cnc parts|Did you choose the wrong fixture?

At present, mechanical processing can be divided into two categories according to the production batch: one is single-piece, multiple varieties, and small batches (referred to as small batch production); the other is small varieties and large batches (referred to as mass production). Among them, the former accounts for about 70-80% of the total output value of machining, and it is the main body of machining.
For the same machine tool, why is the production efficiency different by several times? The conclusion is that the selected fixtures of CNC machine tools are not suitable, which greatly reduces the production efficiency of CNC machine tools. Today, we will introduce in detail the reasonable selection and application of CNC machine tool fixtures.
How to improve the utilization rate of CNC machine tools? Through technical analysis, the use of fixtures has a great relationship.
Small batch production cycle ﹦production (preparation/waiting) time + workpiece processing time Since the "workpiece processing time" of small batch production is very short, the length of the "production (preparation/waiting) time" has a crucial influence on the processing cycle . If you want to improve production efficiency, you must find ways to shorten the production (preparation/waiting) time.
The following recommend three types of CNC machine tool fixtures that can be given priority for small batch production:

Combination fixture
Modular fixture is also called "building block fixture". It consists of a series of standardized design, different functions, and different specifications and sizes of machine tool fixture components. Customers can quickly assemble various types of fixtures according to processing requirements, just like "building blocks". Types of machine tool fixtures. Because the modular fixture saves the time for designing and manufacturing special fixtures, and greatly shortens the production preparation time, it effectively shortens the small batch production cycle, that is, improves the production efficiency. In addition, the modular fixture also has the advantages of high positioning accuracy, large clamping flexibility, repeated use, energy saving and material saving in manufacturing, and low use cost. Therefore, small batch processing, especially when the product shape is more complex, can be given priority to using modular fixtures.

Precision combination flat-nose pliers
The precision combined flat-nose pliers are actually the "combined parts" in the combined clamp. Compared with other combined clamp components, it has stronger versatility, higher standardization, easier use, and more reliable clamping. Therefore, it has been obtained worldwide Wide range of applications. The precision combination flat-nose pliers have the advantages of quick installation (disassembly), quick clamping, etc., so it can shorten the production preparation time and improve the efficiency of small batch production. At present, the clamping range of precision combined flat-nose pliers commonly used in the world is generally within 1000mm, and the clamping force is generally within 5000Kgf.
It should be noted that the precision combination flat-nose pliers mentioned here are not old-fashioned machine-plus-vises. The old-fashioned machine-plus-vises have a single function, low manufacturing accuracy, cannot be used in groups, and have a short service life. They are not suitable for use in CNC machine tools and machining centers. Used on. The precision combination flat-nose pliers mentioned here are a series of new-type flat-nose pliers originated from industrialized countries such as Europe and the United States, specially designed for the characteristics of CNC machine tools and machining centers. Such products have large clamping flexibility, high positioning accuracy, and fast clamping. , It can be used in groups, and it is especially suitable for CNC machine tools and machining centers.

Electric permanent magnet fixture
The electric permanent magnet fixture is a new type of fixture designed by using new permanent magnet materials such as neodymium iron boron as the magnetic source and using modern magnetic circuit principles. A large number of machining practices show that electric permanent magnet fixtures can greatly improve the comprehensive machining efficiency of CNC machine tools and machining centers.
The clamping and unclamping process of the electro-permanent magnet fixture only takes about 1 second, so the clamping time is greatly shortened; the positioning and clamping elements of the conventional machine tool fixture occupy a large space, while the electro-permanent magnet fixture does not take up space. Therefore, compared with conventional machine tool fixtures, electro-permanent magnet fixtures have a larger clamping range, which is conducive to making full use of the worktable and processing stroke of the CNC machine tool, and is conducive to improving the comprehensive processing efficiency of the CNC machine tool. The suction force of the permanent magnet fixture is generally 15~18Kgf/cm2, so it is necessary to ensure that the suction (clamping force) is sufficient to resist the cutting force. Generally, the suction area should not be less than 30cm2, that is, the clamping force should not be less than 450Kgf.

CNC machine tool fixture suitable for mass processing
Large batch processing cycle = processing waiting time + workpiece processing time + production preparation time "processing waiting time" mainly includes the time for workpiece clamping and tool change. The "workpiece clamping time" of traditional manual machine tool fixtures can reach 10-30% of the mass processing cycle, so "workpiece clamping" has become a key factor affecting production efficiency, and it is also a key object of machine tool fixtures "potential tapping".
Therefore, special fixtures with fast positioning and quick clamping (releasing) should be used for mass processing. The following three types of machine tool fixtures can be given priority:

Hydraulic/pneumatic fixture
The hydraulic/pneumatic fixture is a special fixture that uses oil pressure or air pressure as the power source to realize the positioning, support and compression of the workpiece through hydraulic or pneumatic components. The hydraulic/pneumatic fixture can accurately and quickly determine the mutual position of the workpiece, the machine tool, and the tool. The position accuracy of the workpiece is guaranteed by the fixture, and the machining accuracy is high; the positioning and clamping process is fast, which greatly saves the clamping and releasing of the workpiece. Time; At the same time, it has the advantages of compact structure, multi-station clamping, high-speed heavy cutting, and automatic control.

The above advantages of hydraulic/pneumatic fixtures make them particularly suitable for use in CNC machine tools, machining centers, and flexible production lines, especially for mass processing.

Electric permanent magnet fixture
The electric permanent magnet fixture has the advantages of fast clamping, easy realization of multi-station clamping, multi-face machining in one clamping, stable and reliable clamping, energy saving and environmental protection, and automatic control. Compared with conventional machine tool fixtures, electro-permanent magnet fixtures can greatly shorten the clamping time, reduce the number of clamping times, and improve the clamping efficiency. Therefore, it is not only suitable for small batch production, but also suitable for mass production.　　

Smooth fixture base
There are not many applications of smooth fixture bases in China, but it is widely used in industrialized countries such as Europe and the United States. In fact, it is the finished blank of the fixture base after finishing, and the positioning connection part of the component and the machine tool and the positioning surface of the part on the fixture have been finished. Users can manufacture special fixtures by themselves according to their actual needs.
Glossy fixture base can effectively shorten the cycle of manufacturing special fixtures and reduce production preparation time, thus can shorten the cycle of mass production as a whole, and improve production efficiency; at the same time, it can reduce the manufacturing cost of special fixtures. Therefore, the smooth fixture base is particularly suitable for mass production with tight cycle times.
Use fixtures rationally to tap the potential of equipment