Write a toolbox talk on Router and laser room

Source excerpt

# CNC router and cutting tables Computer numerical controlled (CNC) routers remove material from a work piece by rotating a cutting tool (cutter) and moving it into the work piece, but operate at higher speeds than milling machines. CNC routers are usually used to cut or shape more ornate designs into thinner and softer materials such as wood, plastic, and soft metals like aluminum. CNC cutting tables use plasma, lasers, or high-powered waterjets instead of a rotating tool, to cut and engrave metal, and other hard or soft materials. CNC routers and cutting tables, either vertical or horizontal, are commonly found in wood shops and metal fabrication shops, and vary in size to accommodate smaller work pieces, or large sheet stock. The general construction of these highly automated machines consists of a stationary table or bed featuring a turret (Z axis) with a spindle or cutting tip that moves back and forth on the rails (X axis) of a moving gantry (Y axis) above the work piece. Depending on size and application, CNC routers and cutting tables can be completely open, or partially or totally enclosed by interlocked metal enclosures equipped with thermoplastic vision panels. Operators initiate start/stop sequences from a control console that is usually a safe distance away from the point of operation. ## Hazard Serious lacerations, fractures, burns, and amputations can occur if an operator contacts the rotating cutting tool, or cutting tip/nozzle during operation. Fractures, lacerations, and even death can occur to the operator and others in the area from being struck by ejected material, parts, and tooling. Metal shavings and lubricating/cooling fluids might also present a risk from the point of operation area. Plasma and laser cutting produces toxic fumes and particulates, and also produces intense light and/or radiation that can cause eye damage and skin burns. Sparks and hot slag from these hot processes can ignite nearby combustibles. A potential for sho…

Source excerpt

# CNC router and cutting tables (cont.) ## Solution (cont.) Ensure adequate ventilation is provided to exhaust hazardous fumes and particulates. Keep dust collectors clean. Do not allow the accumulation of flammable or combustible materials and debris such as metal dust, baled paper, bulk sulfur, and oily rags. Keep a fire extinguisher readily available in the immediate area. Use proper personal protective equipment such as hearing protection, safety glasses and face shields, shock resistant gloves, and welding curtains to protect operators and others from hazards caused by hot processes. CNC router table equipped with a dust collection system around the cutting tool Establish a laser safety program and appoint a laser safety officer in accordance with ANSI Z 136.1 when workers use or are exposed to Class IIIB or Class IV lasers. ## References ## General Industry • Oregon OSHA Division 2/Subdivision O, 1910.212, General Requirements for All Machines • Oregon OSHA Division 2/Subdivision Q, Welding, Cutting, and Brazing • Oregon OSHA Division 2/Subdivision I, 437-002- 0134 Personal Protective Equipment • ANSI B 11.23, Safety Requirements for Machining Centers and Automatic Numerically Controlled Milling, Drilling and Boring Machines - ANSI B11.25, Safety Requirements for Large Machines • ANSI Z 136.1, Safe Use of Lasers • ANSI O 1.1, Safety Requirements for CNC Machining Centers for the Woodworking Industry 222 22 22

Source excerpt

# VI. Control Measures and Safety Programs (cont.) ## 3. LIMITATIONS ON SPECTATORS (cont.) the appropriate MPE levels.) This generally applies only to Class IIIB and Class IV lasers. All laser eye wear shall be clearly labeled with OD values and wavelengths for which protection is afforded. Skin protection can best be achieved through engineering controls. If the potential exists for damaging skin exposure, particularly for ultraviolet lasers (0.200-0.400 m), then skin covers and or sun-screen creams are recommended. For the hands, gloves will provide some protection against laser radiation. Tightly woven fabrics and opaque gloves provide the best protection. A laboratory jacket or coat can provide protection for the arms. For Class IV lasers, flame-resistant materials may be best. In general, other controls should serve as primary protection rather than depending on employees to use protective eye wear. Many accidents have occurred when eye wear was available but not worn. This may be because laser protective eye wear is often dark, uncomfortable to wear, and limits vision. ## Laser Barriers and Protective Curtains Area control can be effected in some cases using special barriers specifically designed to withstand either direct or diffusely scattered beams. The barrier will be described with a barrier threshold limit (BTL): the beam will penetrate the barrier only after some specified exposure time, typically 60 seconds. The barrier is located at a distance from the laser source so that the BTL is not exceeded in the worst-case exposure scenario. Currently available laser barriers exhibit BTLs ranging from 10 to 350 W/cm² for different laser wavelengths and power levels. An analysis conducted in a manner similar to the NHZ evaluations described previously can establish the recommended barrier type and installation distances for a given laser. It is essential that the barrier also not support combustion or be itself consumed by flames during or following a l…

Source excerpt

# VI. Control Measures and Safety Programs (cont.) ## 2. LIMITED OPEN BEAM PATH (cont.) Protective equipment (eye protection, temporary barriers, clothing and/or gloves, respirators, etc.) would be recommended, for example, only if the hazard analysis indicated a need or if the SOP required periods of beam access such as during setup or infrequent maintenance activities. Temporary protective measures for service can be handled in a manner similar to service of any embedded Class IV laser. ## 3. TOTALLY UNENCLOSED BEAM PATH There are several specific application areas where high power (Class IIIB and Class IV) lasers are used in an unenclosed beam condition. This would include, for example, open industrial processing systems (often incorporating robotic delivery), laser research laboratory installations, surgical installations, etc. Such laser uses will require that the LSO conduct a hazard analysis and NHZ assessment. Controls are chosen to reflect the magnitude of hazards associated with the accessible beam. ## E. Laser-Controlled Area When the entire beam path from a Class IIIB or Class IV laser is not sufficiently enclosed and/or baffled to ensure that radiation exposures will not exceed the MPE, a "laser-controlled area" is required. During periods of service, a controlled area may be established on a temporary basis. The controlled area will encompass the NHZ. Those controls required for both Class IIIB and Class IV installations are as follows: ## 1. POSTING WITH APPROPRIATE LASER WARNING SIGNS Class IIIA (beam irradiance 2.5 mW/cm²), Class IIIB and Class IV lasers: Require the ANSI DANGER sign format: white back-ground, red laser symbol with black outline and black lettering (see Appendix III:6-4). Note that under ANSI Z 136.1 criteria, area posting is required only for Class IIIB and Class IV lasers. Class II or Class IIIA areas (if area warning is deemed unnecessary by the LSO): All signs (and labels) associated with these lasers (when beam irradi…

Source excerpt

# VI. Control Measures and Safety Programs (cont.) ## 1. NONDEFEATABLE ENTRYWAY CONTROLS A nondefeatable control, such as a magnetic switch built into the entryway door which cuts the beam off when the door is opened, is one option. In this case, training is required only for those persons who regularly work in the laser area. ## 2. DEFEATABLE ENTRYWAY CONTROLS Defeatable controls may be used at an entryway, for example, during long-term testing in a laser area. In this case the controls may be temporarily made inactive if it is clearly evident that there is no hazard at the point of entry. Training is required for all personnel who may frequently require entry into the area. Such defeatable controls shall be designed to allow both rapid egress by the laser personnel at all times and admittance to the laser controlled area in an emergency condition. A readily accessible "panic button" or control/disconnect switch shall be available for deactivating the laser under such emergency conditions. Under conditions where the entire beam path is not completely enclosed, access to the laser- controlled area shall be limited only to persons wearing proper laser protective eye wear when the laser is capable of emitting a beam. In this case, all other optical paths (for example, windows) from the facility shall be covered or restricted in such a way as to reduce the transmitted intensity of the laser radiation to levels at or below the MPE for direct irradiation of the eye. ## 3. PROCEDURAL ENTRYWAY CONTROLS A blocking barrier, screen, or curtain that can block or filter the laser beam at the entryway may be used inside the controlled area to prevent the laser light from exiting the area at levels above the applicable MPE level. In this case, a warning light or sound is required outside the entryway that operates when the laser is energized and operating. All personnel who work in the facility shall be appropriately trained. ## 4. ENTRYWAY WARNING SYSTEMS In order to s…