1. Automobile mold casting
Casting is a production method in which molten metal is poured into the cavity of an automobile mold and cooled and solidified to obtain a product. Sand molds are usually used to make iron castings. The raw material of the sand mold is mainly sand, mixed with a binder and water. Sand materials must have a certain bond strength in order to be formed into the required shape and resist the erosion of hot metal without collapsing. In order to mold a cavity in a sand mold according to the shape of the casting, it is necessary to make an automobile mold from wood, which is called a wood mold. The volume of hot molten iron will decrease after cooling. Therefore, the size of the wooden mold needs to be increased according to the shrinkage rate on the basis of the original size of the casting, and the surface to be processed will be thickened accordingly. With the wooden mold, the cavity sand mold can be turned over (casting is also called "turning sand"). When making sand molds, it is necessary to consider how to separate the upper and lower flasks and take out the wooden molds, the molten iron flows into the wooden molds, and how to fill the cavity to obtain high-quality castings.
2. Automobile die forging
Forging is widely used in automobile manufacturing. Forging is divided into free forging and die forging. Free forging is a processing method (called "ironing") in which a metal blank is placed on an anvil to withstand impact or pressure. Automobile gears and shaft blanks are processed by free forging. Die forging is a processing method in which a metal blank is placed in the cavity of a forging die and subjected to impact or pressure. Forging is a bit like the process of pressing dough into a biscuit shape in a mold. Compared with free forging, the shape of the workpiece processed by die forging is more complicated and the size is more accurate. Typical automobile die forgings include: engine connecting rod and crankshaft, automobile front axle, steering knuckle, etc.
Four, automotive mold metal cutting processing
Metal cutting is the use of tools to cut the metal blank layer by layer; a processing method that allows the workpiece to obtain the desired shape, size and surface roughness. Fitter is a processing method that workers use hand tools to cut. It is flexible and convenient to operate and is widely used in assembly and repair. Processing is done by machine tools, including turning, planing, milling, drilling and grinding.
5. Heat treatment of automobile mold
Automobile mold heat treatment is to reheat, heat or cool solid steel to change its structure to meet the requirements of the use or process of parts. Heating temperature, holding time and cooling rate can produce different microstructure changes. The blacksmith dips a piece of heated steel into water for rapid cooling (experts call it quenching), which increases the hardness of the steel. This is an example of heat treatment. Annealing is the process of heating a piece of steel, holding it for a certain period of time, and then slowly cooling it with the furnace to obtain a finer and more uniform texture, reduce hardness, and facilitate cutting. Normalizing is to heat steel parts, heat them out of the furnace, and then cool them in the air, which is suitable for refining low carbon steel. Tempering is usually the subsequent process of quenching. The quenched steel parts are reheated, insulated, and then cooled to stabilize the microstructure and eliminate brittleness. Many auto parts need to use surface induction hardening, carburizing, cyanidation and other heat treatment processes to maintain the toughness of the core, change the surface structure, and increase the hardness.
6. Auto mold assembly
According to certain requirements, assembly is to combine various parts into parts with connecting parts (bolts, nuts, pins or buckles, etc.). ), and then connect each part to form a complete car. This centering method is not adjusted by the assembler (assembler) during the assembly process, but is guaranteed by design and manufacturing. If you visit a car factory, the most fascinating thing is the car assembly line. On this assembly line, a car leaves every few minutes. Take the FAW Jiefang truck assembly line as an example. This assembly line is a 165-meter-long drive chain through which the car is moved to various stations and assembled step by step. There is also a transmission suspension chain around it, which can continuously transport the engine assembly, cab assembly, wheel assembly, etc. from each workshop to the corresponding station on the assembly line. For the starting position of the drive chain, first put the frame (inverted), and then install the rear axle assembly (including leaf spring and center) and front axle assembly (including leaf spring, joints and center) on the frame, and then install it upside down to the frame Steering gear, air tanks and brake pipes, oil tanks and oil pipelines, wires and wheels, etc. Finally, install the engine assembly (including clutch, transmission and central brake), connect the drive shaft, and then install the cab and the front. At this time, the car can be off the assembly line.
