So it's finally happened - after more than a year of stuffing around contemplating CNC machines I finally have one!
For those who haven't been following the CNC Machining for Miniatures thread
I recently bit the bullet and ordered a "Walter 2520"
machine from CNCDIY. They're a cheap Hong Kong/China based manufacturer and all up I paid about AU$800 to land it here (around $300 of which was shipping). Shipping was via UPS and only took about a week. I was pleasantly surprised to find that it had arrived not only without any noticeable damage but also without requiring any assembly!
Here's pics from the moments following unpacking:
The control electronics for the system are designed for use with an old x86 PC with a parallel port, however I'm planning to use my laptop to run it (admittedly against the recommendation of some, but it's a challenge I'm willing to accept). In order to do so I will be building a Planet CNC USB CNC controller
. In order to protect my laptop I will be ensuring that all signals between the USB controller and the machine are optically isolated. Because of this I had to wait until the machine arrived so I could see exactly what kind of isolation (if any) the control electronics offered. So I popped op the control box and had a look:
The board on the right is the spindle variable speed power supply. The red board on the left is the parallel interface and stepper drivers (heatsink mounted underneath). Underneath the whole lot is a large switchmode power supply. Good news is that the interface card looks like it has optical isolation on every signal - when I get a chance I'll test it out with a multimeter to confirm! I will be designing a PCB for the USB controller myself, so with the driver board already having optical isolation I'll only need to include isolation for the limit switches. The machine as purchased doesn't come with limit switches, but adding a few microswitches will be a piece of cake. Plus they'll wire up so nicely with the movable cable ducting on the X and Y axes.
In terms of software my plans for starting out with routing/engraving are:
for drawing the design -> saved natively as .SVG
-> SVG import into PyCAM
to generate G-code
-> Planet CNC USB CNC control software to control the machine from the G-code file
The only cost in the above toolchain is the USB CNC controller, at $100. Inkscape is a fantastic piece of open source (free) software I use for both hobby and professional work projects. PyCAM is also open source and my evaluation of it so far has proven it to be quite good. Only actually running the output on the machine will tell!
So as noted above, my next step is to build my USB interface card. In the long term I'd like to mount all of the control electronics under the base of the machine, but for now I just want to get moving so I'll simply retrofit the existing control box.
Watch this space!
Oh yeah I can make that....