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Milling Machine

Version 1.0

A few, minor improvements caused me to call this my first, stable working CNC-mill. I added a horizontal stability beam on the back, thus significantly reducing the backlash in the X-Axis due to torsion. Furthermore, I did tidy up the electronics, mounted the PCBs onto the machine and changed the quiet bulky 12V, 13A PC-power supply to a small 15V, 2.4A power supply. Furthermore, the printed H-Bridges work stable and reliable, as desired. The input and output are now separated by an optocoupler. Thus avoiding damage to the PC if the output gets damaged in case the output stage brakes.

The core components I used are:

• 3x Stepper Motor
• 3x H-Bridge PCBA
• 1x Parallel Port PCBA
• 1x Microcontroller (parts of the OLIMEX: PIC-WEB rev. B Users Manual)
• 1x Firmware
• 1x 15V, 2.4A power supply (Each stepper motor can consume up to 0.8A.)
• 1x PC with Parallel Port connection
• 1x EMC2 configuration (The former LinuxCNC)
• 1x Dremel with flexible Axis
• 1x 3.3V Insulated Power Supply
• 1x Emergency Stop Button
  I seriously recommend an emergency button for everybody. It saved me a lot of trouble.

For the future I would want to include a few more changes to the system:

1. Moving from normal 15mm normal multiplex to 9mm hard multiplex.
2. Packing up all electronic in a standard 3.5" drive bay. At the moment it is mounted on a board with 3.5" footprint.
3. Finding a new solution for the flexible axis. For some reason the drill chuck is extremely hard to loosen.
4. Increasing the length of X and Y-Axis to get a bigger movement area.
5. Include end of stroke switches.

Version 0.3

With the first successful milled parts from version 0.2 and four angle brackets from the local hardware store, the setup is mechanically stable. Of course it is not yet perfect, but with this setup I met my first milestone and can start working on version 1.0. Mostly improving mechanical stability, resolving the last problem with the H-Bridges and tidy up the electronics.

Version 0.2

Finally, I managed to got it up and running. It is running stable, but has a few problems:

1. The Y-Axis is not stable, I designed it for a different width of the Axis. -> Automatically fixed in the next version.
2. The X-Axis has a movement of approximately 1.5mm, a flaw in my design. The mounting for the ball bearing has to be improved. -> I'll have to try a different design for the next version
3. The arrangement between the X and Y-Axis has to improve, I'll probably use angle brackets.

Version 0.1

My first attempt to build a CNC-mill. I don't clearly recall how long ago I thought about building one, but it was some when between 2001 - 2003 (now it is 2013). Furthermore, I was never interested in putting together bought building blocks, I wanted to actually build it myself. After all I am an electronic engineer, and this is a bit a playground for me to experiment.