Roller nc machine tool castings cast iron characteristics and measures to reduce the heat source

For the determination of nc machine tool castings shrinkage rate, simple to 1% by 1%, complex parts by first making a test, to determine each kind of large machine tool castings suitable shrinkage rate.Some castings, according to the test results in length, width and height of three direction take different shrinkage rate.The selection of process parameters and process parameters on the casting dimension accuracy and outline sharpness has great influence.After many process test, choose carefully for each process parameters.Draft Angle, for example, take the minimum value, and press the add and subtract thickness method selected;Parting negative should be fully considered and the casting contraction of mutual compensation.Appearance quality refers to the large machine tool casting surface roughness, surface defect, size deviation, deviation of shape, and weight deviation;Inner quality refers to the large machine tool castings chemical composition, physical properties, mechanical properties, microstructure and exists in the casting internal hole, crack, inclusion, segregation, and so on and so forth;Use quality refers to the large casting endurance ability to work under different conditions, including wear resistance, corrosion resistance, resistance to chilling induced fever, fatigue, shock absorption performance, and such as are cutting resistance, weldability and so on process performance.Low alloying cast iron on the basis of ordinary cast iron in cupola and electric furnace smelting, contains a small amount of antimony, chromium alloy, manganese content is low, and do inoculation in front of the furnace, the characteristics of cast iron is antimony containing chromium eutectic organization, casting performance is good, small white, tensile strength of 6 b & ge;30 + KGF\/mm, modulus of elasticity E≥12000 kg\/mm +, used in machine tool guide rail hardness of castings are more than 180, the cost of materials similar to ordinary cast iron, can be widely used in the foundation of roller machine tool production equipment.& other;Let stand high temperature, low temperature casting & throughout;Is pouring control criterion, in order to reduce blow hole, shrinkage cavity and surface adhering sand castings defects.Improve the level of casting technology, improve the surface quality of export machine tool castings under the influence of internal and external heat source, machine casting parts will occur to varying degrees of thermal deformation, make the relative motion relationship between the workpiece and tool was broken, and machine tool quarterly decline.For nc machine tool, because all the processing process is calculated command control, the influence of thermal deformation is more serious.In order to reduce the thermal deformation and the roller production equipment of CNC machine tool structure usually adopt the following measures in the internal heat generated when the main heat source of hot deformation, should as far as possible to the heat source is separated from the host.After took a series of measures to reduce the heat source, thermal deformation situation will improve.But to completely eliminate machine internal and external heat source is often very difficult, even impossible.So must be good to control the temperature of cooling and cooling, in order to reduce the influence of heat source.Which department is in the machine tool is a effective method of forced cooling heating parts, also can be in low temperature machine parts, by using the method of heating machine each point temperature uniformity, so that we can reduce the buckling deformation caused by temperature difference.Machine tool castings.Lathe bed casting cleaning essence is the beauty of the casting, the so-called clean up is to improve surface quality of castings.For small, a coarse clean-up with hexagonal roller first, reoccupy turntable for the second time the shotblast cleaning fine processing, finally use grinder finishing of the dust removal equipment, qualified brush anti-rust paint after storage.For medium and large with vibrate shakeout machine to besmear first chunk of sand, and then into the room shot blast cleaning, the artificial use portable grinder finishing, qualified brush anti-rust paint into the Treasury.Cast iron melting and pouring molten iron quality influence on the casting surface quality, mainly manifested in two aspects: one is the content of impurities in molten iron, especially iron oxide content, it is easily on the casting surface slag or gas;The gas content in molten iron, high gas content is easy to make the casting on the surface or subcutaneous blowholes.We take the main measures is to improve the hot metal temperature, cupola detection system should be established in order to guarantee the cupola in the normal state.