What kinds of fixtures used in CNC machining
(1) General cnc machining fixture
The universal cnc machining fixture refers to a fixture that has been standardized and can be used to machine different workpieces within a certain range. For example, three-jaw chucks and four-jaw chucks, top and center chucks on lathes, flat-nose pliers, indexing heads, and rotary tables on milling machines. They are very versatile and can be used to hold different workpieces without adjustments or slight adjustments. Such fixtures have generally been standardized. Produced by professional factories and supplied to users as machine tool accessories.
(2) special cnc machining fixture
Dedicated cnc machining fixture refers to a fixture specially designed for the machining of a certain workpiece. It has the advantages of compact structure, rapid operation and convenience. The special fixture is usually designed and manufactured by the user in accordance with the requirements. It is applicable to the production of fixed products and large batch production.
(3) Combination cnc machining fixture
Combination cnc machining fixture is a set of pre-manufactured standard components and parts with different shapes and sizes according to the standardization of machine tool components. According to the principle of combination, the assembly process is required for the workpiece. Into a variety of special fixtures. After the fixture is used, it can be disassembled and left for use when assembling a new fixture.
Combination cnc processing fixtures have a wide range of applications. It is most suitable for many varieties, rapid product changes, new product trials and single small batch production and other occasions, in the batch production can also use the combination fixture to replace the temporary shortage of special fixtures to meet the production requirements. With a combination of fixture components can be assembled into various types of machine fixtures. The emergence of numerically-controlled machine tools and flexible manufacturing units has further promoted the advancement of modular fixture technology and expanded the application range of modular fixtures.
The combined cnc machining fixture has the following features: The combined cnc machining fixture components can be used many times, but once it is assembled into a fixture, the fixture structure is still dedicated and can only be used once. When changing the processing object, generally still need to be completely disassembled and reassembled into a new fixture structure to meet the processing requirements of the new workpiece. Unlike the special cnc machining jigs, the final precision of the combined cnc machining jigs is guaranteed by the precision of each component and is directly combined. It is not allowed to perform any supplementary processing, otherwise the interchangeability of the components cannot be guaranteed. Since the combination fixture is composed of standard components, the rigidity is poor, especially the contact surface stiffness of the component connection, which has a great influence on the machining accuracy. The general combination fixture has a large external dimension and is not as compact as a special fixture. This kind of fixture is not limited by the type of production and can be assembled at any time to meet the urgency of production.
(4) Assembled cnc machining fixture
Assembled cnc machining fixture refers to a specific cnc machining process in which a certain workpiece is processed according to the processing requirements of a certain workpiece. The standardized and serialized fixture components are directly assembled by the special cnc machining fixture assembly method (pin positioning, bolt fastening). Fixtures. The use of assembly fixtures greatly shortens the design and manufacturing cycle of special fixtures, and when the product is modified, most of the components of the original fixture can still be removed and reused, which is suitable for production in many varieties and small batches.
(5) Universal adjustable cnc machining fixture
The universal adjustable cnc machining fixture refers to a special fixture formed by adjusting or replacing individual positioning elements or clamping elements according to different sizes or types of workpieces. The processing object is not very definite, and the general scope is relatively large. It is applicable to many varieties and small batch production.
(6) Group cnc machining fixture
Group cnc machining fixture refers to an adjustable fixture designed for machining a group of parts in a group process. The processing object is clear. Only the adjustment or replacement of individual positioning elements or clamping elements can be used. The adjustment range is limited to the workpieces of this part group and is suitable for group machining.