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Topic: Linear Stepper motor slider mechanism or ?? (Read 3479 times) previous topic - next topic

JimiH

Hello

I've had an idea for a project which would utilize a slider that I could control its position along a x axis.
I've done some research and found out its a stepper motor with a screw feed slider mechanism.

I thought I could get one cheap but they are proving difficult to find or very expensive?
I want one with 60mm max movement from end to end.

Is this the right approach or are there alternatives?

Thanks

Geoff

mjbmikeb

How much precision is required?

Is it for a CNC milling machine or a garden watering system?

JimiH

Hi, sorry,  about +/-0.1 mm would be fine.

Cheers

Geoff

mjbmikeb

Look at the second hand machinery market. You may find something that you can pull apart and re-use.

JimiH

Thanks

I was thinking of taking an old CD/DVD rom drive apart.

Geoff

Erni


Hi

just an idea:

You coul use a standard servo with a 30mm arm, that would give you the 60 mm movement from side to side.

And the precision theoretical 60mm/1023 = 0,06 mm


JimiH

Hey thanks Erni.

That's rotary motion though isn't it? I'm after linear motion, left to right etc.

Cant believe I cant find anything out there for this.

The CD mech seems ideal but I dont think I'll get the 60mm, also trying to figure
out how to dismantle it and use it with the Arduino seems like a headache.

Maybe there is a guide out there?

Cheers

Geoff

Grumpy_Mike

Quote
I was thinking of taking an old CD/DVD rom drive apart.

I recently took apart 30 CD drives and only 8 had stepping motors in them, the rest had DC motors.

A threaded rod and a nut along with a bracket is all you need.

Erni

#8
Aug 22, 2011, 08:50 pm Last Edit: Aug 22, 2011, 09:07 pm by Erni Reason: 1
It is easy to convert the rotary motion to a linear, I tried to make a drawing. In the RC model hobby we do it all the time to move rudders etc.

You can bye kits that do the same fx.

http://www.e-clec-tech.com/lisekits.html

There are also instructions on how to make a normal servo to a linear actuator:


http://www.societyofrobots.com/robotforum/index.php?topic=10044.0





JimiH

Ahhhhh i see, looks good. might be a bit more complicated having more components in the assembly. The screw
and bracket seem like a good idea though.

I'm after the mechanism to move backward & forward about 120 times per minute. So depending on the pitch
of the screw thread this would determine the amount of rotation of the motor. I have an old CD drive lying round
somewhere so I'll dig that out and measure the pitch. I have enough to go on at the moment.

Thanks for all your help

Geoff

Grumpy_Mike

Quote
120 times per minute.

That is quite a fast thrashing about for a 60mm stroke, it think you will struggle to get this.

mjbmikeb

Find a scrap motorcycle engine with a 60mm cylinder stroke.
Remove the cylinder head and drive the crank shaft with a stepper motor.

JimiH

ok looking for a driver circuit now, what would be the best shield with two driver circuit?

Thanks

Geoff


JimiH

Thanks Mike after much research I decided on this

http://www.ladyada.net/make/mshield/

There seems to be a lot of support for this on the web and I think I'll need it.

Thanks

Geoff

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