About a year ago, i decided to build a cnc router. First drafts were made in 3dsmax and the final drawings in CATIA.
As I wanted to fabricate as many parts as possible by myself, i had to find a shop with adequate machinery which i could use. Fortunately there is a public shop with all the tools i needed in Munich. They offer use of their machines for 5€/h, but students only pay half of that.
One of their employees recommended a firm where i could buy the raw aluminiumparts quite cheap.
All parts i could not manufacture myself where bought from eBay. There are many shops which concentrate on cnc-parts, so i quickly found what i needed.
At first i had planned to buy steppermotors and make the control- and driverboards myself. I already had ordered the H-bridges and layed out the boards, when i met a guy at the shop who had build a very big cnc-router in his basement and offered my to give me motors and controlboards for free.
Motors and boards (a nice 19″ rack with slide-in cards) are from dismantled photomachines. The motors are, in contrast to the steppermotors you find in printers/scanners, 5-phase steppermotors.
Two of them are 1.4Nm and one is 0.9Nm. The weaker one will drive the z-axis, which has a 1:2 transmission. The other two drive y- and x-axis. All axes have 14×4 trapezoidal screws and nylatron nuts.
The z-axis is guided by four linear ballbearings on two 12mm steelshafts. 12mm might proof to be a bit sparse, but i think i can fit in 16mm shafts without major redesigns.
The y-axis is also guided by four linear ballbearings, but on two 20mm steelshafts.
The x-axis sits on four linear-rail wagons which run on two rails.
The frame is made from aluminium profiles and everything is held together by steel screws.
Due to exams in September/October 2007 and February/August 2008 (and my laziness) the progress was very slow.
At the moment the mechanics are almost ready (only the couplings between the motors and the spindles are missing). Some of the limitswitches (light barriers) are mounted and the steelframe for the powersupplys and controlboards is nearly complete.
The next step is to etch the interfaceboards, which distribute the signals from the parallelport to the motordrivers, and connect all the cables.
I will try to post regular updates on the progress from now on.