Method of cleaning castings in
lost wax casting process --There are three kinds of casting cleaning methods in
lost wax casting process : mechanical method, physical method and chemical method.Mechanical method is the use of a variety of manual and motor tools or different types of mechanical equipment produced by the pressure, impact, shear, grinding and other forces acting on the casting, in order to achieve the purpose of cleaning.The physical method is to clean up the casting using arc, plasma, laser, ultrasonic wave and shock wave. The chemical method is sticky sand using hydrofluoric acid dissolved silica and salt solution electrolysis, remove small castings; also has the characteristics of cutting and cutting by oxidation of intense oxidation of some metals at high temperature.
In addition to the core and surface cleaning is divided into dry and wet method. Two kinds of dry cleaning method to clean the castings by mechanical devices. The device is simple, high production efficiency, has great adaptability and can effectively clean the surface of the core in addition to the advantages of different types of castings.The disadvantage is the operation of equipment, often flying dust and noise pollution of the environment. No wet cleaning dust, but by using water as medium, the casting surface is easy to rust. To produce a large number of sewage and cement with sand in the work process, bring the sand and water regeneration and sludge treatment and other issues.
Dry and wet cleaning are commonly used in production:①drump cleaning.The casting and ferroplasm together into a circular cylinder, when the drum rotates, rely on iron castings, star, waste sand between the impact and friction of the scavenging effect of casting sand and grinding, the surface of the casting, but also can remove part of burr.Medium and small sized castings of this kind of equipment for cleaning the shape is simple, with thick walls. ②The blasting. The use of high-speed movement of steel, iron balls, abrasive flow impact strength to clear the core, sticky sand, polished surface of casting .③hydroblasting.The high pressure water is injected into the treated castings from the spray nozzle through the pipe, and the core and the casting sand are removed by the kinetic energy and scouring action of the flow.Hydraulic cleaning is usually made consisting of steel and steel exposure to clean up the room is arranged at the bottom of the rotary table, the spray gun is installed on the side wall can move up and down and turn any part of the high-pressure water flow at the bottom surface of the casting except.Sometimes, in order to improve the efficiency of removing sand on the surface of castings, the abrasive sand such as quartz sand is introduced into the proper position of the spray gun to obtain high speed water sand flow.④Water blasting and sand cleaning.After pouring casting, casting cooling to a prescribed temperature hit the box, immediately be immersed in water in the pool, all the water into the gap in mold and metal contact with high temperature rapid vaporization of explosion shock wave can be attached to the sand casting and clearance.Water blasting sand cleaning method has the advantages of short operation time and high efficiency, and has been widely used in China's cast steel workshop. It is generally used to deal with the
steel castings with simple shape with carbon content less than 0.35%.⑤electro-hydraulic cleaning.The use of special high-voltage discharge electrode in the water, a sand wet work shock waves. This method is easy to control, high efficiency and low energy consumption. But the process noise, nitric oxide and ozone, electromagnetic radiation X ray protection, high investment.
