Look here,50% of the machine tools selection Not reasonable
a quick question,Why the manufacturing efficiency of the same machines quite different? The conclusion is that the selection of the machine tools is not suitable which caused the efficiency of CNC machines greatly reduced. Then how to improve the utilization ratio of CNC machines? Through the technical analysis, the use of tools has a great relationship.
According to incomplete statistics, the unreasonable proportion of fixture selection for domestic enterprises’NC machine tools is as high as more than 50% . That is to say, more than half of the NC machine tools are not reasonable because of fixture selection or improper application From another point of view, there is much to be done in the selection and application of CNC fixture, because it contains considerable potential economic benefits. In order to make gold powder can better understand the fixture, the following introduction of several modern CNC machine tool fixture.
1.Adjustable fixture
Adjustable fixture is divided into general adjustable fixture and Group Fixture (also known as special adjustable fixture) two categories. Their common feature is that they can be used for processing various parts by replacing or adjusting individual positioning, clamping or guiding elements So that many parts of a single small batch production into a group of parts on the same fixture “batch production. “. Product updates, as long as the same type of parts, can still be processed on this fixture. Because the adjustable fixture has strong adaptability and good inheritance, the use of adjustable fixture can greatly reduce the number of special fixture, shorten the production cycle, reduce costs.
2.Modular fixture
Modular fixture, also known as “modular fixture” , is composed of a series of modular fixture components with standardized design, various functions and different sizes Fast Assembly of various types of machine tool fixture. Because the modular fixture saves the time of designing and manufacturing special fixture, it greatly shortens the time of production preparation, thus effectively shortens the period of small batch production, that is to say, improves the production efficiency. In addition, the utility model has the advantages of high positioning accuracy, large clamping flexibility, repeated use, energy-saving and material-saving in manufacture, low cost and the like. Therefore, small batch processing, especially when the product shape is more complex can give priority to the use of modular fixture.
3.Precision combination flat jaw pliers
The precision combined flat jaw clamp actually belongs to the “component” of the combined fixture, which is more universal, more standardized, more convenient to use and more reliable to be clamped than other combined fixture components Therefore, it has been widely used in the world. The precision assembled flat jaw pliers have the advantages of rapid installation (disassembly) and rapid clamping, so it can shorten the production preparation time and improve the efficiency of small batch production. At present, the international commonly used precision combination flat jaw clamp clamping range is generally within 1000mm, clamping force is generally within 5000Kgf.
It should be noted that the precision combination flat jaw pliers mentioned here are not the old machine plus vise. The old machine plus vise has a single function, low manufacturing accuracy, can not be used in groups, and has a short service life Not Suitable for use on CNC machine tools and machining centers.
4.Electric permanent magnet clamp
The electro-permanent magnetic fixture is a new type of fixture which uses neodymium-iron-boron and other new permanent magnetic materials as magnetic source and uses modern magnetic circuit principle. A large number of machining practice shows that the electric permanent magnet fixture can greatly improve the overall machining efficiency of CNC machine tools and machining centers.
The clamping and unclamping process of the permanent magnet fixture only takes about 1 second, so the clamping time is greatly shortened The permanent magnet fixture does not have these space-occupying components, so compared with the conventional CNC fixture, the permanent magnet fixture has a larger clamping range, which is conducive to making full use of the CNC machine tool work table and processing trip It is beneficial to improve the comprehensive machining efficiency of CNC machine tools. The suction force of the permanent magnet fixture is usually 147 ~ 176.4 N / CM2. Therefore, it is necessary to ensure that the suction force (clamping force) is sufficient to resist the cutting force. In general, the adsorption area should not be less than 30cm2, that is, the clamping force should not be less than 4.41 kn.
In the modern automatic production, the application of numerical control machine tool has been more and more extensive. In numerical control, the movement of the tool or table is controlled by a program in a certain coordinate position.
The following points should be noted when designing the CNC machine clamping tools:
- The original point (tool setting point) should be set on the CNC machine tools.
- There is no need to set the tool guide device in the fixture of NC machine tool. This is because the machines, clamping tools,cutting tools, and workpiece are always in a strict coordinate relationship, and there is no guide element between the tool and the workpiece to determine the position.
- the workpiece processing on the CNC machines often in several directions, so the CNC fixtures should be open.
- On the numerical control machine tool should choose as far as possible the adjustable Jig, the Assembly Jig and the combination Jig. Because CNC machine tools on the processing of the workpiece, often a single small batch production, must be used flexible, Short preparation time of the fixture.
- The clamping of NC machine fixture should be firm and reliable, easy to operate. The position of the clamping element shall be fixed so as to prevent the element from colliding with the cutter during the automatic processing.
