Mechanical arm vs. White light 3D scanners

The mechanical arm, using a point touch probe like a CMM, is a well–established way of performing 3D measurement. Compared with a white light scanner, it may well be quicker to take a few 3D measurements with an arm. Accuracy is generally good enough for most workshop purposes, but the arm is a very manual piece of equipment – and of course, the arm must be long enough to measure the object. If it is not, it must be leap–frogged around the object.

While the arm is good at measuring a few critical dimensions, when it comes to measuring freeform surfaces, the mechanical arm is outclassed by white light scanners. In the time an arm can take one or two measurements, the white light scanner will have taken millions, digitising, inspecting, measuring or scanning vast areas of the component. At this level, the white light scanner comes into its own, providing measurement in a way quite unlike anything any mechanical system can achieve.

Not only that, the white light scanner can be automated – either as an inspection station with a turntable, or as part of a production line – something which is very difficult with an arm.

In summary, a mechanical arm is ideal for a few critical dimensions, but when it comes to today's freeform shapes and complex curves, white light scanners such as Phase Vision's Quartz family really shine through.