Machine safety is about reducing risk

This is often referred to as “inherently safe” design.

A good example of this would be folding sheet metal edges to get rid of  the sharp cut edges. However, inherently safe design can sometimes be difficult or impossible to achieve with moving machinery. For instance, to cut trees a chainsaw will always need a chain with sharp edged teeth, so it is impossible to eliminate the hazard entirely. 

This is done by using one or more of the following three strategies:

1. Prevent contact between hazard source and people. This can be done by fencing, covers or other physical “guards" 

2. Monitor access of people to the hazard source and end the hazard before people can reach it. This can be done by “interlocking” of doors  such as trapped key systems, or by sensors such as light curtains, laser scanners etc.

3. Let the person control the hazard by “agreeing” to it. This can be done by requiring a “hold-to-run” button, enabling button or two-hand control system. As soon as the person lets go of the control, the hazard is ended.

The signposting of hazards and dangers is important and should also show how they can be avoided.

This can be done by signal lights and horns, signs and labels, or safety messages and warnings in the operating manual. 

Proper training on the correct use of the machinery and it's dangers is also critical.