Process Encyclopaedia
Turning
Overview
Turning is unusual amongst the machining processes in that it is usually the workpiece that moves, whilst the cutting tool remains stationary.
Lathes in metalwork shops usually have single point cutting tools. Lathes in woodwork shops often have tools with simple shapes to make turning of complicated shapes more simple. Lathes in industrial woodworking have large, intricate cutting tools, capable of shaping a complicated piece with only a few inserts of the tool.
Materials and shapes
- Woods and metals are the most commonly turned materials, although difficulties arise with the high-strength metals.
- It is possible, but unusual, to turn polymers. Rigid polymer foams are sometimes turned when producing models for prototypes.
- Turning is usually used to produce parts with radial symmetry (i.e. based on a cylinder).
- It is possible to produce other shapes, e.g. a helix or screw thread, by turning the part slowly and moving the cutting head at a constant rate.
- Wood is the most commonly turned material, as it is easy to produce a wide variety of aesthetic shapes.
Economics
- The use of dedicated lathes for metal turning is rare on an industrial scale, except for prototyping.
- Where metal turning is required industrially, it is usually done as part of the function of a machining centre.
- Wood turning for mass production uses dedicated tooling to dramatically increase production rates and hence reduce costs.
Typical products
- Chair legs
- bowls
- candlesticks
- large threaded shafts