Re: [CAD_CAM_EDM_DRO] Completely new to all this...

Warren,

Nema 34's would be a good choice for that size mill. There are many different configurations for CNC systems. Basically, there are 6 different components.

A computer with 1ghz speed or faster (dell sells a 2.2 ghz for $349).

Controller software, there are many to choose from( I personally recommend Mach2). Downloading demos from various sources for CNC software is a good way to make a selection.

A breakout board that is an interface betwen the PC and the motion control system(If you use artofcnc Mach2, Bob campbells Mach2 breakout board is perfect), There are ways to get around using a Breakout board but it involves soldering and making up DB25 plugs and cables however, The breakout board adds many features to the control like accessory control for spindle start, coolant, etc and travel limits and home limits for the work envelope. Many safety features like "watchdog" that monitors certain pins for inappropriate signals from the PC to prevent unexpected movement, opto-isolation (I think) to prevent high current from the drives going back to the computer port. It does alot and is well worth the investment.

Servo or stepper drives, one for each axis and Geckodrives are an excellent choice. There are others available and thats just the ones that I use.

Power supply and your choice of motors will dictate what its output will need to be

And lastly, Stepper or Servo motors. The debate is long on which is better but here is my spin on it from what I've gathered from these boards and my own personal experience. Steppers are rated in holding torque and their torque dramatically decreases during movement. Stepper drives are more expensive than servo drives. The upside to steppers is that they are generally cheaper to buy and they do not need an encoder to feed back to the stepper drive.

Servos on the other hand will generally be rated at lower torque for the same size as a stepper but, the torque is more even holding and during motion (google "Servo versus Stepper" for a graph displaying performance comparison). A belt reduction is suggested used to get more RPM from the motor and higher torque to the ballscrew. Servos must have an encoder to feed the motors position back to the drive. Servos are generally more expensive and most of the hobby drives will only work with DC brushtype servos. Servos run cooler and the drives are generally less expensive. From reading these boards for a long period of time servos seem to be more reliable and less prone to problems. Whatever motors you intend to use post the info from their dataplates on the list here and you should receive an evaluation There are some really sharp people on here (myself excluded :-) and they can help you out with it. Get a mill and PC then find some appropriate motors and thats the best place to start
selecting the other various components.

This is just a brief overview, largely my own opinion and does not cover all aspects obviously.

Hope this helps,
Ron
wvickery2003 <wvickery2003@...> wrote:



Hello everyone,

I am completely new to all this CNC stuff.

I would like to find out a bit about converting a chinese mill/drill
to CNC operation. I don't don't have anything at the moment.

I am aware that I would need a PC, stepper controller board, power
supply(???) and stepper motors. Would Nema size 34 stepper motors
work (well) with a mill/drill machine? Would a Xylotex 4-axis
controller be able to control size 34 motors (is the amperage etc
correct)? What kind of power supply do you need?

Are there any other reasonable (cheap...) controller boards around
that would work and what could I do if I wanted to control the
spindle and coolant from the computer?

Sorry that I am asking so many questions which probably
seem 'stupid', but I've got to start somewhere...

Thanks in advance
Warren








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