Posts Tagged ‘CNC’

CNC me pt. 4 – what again?

Wednesday, August 15th, 2012

With quite some shame I admit that the reason you did not hear about this project for 8 months (!) is mainly because I was to lazy to drag myself to the next screw specialist. To put the parts together I had drilled in december I needed a special kind of screw with a flat head. They did not have those at my favorite hardware store and 6 weeks of holiday in Thailand distracted me, so it only came to my attention last week that a specialist is actually just around the corner…
Anyway: here’s a first glimpse of the result. I can already see that it is full of design flaws. However, I will continue with it, knowing that I’ll learn a lot in the process. Main problem now will be to design a z-axis that fits around the thing. The table itself is about 60cm long, which means, I’ll need a base of at least 80×80 to fit the support for the last axis. Let’s see what I can do…

The actual table is not installed yet. It can move about 35 cm in each axis.

CNC me pt. 3 – creating realities

Saturday, December 3rd, 2011

Having at least a plan for the cross table I started working on the parts. I struggled for a while trying to find a place with the means of doing precise cuts and drills into aluminum. In the end I did the cutting in a former workplace of mine and had to do the drilling at [c-base] of which I am a member for about a year now. There I had to cope with a cheap drilling stand. I built me an improvised guide to at least have some precision in one axis.┬áSome holes I had to turn into long holes to be able to adjust to tolerances. Those don’t look so good but I hope it will do.

I found some basic flaws in my design already. I made the mistake of not taking sideway pressure from the drill itself into account. The telescope slides have a sideway tolerance of about 1mm. I will continue anyway, maybe I find a way to correct this by adding guides or the machine will at least give me the means of drilling exact holes and help me build the next one ;)

the drilling guide

a long hole. a crater, rather

21st of december: all parts drilled

CNC me pt. 2 – Electronics I

Saturday, November 19th, 2011

Searching for a control solution for my CNC mill I found a whole bunch of possibilities. My requirements were these:

  • cheap (why, of course!)
  • USB solution
  • ready PCBs
  • open source if possible

Most CNC configurations still rely on a computers LPT port. This is due to the fact that a program can access this port in realtime as opposed to the USB port, which is buffered. There are several solutions on the web using microcontrollers to execute the code given through the USB port. I went for the one done by [planet cnc] in combination with classic l297/298 motor drivers by [PMinMO]. Both provide ready to use parts, kits and schematics to do your own board designs. I went for the kit solution instead of designing my own boards because I wanted to spend more time on mechanical design. PMinMO provides a truly great documentation with his boards, by the way! I got a PCB and a preconfigured chip from planet cnc. He provides a software with drivers for windows (costs though) that should also work under Parallels and such.

I soldered one driver and the controller board together but haven’t gotten around to do any tests yet…

soldering the smd parts to the driver board

the controller (w/o chip) and one driver, waiting to be tested

CNC me pt.1

Friday, November 18th, 2011

I started making plans for a CNC mill some weeks ago and totally got sucked into it. Here are some pictures of the plans i made with sketchup. More soon…

the bottom axis

the second axis