Tham khảo tài liệu 'plastics engineered product design 1 episode 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 460 Plastics Engineered Product Design critical. Any product designed with these guidelines in mind should conduct tests on the products themselves to relate the guidelines to actual performance. With more experience more-appropriate values will be developed targeting to use to . After field service of the preliminary designed products has been obtained action should be taken to consider reducing your SF in order to reduce costs. Safety factors Type of load Safety factor Static short-term loads 1 to Static long-term loads 2 to 5 Repeated loads 5 to 15 Variable changing loads 4 to 10 Fatigue loads 5 to 15 Impact loads 10 to 15 Realistic SFs are based on personal or others experience. The SFs can be related to the probable consequences of failure. To ensure no failure where a product could be damaging to a person etc. prototype tests should be run at their most extreme service operating conditions. For instance the maximum working load should be applied at the maximum temperature and in the presence of any chemicals that might be encountered in the end use. Impact loading should be applied at the lowest temperature expected including what occurs during shipping and assembly. The effects of variations in plastic lots and manufacturing conditions must also be considered. Safety Factor Example Due to the unpredictable scheduling and high dollar costs of all weather natural testing much of the environmental testing has been brought into laboratories or other such testing centers. Artificial conditions are provided to simulate various environmental phenomena and thereby aid in the evaluation of the test item before it goes into service under natural environments. This environmental simulation and testing does require extensive preparation and planning. It is generally desirable to obtain generalizations and comparisons from a few basic tests to avoid prolonged testing and retesting. The type and number of tests to be conducted natural or simulated as usual are
