Hi Guy’s and Girl’s my name is Andy from Plymouth in the UK

Posted by: @skippy

Hi I’m 55 but a very young at heart old fart haha. I’ve been an avid amateur programmer for a long long time and I’d like to think that I’m reasonably good at it but mostly I plod along until I find a solution or just give up.

I would like to learn how to write sketches to perform an action of some kind. At the moment I would like to find a stepper motor that can pull and push a metal guide for setting the length of a piece of steel in order to cut it to a set size but I don’t have a clue where to start. Andy

Thanks to Bill for such a brilliant site.

Welcome aboard!

Like you (and I think many of us), I wanted to do something with a stepper motor when I first started with Arduino too - The desire to make something move is overwhelmingly inspiring, isn't it? 🙂

OK, I'm sure we can certainly help with some ideas, but we'll need some detailed information from you too.

For example:

1) Is this like a chop saw, reciprocating saw, etc... scenario, where you want to set the length stop?
2) Will the mechanical assembly be linked to the motor via sprocket and chain, or by gears and a rack?
3) How much weight does the mechanical assembly need to handle?
4) How do you envisage your design to work? (punch in a length, via keypad, etc..., and then hit a go button, etc, etc...)

Once you're able to come up with some basic requirements for your design, then we can help you delve into the project much deeper.

Cheers.

@frogandtoad

Hi mate thanks, for answering my question so promptly. 

I would like the mechanism to be operated via a touch screen in which you can set the length of the item to be cut. It has to be able to withstand a reasonable knock from time to time (2-3kg). The length of travel of the stop is three metres. The weight of the item varies from 1kg up to a max of 10kg.

Posted by: @skippy

@frogandtoad

Hi mate thanks, for answering my question so promptly. 

I would like the mechanism to be operated via a touch screen in which you can set the length of the item to be cut. It has to be able to withstand a reasonable knock from time to time (2-3kg). The length of travel of the stop is three metres. The weight of the item varies from 1kg up to a max of 10kg.

No problem, and sorry about the delayed response... there is a corrupt group of tyrannical arseholes forcing fascism upon all humans around the world right now, and to say that it's pissing me off would be an understatement of biblical proportions!

Sorry, off topic I know, but onward's through the fog we move! 😉

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As you haven't answered all of my questions with the detail I was looking for, I can only still really guess.

1) Touch screen... sure, not a big problem, neither here nor there

2) "withstand a reasonable knock from time to time (2-3kg)"
Is the material/stock on a bed of rollers to reduce sliding friction, and do you intend for it to be moved by hand or by some automated process as well?  I still don't know what cutting process tool you're using either.

3) The length of travel to the stop looks to be quite a distance. which means that even a 3kg weight could have far greater impact against it, depending on it's velocity, so not sure how you determined the knock of 2-3 kg (see above), if the weight could vary up to 10kg?

The more info you can provide, the better.

Cheers

• Hi mate, sorry I took so long to get back to you. The Arduino will control a stepper motor which is mounted on a mechanism which in turn is also the stop that the steel to be cut rests against. When the stepper motor rotates it drives a cog that turns on a piece of threaded bar, the cog then pushes on bearings, which are set either side of it in order to move the stop backwards and forwards. The threaded bar is fixed to the side of the saw to give a fixed point of reference. The steel sits on a fixed angle guide which prevents anything from sliding to far. With the guide we have at the moment I push the steel up to the guide slowly to prevent it from moving.
•  
• Thanks

        Andy

@frogandtoad

@skippy

Posted by: @skippy

• Hi mate, sorry I took so long to get back to you. The Arduino will control a stepper motor which is mounted on a mechanism which in turn is also the stop that the steel to be cut rests against. When the stepper motor rotates it drives a cog that turns on a piece of threaded bar, the cog then pushes on bearings, which are set either side of it in order to move the stop backwards and forwards. The threaded bar is fixed to the side of the saw to give a fixed point of reference. The steel sits on a fixed angle guide which prevents anything from sliding to far. With the guide we have at the moment I push the steel up to the guide slowly to prevent it from moving.
•  
• Thanks

        Andy

 

@frogandtoad

It sounds like you have worked out the mechanics of how you intend for it to work, so I guess it's just a matter of building it. Post back when you need some help with the code, as I or someone will be able to help you get it done. Cheers.

@frogandtoad

Me again I was kinda hoping that you could give me advice on which stepper motor I could use

@skippy

Posted by: @skippy

@frogandtoad

Me again I was kinda hoping that you could give me advice on which stepper motor I could use

It's not so easy to give advice on something like this without very detailed information. 

However, if I were to make something like this, I wouldn't go less than a nema23 (one of the larger ones), and preferably with a reduction gearbox attached - This will help a heavy piece of stock with some momentum behind it from turning the thread/motor on any substantial impact against the stop.

Something like this perhaps?: Nema23-3Nm-L112mm-Stepper-Motor-Driver-Worm-Gearbox-Speed-Reducer-Geared-Kit

Cheers.