By Kip Hanson

What is machining? And how does it differ from fabricating, welding, and all the other manufacturing processes in use today? Technically, machining is a subtractive metalworking process. It uses cutting tools — extremely hard bits of metal — to remove material from chunks of slightly less hard aluminum, steel, and superalloy.

Filed your fingernails lately? If so, you’ve in essence machined them (which is way better than biting them, something my mother once scolded me about). That’s because filing, as with other machining processes, removes small pieces of metal called chips (see the following image). It’s also the reason veteran machinists refer to their profession as chipmaking — because they’re making chips. Get it?

machining-chips
Courtesy: Autodesk

If you’re not making chips, you’re not machining parts.

What are some other types of machining operations? Drilling is perhaps the most common of all machining operations, although you can’t claim to be a machinist just because you drilled some holes in the living room wall last weekend with a hand-operated power tool. There’s also:

  • Boring
  • Face milling
  • Grooving
  • Knurling
  • Reaming
  • Sawing
  • Slotting
  • Tapping
  • Turning

In fact, machinists perform these and literally dozens of other metalworking processes every day.

Watch out! There’s a new kid in Manufacturing Town, and it’s shaking the trees all along Machining Avenue. It’s called additive manufacturing, better known as three-dimensional printing. Where machining is like a sculptor, removing whatever material isn’t needed in the final product, three-dimensional printing is more like a bricklayer, building parts one layer at a time (as shown here). The process is less wasteful than machining, does not require cutting tools, and produces complex geometries far more easily than its chip-making cousin.

machining-3d
Courtesy: Proto Labs

Three-dimensional printing produces metal and plastic parts directly from a CAD file.