Automated Orbital Pipe Welder Stepper Motor Help

[200tdimorgan]

Evening all

I am need of assistance and have been advised some members on here will love to help with this

Basically, I have built an automated orbital pipe welder, which consists of two halves of a gear that clamp around a pipe for a motor to then drive around. As the picture shows, their Is a bracket that holds the bearings on both side of the clamp so that the motor doesn't fall off. On that bracket, a Tig torch will be clamped so that as the motor turns around the pipe, the torch goes with it. The welding part I can sort out, however I haven't much idea about the stepper motor and how to run it. I was told that would be the best motor to get as it has plenty of torque and easily controlled for a smooth operation. The motor is a nema 23.

The problem is, I don't know what I need to be able to programme it to get it turning. idealy, I would like a programmed chip in a circuit board, that will take power from a (PSU I think, 36V voltage reducer from mains) and then control the motor by a driver. I have downloaded arduino as a mate told me that would be best, and thought I need one of their boards to then run the driver (which I think is a cw5045 from cnc4you, where I got the motor). however, I don't want to buy anything yet because I don't know if these are the right things for certain, or if there is a cheaper alternative. the reason I want it to run from a chip and not simply on and off using the laptop is because I want to be able to gradually increase the speed of the motor and then slow it down gradually when the weld is completed. I would also like the chip to be able to send a trigger voltage to the welder and the wire feed motor to turn these on when needed, i.e welder on, wait, motor set off, wire on, motor complete pass, wire off, welder off, motor slow down to stop.

has anyone written programmes for steppers etc, if so, what do I need and where would I start

cheers

[muddy]

Surley someone must know?!

I thought someone on here dabble in this stuff all the time.

Will.

[TheRecklessEngineer]

Any microcontroller would be ideal for this. I'm quite a fan of the Arduino platform because it's so prolific there's a library for just about everything which makes going from idea to prototype very quick and easy. Even if the solution isn't most elegant.

You'll need some hardware to actually drive the stepper - a generic motor shield should do it. I'm certain a google will turn up all you need to know about Arduino and stepper motors.

[LandyManLuke]

If you don't want to do all the hardware and software yourself, stepper drives with built in RFGs (Ramp Function Generators) and positioners are available off the shelf.

You will need to be careful with the HF from the TIG torch, it could well play havoc with the stepper driver, you'll need to take good EMC precautions.

Have a look at the following link for an idea of what people are using for low-cost applications.

http://www.zappautomation.co.uk/en/3-stepper-drivers?orderby=price&orderway=asc

This driver for example has an RS232 interface.

http://www.zappautomation.co.uk/en/single-rs232-stepper-systems/618-uim24104-rs232-stepper-driver.html

If you make your own position controller, it can talk 'step and direction' to the stepper motor driver, which will look after the detail of stepping (and microstepping) the motor

Luke

[200tdimorgan]

cheers for the replies, even more confused now haha

i understand the HF will be an issue, so whats an EMC?

The driver in the link, does this not require a micro controller, simply plug into laptop and send programme to it? and can the programme be written using the arduino interface (because there are lots of tutorials for this so when i plug it in i will be able to see how it works)

Also, whats a position sensor, and how would i make one. Basically, i have no idea about these things and am quite lost.

cheers again folk