Application of Group Technology in NC Machining

Group technology GT is based on the similarity of things. The principle of group technology can be applied to any situation where similarity exists. At present, group technology has been successfully applied in all aspects of production activities, including product design, manufacturing process and production management. Especially in recent years, the development of group technology has emerged a new situation combined with numerical control technology. Both group technology and numerical control technology are aimed at improving the production level of multiple varieties and small batches. The former is through the rational organization of the processing object, and the latter is through the flexible automation of the realization process. Although the numerical control processing has various advantages, if it is not properly organized in production, it is still difficult to obtain good economic effects. A considerable number of CNC machines are not able to fully utilize their performance. More companies are conducting economic analysis based on current production methods, and it is even impossible to generate motives for purchasing CNC machine tools. This has made advanced equipment and processing methods aimed at improving the production level of multi-variety and small batches long-term rejected by many varieties. In addition to small-volume production companies, or even the introduction of enterprises, they can not play their due role. The implementation of the group technology will enable the enterprise to solve the above problems in the case of normal production tasks, and the numerical control processing is used in the enterprises that implement the group technology, and the implementation effect of the group technology is further improved. The combination of grouping technology and CNC machining will make it possible for these two technologies with common goals to maximize their benefits. This article makes a simple discussion on how to apply group technology in NC machining, and hopes to get the criticism from peers. Correction 1 Group technology applied in CNC machining 1.1 Selecting the appropriate and sufficient processing price of CNC machine tools for CNC machine tools Ordinary machine tools are much higher. Only when the investment of CNC machine tools can be rewarded in a short period of time can the economic effect of CNC machining be revealed. Therefore, it is necessary to select appropriate machining parts for the CNC machine tools to make them work at full capacity. Foreign studies believe that general CNC machine tools are better to maintain continuous work in the two-shift system (taking into account the high wages of night shifts), so it is possible to recover equipment investment within 7 years. However, in the case of machine tools that are particularly expensive, many companies make it work day and night in addition to maintenance. However, there are still many problems in the rational use and improvement of the utilization rate of CNC machine tools in many enterprises. The contradiction between high-efficiency equipment and low utilization rate has not been completely solved, especially in some enterprises in China.

If the parts have been coded and grouped in the factory, appropriate criteria can be specified for the parts that are suitable for machining for each CNC machine and a search command can be formed. With this search command, a part or part family suitable for machining on each CNC machine can be retrieved from a large number of parts produced by the company. The parts in the new products that will appear in the future can also be judged by this method to be suitable for machining on CNC machine tools. This can make appropriate and sufficient selection of the parts machined on the CNC machine tools, so that the CNC machine tools can be used reasonably. .

1.2 Programming the part family In order to be able to machine a part on a CNC machine, a CNC machining program must be programmed for the part. The usual CNC machining programming work is done separately for each part, which takes a lot of manpower, time and expense.

Even with computer-aided programming, it is necessary for people to carry out the process analysis of the parts, write the source program, and then add calculations until the control strip is made and the control strip is verified, which not only has a large workload, but also has a long programming cycle, and There are often many repetitive tasks.

If the group technology is implemented and the parts are organized, the various parts in the part family have similar process characteristics, so the NC machining program must be similar. At this time, a unified CNC machining can be developed for each part family. The program system, which includes all common or similar program units of the same CNC machining process of the part family, and is stored in the computer program in the form of a computer program, as the basis of the NC machining programming of each part family, which is called "part family programming". ”

When a part programming data processing program is called, the main program of the corresponding part family is called, and a small amount of different information of the part is input, and the numerical control processing program of the part can be compiled on the basis of the main part of the part family. Get the control belt.

1.3 Using group technology to organize production, give full play to the performance of CNC machine tools Although CNC machining realizes the automation of the process, it saves the auxiliary time of the machining process, and at the same time, because of its adaptability to the transformation of the machining object, the adjustment time of the machine tool is greatly reduced. However, if the production is still organized in a conventional manner, there are problems such as long and complicated transportation routes of the workpieces in multi-variety and small-volume production, large amount of products in production, long production cycle, and frequent machine stoppages. In this way, CNC machining can not play its due role in improving the production level of multiple varieties and small batches.

According to the group technology, the above problems can be satisfactorily solved by scientifically organizing the processing objects and processing equipment, rationally distributing the machine load and scheduling the operation plan. In such a production environment, CNC machining has the opportunity to fully exploit its superiority.

Second, a group of devices organized according to group technology is always a group or groups of similar parts. For each machine tool, the machining object has only a small range of variation, which reduces the requirement for the adaptability of the CNC machine. In this case, a CNC machine with fewer functions or smaller specifications can be selected. Therefore, it is possible to save investment in numerical control equipment.

1.4 Improve the production level of group production units Table 3 Various types of mining machinery noise intensity Equipment type Noise level dB belt conveyor 75-85 motor, gear transmission 85-95 compressor, diesel engine, fan 9-100 pneumatic filling machine 95 -105 Ground Main Fan 100 120 Scraper 10th110 Pneumatic Rock Drill, Pneumatic Loader 105-120 Two Pneumatic Rock Drills in the Alleys 12th130 Table 4 Downhole Gas Hygiene Standards Efforts: First, improve the equipment that affects the dust concentration, in rock drilling The crushing machine is equipped with an effective dust removing device; the second is to use a local airflow system to alleviate the dust problem, that is, the ventilation device is used to change the main airflow direction to avoid the dust source or change the flow direction of the dusty air to avoid the equipment operator.

3 Pay special attention to safety. Of course, mining machinery must make continuous efforts for the safety of mining operations. At present, there are several trends in this respect: 1 to improve equipment reliability; 2 to use remote control equipment; 3 to focus on ergonomics. For all mobile equipment in mines, especially mining vehicles, in order to ensure safe operation, the reliability of the braking system, steering system and operating system will be continuously improved.

Mechanization of mines can increase productivity, which has been recognized by everyone, but mechanization itself may not improve production safety conditions. In fact, some safety accidents are caused by equipment, and of course there are some environmental hazards other than machinery. The use of remote control equipment can achieve the dual goal of improving labor productivity and improving production safety conditions. V For mining vehicles such as scrapers, the use of ergonomics to create comfortable working conditions for drivers is essential to the safety of drivers. For example, the size of the cab should meet three basic requirements: 1 space comfort; 2 work comfort; 3 observation comfort.

4 Conclusions 4.1 All countries in the world attach great importance to the safety of mining operations. 4.2 During the entire life cycle of mining machinery, especially in the planning, design, manufacturing and other stages, it is essential to pay great attention to improving the reliability and maintainability of mining machinery. of.

4.3 The environmental pollution caused by mining machinery is mainly noise, exhaust and dust. Therefore, the key to controlling environmental pollution is to control it within the limits set by the standards.

(Finish)

PSA Oxygen Generation Plant

Pressure swing adsorption (PSA) is a technique used to separate some gas species from a mixture of gases (typically air) under pressure according to the species' molecular characteristics and affinity for an adsorbent material. It operates at near-ambient temperature and significantly differs from the cryogenic distillation commonly used to separate gases. Selective adsorbent materials (e.g., zeolites, (aka molecular sieves), activated carbon, etc.) are used as trapping material, preferentially adsorbing the target gas species at high pressure. The process then swings to low pressure to desorb the adsorbed gas.