tailieunhanh - The gauge block handbook Episode 2

Tham khảo tài liệu 'the gauge block handbook episode 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | There are four defined tolerance grades in ISO 3650 00 0 1 and 2. The algorithm for the length tolerances are shown in table and there are rules for rounding stated to derive the tables included in the standard. Table Grade Deviation from Nominal Length gm 00 0 1 2 Where L is the block nominal length in millimeters. The ISO standard does not have an added tolerance for measurement uncertainty however the ISO tolerances are comparable to those of the ANSI specification when the additional ANSI tolerance for measurement uncertainty is added to the tolerances of Table . Figure . Comparison of ISO grade tolerances black dashed and ASME grade tolerances red . 15 A graph of the length tolerance versus nominal length is shown in figure . The different class tolerance for ISO and ANSI do not match up directly. The ANSI grade 1 is slightly tighter than ISO class 00 but if the additional ANSI tolerance for measurement uncertainty is used the ISO Grade 00 is slightly tighter. The practical differences between these specifications are negligible. In many countries the method for testing the variation in length is also standardized. For example in Germany 15 the test block is measured in 5 places the center and near each corner 2 mm from each edge . The center gives the length of the block and the four corner measurements are used to calculate the shortest and longest lengths of the block. Some of the newer gauge block comparators have a very small lower contact point to facilitate these measurements very near the edge of the block. 16 3. Physical and Thermal Properties of Gauge Blocks Materials From the very beginning gauge blocks were made of steel. The lapping process used to finish the ends and the common uses of blocks demand a hard surface. A second virtue of steel is that most industrial products are made of steel. If the steel gauge block has the same thermal expansion coefficient as the part to be

TỪ KHÓA LIÊN QUAN
crossorigin="anonymous">
Đã phát hiện trình chặn quảng cáo AdBlock
Trang web này phụ thuộc vào doanh thu từ số lần hiển thị quảng cáo để tồn tại. Vui lòng tắt trình chặn quảng cáo của bạn hoặc tạm dừng tính năng chặn quảng cáo cho trang web này.