Mechanical components machined to high levels of ac cu racy are vital to achieve various functional requirements in engineering product s. In particular, the geometric accuracy of turned components play an important r...Mechanical components machined to high levels of ac cu racy are vital to achieve various functional requirements in engineering product s. In particular, the geometric accuracy of turned components play an important role in determining the form, fit and function of mechanical assembly requiremen ts. The geometric accuracy requirements of turned components are usually specifi ed in terms of roundness, straightness, cylindricity and concentricity. In pract ice, the accuracy specifications achievable are influenced by many factors such as component materials, production equipment, environmental factors, and machini ng process variables. While the sources of geometric errors due to materials, ma chinery and environment can be predicted to a large extent, the geometric accura cy due to the machining practice is unpredictable and difficult to determine. Since the fundamental geometric tolerances of work-pieces machined by tur ning a re sensitive to the cutting conditions, optimizing the cutting parameters such a s cutting speed, feed rate, and depth of cut is important for achieving the requ ired accuracy levels. Optimization studies of process variables in turning have not been well documented in the literature. Some experimental studies show the e ffect of process variables like cutting speed, feed rate and depth of cut on sur face roughness, production rate, production cost, etc. However, there have been no in-depth studies of the influence of the process variables on mechanical acc uracy related to the geometrical tolerances. In practice, a mechanical part usually consists of several geometrical features. For many mechanical parts, the geometric tolerances determine their functional characteristics. For example, diameter of a shaft and diameter of a hole decide the clearance of a cylindrical fit. The features of the cylindrical fit depend o n the dimensional tolerances of the size as well as several other geometrical to lerances like, roundness, cylindricity, and concentricity. In the study reported here, the dimensional and geometric tolerances achieved using turning experimen ts over a wide selection of cutting conditions will be used to analyze their inf luence on satisfying the functional requirements. The study will also show a met hodology of optimizing the process variables to achieve dimensional and geom etric tolerances to meet the requirements of specific functional features.展开更多
文摘Mechanical components machined to high levels of ac cu racy are vital to achieve various functional requirements in engineering product s. In particular, the geometric accuracy of turned components play an important role in determining the form, fit and function of mechanical assembly requiremen ts. The geometric accuracy requirements of turned components are usually specifi ed in terms of roundness, straightness, cylindricity and concentricity. In pract ice, the accuracy specifications achievable are influenced by many factors such as component materials, production equipment, environmental factors, and machini ng process variables. While the sources of geometric errors due to materials, ma chinery and environment can be predicted to a large extent, the geometric accura cy due to the machining practice is unpredictable and difficult to determine. Since the fundamental geometric tolerances of work-pieces machined by tur ning a re sensitive to the cutting conditions, optimizing the cutting parameters such a s cutting speed, feed rate, and depth of cut is important for achieving the requ ired accuracy levels. Optimization studies of process variables in turning have not been well documented in the literature. Some experimental studies show the e ffect of process variables like cutting speed, feed rate and depth of cut on sur face roughness, production rate, production cost, etc. However, there have been no in-depth studies of the influence of the process variables on mechanical acc uracy related to the geometrical tolerances. In practice, a mechanical part usually consists of several geometrical features. For many mechanical parts, the geometric tolerances determine their functional characteristics. For example, diameter of a shaft and diameter of a hole decide the clearance of a cylindrical fit. The features of the cylindrical fit depend o n the dimensional tolerances of the size as well as several other geometrical to lerances like, roundness, cylindricity, and concentricity. In the study reported here, the dimensional and geometric tolerances achieved using turning experimen ts over a wide selection of cutting conditions will be used to analyze their inf luence on satisfying the functional requirements. The study will also show a met hodology of optimizing the process variables to achieve dimensional and geom etric tolerances to meet the requirements of specific functional features.
