For a long time, metals that are durable and have good thermal conductivity have always appeared in the production of food utensils.
With good forming characteristics, metal products can be said to be ever-changing, ranging from a spoon to a large iron steam oven, which enriches our daily lives. How to choose the appropriate process for the development of new products?
The origin of various forming processes: casting and forging
Although there are many advanced technologies today, most of them just replace manpower with the operation of various machines and implement the two unchanging methods of metal forming, such as casting or forging.
Due to the characteristics of metal melting, casting forming by pouring liquid metal into a mold to condense and solidify has always been one of the main processing methods. Common execution methods include sand turning, dewaxing, gravity, centrifugal or pressure casting, etc., depending on the forming requirements.
The advantage of casting that is difficult to be replaced is that the shape, type of raw material, and size are almost unlimited, especially for objects with complex inner cavity shapes; the investment in equipment is relatively low, and the recycling of waste materials is also easy.
Castings can have high hardness, but generally the surface fineness and mechanical properties are poor, and the scrap rate is also high.
The beginning of the industrial age: machining technology
Subtractive processing such as cutting metal with power machinery has greatly improved accuracy and productivity, and realized the concept of "machine production by machine". It is an important technology that opened the industrial age.
Among them are the familiar lathes, milling machines, and boring machines. , CNC or multi-axis machining machines developed in combination with digital technology have always been the mainstream of the current precision industry.
Through appropriate tools and procedures, machined objects can easily achieve extremely high precision and surface quality, and easily replicate the results. In terms of low-volume production of high-precision products or parts, and reducing the cost of surface treatment.
Although the machining accuracy is extremely high, it is difficult to compare with casting or stamping in production efficiency. It is suitable for forming solid objects with high tolerance requirements, such as equipment parts, molds, or metal products with simple appearance but delicate positioning.
The feature of piece-by-piece processing is also very suitable for early-stage proofing development.
Exquisite production in small batches: spinning forming
Spinning is a process in which the cutter wheel and tools are driven manually or by a machine, and the metal sheet is gradually pushed to the rotating mold to form, which can greatly improve the efficiency of manufacturing axisymmetric circular objects.
Although it has been largely replaced by mature stamping technology today, it still has its own unique advantages.
Spinning forming objects will have stronger mechanical properties, stretch the blanks to a greater degree, and are not prone to tearing.
The cost of the mold is low, and generally only a pair of core molds are required to make; the requirements for materials and machines are also low, and it is common to use a lathe instead of a spinning machine.
Spinning forming requires less process equipment than stamping, but manual production is often used, and the efficiency is lower. It is suitable for the production of many items but small batches.
In industrial mass production, automatic machines are often used for crimping or necking to process stamped objects. However, when forming thin products, skilled labor can obtain a more beautiful surface appearance than the machine.
The core technology of contemporary mass production: stamping
Most of the mass production of modern metal products is the application of stamping technology, the process of which can be divided into punching, forming, riveting and deep drawing.
Stamping generally has two sets of molds, the upper and lower molds are placed in the middle to apply pressure, the deformation, cutting or joining can be completed, and then the object can be completed.
It is most commonly used for the bending, punching, shape cutting or extrusion of sheet metal components to increase structural strength. It can even directly punch out decorative patterns; but these are almost all flat materials that are bent and formed, and will not be large. Affect the thickness of the material.
Deep drawing forming is a more special project. It can draw a flat sheet into a solid hollow blank. The drawing process will also produce a change in wall thickness. It is an important process for the production of various cups and utensils. It has a large scale in mass production. Replace the traditional spinning forming.
Good stamping parts are light in weight but have high rigidity, rapid mass production and very uniform quality. The manufacturing process has strict requirements for molds, especially compound molds or continuous molds that combine multiple processes, and the cost is even higher, which is suitable for large-scale and single-type production.
The future trend of heavy industry: metal 3D printing
The cost of metal processing molds and tools is very high, and the existing manufacturing process also has many limitations.
Metal printing is a highly potential project in 3D forming, which greatly reduces the cost of development and correction. When making complex and organic shapes, there is no problem of weak casting strength.
In addition to accelerating development and challenging more diverse appearances, metal 3D printing is particularly effective in medical or aerospace technology, such as the repair of bones or joints, which can be freely printed according to the patient's condition or wound contour.
The shape, combined with the honeycomb structure to reduce the weight, is not easy to achieve with traditional processing methods.