OT - Stepper motor driving...

I have been tasked with a small project for the day-job, we need a feed/rewind system for a foil printing machine.

It's a simple task - the device needs to take a start signal from the machine, accelerate a motor, run for a preset time, decelerate and stop.

Now, we can either go with a timed duration and adjustable speed or a fixed duration taken from the machine as a start & stop signal with adjustable speed.

The speed needs to be adjustable as the machine is variable speed and also the amount of foil to feed will vary depending on the job design.

So, my question is - how simple can we make this?

I would go straight for a Nema23, 4NM motor i think with a step/dir drive and simple PSU - these I have proven to be tough little cookies on my other machines.

But the control side - how would i look to achieve the speed ramping and velocity in the simplest way?

User input would just need to be a simple pot for the overall speed - this would set the amount of foil fed in the window provided by the start/stop signals.

The Arduino has been suggested but I have never used one and do not have the time to learn it really.

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Another RS Ormerod Mk1 meets the world

Retired now but I used to make....
CNC Machined Mk1 aluminium bed support plates for the Ormerod
CNC machined X-plates and ribs for Mk1 & Mk2 Ormerods
CNC machined bed support arms for the Mk2 Ormerod.
Dual Hot-End heatsink blocks.

I would definitely use a small cheap single chip low-end CPU to control the stepper (a PIC would do nicely), but unless you have experience with such design & programming I fear you will need to outsource that task unless you are willing to go through a steep learning curve. Or use an Arduino or similar if you want ready-made electronics without needing to make your own board. It would be possible to achieve without using a CPU, but such a circuit will be quite complex. Another approach would be a DC motor with a sensor (maybe magnet & Hall effect sensor on the reel) with a PWM feed to control the speed of the motor, but again a CPU is really the best way to drive that as well.

If you want to go the Arduino route, here's a good starting place to give you an idea for some off-the-shelf hardware that would work, and get you started on the code:
[brainy-bits.com]

But as said, if you have never programmed before, there will be a lot of learning to do!

Dave

It could be done easily with a 5V Arduino (e.g. Arduino Uno), plus an external stepper motor driver module suitable for your Nema 23 motor that you can pick up on eBay. Try asking for help here [forum.arduino.cc].

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks all, i will browse the Arduino site.

It has also been suggested to use a small 3ph motor with gearbox and a small VFD as these have ramp up/down built in. I ave no idea if they have a start/stop limit though as this will need to trigger and cycle at up to 25 times a minute

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Another RS Ormerod Mk1 meets the world

Retired now but I used to make....
CNC Machined Mk1 aluminium bed support plates for the Ormerod
CNC machined X-plates and ribs for Mk1 & Mk2 Ormerods
CNC machined bed support arms for the Mk2 Ormerod.
Dual Hot-End heatsink blocks.