How To Select The Fixture And The Determination Of The Work Part Clamping Method Of The CNC Lathe

The fixture chosen by CNC machine tools is not suitable and will directly affect the productivity of CNC machine tools. According to incomplete statistics, domestic enterprises CNC machine tool selection of the unreasonable proportion of more than 50%. How to choose fixtures to improve the utilization rate of CNC machine tools? This has become something that machiners have to consider. Today for you to introduce the choice of CNC lathe fixtures, work parts clip the correct determination method.

One. The choice of fixtures.

There are two main requirements for fixtures in CNC processing: first, the fixtures should have sufficient precision and stiffness; When choosing a fixture, the following points are usually considered:

(1) Try to choose adjustable fixtures, combination fixtures and other applicable fixtures, avoid the use of special fixtures, in order to shorten production preparation time.  

(2) In mass production, only consider the use of special fixtures, and strive for simple structure.

(3) Loading and unloading work parts should be quick and convenient to reduce machine downtime.

(4) The fixture should be installed accurately and reliably on the machine to ensure that the work piece is machined in the correct position.

Two. The type of fixture.

There are two main types of fixtures on the CNC latha bed: one for disc or short shaft parts, work parts blanks clamped in the adjustable claws of the chuck (three claws, four claws), by the chuck drive rotation;

Three. Installation of parts.

The installation method of CNC lathe parts is the same as that of ordinary lathe, so we should reasonably choose the positioning reference and clamping scheme, and pay attention to the following two points:

(1) Strive to design, process and bias calculation of the benchmark unity, which is conducive to improve the simplicity and accuracy of numerical calculation in programming.

(2) Minimize the number of clamps, as far as possible after a clamping, processing out all the surfaces to be processed.

Four. Several modern CNC machine fixtures.

1, adjustable fixture.　　

Adjustable fixtures are divided into general adjustable fixtures and groups of fixtures (also known as special adjustable fixtures). What they all have in common is that individual positioning, clamping or guiding elements can be used for the machining of multiple parts, thus transforming a small batch production of multiple parts into a "mass production" of a group of parts on the same fixture. After the product is updated, as long as it belongs to the same type of part, it can still be processed on this fixture. Because adjustable fixtures have strong adaptability and good inheritance, the use of adjustable fixtures can significantly reduce the number of special fixtures, shorten the production preparation cycle, reduce costs.　　

2, combination fixture.　　

The combination fixture, also known as the "building blocks fixture", consists of a series of standardized design, different functions, different sizes of machine tool fixture components, customers can according to processing requirements, like "building blocks", quickly put together various types of machine tool fixtures. Because the combination fixture saves the design and manufacture of special fixture time, greatly shortens the production preparation time, thus effectively shortens the small batch production cycle, that is, improves the production efficiency. In addition, the combination fixture also has the advantages of high positioning accuracy, flexible clamping, recycling, energy saving, low cost of use and so on. Therefore, small batch processing, especially when the product shape is more complex, priority can be given to the use of combination fixtures.

3, precision combination of flat-jaw pliers.　　

Precision combined flat-jaw clamps are actually "joints" in combination fixtures, and are more versatile, standardized, easier to use and more reliable to clip than other combined clamps, making them widely used worldwide. Precision combination flat jaws have the advantages of fast installation (removal), quick clamping, etc., so it can shorten production preparation time and improve small-volume production efficiency. At present, the international commonly used precision combination flat-jaw clamp clamping range is generally within 1000mm, clamping force is generally within 5000Kgf.　　

4, electro-permanent magnetic fixture (electric permanent magnetic suction cup)　　

The electro-permanent magnetic fixture is a new type of fixture designed by using the principle of modern magnetic circuit based on new permanent magnet materials such as ferrite boron as the magnetic source. A large number of machining practices show that electro-permanent magnetic fixtures can greatly improve the comprehensive processing efficiency of CNC machine tools and processing centers.