In the previous article we learnt about CNC machines and started off to make one of our own home made CNC machines which could carry out some simple tasks such as etching your name of a sheet of plastic or a flat piece of wood. In this article we will proceed to complete that process and here you go.
Since we are talking about a self made CNC machine, we certainly need to collect some preliminary stuff before we could go ahead and assemble one such machine. Some people have the habit of collecting junk stuff in their backyard and though this may not seem to be a very good practice from aesthetic point of view, it could be very handy in such situations. For example if you still have your old dot matrix printer lying in your junkyard which was disposed off you could check it out for some parts which could be useful.
Stepper Motor – old stepper motors can be found inside several dot matrix printers such as the ImageWriter printers from Apple. In simple words a stepper motor moves in steps because of its peculiar construction and arrangement of coils. A stepper motor controller is also required along with the stepper motor and also a drive arrangement is necessary to couple the motor to the rotating shaft which has to rotate with the motor.
Slides – these could either be bought first hand as XY tables or again they could be scavenged from sources such as old printers or any similar machinery.
How to go about it?
Well I must say that because of the nature of the work involved it is not easy to give an exact description of what must be done. This is because each of you could be using different parts, dimensions and so forth. So basically I would demonstrate the basic principles rather than the actual stuff. You certainly are on your own and have to bring out the engineer within you to take this task to completion.
Mainly you need to arrange the motors, the stepper control circuit and the framework in such a manner that a tool holder (remember the tool could be a simple sketch pen or a sharp edged and pointed tool) can be guided across on a two dimensional surface within the defined limits and can be controlled by the arrangement of linear slides, drive shafts, stepper motors, controllers and possibly the PC.
I can give you a rough idea from the sketch shown below which clearly shows the arrangement. You would have to actually work out to configure the same in an actual setup. If you really think you have it in you, then just go ahead and try making one as a part of your holiday hobby or for sake of a challenge.
If this article has aroused your interest and you really want to study and make some more sophisticated CNC machine then I would strongly suggest you the following readings
CNC Robotics: Build Your Own Workshop Bot by Geoff Williams (McGraw-Hill Publications)
Online Magazines such as Engadget
Mastering CNC Lathe Setup by Ian Wallace and Stan Robinson (Axis Publishing)