Milling is one of the common machining methods in machining, and its products are widely used in mechanical production. In the process of milling, the milling cutter will produce milling force because of its high-speed operation. Milling force has a great influence on milling processing. Then, what are the effects of milling force on milling? Now let's talk about hook net in detail.
Milling resistance and milling force
1. Milling resistance: during milling, the resistance of workpiece material to milling cutter cutting is called milling resistance. Milling resistance is mainly:
(1) In the process of chip formation before and after the material to be cut becomes chip, the resistance to the tool caused by elastic deformation and plastic deformation, and the friction resistance to the tool when the chip flows out from the front of the milling cutter.
(2) The extrusion deformation (elastic deformation and plastic deformation) force and friction resistance of the transition surface of the workpiece and the processed surface layer material on the back of the milling cutter.
2. Milling force: in the process of milling, in order to overcome the resistance of the workpiece to milling by the material of the cutting layer, the tool must have a strong effect on the workpiece. The force of the milling cutter on the workpiece is called milling force. Milling force includes two aspects:
(1) The force required to make the workpiece produce elastic deformation and plastic deformation by the cutting layer material, and the force required to overcome the friction resistance between the front of the milling cutter and the chip.
(2) The force required to make the transition surface of the workpiece and the processed surface layer material produce extrusion deformation, and the force required to overcome the friction resistance between the back of the milling cutter and the processed surface of the workpiece.
Milling cutter is a multi edge tool. During milling, the synthesis of resistance acting on the cutting edge involved in cutting is the total milling resistance; The total milling force is the sum of the forces exerted by all the cutting edges on the workpiece. Obviously, the total milling resistance and the total milling force are a pair of forces and reactions, which are equal in size and opposite in direction.
2、 Factors affecting total milling resistance
(1) Influence of workpiece material on total milling resistance: the higher the strength and hardness of workpiece material, the greater the deformation resistance. For materials with similar strength and hardness, the better the plasticity, the greater the plastic deformation generated in the milling process, the larger the friction coefficient between the chip and the front of the milling cutter, and the longer the contact area, so the milling resistance increases. Materials with high toughness have great resistance to deformation and fracture. When milling brittle materials, due to the small plastic deformation, the milling resistance is small.
(2) The influence of milling parameters on the total milling resistance: when the milling depth, milling width and feed per tooth increase, the total milling resistance increases due to the increase of the total cutting area. Under the condition of constant total cutting area, reducing the width of cutting layer and increasing the depth of cutting layer can reduce the total milling resistance. The milling speed has no significant effect on the total milling resistance, but when other milling conditions remain unchanged, increasing the milling speed will increase the milling power.
(3) The influence of milling cutter on the total milling resistance: the increase of rake angle can reduce the friction of extrusion deformation of the material being cut, smooth chip removal, and reduce the total milling resistance. With the increase of the back angle, the extrusion deformation and friction between the back of the milling cutter and the transition surface of the workpiece and the machined surface are reduced, and the total milling resistance is reduced. The angle of the cutting edge has little effect on the total milling resistance, but changing the size and direction of the angle of the cutting edge can change the direction of the total milling resistance. The magnitude of the main deflection angle can change the direction of the total milling resistance. The diameter of milling cutter has little effect on the total milling resistance, but the wear of milling cutter blade will rapidly increase the total milling resistance.
(4) The influence of cutting fluid on the total milling resistance: the water solution dominated by cooling has little effect on the total milling resistance, while the oil cutting fluid with strong lubrication reduces the friction resistance between the front of the milling cutter and the chip, the back and the workpiece surface due to its lubrication, and also reduces the deformation of the chip stagnant layer, thus reducing the total milling resistance.
