Urgent Help\Advice please.

[Kosa]

Ok I have decided to make my own 3 axis CNC Router Machine due to the lack of options for Commercial Hobby Priced systems in Australia.

My dilema is this: I only need a working surface area of 48" x 24" (and thats plenty) so a small 200oz\in stepper setup would do the job easily.

My dilema is this: A friend of mine who was building a 10x6 foot plasma machine for his business has changed his mind and cancelled the project. Now he has offered to sell the Servo Controller, Power Supply and 3 600oz\in Servo Motors to me at a "can't say no price".

Now this is a complete plug and play setup, but at 600oz\in, 20amp Controller and a 48V High Torque Power Supply, can this system be tamed to be use to finely cut 3mm balsa (OK YOU CAN STOP LAUGHING NOW) accurately or not.

Would really appreciate your comments.

Cheers
Kosa

[mxtras]

Yes. If the 200oz/in stepper motors will do the job, the 600oz/in servos will be more than adequate. However, if this is your first build, doing a servo system may add an element of complexity for you.

If the price is good then I would sugggest scooping up the parts and giving it a go.

Scott

[Kosa]

Thanks very much for your comments Scott. After doing alot of reading I've decided to do just that and give it a go. And yes this is my first build.

When you say that a servo system may add an element of complexity over a stepper build, could you ellaborate on that please.

Cheers
Kosa

[mxtras]

A servo system requires feedback while steppers do not. The feedback signals can easily be distorted by EMF (interference), so shielding the feedback cables from the encoders and protecting the feedback signal becomes critical to get a clean signal. If possible, plan from the start to run the encoder cables away from the motor power cables and run them in shielded cables.

Also, a servo system is less forgiving than a stepper system to get set up - at least that has been my experience. I have yet to set up a "hobby" level servo system - my experience with servos has been industrial and is a little limited. Tuning the motors is a bit more of a challenge than with steppers - there's more involved than just setting steps/per unit, velocity and acceleration as you typically do with a stepper. You will have a bit more research to do but I think it will be worth it and you will quickly become proficient, I am sure.

Scott

[Kosa]

Thanks again Scott, really appreciate your comments.

Cheers
Kosa