Monday, March 28, 2011

CNC Machine: Microcarve A4

I've been looking at setting up my own CNC machine for about ten years now. I've worked with CNC and CMM machines off and on since the early 80s. I remember hooking up a CP/M computer to a CMM machine, wowing the lab with its ability to automatically record measurements then produce a compliance report on each part as it was inspected. The next day we went back to doing it manually. Everyone was impressed, but they weren't prepared to add computer infrastructure to the lab at that point.

In my case, I wasn't looking to add supporting a CNC machine to my workload before now. Whenever I read the online forums for adding computer control to milling machines, or building up simple hobbyist CNCs, it looked like working on the CNC itself became the prime object of the effort, rather than using the low-cost CNC for production.

There are a lot of bits and pieces to a CNC. There's also a lot of work represented by the physical machine's construction. I'm aware of this from the professional CNCs I've seen at work. They're high precision equipment, with a team of skilled people supporting their operation. Like a machinist, a machinist's assistant, an electronics tech, a programmer at least part time, and a metrology tech or two checking up on it periodically.

As a hobbyist, I have to do bits of all their jobs, plus the jobs of the design engineers, manufacturing engineers, materials engineers, and their technicians to produce things with a home CNC. Needless to say, I won't be trying to do quite the same thing.

I've started by purchasing an existing CNC machine bed rather than trying to design and build my own. I'm also purchasing a commercial motor controller system. My engineer ego is not in the least bit challenged. My engineer superego knows well the tremendous value of the design work that's gone into the pieces. Cookbook integration is good enough for me here. It's the stuff I make with it that I'll set my ego loose on.

The machine I've purchased is a Microcarve A4. The designer did the commercial Fireball V90 previously. The Microcarve A4 is a smaller unit built for high precision. Which suits me perfectly--a specialized machine is just what I'm looking for.

The controller I've purchased is the Gecko 540. It looks like a well integrated unit with a lot of design fine-tuning in it.

Both should arrive soon, the controller (driver in CNC terms) may come tomorrow if the USPS package tracker is telling me what I think it is. I've got a computer running EMC2 that I've been learning how to use to some degree, that I'll hook up the Gecko and motors to once they're here to shake out that element.

I've got some decent software for 2.5 dimensional conversion of images and such (including the image to gcode software included with EMC2), I'm still trying out CAD packages for real 3D work and CAM programs for converting those designs to tool control instructions on the CNC machine. I want to get that all shaken out to make for as little obstruction between idea and finished part as possible.

It'll be an exciting next couple of weeks. I'm looking forward to getting things assembled, functional, calibrated, and churning out parts. With breaks for infrastructure work (like dust/chip collection and an enclosure) between production runs..

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