Linear Stepper motor slider mechanism or ??

Using Arduino Project Guidance
1

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

2

How much precision is required?

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

3

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

Cheers

Geoff

4

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

5

Thanks

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

Geoff

6

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

7

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

8

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.

9

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.

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

servo.jpg
servo.jpg323×978 16.8 KB

10

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

11

120 times per minute.

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

12

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

13

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

Thanks

Geoff

14

These are good:-

15

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

16

It's a bit overkill for just running a single motor, but useful if you want to drive more stuff.

17

Yes I know but found it cheap,

http://www.ebay.co.uk/itm/Arduino-Special-Motor-Drive-Shield-/280531168628?_trksid=p5197.m7&_trkparms=algo%3DLVI%26itu%3DUCI%26otn%3D5%26po%3DLVI%26ps%3D63%26clkid%3D2539622117301841963#ht_3396wt_1139

I can use it for other stuff too.

Cheers

Geoff

18

I basically want to do this but with a 60mm stroke.

Regards

Geoff

19

Yes as I said before you might struggle, the key is getting a rod with a small number of TPI (threads per inch). The CD drive as a very spaced out thread on the spindle. I am not sure where you get these from.

20

Hello Jim, I sell linear actuators as part of my job , that speed you require is very fast, and you will have a hard time finding anything , you would have to go to a big linear actuator. even then they have a 10% duty cycle, this means you can run it for 10 minutes and then needs a 1 minute rest to cool down.