Stepper Motor for Joinery Jig?

adri

Hi

I'd like to have a go at making a propeller version of this...

woodgears.ca/box_joint/computer_jig.html

I'm completely new to stepper motors though and would appreciate any guidance anyone might have as to which motor to use.

There are some on ebay...

cgi.ebay.co.uk/Powermax-II-1-8-Stepper-motor-73W-2-3A-Bipolar-Series_W0QQitemZ270455044028QQcmdZViewItemQQptZUK_BOI_Electrical_Components_Supplies_ET?hash=item3ef86077bc&_trksid=p3286.c0.m14

Would they be OK?

Also, is there an object in the object exchange that might be used?

TIA

Adri

Leon

That motor looks as if it should be OK. You could always contact the author to get the spec. of the motor he used.

You'll need an H-bridge driver circuit to use it in bipolar mode. Plenty of examples are available on the web.

Leon

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Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle

Post Edited (Leon) : 9/18/2009 10:52:34 AM GMT

Agent420

I'm no stepper guru, though I have done several stepper projects of my own.· I can't provide all the inofrmation you're going to need, but I will point out a couple of things to think about ;-)

I'll preface this by suggesting one of the best links that is often associated with stepper discussion.

Creating the signalling to control the motor is composed of 2 parts - the software doing math of start, stop and speed calculations and converting those to the patterns required by the motor coils.··The·coil pattern conversion is usually a fairly simple operation (I·say usually because there are some recent threads here where it has become not so simple).· But don't overlook how you're going to input that information or what you need to do with it.

The actual power control of the motor deserves some consideration...· Stepper motors require a somewhat complex method of current control and if you are not well versed in electronics design or have prior stepper experience you may really want to purchase a pre-assembled control unit - and the bigger the motor or more power you need to control the more you should consider this imo.· In addition to getting a known working control, these typically also provide the coil pattern element, so you just send them commands of direction and how many steps.· Features like microstepping (that can provide smoother movement in addition to finer control), power monitoring (motor jammed?), etc are also things that are nice to have, especially when you are controlling a potentially dangerous machine like a saw.

Speaking of motors, when you are designing something like the example you provide, you should understand the motor requirements in terms of power and torque.· I'm not an expert in this area, but I would think that somebody might have some insight.

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Post Edited (Agent420) : 9/18/2009 10:59:52 AM GMT

CounterRotatingProps

Agent420 said...
Stepper motors require a somewhat complex method of current control
and if you are not well versed in electronics design or have prior stepper experience
you may really want to purchase a pre-assembled control unit - and the bigger the
motor or more power you need to control the more you should consider this imo.

This is good advice. When I first started working with steppers, it was easier to get going using a prebuilt controller. I wasn't forced into learning the lower-level stuff at the same time as trying to get things working. (Stuff =· how to control the H-bridge, what coils to fire when, etc.)· This bought time to gradually get into controlling them directly.·
And it wasn't a waste of time or money to have a couple of these controllers - they are very nice to use because they are command driven, usually just needing a serial connection. Some of them allow you to use simple discrete components instead of, or with, a microC.


cheers
- Howard

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