A machine breakdown causes devastating loss of production.
Nearly 50% of all machine breakdowns are caused by misalignment.

Shaft alignment can be performed with different tools. The easiest way is to use a ruler or a straight edge over the two coupling halves and align by eyesight.

The result is not very accurate and it is very operator dependent.
A better result can be achieved by the use of mechanical dial indicators.

A skilled and experienced operator can obtain good and reliable measurements, but it takes time and patience.

A far easier and highly accurate way is to use laser based alignment systems.
They do not require special skills and deliver accurate and reliable results.