Friday, October 30, 2015

Learning about Lasers: Laser Categories

Ever since pre-ordering the Glowforge, I’ve been obsessed about learning more about laser cutting and etching equipment.  It’s the largest expense made to date so I wanted to ensure I know how to take care of it.  Since Glowforge is so new, they haven’t finalized their design yet.  No online manuals yet for us.  The internet contains a wealth of information.  The Glowforge machine is really a scaled down version of the industrial machine.

Since I’m reading up on it anyway, why not share some of the knowledge with beginners just like me.  If you have any feedback and / or comments, please let me know!

Glowforge offers a Class I laser and a Class 4 laser

  • Class I (Basic model) means you don’t have to take additional safety precautions to be safe
  • Class 4 (Pro Model) means you have to take precautions like posting warning signs and wear proper safety glasses

I’m looking forward to reading Glowforge’s safety precautions about it when it become available.  However, it’s good to know about all the classes so you know where your machine fits in the industry.  So I copied and pasted this excerpt that I found very helpful from the Ackland’s Grainger Website

Disclaimer: I’m not an expert and you must always refer to the guidelines from the manufacture or your machine or their website for your safety and safety of those around you.

Laser Categories (Excerpted from Acklands Grainger):

Vision damage can occur from directly viewing the laser source or if the laser beam hits the eye. Damage is usually severe, and may result in blindness, which is why direct viewing of the laser source and its reflections should be avoided. A laser's reflective beam intensity may equal its direct beam intensity; therefore, no reflective objects or surfaces should be in the area with the laser.

Light is radiant energy and is defined as electromagnetic radiation. It is measured in wavelengths and described in nanometers (nm). A laser produces an intense beam of light of a single wavelength (or color) and frequency. Laser intensity varies from low power (Class 1, 2, and 3A lasers), to medium (Class 3B) to high power (Class 4). The American National Standards Institute (ANSI) classifies lasers into categories and gives guidelines on laser safety in the standard Z136.1. Following are laser categories as outlined by ANSI.

Class 1: Cannot emit laser radiation at known hazard levels. Users of Class 1 lasers are generally exempt from radiation hazard controls during operation and maintenance, but not necessarily during service. Most Class 1 industrial lasers consist of a higher class laser enclosed in a properly interlocked and labeled protective enclosure.

Class 2: Low-power visible lasers. Emit laser radiation above Class 1 levels and radiant power not above 1mW. The human aversion reaction to bright light will protect the person from this low level. Example: a supermarket laser scanner.

Class 3A: Intermediate-power lasers. Only hazardous for intrabeam viewing. Some limited controls are usually recommended. Example: a helium-neon laser used in the construction industry.

Class 3B: Moderate-power lasers. Not generally a fire hazard and not capable of producing a hazardous diffuse reflection, except in instances of intentional staring at distances close to the diffuser. Specific controls are recommended.

Class 4: High–power lasers. Hazardous to view under any condition (directly or diffusely scattered). Potential fire hazard and a skin hazard. Significant controls are required for Class 4 laser facilities. Example: an Excimer laser operating in the ultraviolet.

A laser's danger varies depending on which area of the light spectrum it is generating. The ultraviolet radiation laser (180-400nm) causes corneal burns. Lasers in the near-infrared region (780-1800nm) cause retinal damage. These are usually Class 2, 3A, 3B and 4 lasers. The high-powered lasers, Class 3B and 4, can also cause electrical shock and skin burns. A skin cover, like opaque gloves and tightly woven fabrics, and or a "sun screen" may be recommended.

A laser consists of a resonant optical cavity filled with an active medium. The medium is acted upon by some source of excitation energy. The media could be one of three types: a solid state, a gaseous state, or a semiconductor or injection-type. Solid lasers use a crystal, e.g., ruby, glass or a semiconductor (argon) as the light amplifying substance, producing a pulsating laser beam. A gaseous state laser (helium-neon) produces a continuous beam.

For information on the laser’s wattage or power of the laser, refer to the instruction/maintenance manual.

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