Characteristics of fixtures

Characteristics of fixtures When processing workpieces on machine tools, we can see two different situations: one is to use measuring tools such as a scribe needle or indicator to align according to a certain surface of the workpiece, or according to the line drawn on the surface of the workpiece, so that the workpiece is in the correct position required on the machine tool, and then clamp the workpiece for processing; the other is to install the workpiece on a fixture for processing. In order to process a surface that meets the specified technical requirements on a certain part of the workpiece, various devices are generally used to accurately, conveniently and reliably install the workpiece on the machine tool according to the structural shape of the workpiece, the processing method and the production batch, and then process it. The device used to install the workpiece to determine the relative position of the workpiece and the cutting tool and clamp the workpiece is called a 'machine tool fixture'. In actual production, such as piston and connecting rod production lines, fixtures are used in almost every process. It is very obvious that if the fixture is not used, not only the processing accuracy of the workpiece will be difficult to guarantee, but the processing productivity will also be greatly reduced, and sometimes it will even become impossible to process. In addition to the use of fixtures during machine tool processing, fixtures are sometimes used in inspection, assembly, etc. processes. Therefore, the fixtures used in such occasions can be called 'inspection fixtures' and 'assembly fixtures' respectively.

Machine tool fixtures usually refer to devices used to clamp workpieces; as for devices used to clamp various cutting tools, they are generally called 'auxiliary tools'. Auxiliary tools are sometimes broadly included in the scope of machine tool fixtures. According to the application scope of machine tool fixtures, they can generally be divided into general fixtures, special fixtures and adjustable fixtures.

Universal fixtures are generally attached to ordinary machine tools, such as chucks on lathes, rotary tables on milling machines, dividing heads, center seats, etc. They are all standardized, have certain versatility, and can be used to install various workpieces within a certain range of shapes and sizes without special adjustments. However, in actual production, general fixtures are often unable to meet the needs of various parts processing; or the general fixtures must be appropriately improved due to low productivity; or due to different shapes of workpieces, processing requirements, etc., a special fixture must be specially designed and manufactured to meet the actual needs of production.