Domestic demand for engineering and hoisting and transporting machinery is increasing with the rapid development of the national economy. In order to meet the needs of well-known foreign brands entering China after China's accession to the WTO, the major manufacturers of engineering and lifting and transport machinery, Have been committed to the development of new products, expand the market, improve product quality and enhance product quality, and now the OEMs on the quality of parts and components, especially the reliability of parts quality is getting higher and higher, as the host infrastructure components Of the hydraulic valve, compared with the performance of well-known brands abroad, the difference is mainly poor reliability, easy to leak. Hydraulic parts to oil as a working medium, the system is more sensitive to pollution, the troubleshooting process is complex, so the quality of auxiliary processing is particularly important, more and more by the OEM attention. As auxiliary processing removal of sticky sand, burrs and other hydraulic parts and their systems will bring the following effects: (1) With the host of the ongoing commutation, vibration, sticky sand, burrs will fall off at any time, while the pollution system Oil and cause the card valve, cylinder and filter clogging, which is leading to poor reliability of the host key factors; (2) reduce the valve assembly rate of qualified assembly, affecting the production efficiency; (3) reduce the body and paint Adhesion, affect the appearance of the product. Foreign hydraulic parts manufacturers attach great importance to the auxiliary processing, auxiliary processing investment accounted for 20% to 30% of production costs, and even more. In China, some hydraulic parts manufacturing plant did not pay enough attention to the auxiliary processing. The equipment used was simple, the quality of personnel was poor and the method was more primitive. Therefore, the auxiliary processing quality severely restricted the gap between domestic hydraulic valve and hydraulic valve of well-known foreign brands The process. How to improve the auxiliary process quality, improve the cleanliness level, to ensure the reliability of product quality, hydraulic valve manufacturers are faced with a thorny issue, combined with the actual situation in our plant, hydraulic valve auxiliary processing point of view, and Explore with colleagues to improve the quality of domestic products hydraulic parts. Auxiliary hydraulic parts processing include: body cleaning, deburring parts, heat treatment to the residue and cleaning content 1, the body of the class of sand-made hydraulic valve body to the vast majority of ductile iron, vermicular iron, gray iron Material, resin sand as a molding medium Flour sand casting, with small size, compact structure, complex shape and high accuracy requirements, the quality of the casting largely determines the grade of the hydraulic valve. Because of the sand body for the valve body shape of the material, it is inevitable in the casting of sticky sand there. Sticky sand is more dangerous to hydraulic systems. There are many ways to remove sticky sand, commonly used in China are cylinder sand cleaning, shot blasting, electrochemical sand cleaning and water blasting sand. Shot peening sand generally used for open or large oil passage of the valve body and after roughing the body of sand, it can not only remove the sticky sand, but also remove the rust and roughing generated burr, in particular Liquid sandblasting, but also play the role of decorative surface castings. Electrochemical sand cleaning is the use of (SiO2) and molten NaOH starting electrochemical reaction of sodium metasilicate and water can be relatively clean to remove sticky sand within a narrow oil, so the two methods shot peening and electrochemical sand as the Valve body to fine sand method, widely used by various manufacturers. However, these two methods have some shortcomings: (1) sand blasting is suitable for larger oil chambers or open oil bodies, which have great limitations on complicated structures and small oil passage holes. Effective removal of sticky sand, and the processed surface is more likely to cause damage, thus affecting the sealing, aesthetics and product accuracy, and is not conducive to the processing arrangements; ⑵ electrochemical clear sand for some acyclic cavity is difficult to effectively go Net sticky sand, and high energy consumption, great damage to the environment, the workers operating intensity is high, so the complex pieces of sand are still under exploration. For small and complex castings sand, I introduce a method for your reference: artificial aging - pickling - rinsing - rust - ultrasonic cleaning. Its mechanism of action is: the use of artificial aging to reduce the bonding strength of the casting and sand, the use of pickling to remove the sand and casting at the junction of the oxide, sand and casting stripping, and then the use of ultrasonic cleaning burst of compressed air so that the sand off to achieve Purposes purpose. The method compared with other sand: ⑴ affected by the structure of the casting less; ⑵ before machining, does not affect the machining process arrangements; ⑶ although the environment has a certain impact, but add anti-fogging agent pickling, So that its impact on the environment to reduce; ⑷ casting surface was more beautiful silver white; ⑸ higher efficiency. The method should pay attention to the following points: ⑴ acid pickling must be added with the acid used to match the corrosion inhibitor; ⑵ Rinse immediately after the anti-rust treatment, and should pay attention to rust and deburring between subsequent processes. 2, slide valve parts to deburring and heat treatment residue hydraulic parts auxiliary process Another big problem is to machining burrs, heat treatment residues. The presence of burrs will have an adverse effect on the hydraulic parts, such as stem clamping, clogging of the damping orifice, in particular chrome-plated stem balance groove grinding, glitches with the radial hydraulic fluid into the valve stem and Valve hole clearance, not only can not eliminate the role of hydrodynamic, but will lead to the stem clamping, increased operating pressure or system pressure instability, fretting and pressure modulation performance degradation. Machining should use reasonable cutting parameters to control the generation of burrs, burrs generated should be arranged to remove the process, deburring methods are: manual method, vibration light decoration, belt grinding method, copper wheel or grinding Polishing machine polishing method, stainless steel wire brush polishing method, such as liquid sandblasting. The choice of method should depend on the actual situation. Relatively speaking, the valve body parts use a ball nylon brush or stainless steel wire brush to remove the valve hole burr, that is, before the fine hinge with a hand drill to clamp the brush to remove the cutting groove, the rough hinge sequence generated by the burr. Belt or copper wheel on the outer surface of the valve body to remove burrs and rust is more ideal for some of the thicker grinding flash should be first cut with a hacksaw blade, the inner cavity of other burrs liquid blasting method can be used to clean, for Quenching parts can be used special tools or wire brush to remove the oxide after quenching and other general vibration or acid wash can be removed, of course, pickling should be based on different materials with different acid and add appropriate degreasing agent and corrosion inhibition Agent. Generally, the addition of corrosion inhibitor will greatly reduce the corrosion of the parts by acids (generally reduce the corrosion by more than 85%). However, the addition amount should be strictly controlled, and excessive addition will reduce the corrosion resistance. After pickling parts anti-corrosion agent soaked, so parts will be silver-white and can completely remove the heat treatment residues and other dirt, significantly improve the cleanliness of quenching parts. Burr stems generated when the burr, especially chrome plated stem with balanced groove, rough grinding must be less than 0.1mm diameter wire wheel to remove the balance groove burr and sharp edge burr, the surface is not refined Allows the use of wire wheel polishing, but the cloth can be used sticky wax polishing, polishing must be washed with hot water, so as to avoid polluting wax paraffin oil. 3, hydraulic valve parts cleaning Hydraulic valve cleaning parts in hydraulic parts production is a key ancillary processes, its quality restricts the reliability and stability of the hydraulic valve. Cleaning quality and cleaning methods, cleaning fluid preparation, cleaning equipment and staff responsibility has a great relationship. 3.1 The valve body cleaning Body cleaning can be divided into four levels, namely, rough cleaning, ultrasonic cleaning, rinsing, high pressure flushing. Rough washing and rinsing should be sub-tank cleaning, the method can be a certain pressure of gas and water Chong, grinding class valve body should have burrs, demagnetization, polishing and other pretreatment. Rough and rinse cleaning fluid formulations the same, after rinsing with a large flow of diesel or antirust agent aqueous solution for irrigation. Ultrasonic cleaning fluid to be recycled, and added in the cycle of cleaning agents to improve cleaning performance. Cleaning considerations: (1) cleaning agent and anti-rust agent selection should be reasonable on the black metal and non-ferrous metals should be different, and even the selection of summer and winter are also different; (2) the water temperature should be able to meet the requirements, and Parts soaking time can not be too short, the general control of more than 10 minutes; (3) as much as possible to increase the rough, rinse water flow; (4) conditions allow the parts should be dried; (5) Punch and valve body should be the relative rotation or movement. 3.2 parts cleaning Now, the general manufacturers pay more attention to the cleaning of the valve body, while the slide valve and other parts of the cleaning is less attention, but in the actual production of sliding valve failure led to decline in assembly qualification rate, the factory Decreased reliability also occur from time to time. Parts of the cleaning, due to many types, the workload is also larger. Cleaning parts include cleaning glitches and dirt, chrome parts also include cleaning the inner hole residual chromate, parts can be cleaned using ultrasonic cleaning and then gas and water Chong Chong method, before cleaning the cleaning of the inner hole is more important, available with the same diameter Drill or reamer, the brush to remove dirt in the hole, the small hole should also check one by one to clear. Parts of the cleaning equipment and methods similar to the body, but should be high pressure and low flow of gas and water Chong, do not need to use diesel or anti-rust agent aqueous solution of high-pressure washing, cleaning rust treatment can be. Hydraulic valve auxiliary processing is a complex system engineering, it involves a very wide range, not only from the equipment to provide protection, technical continuous practice, summary, improvement. But also from the management seriously to grasp, to control, the only way to hydraulic valve auxiliary processing engage in, the content involved here is only some superficial experience, hoping to be able to domestic hydraulic valve assist The quality of processing has some benefits.
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