Some standard content:
GB18151.-2000
This standard is equivalent to the International Electrotechnical Commission JEC60825-4:1997 Laser Product Safety Part 4, Laser Protection Screen. It is consistent with 1FC 60825-4 in terms of technical content, and the writing format is slightly changed. Through the formulation of this standard, it can standardize and develop the quality and variety of laser protection urine and other special laser protection screens used in laser processing machines in China, ensure and improve the safety performance of various laser protection screens and their working areas, and provide favorable conditions for my country's laser products to enter the international market and carry out international competition. Appendix A, Appendix B and Appendix C of this standard are all suggested appendices. This standard is proposed and assigned by the National Economic and Trade Commission Safety Production Bureau. The originator of this standard is the China Institute of Metrology. The main drafters of this standard are Ma Zhong and Xu Dagang. C35
G#18151-2000
IEC Background
1) IEC (International Electrotechnical Commission) is a progressive standardization organization composed of national electrotechnical committees (IEC National Committees) from all over the world. The purpose of IEC is to promote international cooperation on various standardization issues in the electrical and electronic fields. For this purpose, among other activities, IEC publishes International Standards. The formulation of each standard is entrusted to technical committees: any JEC national committee interested in the subject under discussion can participate in the formulation of the standard, and all international governmental and non-governmental organizations with ties to IEC also participate in the formulation. There is an agreement between IEC and the International Organization for Standardization (ISO) for close cooperation. 2) Each technical committee has representatives from all national committees, so that the formal decisions of IEC on technical issues are based on the widest possible international consensus on the subject. 3) The documents thus produced are published in the form of standards, technical reports or guidelines and are used in the public domain in a recommended manner and they are adopted by the national committees in this sense. 4) In order to promote international unification, IEC national members will clearly take the lead in applying IEC international standards to their national and regional standards to the greatest extent possible. Any differences between IEC standards and corresponding national or regional standards should be clearly stated in the latter category.
5) IEC does not provide any marking method to indicate recognition and is not responsible for any equipment claiming that it conforms to a standard of IEC committees.
6) Attention is drawn to the fact that some parts of this international standard may involve patent rights. IEC is not responsible for identifying any or all such patent rights.
International Standard IEC 60825-4 was prepared by IEC 76 \Optical Radiation Safety and Low-Light Equipment\Technical Committee. This standard is based on the following documents: Draft
76/159/FDIS
Reference Report
76/168/RVDbzxz.net
The full details of the voting for this standard can be found in the voting report listed in the table. Annexes A, B and C are informative appendices. 6.36
GE18151-2000
At low irradiance or low irradiance, the choice of material and thickness to shield the laser radiation depends mainly on the required optical attenuation. However, at commercial or high irradiance, it is also necessary to consider that the laser radiation may melt, oxidize or cut the shielding material and cause it to erode. This process can cause the laser radiation to penetrate materials that were originally impenetrable. GB7247-1995 details the issues related to laser protection screens, including personnel contact, interlocking and marking. It also provides general guidelines for the design of high-power laser shields and enclosures. The standard only covers protection against laser radiation. The hazards of secondary radiation occurring during material processing are not covered. Laser protection screens can also comply with the standards for laser protective glasses, but this is not enough to meet the requirements of this standard. 637
1 General
1.1 Specifications
National Standard of the People's Republic of China
Laser guards
GB 18151---2000
eqvIEC60825-4:1997
This standard specifies the requirements for various long-term and temporary (such as maintenance) laser protection screens used to enclose the working area of laser processing machines, as well as the specifications for special laser protection screens.
This standard applies to all components of the protective screen, including visual display and distance, laser (protective) curtain and wall. The requirements for other parts such as laser beam devices, light barriers and protective covers that do not enclose the processing area of laser products are included in GB7247. In addition, this standard points out:
) How to evaluate and standardize the protective properties of laser protective screens; b) How to select laser protective screens.
1.2 Referenced standards
The provisions contained in the following standards constitute the content of this standard through reference in this standard: The versions shown are valid at the time of publication of this standard. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. (B7247-1995 Laser product safety, equipment classification, requirements and user guide IFC60825-3: 1384) GB/T15706.1·1995 Basic concepts and design general principles for mechanical safety Part 1: Basic techniques and methodology (eqv ISO/RR 12100 1.1992)
G/T15706.2—1995 Basic concepts and design general principles for mechanical safety Part 2: Technical principles and specifications (eqv ISO/TR 12100-2:1992)
IS11553.199 Mechanical safety Safety requirements for laser processing machines 1.3 Definitions
The following definitions in this standard supplement the definitions given in GB7247. 1.3. Laser guard
Also called laser shield, it is a physical shield that limits the scope of the danger zone by preventing its rear surface from being exposed to laser radiation exceeding the Class 1 AEL (AEI.).
1.3.2 Active laser guard Active laser guard A laser protection screen that is part of a safety control system. The control system is capable of generating an active laser guard signal when laser radiation exceeding Class 1 AEL acts on the front surface of the laser protection screen. 1.3.3 Passive laser guard Passive laser guard A laser protection screen that relies on its own physical properties. 1.3.4 Proprietary laser guard A non-controlled active laser guard with a specific protection exposure limit provided by the manufacturer. 1.3.5 Temporary laser guard A controlled or passive laser protection solution that replaces or supplements the scope of the danger zone in certain operations of the laser processing machine. 3.6 front surface
National Quality and Technical Supervision Bureau 2000-07~24 Standard 638
2000-12-01 implementation
GR 18151--2000
Surface of the laser shield intended to be exposed to laser radiation. 1.3.7 rear surface
Surface of the laser shield away from the relevant laser beam and which may contact the user through the laser beam. 1.3.8 protective exposure limit protective exposure limit PEL> The maximum exposure of the front surface of the laser shield to prevent the rear surface from being exposed to laser radiation exceeding Class 1 AEI. NOTE
1 In actual operation, this may be greater than the maximum exposure of the laser beam. 2 Different PELs may be applied to different parts of the laser shield if these parts are clearly visible (e.g., visible part of the laser shield). 1.3.9 Foreseeable Exposure Limit (FEL) The maximum laser exposure on the front surface of the laser shield during the maintenance period calculated under normal and reasonably foreseeable conditions. 1-3.10 Aesthetic Protection Screen Termination Signal The signal issued by the active shield in response to excessive exposure in front of it in the event of automatic laser interruption. Note: Safety function is omitted and is not considered as a signal in this document. 1.3.11 Active Protection Screen Protection Time The shortest time, from the issuance of the active protection screen termination signal, that the shield can safely withstand laser exposure exceeding Class 1 AE on its surface under a given laser exposure in front of the active laser shield. 1.3.12 Laser termination time The maximum time that the active protection screen emits a signal to terminate the laser beam. Note: The laser termination time is not related to the response time of the active protection screen, but to the response time of the laser processing machine, especially the laser safety shutter: 3.13 Maintenance inspection interval The time between maintenance inspections. 1.3.14 Laser processing machine Laser process in machine Machines that use lasers to process materials within the scope of 1S011553. 1.3.15 Processing zone Process zone The area where the laser beam interacts with the processed material. 1.3.16 Events (or conditions) that may occur and whose possibility of occurrence (or existence) cannot be considered. 1.3.17 Safety inspection Save type inspection Recorded inspection according to the instructions. 1.3.18 Accessible emission limit (AEL) The maximum emission level allowed for a given category of laser products. 2 Protective screens for laser processing machines
This chapter specifies the requirements for protective screens provided by laser processing machine manufacturers for closed-circuit areas. 2.1 Design requirements
Laser protective screens shall meet the more specific requirements of GB/T 15705.2-1995 on the general requirements for protective screens and their positioning and fixing methods. In addition, they shall meet the following special laser requirements. 2.1.1 General requirements
When the laser protective screen is in its pre-positioned position and is exposed to laser radiation below FEL, it shall not cause various related hazards in the area behind the protective cover and outside the area.
! Examples of related hazards include: venting of solid materials, fire, explosion, static electricity. 2 See Appendix B (Informative Appendix) of FEI, 633
2.1.2 Consumable parts of laser protection screens
GB 18151—2000
In order to replace the parts of laser protection screens that are susceptible to damage by laser radiation, backup should be provided. Design: For example, test or replaceable screens.
2.2 Performance requirements
2.2.1 General
At any time during the maintenance inspection period of the laser protection screen, when its front surface is exposed to FEI laser radiation, it should be prevented from transmitting laser radiation through its rear surface exceeding Class 1 AEL. For automatic laser processing machines, the maintenance inspection interval should not exceed 8 hours. This requirement should be met during the expected life of the laser protection screen under the expected working conditions. 1 This requirement includes two aspects: low laser radiation transmission and resistance to laser-induced damage. 2 Due to aging, ultraviolet radiation exposure, certain gases, temperature, humidity and other environmental conditions, some materials may lose their protective properties. In addition, under high-intensity laser irradiation, some materials transmit intercepted light even if there is no visible damage (such as unacceptable whitening effect). 2.2.2 Active laser shield
a) Under FEI, the active shield protection time should exceed the laser termination time. h) The active shield termination signal issues a visible or audible warning. It needs to be reset manually before the laser emission starts again.
Go: See Appendix C2 of the Appendix (Instructions) for detailed explanation of terms. 2.3 Verification
If the laser processing machine manufacturer is willing to manufacture a laser shield, the manufacturer shall confirm that the shield complies with the design requirements of 2.1 and can meet the performance requirements given in 2.2.
Note: For guidelines on the design and selection of laser shields, see Appendix A (Instructions). 2.3.1 Performance verification
2.3.1.1 The entire laser shield or a suitable sample of its structural materials shall be tested at each FEL to be verified. NOTE
1 Tables of expected FELs for various laser and shield materials and applicable test procedures will be published as informative appendices in future amendments to this standard. 2 For estimation of FEL, see Appendix B (Informative Appendix): 2.3.1.2 For testing purposes, FEL exposure should be achieved by: a) calculating and measuring the exposure to replicate the conditions; or h) creating the conditions under which the laser processor produces FEI. The laser shield or sample should replicate the physical conditions of the front surface allowed by the routine inspection requirements and the maintenance period of the shield, including conditions that significantly reduce the laser protection performance of the laser shield (such as cracks, scratches and surface contamination) (see 2.4.2). 2.4 USER INFORMATION
2.4.1 The manufacturer shall provide documentation detailing the inspection and test methods, cleaning, replacement or treatment of damaged parts, and usage restrictions. The user shall be given a maintenance inspection period.
2.4.2 The manufacturer shall provide documents to inform the user of the operation, damage causes and inspection after the safety control system of the active protection screen is activated, and the necessary supplementary measures before restoring the control system. 3 Special laser protection screens
This chapter specifies the requirements that the supplier of special laser protection screens should meet. 3.1 Design requirements
Special laser protection screens shall be used in accordance with the provisions of the user instructions. When they are exposed to laser radiation below FEL, various related hazards shall not be generated on the rear surface of the protection screen (see 3.6).
3.2 Performance requirements
When its front surface is subjected to the specified PEL, the laser radiation that can be exposed to the rear surface of the laser protection screen shall not exceed Class 1 AEI. For active laser protection screens, this requirement applies to the micro-light radiation that the active laser protection screen is exposed to during maintenance. This requirement shall be met during the expected life of the laser protection screen under the expected working conditions. 3.3 Specification Requirements
All E1. The specification shall include the following: a) the irradiance and irradiance on the front surface of the laser shield under the specified upper limit of the irradiation area (in W/m2 or J/m* respectively) and their variation with time; b) the total exposure duration under the above conditions + the wavelength of the PEL application: d) the incident angle and polarization of the laser radiation (if relevant); e) the minimum size of the irradiation area (for example, if the active laser shield uses a separate sensing element, a micro beam with a small diameter may pass through the shield without a detector); and the protection time of the active laser shield (for active laser shields). Notes
1 See Section B1 of the Technical Notes:
2 Generally, a range or a group of values is stated instead of a single value. 3 Formally expressed (for example, irradiance and duration + other parameters remain unchanged). 3.4 Testing requirements
3.4.1 Overview
The entire laser shield or its appropriate sample should be used for testing. Regardless of the method of testing, the conditions of the laser shield or sample should reproduce or exceed the worst physical conditions allowed for the front surface, including reduced surface reflection and damage allowed by routine maintenance (3.6).
The front surface should be exposed to the PEL as specified., or in the case of sample testing, in accordance with the provisions of 3.4.2 below. When the front surface is under the PEL irradiation condition, the accessible laser radiation measured on the rear surface of the laser shield should not exceed Class AEL (testing is in accordance with the provisions of GB7247). This requirement applies to the exposure duration specified by the PEL or the specified active shield protection time.
3. 4.2 Sample testing
3.4.2.1 The sample shall be uniform in size and composition, round or square, with a diameter or side length of not less than 50mm. During testing, the sample shall be irradiated on the surface and the sample shall be held by a clamp with the edge of the sample not exceeding 2.5mt. The holding material in contact with the sample shall be of low thermal conductivity, at least mm thick, and suitable for use at the temperatures generated.
3.4.2.2 When the PEL is cited without specifying a limit on the irradiated area, see 3.3a)], the test shall expose not less than 90% of the sample area, and the total laser power or energy coverage projected on the sample divided by the total irradiated area shall not be less than the specified irradiance or irradiance. 3.5 Label requirements
3.5.1 All labels shall be placed on the rear surface of the protective screen. 3.5.2 If the orientation of the protective screen is important, the rear surface of the protective screen shall be clearly legible. 3. 5. 3 If only part of the front surface of the shield is a laser shield, this area should be marked with a conspicuous color wheel and text to facilitate identification.
3.5.4 The label should state the full PEL specification. 3.5.5 The manufacturer's name, date and place of manufacture should be provided, and a statement should be made in accordance with this standard. 3.6 User Notices
Except for 3.In addition to the specifications listed in 3, the manufacturer of the dedicated laser protection screen should also provide the user with the following information: a) Instructions on the permitted use of the laser protection screen:
b) Instructions on the placement and connection of the laser protection screen: ) Installation information of the laser protection screen - For active laser protection screens, this will include the interface and power supply requirements of the protection screen, 641
GB 18151 2000
d) Maintenance requirements, including inspection and testing steps, cleaning, replacement and treatment of damaged parts; e) Operation after the active protection screen safety control system is activated, analysis and inspection of damage causes, and taking necessary remedial measures before restarting the control system,
f) The sign and its location of 3.5. If the front surface of the instrument is a part of the protection screen, this area should be marked; more) Declaration of compliance with this standard.
A1 Design of laser protection screen
AI.1 Passive laser protection screen
Examples of passive laser protection screens are as follows:
GB 18151—2000
Attachment A
(Indicative Appendix)
General guidelines for design and selection of laser protection screens a) A metal plate based on the principle of thermal conductivity. If its performance is to be enhanced, the surface temperature should be kept below its melting point under normal and reasonably foreseeable fault conditions by forced air cooling or water cooling. 5) A transparent sheet that is not transmissive at the laser wavelength, which can withstand weak laser irradiation under normal working conditions of the laser processing machine. A1.2 Active laser protection screen
Examples of active laser protection screens are as follows:
4) A protective housing with a heat sensor embedded to detect overheating. Note: The spacing between heat sensors should be determined based on the minimum beam displacement. 1) Laser shields with a sealed panel containing a body or gaseous atmosphere and a pressure-sensitive device that detects the pressure difference behind the front surface of the shield.
A1.3 Hazard indication (passive shields)
If possible, a protective indicator should be provided when the laser shield is exposed to hazardous laser radiation (e.g. by applying a suitable paint on both sides of the laser shield).
A1.4 Power supply (active shields)
If the active shield itself requires power supply, it should be provided to ensure that it can work properly with laser protection. A2 Selection of laser shields
The selection process is as follows:
: 1) Determine the selected position for the laser shield and estimate the FEL at that position. Appendix B (Recommended Notes) gives the guide for estimating the FEL value.
b) If necessary, minimize the internal FEI under fault conditions. This is particularly true for laser processing machines with automatic monitoring functions, which can detect fault conditions and eliminate the time of exposure.
Other examples include:
Make sure that the laser protection shield is far enough away from the focal point produced by the focusing optical system; - Place the vulnerable parts of the light protection shield (such as the viewing area) away from the area where it can be exposed to high irradiance; - Move the laser protection shield away from the low-light processing area; "For temporary laser protection shields, it is also necessary to add to the main maintenance document, such as: One or more people participate in supervising the front surface status of the laser protection group to reduce the estimated irradiation time of the passive shield: The halved-operate controller is used to monitor the front surface status of the laser protection shield In order to reduce the estimated time of passive protection group:
, use additional temporary flat protection screens, light barriers and beam cleaners to collect various strong drifting beams: · Drift laser detectors are used in dangerous areas, and the protection screens are placed outside the dangerous areas to reduce the estimated irradiation time. When using laser protection screens, add beam control functions to the machine design to improve the control of the moving beam during maintenance, such as
precision positioning clamps, which are used to provide additional optical shaping parts (such as rotating mirrors) during maintenance: 543
only allows the beam to be adjusted within a limited range. GB 181512000
The order of the three options is irrelevant to whether they are preferred. A2.1 Option 1: Passive laser shield
This is the simplest option.
Note: In the case of a few additives (such as dyes in plastics) that dominate the absorption at the laser wavelength, design and quality control history should be given special consideration. In this case, the material preparation does not indicate the concentration of the absorber or the optical attenuation of the material at the laser wavelength. A batch of material samples should first be tested as described in 8.1. A2.2 Option 2: Active laser protection screen If the FEL cannot be reduced to provide suitable protection in the form of ordinary passive protection screen, active laser protection screen is generally used. A2.3 Option 3: Special laser protection screen
If the estimated FEL value is lower than the PEL value stated by the laser protection screen manufacturer, a special laser protection screen can be used. Appendix E
(Suggestive Appendix)
Estimates of predictable exposure limits
B1 Overview
FEI. Values can be determined by measurement or calculation. Hazard estimation should take into account the cumulative exposure during normal operation (such as each machine processing) during the maintenance and inspection period. The most important auxiliary exposure and irradiation area should be identified from the calculation. and duration. It is possible to identify several FEIs: for example, one case is to make the irradiation time as long as possible at a low irradiance, and another case is to make the irradiance as high as possible at a shorter irradiation time. The full FFI characteristics contain the following data and related information: a) Maximum irradiance (or irradiance) on the front surface of the laser shield. Note: The irradiance (or irradiance) is expressed as the total power or energy divided by the front surface of the shield, or a specific area, b) Upper limit of the irradiation area of the front surface of the shield at this irradiance level. Note: No area limitation is appropriate for the suppression of scattered light, while for direct laser beam radiation it is appropriate to limit the irradiation area. c) Single pulse duration and pulse repetition rate of pulsed lasers. d) Total delay time.
Note: See Section B4 for details on irradiation duration. e) Radiation wavelength,
f) Incident angle and radiation polarization (if relevant). Method
1 For laser protection that uses interference layers to reflect external laser radiation, the regulation of the incident angle is particularly important. 2 Note that under Brewster angle radiation, p\ deflects the radiation from the protective screen surface. g) Minimum irradiation area (also for active laser protection screens with separate sensor elements, laser beams with very small beam diameters may pass through without being detected>.
h) Protection time of active laser protection screens. B2 Reflection of laser radiation
B2.1 Reflection
Slow Lambertian reflector with 100% reflectivity EA
-+(B1)
B2- 2 Mirror reflection
GB18151-2000
Laser protection screen
Radius
Calculation of diffuse area radiation
For a laser with Gaussian distribution and power P. , the maximum illumination (at the center of the Gaussian distribution) of a circularly symmetric laser beam with a diameter of d and a focal length of f at the focal lens, the vertical distance R from the focus to the plane is 4P.i
where: reflectivity of the working surface.
Note: Some curved surfaces may increase the harm of reflection. Laser protection screen
Figure B2 Mirror reflection calculation
B3 Examples of estimation conditions
The various FELs that are prone to occur when the laser is working can be estimated with the help of the applicable laser parameters, working materials, geometric structure and process and their possible worst combinations (IEC60825-1 Appendix E provides a table of common fault states) 54:
GB 18151-2000
Software failure
Laser protection screen
Twilight protection screen
Working rain bending or improper holding
Protective screen when lifting the light
Working surface express report
Figure B3 Several examples of foreseeable fault conditions1 Passive laser protection screen
Examples of passive laser protection screens are as follows:
GB 18151—2000
Appendix A
(Indicative Appendix)
General guidelines for the design and selection of laser protection screens a) A metal plate based on the principle of thermal conductivity. If its performance is to be enhanced, the surface temperature should be kept below its melting point under normal and reasonably foreseeable fault conditions by forced air cooling or water cooling. 5) A transparent sheet that is not transmissive at the laser wavelength, which can withstand weak laser irradiation under normal working conditions of the laser processing machine. A1.2 Active laser protection screen
Examples of active laser protection screens are as follows:
4) A protective housing with a heat sensor embedded to detect overheating. Note: The spacing between heat sensors should be determined based on the minimum beam displacement. 1) Laser shields with a sealed panel containing a body or gaseous atmosphere and a pressure-sensitive device that detects the pressure difference behind the front surface of the shield.
A1.3 Hazard indication (passive shields)
If possible, a protective indicator should be provided when the laser shield is exposed to hazardous laser radiation (e.g. by applying a suitable paint on both sides of the laser shield).
A1.4 Power supply (active shields)
If the active shield itself requires power supply, it should be provided to ensure that it can work properly with laser protection. A2 Selection of laser shields
The selection process is as follows:
: 1) Determine the selected position for the laser shield and estimate the FEL at that position. Appendix B (Recommended Notes) gives the guide for estimating the FEL value.
b) If necessary, minimize the internal FEI under fault conditions. This is particularly true for laser processing machines with automatic monitoring functions, which can detect fault conditions and eliminate the time of exposure.
Other examples include:
Make sure that the laser protection shield is far enough away from the focal point produced by the focusing optical system; - Place the vulnerable parts of the light protection shield (such as the viewing area) away from the area where it can be exposed to high irradiance; - Move the laser protection shield away from the low-light processing area; "For temporary laser protection shields, it is also necessary to add to the main maintenance document, such as: One or more people participate in supervising the front surface status of the laser protection group to reduce the estimated irradiation time of the passive shield: The halved-operate controller is used to monitor the front surface status of the laser protection shield In order to reduce the estimated time of passive protection group:
, use additional temporary flat protection screens, light barriers and beam cleaners to collect various strong drifting beams: · Drift laser detectors are used in dangerous areas, and the protection screens are placed outside the dangerous areas to reduce the estimated irradiation time. When using laser protection screens, add beam control functions to the machine design to improve the control of the moving beam during maintenance, such as
precision positioning clamps, which are used to provide additional optical shaping parts (such as rotating mirrors) during maintenance: 543
only allows the beam to be adjusted within a limited range. GB 181512000
The order of the three options is irrelevant to whether they are preferred. A2.1 Option 1: Passive laser shield
This is the simplest option.
Note: In the case of a few additives (such as dyes in plastics) that dominate the absorption at the laser wavelength, design and quality control history should be given special consideration. In this case, the material preparation does not indicate the concentration of the absorber or the optical attenuation of the material at the laser wavelength. A batch of material samples should first be tested as described in 8.1. A2.2 Option 2: Active laser protection screen If the FEL cannot be reduced to provide suitable protection in the form of ordinary passive protection screen, active laser protection screen is generally used. A2.3 Option 3: Special laser protection screen
If the estimated FEL value is lower than the PEL value stated by the laser protection screen manufacturer, a special laser protection screen can be used. Appendix E
(Suggestive Appendix)
Estimates of predictable exposure limits
B1 Overview
FEI. Values can be determined by measurement or calculation. Hazard estimation should take into account the cumulative exposure during normal operation (such as each machine processing) during the maintenance and inspection period. The most important auxiliary exposure and irradiation area should be identified from the calculation. and duration. It is possible to identify several FEIs: for example, one case is to make the irradiation time as long as possible at a low irradiance, and another case is to make the irradiance as high as possible at a shorter irradiation time. The full FFI characteristics contain the following data and related information: a) Maximum irradiance (or irradiance) on the front surface of the laser shield. Note: The irradiance (or irradiance) is expressed as the total power or energy divided by the front surface of the shield, or a specific area, b) Upper limit of the irradiation area of the front surface of the shield at this irradiance level. Note: No area limitation is appropriate for the suppression of scattered light, while for direct laser beam radiation it is appropriate to limit the irradiation area. c) Single pulse duration and pulse repetition rate of pulsed lasers. d) Total delay time.
Note: See Section B4 for details on irradiation duration. e) Radiation wavelength,
f) Incident angle and radiation polarization (if relevant). Method
1 For laser protection that uses interference layers to reflect external laser radiation, the regulation of the incident angle is particularly important. 2 Note that under Brewster angle radiation, p\ deflects the radiation from the protective screen surface. g) Minimum irradiation area (also for active laser protection screens with separate sensor elements, laser beams with very small beam diameters may pass through without being detected>.
h) Protection time of active laser protection screens. B2 Reflection of laser radiation
B2.1 Reflection
Slow Lambertian reflector with 100% reflectivity EA
-+(B1)
B2- 2 Mirror reflection
GB18151-2000
Laser protection screen
Radius
Calculation of diffuse area radiation
For a laser with Gaussian distribution and power P. , the maximum illumination (at the center of the Gaussian distribution) of a circularly symmetric laser beam with a diameter of d and a focal length of f at the focal lens, the vertical distance R from the focus to the plane is 4P.i
where: reflectivity of the working surface.
Note: Some curved surfaces may increase the harm of reflection. Laser protection screen
Figure B2 Mirror reflection calculation
B3 Examples of estimation conditions
The various FELs that are prone to occur when the laser is working can be estimated with the help of the applicable laser parameters, working materials, geometric structure and process and their possible worst combinations (IEC60825-1 Appendix E provides a table of common fault states) 54:
GB 18151-2000
Software failure
Laser protection screen
Twilight protection screen
Working rain bending or improper holding
Protective screen when lifting the light
Working surface express report
Figure B3 Several examples of foreseeable fault conditions1 Passive laser protection screen
Examples of passive laser protection screens are as follows:
GB 18151—2000
Appendix A
(Indicative Appendix)
General guidelines for the design and selection of laser protection screens a) A metal plate based on the principle of thermal conductivity. If its performance is to be enhanced, the surface temperature should be kept below its melting point under normal and reasonably foreseeable fault conditions by forced air cooling or water cooling. 5) A transparent sheet that is not transmissive at the laser wavelength, which can withstand weak laser irradiation under normal working conditions of the laser processing machine. A1.2 Active laser protection screen
Examples of active laser protection screens are as follows:
4) A protective housing with a heat sensor embedded to detect overheating. Note: The spacing between heat sensors should be determined based on the minimum beam displacement. 1) Laser shields with a sealed panel containing a body or gaseous atmosphere and a pressure-sensitive device that detects the pressure difference behind the front surface of the shield.
A1.3 Hazard indication (passive shields)
If possible, a protective indicator should be provided when the laser shield is exposed to hazardous laser radiation (e.g. by applying a suitable paint on both sides of the laser shield).
A1.4 Power supply (active shields)
If the active shield itself requires power supply, it should be provided to ensure that it can work properly with laser protection. A2 Selection of laser shields
The selection process is as follows:
: 1) Determine the selected position for the laser shield and estimate the FEL at that position. Appendix B (Recommended Notes) gives the guide for estimating the FEL value.
b) If necessary, minimize the internal FEI under fault conditions. This is particularly true for laser processing machines with automatic monitoring functions, which can detect fault conditions and eliminate the time of exposure.
Other examples include:
Make sure that the laser protection shield is far enough away from the focal point produced by the focusing optical system; - Place the vulnerable parts of the light protection shield (such as the viewing area) away from the area where it can be exposed to high irradiance; - Move the laser protection shield away from the low-light processing area; "For temporary laser protection shields, it is also necessary to add to the main maintenance document, such as: One or more people participate in supervising the front surface status of the laser protection group to reduce the estimated irradiation time of the passive shield: The halved-operate controller is used to monitor the front surface status of the laser protection shield In order to reduce the estimated time of passive protection group:
, use additional temporary flat protection screens, light barriers and beam cleaners to collect various strong drifting beams: · Drift laser detectors are used in dangerous areas, and the protection screens are placed outside the dangerous areas to reduce the estimated irradiation time. When using laser protection screens, add beam control functions to the machine design to improve the control of the moving beam during maintenance, such as
precision positioning clamps, which are used to provide additional optical shaping parts (such as rotating mirrors) during maintenance: 543
only allows the beam to be adjusted within a limited range. GB 181512000
The order of the three options is irrelevant to whether they are preferred. A2.1 Option 1: Passive laser shield
This is the simplest option.
Note: In the case of a few additives (such as dyes in plastics) that dominate the absorption at the laser wavelength, design and quality control history should be given special consideration. In this case, the material preparation does not indicate the concentration of the absorber or the optical attenuation of the material at the laser wavelength. A batch of material samples should first be tested as described in 8.1. A2.2 Option 2: Active laser protection screen If the FEL cannot be reduced to provide suitable protection in the form of ordinary passive protection screen, active laser protection screen is generally used. A2.3 Option 3: Special laser protection screen
If the estimated FEL value is lower than the PEL value stated by the laser protection screen manufacturer, a special laser protection screen can be used. Appendix E
(Suggestive Appendix)
Estimates of predictable exposure limits
B1 Overview
FEI. Values can be determined by measurement or calculation. Hazard estimation should take into account the cumulative exposure during normal operation (such as each machine processing) during the maintenance and inspection period. The most important auxiliary exposure and irradiation area should be identified from the calculation. and duration. It is possible to identify several FEIs: for example, one case is to make the irradiation time as long as possible at a low irradiance, and another case is to make the irradiance as high as possible at a shorter irradiation time. The full FFI characteristics contain the following data and related information: a) Maximum irradiance (or irradiance) on the front surface of the laser shield. Note: The irradiance (or irradiance) is expressed as the total power or energy divided by the front surface of the shield, or a specific area, b) Upper limit of the irradiation area of the front surface of the shield at this irradiance level. Note: No area limitation is appropriate for the suppression of scattered light, while for direct laser beam radiation it is appropriate to limit the irradiation area. c) Single pulse duration and pulse repetition rate of pulsed lasers. d) Total delay time.
Note: See Section B4 for details on irradiation duration. e) Radiation wavelength,
f) Incident angle and radiation polarization (if relevant). Method
1 For laser protection that uses interference layers to reflect external laser radiation, the regulation of the incident angle is particularly important. 2 Note that under Brewster angle radiation, p\ deflects the radiation from the protective screen surface. g) Minimum irradiation area (also for active laser protection screens with separate sensor elements, laser beams with very small beam diameters may pass through without being detected>.
h) Protection time of active laser protection screens. B2 Reflection of laser radiation
B2.1 Reflection
Slow Lambertian reflector with 100% reflectivity EA
-+(B1)
B2- 2 Mirror reflection
GB18151-2000
Laser protection screen
Radius
Calculation of diffuse area radiation
For a laser with Gaussian distribution and power P. , the maximum illumination (at the center of the Gaussian distribution) of a circularly symmetric laser beam with a diameter of d and a focal length of f at the focal lens, the vertical distance R from the focus to the plane is 4P.i
where: reflectivity of the working surface.
Note: Some curved surfaces may increase the harm of reflection. Laser protection screen
Figure B2 Mirror reflection calculation
B3 Examples of estimation conditions
The various FELs that are prone to occur when the laser is working can be estimated with the help of the applicable laser parameters, working materials, geometric structure and process and their possible worst combinations (IEC60825-1 Appendix E provides a table of common fault states) 54:
GB 18151-2000
Software failure
Laser protection screen
Twilight protection screen
Working rain bending or improper holding
Protective screen when lifting the light
Working surface express report
Figure B3 Several examples of foreseeable fault conditionsMinimize, especially for laser processing machines with automatic monitoring functions, which can detect fault conditions and eliminate the time of exposure.
Other examples are:
Make sure that the laser shield is far enough away from the focal point produced by the focusing optical system; - Place the vulnerable parts of the laser shield (such as the viewing area) away from the area where it can be exposed to high irradiance; - Move the laser shield away from the low-light processing area; "For temporary laser shields, it is also necessary to add to the main maintenance document, such as: One or more people participate in supervising the front surface status of the laser shield group to reduce the estimated irradiation time of the passive shield: The halved-operate controller is used to monitor the front surface status of the laser shield In order to reduce the estimated time of passive protection group:
, use additional temporary flat protection screens, light barriers and beam cleaners to collect various strong drifting beams: · Drift laser detectors are used in dangerous areas, and the protection screens are placed outside the dangerous areas to reduce the estimated irradiation time. When using laser protection screens, add beam control functions to the machine design to improve the control of the moving beam during maintenance, such as
precision positioning clamps, which are used to provide additional optical shaping parts (such as rotating mirrors) during maintenance: 543
only allows the beam to be adjusted within a limited range. GB 181512000
The order of the three options is irrelevant to whether they are preferred. A2.1 Option 1: Passive laser shield
This is the simplest option.
Note: In the case of a few additives (such as dyes in plastics) that dominate the absorption at the laser wavelength, design and quality control history should be given special consideration. In this case, the material preparation does not indicate the concentration of the absorber or the optical attenuation of the material at the laser wavelength. A batch of material samples should first be tested as described in 8.1. A2.2 Option 2: Active laser protection screen If the FEL cannot be reduced to provide suitable protection in the form of ordinary passive protection screen, active laser protection screen is generally used. A2.3 Option 3: Special laser protection screen
If the estimated FEL value is lower than the PEL value stated by the laser protection screen manufacturer, a special laser protection screen can be used. Appendix E
(Suggestive Appendix)
Estimates of predictable exposure limits
B1 Overview
FEI. Values can be determined by measurement or calculation. Hazard estimation should take into account the cumulative exposure during normal operation (such as each machine processing) during the maintenance and inspection period. The most important auxiliary exposure and irradiation area should be identified from the calculation. and duration. It is possible to identify several FEIs: for example, one case is to make the irradiation time as long as possible at a low irradiance, and another case is to make the irradiance as high as possible at a shorter irradiation time. The full FFI characteristics contain the following data and related information: a) Maximum irradiance (or irradiance) on the front surface of the laser shield. Note: The irradiance (or irradiance) is expressed as the total power or energy divided by the front surface of the shield, or a specific area, b) Upper limit of the irradiation area of the front surface of the shield at this irradiance level. Note: No area limitation is appropriate for the suppression of scattered light, while for direct laser beam radiation it is appropriate to limit the irradiation area. c) Single pulse duration and pulse repetition rate of pulsed lasers. d) Total delay time.
Note: See Section B4 for details on irradiation duration. e) Radiation wavelength,
f) Incident angle and radiation polarization (if relevant). Method
1 For laser protection that uses interference layers to reflect external laser radiation, the regulation of the incident angle is particularly important. 2 Note that under Brewster angle radiation, p\ deflects the radiation from the protective screen surface. g) Minimum irradiation area (also for active laser protection screens with separate sensor elements, laser beams with very small beam diameters may pass through without being detected>.
h) Protection time of active laser protection screens. B2 Reflection of laser radiation
B2.1 Reflection
Slow Lambertian reflector with 100% reflectivity EA
-+(B1)
B2- 2 Mirror reflection
GB18151-2000
Laser protection screen
Radius
Calculation of diffuse area radiation
For a laser with Gaussian distribution and power P. , the maximum illumination (at the center of the Gaussian distribution) of a circularly symmetric laser beam with a diameter of d and a focal length of f at the focal lens, the vertical distance R from the focus to the plane is 4P.i
where: reflectivity of the working surface.
Note: Some curved surfaces may increase the harm of reflection. Laser protection screen
Figure B2 Mirror reflection calculation
B3 Examples of estimation conditions
The various FELs that are prone to occur when the laser is working can be estimated with the help of the applicable laser parameters, working materials, geometric structure and process and their possible worst combinations (IEC60825-1 Appendix E provides a table of common fault states) 54:
GB 18151-2000
Software failure
Laser protection screen
Twilight protection screen
Working rain bending or improper holding
Protective screen when lifting the light
Working surface express report
Figure B3 Several examples of foreseeable fault conditionsMinimize, especially for laser processing machines with automatic monitoring functions, which can detect fault conditions and eliminate the time of exposure.
Other examples are:
Make sure that the laser shield is far enough away from the focal point produced by the focusing optical system; - Place the vulnerable parts of the laser shield (such as the viewing area) away from the area where it can be exposed to high irradiance; - Move the laser shield away from the low-light processing area; "For temporary laser shields, it is also necessary to add to the main maintenance document, such as: One or more people participate in supervising the front surface status of the laser shield group to reduce the estimated irradiation time of the passive shield: The halved-operate controller is used to monitor the front surface status of the laser shield In order to reduce the estimated time of passive protection group:
, use additional temporary flat protection screens, light barriers and beam cleaners to collect various strong drifting beams: · Drift laser detectors are used in dangerous areas, and the protection screens are placed outside the dangerous areas to reduce the estimated irradiation time. When using laser protection screens, add beam control functions to the machine design to improve the control of the moving beam during maintenance, such as
precision positioning clamps, which are used to provide additional optical shaping parts (such as rotating mirrors) during maintenance: 543
only allows the beam to be adjusted within a limited range. GB 181512000
The order of the three options is irrelevant to whether they are preferred. A2.1 Option 1: Passive laser shield
This is the simplest option.
Note: In the case of a few additives (such as dyes in plastics) that dominate the absorption at the laser wavelength, design and quality control history should be given special consideration. In this case, the material preparation does not indicate the concentration of the absorber or the optical attenuation of the material at the laser wavelength. A batch of material samples should first be tested as described in 8.1. A2.2 Option 2: Active laser protection screen If the FEL cannot be reduced to provide suitable protection in the form of ordinary passive protection screen, active laser protection screen is generally used. A2.3 Option 3: Special laser protection screen
If the estimated FEL value is lower than the PEL value stated by the laser protection screen manufacturer, a special laser protection screen can be used. Appendix E
(Suggestive Appendix)
Estimates of predictable exposure limits
B1 Overview
FEI. Values can be determined by measurement or calculation. Hazard estimation should take into account the cumulative exposure during normal operation (such as each machine processing) during the maintenance and inspection period. The most important auxiliary exposure and irradiation area should be identified from the calculation. and duration. It is possible to identify several FEIs: for example, one case is to make the irradiation time as long as possible at a low irradiance, and another case is to make the irradiance as high as possible at a shorter irradiation time. The full FFI characteristics contain the following data and related information: a) Maximum irradiance (or irradiance) on the front surface of the laser shield. Note: The irradiance (or irradiance) is expressed as the total power or energy divided by the front surface of the shield, or a specific area, b) Upper limit of the irradiation area of the front surface of the shield at this irradiance level. Note: No area limitation is appropriate for the suppression of scattered light, while for direct laser beam radiation it is appropriate to limit the irradiation area. c) Single pulse duration and pulse repetition rate of pulsed lasers. d) Total delay time.
Note: See Section B4 for details on irradiation duration. e) Radiation wavelength,
f) Incident angle and radiation polarization (if relevant). Method
1 For laser protection that uses interference layers to reflect external laser radiation, the regulation of the incident angle is particularly important. 2 Note that under Brewster angle radiation, p\ deflects the radiation from the protective screen surface. g) Minimum irradiation area (also for active laser protection screens with separate sensor elements, laser beams with very small beam diameters may pass through without being detected>.
h) Protection time of active laser protection screens. B2 Reflection of laser radiation
B2.1 Reflection
Slow Lambertian reflector with 100% reflectivity EA
-+(B1)
B2- 2 Mirror reflection
GB18151-2000
Laser protection screen
Radius
Calculation of diffuse area radiation
For a laser with Gaussian distribution and power P. , the maximum illumination (at the center of the Gaussian distribution) of a circularly symmetric laser beam with a diameter of d and a focal length of f at the focal lens, the vertical distance R from the focus to the plane is 4P.i
where: reflectivity of the working surface.
Note: Some curved surfaces may increase the harm of reflection. Laser protection screen
Figure B2 Mirror reflection calculation
B3 Examples of estimation conditions
The various FELs that are prone to occur when the laser is working can be estimated with the help of the applicable laser parameters, working materials, geometric structure and process and their possible worst combinations (IEC60825-1 Appendix E provides a table of common fault states) 54:
GB 18151-2000
Software failure
Laser protection screen
Twilight protection screen
Working rain bending or improper holding
Protective screen when lifting the light
Working surface express report
Figure B3 Several examples of foreseeable fault conditionsi
Where: reflectivity of the working surface.
Note: Some curved surfaces may increase the hazard of reflection. Laser protection screen
Figure B2 Mirror reflection calculation
B3 Examples of estimation conditions
The various FELs that are prone to occur when the laser is working can be estimated with the help of the laser parameters, working materials, geometric structure and process and their possible worst combinations (IEC60825-1 Appendix E provides a table of common fault states) 54:
GB 18151-2000
Software failure
Laser protection screen
Twilight protection screen
Working surface bending or improper holding
Protective screen when holding the light
Working surface express
Figure B3 Some examples of foreseeable fault conditionsi
Where: reflectivity of the working surface.
Note: Some curved surfaces may increase the hazard of reflection. Laser protection screen
Figure B2 Mirror reflection calculation
B3 Examples of estimation conditions
The various FELs that are prone to occur when the laser is working can be estimated with the help of the laser parameters, working materials, geometric structure and process and their possible worst combinations (IEC60825-1 Appendix E provides a table of common fault states) 54:
GB 18151-2000
Software failure
Laser protection screen
Twilight protection screen
Working surface bending or improper holding
Protective screen when holding the light
Working surface express
Figure B3 Some examples of foreseeable fault conditions
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.