Many years of practice at home and abroad have proved that cutting fluid and its treatment quality have great influence on the processing quality of parts, tool life, operating cost and environmental safety. The machine tools in the engine production line are densely arranged, and the processing requirements are high. Correct selection of cutting fluid treatment method is the key to make good use of cutting fluid and give full play to its processing support function. Yantai chengbo machinery technology department

According to the cooperation experience with many automobile engine manufacturers at home and abroad, the following factors should be considered in the selection of cutting fluid treatment systems for five automobile engine production lines:

◆ Nature and quantity of processing equipment; The process layout of the machine tool and the location and area of the replacement cutting fluid treatment system;

Materials of parts to be processed (castings, steel parts, aluminum alloy parts, etc.). ) and chip production per hour?

◆ Start machining from blank or finish machining from semi-finished products?

◆ Selection of cutting fluid: oil-based? Waterborne? Synthetic? Concentration?

◆ Requirements for filtration accuracy and temperature control of cutting fluid?

◆ Liquid supply and pressure of each machine tool?

◆ Chip removal and drainage mode of production line machine tools?

According to the above factors, the cutting fluid treatment system can be selected correctly, so that the expensive precision machining equipment can give full play to its efficiency. When choosing a real processing system, we should consider the following specific issues: 1. Does the processing system adopt single machine matching or centralized processing? If you choose to concentrate, is it a small regional concentration or a large concentration? Secondly, what kind of filtration method, what kind of liquid supply requirements and liquid return methods are adopted? Finally, cutting fluid quality management-temperature monitoring and control, concentration monitoring and adjustment, automatic liquid preparation and rehydration, oil-water separation, degreasing and sterilization, purification, regeneration and recycling, and other measures to improve operation quality, reduce operation cost and improve environmental protection? Disposal of invalid cutting fluid?

1. Single machine support or centralized processing?

The choice of single machine and concentrator mainly depends on the matching requirements of machine tools for cutting fluid treatment equipment and the overall design intention of the factory. For example, the multi-station processing production line in the form of assembly line can only collect chips and cutting fluids offline for centralized processing; The machining center has completed many original processes on one machine tool, so that chips and cutting fluid can be processed separately and centrally.

This choice is also related to the type and chip removal structure of the machine tool, especially the chip removal and liquid drainage form of the machine tool, which is directly related to the liquid return mode. If these problems are considered when ordering machine tools and equipment, it will be beneficial to the selection of cutting fluid system. The way of liquid return will also affect the environmental quality of the workshop, and the control of these pollution sources is also related to the choice of cutting fluid system.

There are a large number of machine tools in the engine production line, and a single machine will need more auxiliary space, which is not conducive to intensive process layout. With the rapid development and variety of engine products, it needs to be constantly updated, so the flexible production line has great advantages. More and more engine production lines at home and abroad pursue high quality and high efficiency, or adopt cutting fluid for centralized treatment by line or centralized filtration by region. Its advantages are:

◆ It is conducive to the reasonable arrangement of machine tools and logistics, and reduces the occupied area of equipment;

◆ It is beneficial to improve the production environment and realize environmental protection in the workshop;

◆ Conducive to the quality control of cutting fluid, thus stabilizing the machining quality and prolonging the life of tools and machine tools;

◆ Conducive to the purification, regeneration and recycling of cutting fluid, reducing waste liquid discharge and operation cost;

◆ Conducive to the environmental protection treatment of chips and the recycling of resources.

Because the five parts of the engine are processed according to the product assembly line, the liquid supply and return system can be lightened according to the small concentration of the production line area, which is beneficial to the overhead layout of the pipeline and increases the flexibility.

2. Selection of filtration mode of centralized processing system

The choice of cutting fluid filtration mode mainly depends on the requirements of cutting fluid filtration accuracy, because different filtration modes can achieve different filtration accuracy; Secondly, the requirements of different chip performance for filters; Thirdly, we should consider the influence of chip removal and drainage methods on the filtration system. Of course, investment and operating costs and environmental protection are also important considerations.

Due to the differences in workshop, equipment, parts materials, processing technology, chip shape and cutting fluid properties, there are many systematic schemes for centralized treatment of cutting fluid.

1. Selection of filtration precision and filtration mode of cutting fluid

Different filtering methods can achieve different filtering accuracy. In order to meet different processing conditions, multistage combined filtering method is often used. At present, the commonly used large-flow centralized filtration methods, the filtration accuracy that can be achieved and the applicable treatment process can be summarized as follows:

1) paper tape filtration (gravity, negative pressure or positive pressure)

Disposable filter paper has the highest filtration accuracy among all kinds of filtration materials, but when it is used for negative pressure and large flow filtration, the economical and reasonable filtration accuracy is about 20 ~ 60u, especially suitable for wear debris filtration. Because the filter paper is easy to be cut by sharp chips when the chain and scraper push it, it is usually pre-separated by adding chips to separate most of the cutting chips from the cutting fluid, so that the filter paper can be finely filtered. Paper tape filter with chip pre-separation can be used in almost all kinds of machining processes, such as cutting and grinding, from rough machining to general finishing. Suitable chip materials can be steel, cast iron, malleable cast iron, aluminum alloy and powder metallurgy. Filter paper can suck and take away cutting fluid, so it is mostly used for water-based emulsion and less used for cutting oil. In addition, disposable filter materials have waste disposal problems.

2) Circulating belt filtration (gravity type, negative pressure type or positive pressure type)

The gap of the circulating belt can be several microns to several hundred microns, but in the centralized large-flow filter, the circulating belt is cleaned by vibration and clear liquid backwashing, and the fine circulating belt will increase the backwashing difficulty, so the economic filtration accuracy is about 100~230u ~ 230 U, and the circulating belt filtration is more suitable for cutting, and the suitable chip materials are steel, aluminum alloy and other materials without fine powder.