Sand casting process, 8 steps detailed analysis
Sand casting process, 8 steps detailed analysis
The sand mold casting process is a casting method for preparing molds with sand as the main molding material. Sand casting is the most traditional casting method.
Due to the characteristics of sand casting ( not limited by the shape, size, complexity and alloy type of parts, short production cycle and low cost ), sand casting is still the most widely used casting method in casting production, especially single or small batch castings !
The traditional sand casting process has the following steps : sand matching, mold making, core making, molding, pouring, sand dropping, grinding, inspection and other steps.
1. sand mixing stage, the preparation of molding sand and core sand, for the use of modeling, the general use of sand mixer into the old map and an appropriate amount of clay line stirring.
2.Molding stage, according to the parts of the drawings to make molds and core boxes, generally a single piece can be used wood molds, mass production can be made of plastic molds or metal molds ( commonly known as iron molds or steel molds ), large quantities of castings can be made mold board. Now the mold is basically used engraving machine so the production cycle is greatly shortened, the mold generally takes 2 to 10 days.
3.molding ( core making ) stage : including molding ( using sand to form the cavity of the casting ), core making ( forming the internal shape of the casting ), mold matching ( putting the core into the cavity, closing the upper and lower sand boxes ). Molding is the key link in casting.
4.melting stage : according to the required metal composition with good chemical composition, select the appropriate melting furnace melting alloy material, forming a qualified liquid metal ( including qualified composition, temperature qualified ). Melting generally adopts cupola or electric furnace ( due to environmental protection requirements, cupola is now basically banned, basically using electric furnace ).
5.pouring stage : the molten iron in the electric furnace is injected into the mold with the molten iron ladle. Pouring molten iron needs to pay attention to the speed of pouring, so that the molten iron fills the entire cavity. In addition, pouring molten iron is more dangerous to pay attention to safety !
6.cleaning stage : after pouring melt metal solidification, take the hammer to remove the gate and shake off the casting sand, and then use the sandblasting machine for sandblasting, so that the casting surface will appear clean ! The casting blanks that are not strictly required can be basically sent out after inspection.
7.casting processing, for some special requirements of the casting or some casting can not meet the requirements of the casting, may need simple processing. Grinding wheels or polishing machines are generally used for processing and polishing to remove burrs and make castings smoother.
8.casting inspection, casting inspection generally in the process of cleaning or processing stage, unqualified generally have been found out. However, some castings have individual requirements and need to be checked again. For example, some castings need a central hole to insert a 5 cm shaft, so you need to take a 5 cm shaft to try.
Conclusion : After the above eight steps, the casting is basically formed. For the castings that require high precision, machining is needed, because it does not belong to the casting scope. With the progress of casting technology, traditional sand casting is either improved or replaced by other casting methods. Continuous innovation is the eternal theme, and it is the inherent quality and foundation that a foundry must possess !