green as they come

[SILVERBACK]

I am as green as they come. I would like to know if anybody would like to take the time to help me find out hat i need to know to use a cnc to make scale model engines, and guide me to any reading material that will help me?hagardvd@aol.com

[Ron111]

Silverback,
Welcome to the forum. It sounds like you know what you want to do with the cnc equipment, that's half of the battle. Now for the other half.

The three main components needed to a cnc a machine are the Software, the controller electronics (power supply, Stepper motor drivers, and stepper motors), and the mechanicals (Ballscrews, ballnuts, bearing mounts and bearings).

So, if we keep it simple, it's easier to understand. Most of the guys use Mach2 (or mach3 newer version), This can run on a XP computer. Go to http://www.artofcnc.com and download the demo version along with the instruction manuel. Good reading!!!!!

Also go to the tormach site and download their user manuel, it uses the Mach2 software and gives a good overview of a cnc milling machine.
http://www.tormach.com

You most likely will build your own power supply like the rest of us. So I will attach a power supply tutorial from Campbell designs. It is a PDF document.

Alot of the guys use Gecko drives (to drive their stepper motors. Gecko has a good tutorial on their web page, and I will also attach it.

Well, we can start with that. It's all going to be a little greek in the beginning, but the key to understanding cnc is simply understanding that Mach2 is going to use the parellel port which has 25 pins. To move the table in the x position, it is going to use one pin for direction and another of the 25 pins for the steps. This requires 6 pins for the X,Y, and Z axis. The other pins can be used for limit switches, home switches or what ever.

For example, to turn a ball screw and move an axis 1 inch, the motor may have to move 10 revelutions. Typically, it takes 200 pulses to move 1 revolution for a typical stepper motor, so to move 10 revolutions the 2000 steps signal are sent to the stepper motor with a dir signal to indicate which direction. When, you read about stepper drivers, you will see where they support microstepping. a 1/10 microstepping driver would require 20,000 step signals to move our example 1 inch. Microstepping allow for smaller incremental moves.

This is a good start, just ask questions and start reading some of the posts and I will help all that I can, and others will jump in as questions are more specific. There are alot of guys here that are willing to share their knowledge.

Ron

[Ron111]

Now for the attachments !!

[msomerville]

silverback
Are you looking to build a machine or just how to program one?

[Ron111]

For some reason I'm having to attach the documents 1 at a time, so this is the power supply doc.

[wildcat]

If you are interested in programming CNC you may also want to look at the book "CNC Programming Handbook" by Peter Smid. Even if you plan on using CAM software this book would be a good reference to have. Actually, while I use only manual machines I have found more useful information in this book than in my other machining books. The book is about $40 used on Amazon and quite worth it.

[Zumba]

For precision projects like engines, you'll want plenty of manual machine experience. You really don't need to jump into CNC right away. Your main obstacle is work holddown (constant repositioning for each machining operation), and a CNC will do absolutely nothing to help you here. You can't just "carve" an engine out of a solid billet unless you have a 5-axis machine.

The added speed of a CNC will be useless to you, as you'll constantly be changing tools. And you still need a lathe to make your pistons.

How much machining experience do you have? Let us know and we'll go from there.