Smooth stepper question

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Tin Falcon

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I am thinking about a smooth stepper.
Not sure if I need one or even want one at the present time.
I know some of the reasons advantages to have one
1) enable mach 3 use with laptop.
2) transfers motion control logic from the computer to the SS mc
3) enables more I/O logic ports for relays to control stuff
a total of 40 I/O 16/24 24/16
am I missing other good reasons to pay out the $155 for one of these.
Is this one of those Items if you have to ask why you need it you problem do not or more like something if you have one you wonder how you lived with out it.
I should probably get the train moving down the track before I worry too much about bells and whistles.
I noticed the smooth stepper is part of the Mill Build package at the CNC seminar. So got me thinking to I need one or would I benefit from one?
Tin
 

picclock

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AFAIK smooth stepper drivers are anything but. They turn a 200 step motor into a 400 or 800 step device by altering the phase drive in the windings. So although it may look smoother it really is just made up of smaller steps. The downside of this is that the torque is reduced, the upside is they are quieter and because of the reduced torque/movement per step kinder to the drives.

Just my 2 cents worth

picclock

 

RonGinger

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You are confusing smoothstepper with microstepping.

The smoothstepper is an external motion control board designed for Mach. It off loads from the proceessor the real-time issues of generating step pulses. As Tin noted it makes reliable pulsing even for laptops.

It is not essential, but it can be helpful. The reason is simple. Mach has a basic kernal frequency, by default is 25khz, it can be stepped up to as much as 100khz, but that only on the most powerful of PC. For number lets look at the 25khz case.

Mach gets to decided to put out a pulse, or not, every time the clock ticks, thats at 25khz, or every 40 microseconds. Lets suppose we are running along at a velocity that requires a pulse every 50 uSec. The clock ticks, Mach looks and sees it not yet time for a pulse, so no output. 40 uSec later it ticks again and the pulse is late by 30 Usec.

This leads to jitter- the pulse stream is not 'smooth' Stepper motors dont like jitter.

Smoothstepper works the same (all digital systems must work on clock ticks) but the tick rate is 4Mhz, Now the max possible pulse jitter is 4 microec, not 40microSec, much smoother.

On my knee mill I elevate the entire knee for Z. I was loosing steps. I tried slowing way down and still had the problem. I switched to a smoothstepper and knee runs great.

picclock, you are making a common mistake the microstepping is done to increase resolution- the number of steps per inch. It is not, It is used to smooth the motion and reduce resonance problems. I think it is almost essential to use a microstepping driver on any modern machine. Just dont think you are getting more resolution, look for smoothness.
 

stevehuckss396

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One other thing, the smoothstepper is a USB device. The parallel port is becoming a thing of the past so in the future if your computer goes south, it may be easier to find a replacement with a usb. Usb is a faster Com port.
 

Tin Falcon

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who makes the smooth stepper It appears to be warp 9 but i see them for sale at various sites.

Ron thanks for the refresher. I know you went over that at the CF seminar. Guess I was distracted buy lusting over the kx1 we the attendees were all hoping to win.
Tin
 

RonGinger

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Smoothstepper is made by Warp9. But since he is a one man company he sells them through dealers. In the early days he got so tied up in shipping and handling the details of sale he couldnt keep working on the project. Once he put it out to dealers that seems to have cleared up.


 

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