Animated Illustrations Of 26 Metal Processing Technology Principles, Including Die-casting, Casting, And Stamping. Have You Learned Them All?
Die casting (note that die casting is not an abbreviation for pressure casting) is a metal casting process characterized by applying high pressure to molten metal using a mold cavity. Molds are typically machined from stronger alloys, a process somewhat similar to injection molding.
Sand casting uses sand to make casting molds. Sand casting requires placing a model of the finished part or a wooden pattern (form) into sand, which is then filled into the mold. After the mold is opened, the sand forms the mold. In order to take out the model before pouring the metal, the casting mold should be made in two or more parts; during the mold making process, holes and vents for pouring the metal into the mold must be left to form a pouring system. After the molten metal is poured into the mold, it is kept for an appropriate time until the metal solidifies. After the parts were removed, the molds were destroyed, so new molds had to be made for each casting.
Investment casting, also known as lost wax casting, includes processes such as wax pressing, wax trimming, tree assembly, dipping, wax melting, molten metal casting and post-processing. Lost wax casting uses wax to make a wax pattern of the part to be cast, and then coats the wax pattern with mud. This is the clay mold. After the clay mold is dried, it is baked into a pottery mold. Once fired, all the wax mold melts and disappears, leaving only the pottery mold. Generally, a sprue is left when making the clay mold, and then the molten metal is poured into the sprue. After cooling, the required parts are made.
Die forging is a forging method that uses a die to form a blank on a special die forging equipment to obtain a forging. According to different equipment, die forging is divided into hammer head die forging, crank press die forging, flat forging machine die forging, friction press die forging, etc. A pair of counter-rotating dies are used to obtain the desired forging or forging blank. It is a special form of forming rolling (longitudinal rolling).
Forging is a processing method that uses forging machinery to apply pressure to a metal blank to cause plastic deformation to obtain forgings with certain mechanical properties, shape and size. It is one of the two major components of forging (forging and stamping). Forging can eliminate defects such as loose castings produced during the smelting process and optimize the microstructure. At the same time, due to the preservation of complete metal streamlines, the mechanical properties of forgings are generally better than castings of the same material. Important parts in related machinery with high loads and severe working conditions mostly use forgings, except for rollable plates, profiles or welded parts with simple shapes.
Rolling, also known as calendering , is the process of passing a metal ingot through a pair of rollers to shape it. If the metal temperature exceeds its recrystallization temperature during rolling, the process is called "hot rolling", otherwise it is called "cold rolling". Calendering is the most commonly used method in metal processing.
The essence of pressure casting is a method of filling the cavity of a die-casting mold (die-casting mold) with liquid or semi-liquid metal at high speed under high pressure, and forming and solidifying under pressure to obtain a casting.
Low-pressure casting is a casting method in which liquid metal fills the mold and solidifies into a casting under the action of low-pressure gas. Low-pressure casting was initially mainly used to produce aluminum alloy castings, and later its use was further expanded to produce high melting point copper castings, iron castings and steel castings.
Centrifugal casting is a technology and method that injects liquid metal into a high-speed rotating mold so that the molten metal fills the mold under the action of centrifugal force and forms a casting. The mold used in centrifugal casting, depending on the shape, size and production batch of the casting, can be a non-metallic mold (such as a sand mold, a shell mold or an investment shell mold), a metal mold or a coating or resin sand layer inside the metal mold. Casting.
Lost foam casting is to bond and combine paraffin or foam models similar in size and shape to the castings into model clusters. After the refractory paint is applied and dried, it is embedded in dry quartz sand and vibrated into shape. They are cast under negative pressure to vaporize the model. , a new casting method in which liquid metal occupies the position of the model and solidifies and cools to form the casting. Lost foam casting is a new process with almost no margin and precise molding. This process does not require mold taking, no parting surfaces, and no sand cores. Therefore, the castings are free of flash, burrs, and draft, reducing the number of core defects. Dimensional errors caused by combination.
Squeeze casting , also known as liquid die forging, is to inject molten metal or semi-solid alloy directly into an open mold, then close the mold to generate a filling flow to achieve the external shape of the workpiece, and then apply high pressure to plastically deform the solidified metal (shell) , the unsolidified metal is subjected to isostatic pressure. High-pressure solidification occurs and the final product or blank is obtained. The above method is direct squeeze casting; there is also indirect squeeze casting, which refers to injecting molten metal or semi-solid alloy into a closed mold cavity through a punch and applying high pressure. , a method of crystallizing and solidifying under pressure to finally obtain parts or blanks.
Continuous casting is a casting method that uses a penetrating crystallizer to continuously pour liquid metal into one end and continuously pull out the molding material from the other end.
Deep drawing is a plastic processing method that uses external force to act on the front end of the drawn metal to pull the metal blank from the die hole that is smaller than the cross-section of the blank to obtain products of corresponding shapes and sizes. Since drawing is mostly carried out in a cold state, it is also called cold drawing or cold drawing.
Stamping is a forming processing method that relies on presses and molds to apply external force to plates, strips, pipes and profiles to cause plastic deformation or separation, thereby obtaining workpieces (stamping parts) of the required shape and size.
Metal injection molding (MIM) is a new powder metallurgy near-net shape technology originating from the plastic injection molding industry. As we all know, plastic injection molding technology can produce products of various complex shapes at low prices, but the strength of plastic products is not high. In order to improve its performance, metal or ceramic powder can be added to the plastic to obtain products with higher strength and good wear resistance. In recent years, the idea has been developed to maximize the solid particle content and completely remove the binder and densify the parison during the subsequent sintering process. This new powder metallurgy molding method is called metal injection molding.
Turning processing refers to lathe processing and is a part of mechanical processing. Lathe processing mainly uses turning tools to turn rotating workpieces. Lathes are mainly used to process workpieces with rotating surfaces such as shafts, discs, and sleeves. They are the most widely used type of machine tool processing in machine building and repair shops. Turning is a method of cutting a workpiece on a lathe by rotating the workpiece relative to the tool. The cutting energy for turning is mainly provided by the workpiece rather than the tool. Turning is the most basic and common cutting processing method and plays a very important role in production. Turning is suitable for machining rotating surfaces. Most workpieces with rotating surfaces can be processed by turning methods, such as internal and external cylindrical surfaces, internal and external conical surfaces, end faces, grooves, threads and rotary forming surfaces, etc. The tools used are mainly turning tools.
Milling processing: Milling is to fix the blank and use a high-speed rotating milling cutter to cut the required shape and features on the blank. Traditional milling is mainly used for milling simple shapes/features such as contours and slots. CNC milling machines can machine complex shapes and features. The milling and boring machining center can perform three-axis or multi-axis milling and boring processing, and is used to process molds, inspection tools, molds, thin-walled complex curved surfaces, artificial prostheses, blades, etc. When choosing CNC milling, you should give full play to the processing content, advantages and key roles of CNC milling machines.
Planing is a cutting processing method that uses a planer to make horizontal linear reciprocating motion on the workpiece. Mainly used for shape processing of parts. The planing precision is IT9~IT7, and the surface roughness Ra is 6.3~1.6um.
Grinding Grinding refers to a processing method that uses abrasives and grinding tools to remove excess material from the workpiece. Grinding is one of the most widely used cutting methods.
Selective laser melting is performed in a groove covered with metal powder , and a computer-controlled high-power carbon dioxide laser selectively scans the surface of the metal powder. Wherever the laser irradiates, the metal powder on the surface is completely melted and bonded together, while the areas not irradiated by the laser remain in the powder state. The entire process needs to be carried out in a sealed chamber filled with inert gas.
Selective laser sintering is a SLS method that uses infrared laser as energy. Most of the modeling materials used are powder materials. During processing, the powder is first preheated to a temperature slightly lower than its melting point, and then the powder is scraped flat under the action of a scraper; the laser beam performs selective Z-direction sintering based on layered cross-section information under computer control, and one layer is completed. Then proceed to the next layer of sintering. After all sintering is completed, remove excess powder to obtain a sintered part. The current mature process materials are wax powder and plastic powder, and the sintering process using metal powder or ceramic powder is still under research.
Metal deposition is somewhat similar to "squeezing cream" fused deposition, but the metal powder is ejected. The nozzle also provides high-power laser and inert gas protection while spraying metal powder materials. In this way, it is not limited by the size of the metal powder box, can directly manufacture larger parts, and is also very suitable for repairing partially damaged precision parts.
Roll Forming The roll forming method uses a series of continuous frames to roll stainless steel into complex shapes. The roller sequence is designed so that the roller profile of each rack deforms the metal continuously until the desired final shape is achieved. If the part shape is complex, up to thirty-six racks can be used, but for parts with simple shapes, three or four racks are sufficient.
Die forging refers to a forging method that uses a die to form a blank on a special die forging equipment to obtain a forging. The forgings produced by this method have precise dimensions, small machining allowances, complex structures, and high productivity.
Die cutting is a blanking process. Position the film formed in the previous process on the male die of the die-cutting die. Excess material is removed by closing the mold, retaining the 3D shape of the product and matching it to the mold cavity.
Die-cutting process - The die-cutting process positions the film panel or circuit on the base plate, secures the die to the machine template, and uses the force provided by the machine's downward pressure to control the blade to cut the material. It differs from the punching die in that the cuts are smoother; at the same time, by adjusting the cutting pressure and depth, effects such as indentations and half-breaks can be punched out. At the same time, the molding cost is low, and the operation is more convenient, safer and faster.
