Patent

Thermal deburring principle (2)

2019-06-03

Electrochemical deburring




    Rough and burr at the intersection of the channels inside the part has been a headache. Electrochemical deburring is a good way to solve these problems. This technology uses forming tooling to process selected parts of the workpiece. The electrolyte that turns on the current passes between the workpiece and the tooling, dissolves the burrs instantaneously, deburring, and produces uniform and precise intersections at the inner passages. Round the corners. Processing time is generally between 10 seconds and 30 seconds. Most workpieces use multiple tip tooling for higher productivity. The amount of removal depends on the amount of current between the workpiece (positive electrode) and the tooling (negative electrode). The electrode tip is typically designed to be symmetrical to the surface of the workpiece. The deburring operation is automatically and selectively performed on the parts made of the metal material. It can be widely used in the deburring of parts such as pneumatic, hydraulic, engineering machinery, nozzle oil pump, automobile, engine and other metal materials such as pump body, valve body, connecting rod and plunger needle valve.




    Electrochemical deburring is a characteristic and efficient production technology. It is suitable for processing various metal parts for deburring, forming machine processing, corner rounding and finishing. Cast, forged, machined, or EDM parts can be polished electrochemically. The amount of removal is between 0.01 mm and 0.5 mm. In general, the finish can be improved by 5 to 10 orders of magnitude. The polished product has a smooth surface and a shiny mirror.




    Typical applications for electrochemical polishing include: parts with high purity requirements; human surgical implants; bottle molds; and a wide variety of stainless steel parts. For example, when electrolytically processing the injector nozzle parts, a quantitative cavity with a smooth wall surface is machined at the center hole, and the intersecting holes and corners are rounded.




    The American electrolytic deburring device has the ability to process hundreds of products in one hour. The housing on the airbag device for an automobile is processed on an electrochemical deburring automatic system, and each housing has a total of 48 small holes, and the eight housings are simultaneously processed, and all the holes are deburred within 10 seconds.


     


    Polishing is an important process in the manufacture of cavity molds. Its cost accounts for 5% to 30% of the cost of the mold, and the molds that are urgently needed often cannot be kept in the polishing time. Electrochemical mechanical polishing, combined with the unique liquid polishing technology of the SD1 type, has been applied to various metal mold parts of complex shapes and received excellent results.


     


    Principle of electrochemical deburring


     


    Chemical polishing is the use of metal electrochemical anode dissolution principle for grinding and polishing. The combination of electrochemical pre-polishing and mechanical polishing is the combination of electrochemical and mechanical polishing. It is not limited by the hardness and toughness of the material, and it can polish a variety of complex shapes of the workpiece. The method is similar to electrolytic grinding. The conductive polishing tool uses a diamond conductive crucible or graphite stone, which is connected to the cathode of the power source, and the polished workpiece (such as a mold) is connected to the anode of the power source.


     


    The electric grinder can be used to grind and polish a variety of complex starting parts and molds, independent of the hardness of the material.


     


    ◆ After cavity machining by EDM, the hardness of the hardened layer composed of the molten layer and the heat-affected layer is as high as 60~70HRC. It is very difficult for the fitter to grind by hand. Electric grinding and polishing can effectively remove this layer of "hardened layer", and the roughness of the original performance of Ra4~7um is improved to Ra0.35~0.6um, and the productivity is about 3 minutes per square centimeter.


     


    ◆Use it to grind and polish complex shapes, especially the narrow slits, grooves, corners, roots and inner holes of the mold, which can significantly improve labor productivity.


     


    ◆Electric grinding can also be used to remove the residual burrs after machining the complex shapes or thin-walled parts of stainless steel and heat-resistant alloys, and flatten the sharp edges to improve the surface finish.


     


    ◆ Electrolytic polishing produces a very thin layer of black film on the surface, and then use a multi-purpose soft shaft mechanical polisher of 8000~2000 rpm, min to clamp the appropriate felt wheel, and apply a little green grease for surface polishing. , to produce a shiny surface. Its finish can also be increased by more than two. In addition, the mechanical soft shaft handle can be clamped with corresponding tools for drilling, milling, grinding, carving, cutting, polishing, etc., which is very flexible and convenient to use.


     


    Finishing technology of inner hole containing abrasive grinding brush


     


    The mechanical parts are subjected to the internal hole to be punctured and finished, which is an indispensable ** process in the production process of modern products, and the burr polishing process is performed without changing the original dimensional accuracy of the parts. The deburring polishing brush can remove the burrs generated by the deep holes, cross-correlation holes and concentric holes of the mechanical parts during the processing, and improve the quality of the parts. It is a necessary, economical and economical method for the machining process.


     


    The abrasive nylon yarn is a new type of polishing abrasive material, and the nylon filament is uniformly doped with an abrasive such as alumina or silicon carbide. According to processing requirements. Abrasive nylon yarns have excellent memory properties and bending recovery; they are almost unaffected by water and oil, and are resistant to most chemicals.


     


    The abrasive nylon yarn is equivalent to the same number of flexible boring tools. When machining the parts, it can be bent freely, naturally fits to the contour of the inner hole of the workpiece, and enters the place where the general tools such as grooves and cracks are difficult to enter, and the burrs are removed. The blunt is a smooth and even arc, which is ideal for deburring, edge passivation and surface finishing.


     


    Abrasive polishing brush can be used for hydraulic pump steering pump and hydraulic valve bore (including rotor, stator, oil distribution plate, valve hole, pump ** bore and connection plane), such as friction parts for the engine (including crankshaft After the inner hole, the inner hole of the camshaft, the inner hole of the piston, various gears, bushings, etc., the finishing process can be obtained.


     


    Abrasive-containing abrasive brushes can also be used for electroplating, before finishing coating, finishing of metal surfaces, finishing of aluminum profiles, finishing of cut surfaces, denim grinding, and sanding machines.


     


    Abrasive grinding brush deburring polishing processing features: Effectively remove the burrs and flash edges of the surface after processing, edge rounding, rust removal, descaling, etc.; on the original basis can improve the surface roughness level of parts 1-2 The physical and mechanical properties of the surface of the part are significantly improved and improved, such as eliminating surface stress concentration and micro cracks, increasing surface hardness, increasing the thickness of the wear layer, improving the performance of the parts, and prolonging the fatigue life.


     


    Improve the appearance quality and assembly performance of the parts, improve the quality and cleanliness of the whole machine, complete the initial wear of the transmission parts, and shorten the factory running-in time of the whole machine.


     


    Thermal deburring machine


     


    The thermal deburring machine uses gas (H2 or CH4) and oxygen as the main medium to generate instantaneous high temperature through the thermochemical action of the two. Under the action of differential heating law, the burrs and metal chips are immediately melted, and oxygen is enriched. Continue to oxidize to become ash ash and deposit on the working surface to achieve satisfactory deburring**.


     


    Thermal deburring principle


    The thermal deburring method uses high temperature to remove the burrs and flash of the parts. The machined parts are placed in a sealed combustion chamber, and the combustible gas (natural gas/methane/hydrogen) and oxygen are charged into the cavity at a certain ratio and pressure. The flammable gas wraps the inside and outside of the parts as well as the burrs and flash edges, and densely fills the parts. Inside, outside, inside the hole, even inside the blind hole. The gas is ignited by the spark plug to instantaneously generate a high temperature above the ignition point. Since the burr and the flash edge are higher than the surface of the component, when the temperature rises sharply above the burr or flash ignited point, the small volume of the burr and the flash edge burn. The burr burns to the main body of the workpiece, and when the temperature rapidly drops below the self-ignition point, the excess oxygen and burrs in the cavity are mixed into oxidized dust. This process is short enough to burn the burrs and flash without affecting the workpiece itself. After combustion, the oxidized residue of burrs and flashes that fall on all surfaces of the workpiece can be washed away with a solvent.


     


    Advantages: Thermal deburring has the characteristics of removing burrs and flashing without affecting and damaging the size or metallographic structure of the workpiece. The thermal method removes burrs from any part of the part, including parts that cannot be reached by hand, intersections of holes in the parts, and even burrs in blind holes. It is better than manual deburring is:


     


    ◆ It is not necessary to check whether there are unremoved and unremoved burrs after processing, which is reliable and efficient;


    ◆ Can handle a variety of materials: zinc, aluminum, copper, steel, stainless steel, cast iron, and hot melt plastic parts;


    ◆ Similar parts, even if they are slightly different in size, can be put together for processing; for parts with different sizes, only some processing parameters need to be adjusted slightly, and even without changing the time;


    ◆ greatly reduce production costs and ensure the quality and longevity of parts.


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