Newbie Question Where to Start?

[electromech31]

Ive been in the machinist trade for 19 years, manuals and CNC. I have had classes in electronics, Hydraulic, and pnuematics, classes were for maintenance. no shop experience. I want to build a Bridgeport type CNC mill for my garage. I already have manuals mill, lathe, grinder, and welder, so fabrication is no problem. I do not know what I am looking for? Where do I start? I like the idea of servos with the feedback, but its not necessary. I would like a bridgeport series 1 CNC with bad controller and rebuild. I have looked at Cardinial Engineerings classes, but I have not heard any feedback from this route? Can some of you that have done this give me advice to were to start. Thanks you very much

[electromech31]

wow slow down with the advice from all of you with experience. Thanks for nothing

[machintek]

This is way too open ended. You must understand that this will be quite a project involving countless hours of design, fabrication, scrap, start over, etc. I am not qualified to design an entire machine, there may be patents that you will step on, etc.
Frankly, there are plenty of machines out there that will be a lot more cost effective to purchase and modify to your hearts content.
Good luck.

George

[Ron111]

electromech31,
Sorry, have not seen your post. To get the idea of the basics, I would recommend recommending downloading a free version of Mach3 from http://www.artofcnc.com along with the users manual. This is the controller software and you can simulate a stepper motor conversion (which the computer does not need servo feed back) and the computer will actually think that it is running a machine. There is a tool path display so you can actually watch the performance of the controller.

The main thing is to understand how to configure the controller which uses the IEEE488 printer port to interface with the stepper motors and the almost 200 page mach2 (or mach 3) pdf manual will explain what's required for machine configuration and will explain servo's and stepper motor configuration (it's also interesting reading)!!

The next thing to download (for free) is the gecko "Stepper Motor Basics" pdf, this will explain the different configurations of stepper motors, and how to use gecko drives for stepper motors.

Once you have these and have looked them over, then there are a couple of simple power supply design note pdf from campbell's site that I can find for you.

Sometimes the benchtop forum is a better place to look for info on how to get started at looking into cnc issues, where this forum is usually (but not always) specific questions or problem resulting from equipment or component failures and how to get the machine back up and running.

Hope this gives you some encouragement!!

Welcome aboard,

Ron

[electromech31]

Thats exactly what I was looking for. I know the end result I want, a 3 axis knee mill. I have no worries about the fabrication of parts (been doing that for 17 years). I guess I was looking for advice on if you were to do it again what would you have changed? I am still looking for people that have used that Cardinal Engineering controller and what they think of it? Thank you for your advice.

[Ron111]

I am not sure of what the cardinal engineering controller is. If there is a web site link, I'll be glad to look at it.

A lot of guys here will tend to build their own controller which is comprised of software running on a PC (Mach3 $159), controller interface electronics (comprising of a easy to built linear power supply ($100 to $200 depending power requirement), a break out board (either passive ($15)or optically isolated($100)), and three gecko ($115 ea. stepper, or not much more for servo's).

An advantage of doing your own controller is that you know what is in and you easily repair it when necessary and upgrade it for additional capabilities with out having to deal with proprietary hardware or software.

I also would like to cnc a knee mill, but don't own one at this time.

Let us know what other info would be of help.

Ron

[electromech31]

I have talked to the gentleman who runs cardinal. He offers a week course for a week, at his shop, in southern Ill. It was designed for replacing controllers on series 1 Bridgeports. http://www.cardinaleng.com/
Software runs on pc, using EMC, mach3, etc. He claims it will run servo or stepper.
I have not heard of anybody running it, and what they think of such a set up.

[Ron111]

This is certainly an option, do you have an bridgeport already or are you going to get an import. It sounds like Cardinal may build controller for CNC bridgeports where the controller has died (I'm just guessing), but if you had a certain type of controller with know motors this company might be able to build a replacement controller which used mach 2 or 3 and set the driver for the existing servo or stepper motors. This would be worth while if you wanted to retrofit to existing hardware and motors.

But if you are starting from scratch, it's really no big deal building your own controller, but there are a lot of little details such as limit switches, homing switches, calculating your steps per inches (or mm), the resulution of your encoders assuming that you are using servo's. All of these details are explained in the Mach 2 (free ) down loadable manual. Like I say, it's a lot of little things and the guys around here will help. They are more helpful when you post pictures.

Keep digging,

Ron