Beyond the educated guess: General Industry Coverage

When I began machining, CNCs were just coming into mainstream use. The first shops I worked in had only conventional (manual) machines. It wasn’t until the mid-1980s that I started to notice the incredible versatility of CNC machines. The complex contours and shapes the machines could generate made many jobs much easier. The use of templates to file and sweep in surfaces was rapidly becoming a thing of the past.

Initially, I was intimidated by the technology. The mysterious code that ran the machines seemed to be the domain of computer experts; it was seemingly beyond my comprehension. It wasn’t until I took a class in programming that the mysteries started to dissolve.

Parts are often easier to model than they are to machine. All images courtesy J. Harvey.

As versatile as CNC machines are, they are only as good as the people programming and operating them. The cliché “garbage in, garbage out” is well-suited to CNC programming and machining. There is simply no substitute for proper planning and machining know-how. In addition, a programmer without much machining experience would likely struggle to consistently produce good parts.

One of the great virtues of CNC machines is that, while they are running, machinists can work on other tasks. In essence, CNC machines take the labor out of machining.

Another virtue of CNC machines is that the cut-and-measure processes so prevalent in conventional machining are virtually eliminated. If programmed and set up correctly, the cutting tool will go precisely where it should so that dimensional accuracy comes quickly. Usually, only minor adjustments are needed to compensate for slight variations in tool size.

For anybody who wants to learn the machining trade, gaining experience on manual machines has advantages, but it’s not entirely necessary. For example, I taught an inexperienced industrial engineer how to use our CAD/CAM software and CNC machines. Once he became familiar with the software and the different speeds and feeds suitable for various cutters and workpiece materials, he became an asset to our shop.

It’s important to initiate a new project with proper planning. It is one thing to create a beautiful model or drawing on a computer. It is quite another to figure out how to hold the part for machining.