Motor sizing

[cmengnr]

hello everybody
i am going to design a cutting machine in x and y.
i am not able to decide which motor should i choose.how can i decide the torque required for my application.

[Al_The_Man]

Download Motioneering s/w
http://www.kollmorgen.com/website/co...tioneering.php
Al.

[cmengnr]

hi Al_The_Man
thanks for quick reply.I want to confirm that which one of the better fo making mini cnc machine, Stepper or Servo Motor.
Also Is there any need of special type of controller to control x and y direction of motor. commercial controller through pwm can able to do this or not.

[Al_The_Man]

Servo is better, stepper is cheaper, especially on a mini machine.
Mach s/w is free, step direction through the parallel port.
Al.

[cmengnr]

hi Al_The_Man
i know about Mach Software.
But i want to do it without using Computer.
Using some Microcontroller,Keypad and Electronics Circuitry.

[Al_The_Man]

If this is simple one axis positioning you could either use either a PicMicro product with a keypad and 2-4 line display or one of the surplus stand alone Galil cards off ebay with a Maple systems small operator interface.
I have built a few using both ways.
Al.

[cmengnr]

My machine has to take two motion.One in X and other is Y.
In some job only one motion takes place, but in some job two motion x and y has to take place simultaneously.
Also i have a great command on PIC Micros.

[Al_The_Man]

PicMicro should work with 2 axis as long as you do not require interpolated moves.
Al.

[cmengnr]

Thanks for your kind support
Ur Motioneering s/w helped me.
Any other calculations which helped me in selecting servo motor and helped me in distinguishing selection of servo motor / stepper motor / DC ,motor.

[Al_The_Man]

I would say that a few things that determine which method such as Cost, how much experience you have, servo's usually require a bit knowledge to set up, PID loop etc, steppers are not closed loop.
Overall servo's are considered superior, just whether you want to justify using them over steppers.
If you try some numbers in the Kollmorgen s/w, you can get an idea what happens when you change parameters such as motor size and gearing.
Torque increases directly proportional to the reduction, and the motor to load inertia ratio decreases by the square of the reduction.
The industry standard has traditionally been to keep the motor to load inertia ratio less than 10:1 and depends on accel/deccel rate for a Given system.
BTW, the Galil cards I use typically use analogue control to PWM drives in torque mode of operation.
Al.

[cmengnr]

i want to use stepper motor as i have already worked on them along with pic to convert a manual lathe machine into automatic lathe using some programming concepts.
so should i move forwad along with stepper and pic processor.

[Al_The_Man]

Your decision, if you feel confident in using the Pic, then go for it, if it does not work out and you have to switch to another plan, it will have not cost alot, except time, maybe.!
Probably less engineering too with steppers using a Pic.
Al.