I have seen a few of these floating around the internet and always wanted to build one. The other day at the space, I figured it was time. We had plenty of CD drives kicking around so I pulled a few apart. The intent of this machine will to be to wield a pen and draw some pictures or something. I'm just doing this for fun with no serious reason.
I started with the frame, which is made from two CD drive cases and some L-brackets that were on hand. I used epoxy to adhere the brackets to the cases. After applying the pieces together, I used a square to make sure everything was at right angles and held it until the epoxy set.
The y axis CD drive innards was mounted to the base. The spacers that keep it off of the base are actually from drum lugs. Yes, drum drums. I used whatever was available and winged the entire build. The plexi glass bed has a single countersunk hole in the middle. The screw holds down the bed by means of a nut that is epoxied to the bottom of that large fender-washer. The fender-washer provides a flat surface for the plexi glass and is itself, epoxied to the moving carriage of the CD drive.
The x axis is the same CD drive guts, just turned sideways and mounted on the back part of the frame. The spacers that keep the axis away from the frame are much longer so that the pen is closer to the center of the bed. It is surprisingly sturdy compared to what it looks like.
The z axis is made from an inkjet printer belt tensioner. The axis can freely move up and down. There are 2 solenoids from a laser printer that hold the pen up. The entire travel is maybe 1/4 inch. When the solenoids are energized, the pen is pulled down by gravity.
To control this beast, the plan is to use an arduino that reads stored g-code files off an SD card, and executes that file. I'll post how I did that when I figure it out. A couple of members that are relatively familiar with programming arduinios said they would give me a helping hand in this department. Thanks guys!