How to solve the problems in CNC lathe processing?

2023-12-15 11:33:08

Large CNC Lathe processing whether there is residual stress, a direct impact on the performance of the machine, such as straightness, verticality and other precision. Especially recently, the use of CNC Machine Tools and industrial robots has made intelligent production or "unmanned" factories a trend. Good situation gave birth to high-quality CNC machine tools. Do not eliminate the residual stress, but also can use a year of excellent machine tools, therefore, the elimination of stress is very important. We mainly analyze and solve the problem of stress from his casting. Next, we will look at the formation of two stresses in the die casting process of CNC Machining: 1. Mechanical stress: the internal stress formed by the mechanical obstruction of the linear shrinkage of the alloy by the mold or core. The mechanical stress is temporary and disappears on its own when the sand falls. The joint action of mechanical stress and thermal stress may increase the crack tendency in some parts. Prevention methods: improve the yield of casting mold and core. 2 Thermal stress: uneven thickness of casting, different cooling rates and inconsistent shrinkage. Prevention methods: 1. Uniform wall thickness. 2. Simultaneous solidification-setting of gates at thin places. Advantages of cooling iron at thick places: saving risers, labor and material elasticity: lower than recrystallization temperature, under the action of external force, the metal undergoes elastic deformation, and the stress continues to exist after deformation. It can be seen that the greater the temperature difference of each part, the greater the thermal stress, the slower cooling part forms tensile stress, and the faster cooling part forms compressive stress. Plastic state: the metal is deformed under stress in the solid cooling stage above the recrystallization temperature, resulting in work hardening, and the recrystallization drop hardening occurring at the same time is offset, internal stress disappears on its own. (Simply put, in a yielding state, stress-deformation without stress) Disadvantages: Shrinkage cavities or shrinkage porosity are prone to occur in the heart. When applied to gray iron tin bronze, due to the small shrinkage cavity and shrinkage porosity tendency of gray iron, tin bronze is solidified in paste form, and it is difficult to effectively eliminate its microshrinkage porosity with sequential solidification.