Desktop Fab, Basic Machining and CNC

Desktop fabrication, as discussed in Gersenfeld’s book (Fab: The Coming Revolution on your desktop), and the related Fab Labs pretty much stick to the new small devices – laser cutters, small CNC routers, etc. However manufacturing has long used computers for fabrication on larger machines. CNC (Computer Numeric Control) has been around for a few decades, with Numeric Control predating it by a few more. The underlying machines (lathes, mills, etc) have been around for quite a bit longer.

As I got started on my path to Maui Makers in ernest last summer, I found a local adult school here in So Cal had classes in welding, basic machinist and CNC operation/programming. The welding class is highly regarded and has a 6mo waiting list. I put my name on the list and then turned to the CNC classes. The school (Simi Valley Adult School) requires new students to start with the Basic Machinist class unless they have significant experience and can test out of the class. Since I had minimal experience, I signed up and started the class. It was a great experience learning to use a metal lathe, surface grinder, vertical milling machine, etc. The class has print reading and math components as well as hands on creation of 8 projects. The projects lead you through the basics of using the machines -turning, boring, drilling, milling, tapping, threading, tapers, etc. The print reading was pretty simple for me – thanks to that drafting class way back in high school, before the age of CAD.

The math was very basic review… Odd tidbit here. The instructor (Oygar, great guy) told me american students have a much easier time with the math than europeans and others who grow up with the metric system. Much of the math involves fractions – basic add/subtract/multiply/divide, as well as conversion to/from decimals. This is very important when using SAE/English measurements (inches, feet), since those regularly use 1/4, 1/32, 1/64 etc. People in metric based countries apparently dont do a lot of work with fractions in regular schooling. Anyway, i had no problems with the math portion.

The Basic Machinist section took me a bit over 6 calendar months to complete, mostly because I took off from mid-Nov till end of January. It was very instructive and FUN to learn the bridgeport mill and metal lathes. I got clothes reeking of machine oil now, and a few more scars on my hands. It was a lot of good fun – and I developed a whole new level of respect and understanding of the basic manufacturing biz. Now I’m on to the CNC class – which is pretty trivial basic cartesian coords plus manually creating G-code to run the big Haas CNC machines the facility has. Manually writing cnc code is a pain and nearly archaic approach since there are lots of good CAD/CAM tools that eliminate the need to work in the machine code. However, just like knowing computer assembler (machine code) is (IMHO) essential for software engineers to understand the computer, it is important for CAM designers to understand.  I’ve also been learning g-code as my Makerbot runs on it. The Haas has a much more elaborate set of commands it understands, but essentially its all g-code. pretty cool.

I’ve also started the welding class at SVAS. I think these basic manufacturing skills are essential and am considering including a mill and lathe in the equipment I put in my workshop.  There are some nice small CNC bots as noted on the CrashSpace wiki.  Having one of these would be a great compliment to a laser cutter. A big Haas CNC would be nice, but they are quite a bit more expensive!

5 replies
  1. Troy Morrison
    Troy Morrison says:

    I am looking to complete a few projects with the help of someone that has a cnc machine that can cut wood 3/4″ in thickness. Do you have a shop rate?


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