Designing a lab safety system for a class IV Laser
Duration: Spring 2017-Fall 2017
Additive Manufacturing cold spray group obtained a class IV laser system for the use of etching samples. It is necessary to implement all needed safety measures associated with class IV laser systems to alert and protect personnel from laser radiation exposure.
I was designated the task of designing a safety system that would effectively alert personnel of the status of the laser as well as direct them to proper safety precautions. It would also prevent laser radiation exposure and offer efficient means to make the laser area immediately safe.
Objectives
Design facility setup to best implement safety equipment (lights, signs, buzzers, door interlocks, emergency stop switches).
Use a Programmable Logic Controller (PLC) to program the interaction/communication of the safety equipment with each other and the laser system.
Research and order all necessary safety equipment.
Logic Programming
Think of logic programming simply as: 1 and 0, on and off, enabled and disabled, stop and go, energized and de-energized. It boils down to whether a signal is sent or not in electronics. Logic is the language of electronics. And the interpreter is an "IF, THEN" statement. For example,
Laser ON = 1
Laser OFF = 0
Red light ON = 1
Red light OFF = 0
The PLC receives a signal from the laser system turning on, it reads this as a 1, the path is ENERGIZED. To interpret this, the PLC may be programmed as such:
IF Laser turns on (Laser input = 1 on PLC), THEN red light turns on (red light output = 1 on PLC). Result? A red light turns on alerting personnel that the Laser has been turned on.
*The Laser system and safety components such as warning lights are connected to the PLC via wires and cables.
Green function blocks indicate an activated/energized function. Yellow and white function blocks indicate inactive/dormant function.
This picture depicts the program in a state where the Laser Power is turned ON, resulting in an activated Laser Sign ON and a Yellow Light ON for warning.