Arithmetic progression is a common series. If a series starts from the second term, the difference between each term and its previous term is equal to the same constant. This series is called arithmetic progression, and this constant is called arithmetic progression's tolerance, which is usually represented by the letter D.
1.
Allowable deviation of actual parameter values. Parameters include not only geometric parameters in machining, but also parameters in physics, chemistry, electricity and other disciplines. Therefore, tolerance is a widely used concept. For mechanical manufacturing, the purpose of making tolerance is to determine the geometric parameters of products and make them change within a certain range to meet the requirements of communication or cooperation.
2. Basic meaning
In machine design and manufacturing, the allowable deviation of the actual parameter values of machines or machine parts, such as the upper and lower limits of a product specification are 100 and 60 respectively, is 40; If the upper and lower limits are+100 and-100 respectively, then its tolerance is 200. Tolerances of geometric parameters include dimensional tolerance, shape tolerance, position tolerance and so on.
The parameter values mentioned above include not only geometric parameters in machining, but also parameters in physics, chemistry, electricity and other disciplines. Therefore, tolerance is a widely used concept. For mechanical manufacturing, the purpose of making tolerance is to determine the geometric parameters of products and make them change within a certain range to meet the requirements of communication or cooperation.
classify
Tolerances of geometric parameters include dimensional tolerance, shape tolerance, position tolerance and so on. Dimensional tolerance. Refers to the change of allowable size, which is equal to the absolute value of algebraic difference between the maximum limit size and the minimum limit size. Shape tolerance. Refers to the total allowable variation of the shape of a single actual element, including straightness, flatness, roundness, cylindricity, line profile and surface profile.
Position tolerance. Refers to the total allowable deviation of the position of the relevant actual elements relative to the benchmark, which defines the mutual positional relationship between two or more points, lines and surfaces of the part, including parallelism, verticality, inclination, coaxiality, symmetry, position, circular jump and total jump. Tolerance indicates the manufacturing accuracy requirements of parts and reflects the processing difficulty.