The hottest pulse electrochemical deburring proces

Pulse electrochemical deburring process (1)

the burrs produced in the manufacturing process of mechanical parts not only directly affect the accuracy and appearance quality of the parts themselves, but also affect the service performance and service life of the whole product. In addition, because the deburring process takes man hours and expenses, it will directly affect the cost and price of products and become one of the obstacles to reducing production costs. The annual cost of deburring around the world is about 10billion dollars. At present, foreign countries have studied the burr problem from the perspective of system engineering, and established the "worldwideburrtechnologycommittee" (wbtc) to vigorously implement the "burrengineering". Deburring process belongs to the field of surface finishing. At present, it mainly adopts scraper, oilstone, abrasive cloth, steel, which has become a reality. Manual or mechanical methods such as wire brush wheel, roll grinding, vibration, sand blasting and impact, as well as non mechanical methods such as chemical, high temperature, water jet, abrasive extrusion, electrochemistry, pulse electrochemistry and so on (the aviation industry also adopts robot grinding and other methods to deburr). These different deburring methods have their own advantages and disadvantages. Deburring is generally the final finishing process of parts, so while deburring, it must also ensure that the parts have good surface quality, and its processing effect is closely related to the selected deburring process

2pulse electrochemical deburring mechanism

pulse electrochemical deburring is an advanced deburring process that meets the requirements of "green manufacturing". In this process, pulse power supply is used instead of DC power supply, and processing is carried out in nonlinear electrolyte; During processing, the workpiece is connected to the positive pole of the pulse power supply, and the tool electrode corresponding to the burr part is connected to the pulse deep excavation technology. Using the negative pole of the power supply, a small processing gap is maintained between the workpiece anode and the tool cathode, and the tool cathode has no feed. The process has the following characteristics: ① since the electrolyte used for processing is neutral inorganic salt solution, it will not pollute the environment; ② Because the gap effect of pulse current and the stirring effect of pressure wave improve the electric field and flow field conditions in the machining gap, and reduce the requirements for electrolyte flow characteristics, it is conducive to obtain a stable and ideal machining process; ③ Because there is no cutting force in the machining process, no additional stress and surface modification layer will be formed, so the micro geometric morphology of the machined surface and the physical, chemical and mechanical properties of the parts can be improved

m-ne → mn+

m. In addition, South Korea and China have some new downstream capacity plans to put into operation this year. The basic electrochemical reaction formula of n+n (OH) → Fe (OH) n ↓

tool (cathode) is

2h++2e → H2 ↓

during processing, a thin oxide film is formed near the workpiece anode, which can play an isolation role between the workpiece anode and the electrolyte. The oxide film has high resistance and small conductivity, which can prevent the further dissolution of the anode surface of the workpiece, and has a certain protective effect on the anode of the workpiece. Under the rapid scouring action of electrolyte, the oxide film at the depression of the anode surface of the workpiece is thick because it is not easy to diffuse; The oxide film on the protruding part of the anode surface of the workpiece (such as burrs, micro protruding parts, etc.) is thin because it is easy to diffuse. Due to the uneven distribution of the oxide film, the protruding parts such as burrs are always in contact with fresh electrolyte, so the metal dissolution rate of the burrs is much higher than that of other parts of the anode surface, so that the burrs are dissolved and removed quickly

in the process of anode dissolution, according to the basic law of electrochemical machining (Faraday's Electrolysis law), it can be deduced that the deep etching speed VA (mm/min) of the metal anode (workpiece) along the feeding direction is

where: H - current efficiency

W - Volume electrochemical equivalent of the electrolyzed substance (mm3/a · h)

I - current density (a/cm2)

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nbsp; When the composition, concentration, processing temperature and other parameters of the electrolyte are determined, the etching speed of a certain point of the anode mainly depends on the current density I passing through the point

according to the electric field theory, the charge is concentrated at the protruding parts such as burrs on the surface of the part, and less at the surface depression. Due to the uneven distribution of power lines, the power lines in the protruding parts are densely distributed, the current density is high, and more metal is removed (see Figure 2); The power lines in the depression are relatively sparse, with low current density and less metal removal. Because the current density passing through the burr is much higher than other parts of the anode surface of the workpiece, the burr is dissolved rapidly

to sum up, I also participated in this competition. As the oxide film is unevenly distributed and the oxide film on the protruding parts such as the burrs on the anode surface of the workpiece is thin, it can always be in contact with fresh electrolyte, so the electrochemical reaction speed is fast; Due to the uneven distribution of power lines, the power lines at the protruding parts such as burrs on the anode surface of the workpiece are densely distributed, the current density is large, and the etching speed is fast. Therefore, pulse electrochemical deburring can quickly remove and dissolve burrs and form smooth rounded corners. Through the reasonable use of tool cathode shielding technology, burr can be selectively removed without affecting the original dimensional accuracy and surface quality of the anode surface of the workpiece