Specifications

Diamond™ GEM, G, & K, Integrator’s Guide

sary in order for the product to accomplish its function. The laser

system must be produced to the lowest possible class. This means if

the beam and its reflections can be completely enclosed (practically

and feasibly) then they must be enclosed (to the Class I, or light-tight

level).

There are two criteria for ascertaining the integrity of the protective

housing: first, no part of the human body may be inserted into the

beam or its reflections; and second, no reflection from a single flat

reflecting surface (hypothetical) may exit any hole or opening in the

housing.

Generally, for manufacturers of work enclosures with material

handling equipment, etc., the most difficult portion of the

protective housing is that which must be opened to allow part

entrance/exit, or for operators to clear jams, etc. Normally, a

designer would simply cut a hole for this purpose, or if

concerned about some aspect of safety, install a door over the

hole. For matters of radiation safety, however, the door mecha-

nism can become complex from at least two respects:

1.) A door designed to be closed during the laser operation, but

open to allow parts or humans to enter or exit, must then be

interlocked, [by some approved means] to disable laser opera-

tion when the door is open; and

2.) once you choose the mechanical door and interlock scheme

you must then conduct statistically significant life or endurance

testing for the reliability of the mechanism; predict its life and

maintenance or replacement cycle; and report such information

to both the CDRH and your customers. For these reasons (and

reliability as well), it is generally preferable to provide protec-

tion with as few moving parts as possible. Since light travels only

in straight lines, it may be feasible to construct machinery which

by configuration and use of light baffles, meets the criteria for

protective housings.

Safety Interlocks may be required on any laser product. They must

prevent human access to radiation that exceeds the limits of Class I

whenever a protective housing is opened during operation or main-

tenance (and the said human access is not necessary to the product

function).

If access to the interior radiation is sometimes needed (to verify

alignment, for example) then the interlock may be defeatable (and

the product labeled accordingly). Safety interlocks need not prevent