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### Author Topic: What Ratio Do I use  (Read 2574 times)

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#### LesC

• 3
##### What Ratio Do I use
« on: March 15, 2013, 10:19:19 AM »
Hi,

just wondering if I employ a couple of stepper motors for my X,Y,Z axis how do I go about sizing them , any tips welcome.

What is the normal reduction ratio you guys use on the tooth belt stage, I am guessing about 5:1. Ultimately this should give me my resolution right ?

regards   Les C

#### JohnHaine

• 362
##### Re: What Ratio Do I use
« Reply #1 on: March 15, 2013, 10:59:35 AM »
5:1 would be very high!  Sizing will depend on the machine - what are you trying to drive?  My small Denford mill has a 2:1 reduction and is quite happy with small type 23 steppers.  My Myford lathe has a larger, still type 23 stepper, but direct drive on the X-slide and I think 2:1 on the leadscrew IIRC.

Better resolution comes from using microstepping on the drivers.  On the mill, the screw pitch is 5mm, so one full step is 5/(2x200) = .0125 mm.  Then I use 8 microsteps per step, so the theoretical resolution is .0125/8 = ~1.6 micron.

#### Chaoticone

• 5,626
• Precision Chaos
##### Re: What Ratio Do I use
« Reply #2 on: March 15, 2013, 11:07:07 AM »
Resolution can also be changed with gearing.  You will just need to do some math and a lot of thinking to figure out the best motor,gears,drive for you.  Oriental motor has a pretty good utility to help you figure out what you need.  I would defiantly do the math my self.

Brett
If you could see the things I have in my head, you would be laughing too.

My guard dog is not what you need to worry about!

#### stirling

• 2,188
• UK
##### Re: What Ratio Do I use
« Reply #3 on: March 15, 2013, 11:33:56 AM »
Better resolution comes from using microstepping on the drivers.
Hmmmmm - let's just say - debateable

Ian

#### JohnHaine

• 362
##### Re: What Ratio Do I use
« Reply #4 on: March 15, 2013, 12:03:08 PM »
...up to a point!