What problems should be considered in the redesign of castings
The shape and surface quality of the hollow rectangular tube of Dalian castings. The bending degree of the hollow rectangular tube shall not be greater than 0.5mm per meter, and the total bending degree shall not be greater than 0.1% of the total length. Hollow rectangular tube shall not have obvious torsion. The ends of hollow rectangular tubes shall be cut straight, and small deformation and fine burrs caused by the cutting method are allowed. The inner and outer surfaces of hollow rectangular tubes shall be free of cracks, folds, rolling folds, scabs, delaminations and hairlines. The classification and brand of steel pipes are divided into hot rolling (extrusion, expansion) and cold drawing (rolling). Steel pipes are made of 10, 20, 35, 45 and 16Mn steel. Hot rolled pipe 20-45x3.0 hot rolled pipe represents steel pipe manufactured by hot rolling (extrusion or expansion). 20 represents No. 20 carbon steel. 45x3.0 represents steel pipe with outer diameter of 45 and wall thickness of 3.0. Shape and surface quality of steel pipe. The internal and external surfaces of steel pipes shall be free of cracks, folds, rolling folds, delaminations, hairlines and scabs. These defects must be completely removed. The removal depth shall not exceed the negative deviation of the nominal wall thickness. The actual wall thickness at the removal point shall not be less than the minimum allowable wall thickness.
The layout of the parts inside the box and the relationship with the external parts of the box shall be considered in the design of the box. For example, the shape and size of the box shall be determined according to the height requirements of the two centers of the lathe. In addition, the following problems shall be considered: meet the strength and stiffness requirements. It is an important problem to meet the strength of box parts with great stress; But for most cases, the main index to evaluate the performance is stiffness, because the stiffness of the case not only affects the normal operation of the transmission parts, but also affects the working accuracy of the components. Heat dissipation performance and thermal deformation. Friction and heating of parts in the box will change the viscosity of lubricating oil and affect its lubrication performance; The temperature rise causes the box to produce thermal deformation, especially the thermal deformation and thermal stress with uneven temperature distribution, which has a great impact on the accuracy and strength of the box. The structural design is reasonable. For example, the arrangement of fulcrum, the arrangement of reinforcement, the location of opening and the design of connecting structure should be conducive to improving the strength and stiffness of the box. Good workmanship. Including the process of blank manufacturing, machining and heat treatment, assembly and adjustment, installation and fixation, hoisting and transportation, maintenance and repair, etc. Good design, small quality. The design of different boxes may focus on the above requirements.
