June 16, 2019, 01:27:30 AM

Author Topic: setting steps per inch correctly  (Read 2623 times)

0 Members and 1 Guest are viewing this topic.

setting steps per inch correctly
« on: August 23, 2013, 01:46:24 PM »
So I just started using Mach . Couldn't figure out why road runner.tap was so small when I went to execute the file.
. I never set my motors up.
I went into the setting and told the motors move 1/2 inch it only moved .061 . Well now I know why rr was so tiny.
SO know im trying to understand the whole micro steeping thing.
DO I have to compensate this lack of distance in mach of on my board ?
I have a xylotex board and there are dip switches for the micro stepping.
Am I even thinking correctly? Do the two of these have to do with my setting I need for my motors.
I also have one other questing.
How does mach know my table limits, and were to start a program or were should I start a program.
I thought going from manual machining would be easier I was very wrong .
I cant even figure out how to drill four holes and make one pocket for a bearing.
Re: setting steps per inch correctly
« Reply #1 on: August 23, 2013, 03:24:45 PM »
Go into Mach and select the setting page, then just above the reset button there is a set steps per unit. follow the instructions but have something handy to measure the distance the machine slides moves. I use a digital Vernier clamped one end. Enter the distance moved and Mach will automatically work out and set the axis correctly. Do this for all 3 axis.
If you know the pitch of the ball screw and any pulley ratios you can work it out with a calculator but the set steps per unit is easier.
Hope this helps.
Jim
Re: setting steps per inch correctly
« Reply #2 on: August 23, 2013, 04:04:36 PM »
I thought I  wrote I did that?
But im confused about this whole micro stepping setting should I just leave it at 1/8 and why would I need to change it?
My lead screw is 2.5mm so Im estimating around little over 10 tpi. (iIs that correct 2.5mm x 10 = 25mm 25.4mm = 1 inch)
How does mach3 know my machines limits / boundary? is there a place to enter that? Or is that what m lilit switches are for ?

Offline Hood

*
  •  25,843 25,843
  • Carnoustie, Scotland
    • View Profile
Re: setting steps per inch correctly
« Reply #3 on: August 23, 2013, 04:34:19 PM »
I think Gecko reckon on 10 microsteps being the optimum for a CNC machine and steppers, so as close to 10 as you can would be the best bet. The Chinese drives often just have 2, 4, 8, 16......... so 8 would be what you want (or 1/8 as they often say)
 So Ok you have 8 microsteps and 200mm motor steps (assuming its a 1.8 degree motor) so that means it is 1600 steps per motor rev.
Your ballscrew is 2.5 pitch so that in imperial units equates to 25.4/2.5 = 10.16 turns per inch so 1600 x 10.16 = 16,256 steps per inch. That of course is assuming you do not have any gearing between motor and screw.


Having home switches allows you to home and then you can set up soft limits and that defines the machines boundaries.
If you dont have home switches you can move to the negative extents of X and Y and positive of Z and press RefAll and that will set the machine coordinates to zero and that way you can set softlimits even though you dont have home switches. It does mean however that each time you start Mach you need to move to the extents and press RefAll. If you have home switches then pressing RefAll will make Mach move to the switches and back off until they are closed again and that will be set as machine zero.


Hood
Re: setting steps per inch correctly
« Reply #4 on: August 23, 2013, 04:47:45 PM »
Thanks hood .
THat was very detailed .
Im sure Ill be back with more questions.

Offline Hood

*
  •  25,843 25,843
  • Carnoustie, Scotland
    • View Profile
Re: setting steps per inch correctly
« Reply #5 on: August 23, 2013, 04:53:07 PM »
Sorry I said
Quote
So Ok you have 8 microsteps and 200mm motor steps

Why I put mm in there I have no idea ;D should have just been 200.

Hood
Re: setting steps per inch correctly
« Reply #6 on: August 23, 2013, 08:42:16 PM »
I know what ya ment dont worry