Sheet metal parts are widely used in various forms in our daily lives, such as the interior of industrial products, daily necessities, personal computers, televisions and other electrical equipment, buildings, handicrafts, car bodies, etc. This time, we will introduce the basic matters related to the use, types, and processing procedures of cutting and bending a sheet metal part into a three-dimensional shape.
What is sheet metal?
Sheet metal processing is a processing technique that applies force to metal sheets to deform them. When applying force to a metal material, the material will deform bit by bit, but since initially, the metal will attempt to return to its original state, if the force is stopped midway, the metal will return to its original state. This is called elastic deformation. And when the load continues to be applied beyond a certain point (yield point), the metal cannot recover to its original state. This state is called plastic deformation. Sheet metal processing is a technique used to obtain the desired shape in a plastic deformation state. If excessive force is applied, the material will break, so tools such as molds, baffles, and bending machines will be used to adjust and process at the same time.
The purpose of sheet metal parts
The application range of sheet metal parts is wide and diverse. Especially widely used in industrial products, factory production equipment, food manufacturing equipment, etc., sheet metal parts are used as various sizes of parts such as brackets, cover plates, chassis, guide rails, etc. In addition, box shaped components such as distribution boards and boxes also use sheet metal parts. Sheet metal parts can be flexibly manufactured using universal equipment and molds, making them easy to manufacture in small batches and multiple varieties. They are an indispensable part of FA equipment design.
Types of sheet metal processing
When it comes to sheet metal processing in industrial products, it refers to mechanical sheet metal. In addition, there are traditional handicrafts, handmade sheet metal used in automobile maintenance, and the field of architectural sheet metal using these two processing technologies.
Mechanical sheet metal
In mechanical sheet metal forming, metal plates are formed through molds using hydraulic and other forces, and the entire process, including the pre - and post forming processes, is called sheet metal processing. Mechanical sheet metal is also known as "factory sheet metal" because it requires factory equipment, and is also known as "precision sheet metal" because it can perform precision machining.
Handmade sheet metal
Handmade sheet metal, as the name suggests, is a machining method that uses tools such as hammers to form the desired shape. Handmade sheet metal is not only used for traditional handicraft processing such as hammering sheet metal, but also for repairing dents on the exterior of cars through tapping.
Architectural sheet metal
Building sheet metal is also a field of sheet metal processing for the roof, water pipes, exterior walls, decorations, kitchen equipment, pipelines, and other metal components required for construction. Architectural sheet metal is usually customized for each building. The same product is rarely used multiple times, so manual sheet metal and mechanical sheet metal are usually used for processing.
This time, mechanical sheet metal will be used as "sheet metal processing", and parts made from sheet metal will be used as "sheet metal parts", summarizing the basic knowledge of sheet metal that designers want to know.
The process of sheet metal processing
The processing of sheet metal parts is mainly divided into 8 processes. The homework content of each process is explained in detail in the following report.
Also introduce the basic knowledge of sheet metal processing - advantages, disadvantages, and methods to reduce costs
Here are three main processes for sheet metal processing.
• Punching processing
Also known as the material cutting process. The main purpose is to distinguish between the cutting process using laser cutting machines, the cutting process using shearing machines, and the stamping process using turret punching machines, in order to process the material sheet into the desired shape.
• Bending processing
Installing the mold on a bending machine and applying pressure to the cut sheet metal for bending is called bending processing. It should be noted that "bending machine" is also known as "bending machine", "bending machine", etc., all referring to the same machinery.
Welding processing
Heating metal, melting it, and cooling it, thus joining the metal is welding processing. TIG welding and laser welding are mainly used in sheet metal processing. TIG welding using tungsten electrodes is sometimes referred to as "argon arc welding" due to the use of argon gas as the shielding gas.
Materials of sheet metal parts
The materials used for sheet metal parts include stainless steel, carbon steel (SPCC, SECC), aluminum alloy, and other types. The thickness of the plate also varies depending on the material, ranging from t0.1 to 22mm. Please consider the purpose and processing characteristics of the parts for selection.
Stainless steel
Stainless steel is a material commonly used in products with corrosion resistance and cleanliness requirements. The representative material used for sheet metal is SUS304, which has the characteristics of being easy to purchase, excellent corrosion resistance, and easy to cut, bend, weld, and other processing due to its common characteristics on the market. In SUS304, 2B material is generally used, and when surface gloss is required, a single sided 4K mirror material called "mirror material" can be specified. In addition, SUS430 is often used in water areas and is commonly used in kitchen equipment and building sheet metal.
Carbon steel
Carbon steel in sheet metal processing is usually distinguished and used based on its workability and surface treatment status. The most popular SPCC is a low-cost and easy to process material, but it is prone to rusting, so some surface treatment such as spraying and electroplating needs to be carried out after processing. The SECC of galvanized steel plate is sometimes also called "bond". Easy to spray and with good coloring effect, it is a material that is easy to use for control panels and other materials when spraying in the next process. The SGCC of hot-dip galvanized steel plate has high rust prevention performance, so it is recommended to be used for outdoor use and other products that require rust prevention.
Aluminum alloy
Aluminum alloy has the characteristics of small specific gravity and easy thermal conductivity, making it an ideal choice for products that require lightweight or good heat dissipation. The commonly used aluminum alloy in sheet metal parts is A5052, but compared to other materials, sheet metal processing is more difficult. For example, aluminum alloy is not easily able to absorb laser, so laser cutting requires higher laser power than stainless steel or carbon steel. Specifically, if it is carbon steel, a 3kW fiber laser equipment can process up to a plate thickness of 22mm, but for aluminum alloys to process materials of the same thickness, a 6kW fiber laser equipment is required.
In addition, the thicker the plate, the easier it is to break when bent, the higher the thermal conductivity, and the higher the technical requirements for welding. The material and processing costs may be high, so it is best to use the materials where they are truly needed.
Surface treatment of sheet metal parts
The surface treatment of sheet metal parts includes electroplating to increase corrosion resistance, spraying to increase color and function, and laser marking to increase information according to the purpose.
Spray coating
Spray coating is a surface treatment that increases color, durability, and corrosion resistance by applying paint to the surface of a part and drying it. According to the purpose and required functions of the product, there are various coatings and spraying methods. Therefore, when adding advanced functions, it is recommended to consult spraying experts. When adding color, weather resistance, and corrosion resistance to sheet metal parts such as control panels and mechanical equipment covers, "powder spraying" is generally chosen, which means uniformly spraying powder coating. When entering spray instructions, please refer to the color sample manual issued by the general corporation, the Japan Coatings Industry Association, and specify the Marshall value.
Electroplating
The electroplating treatment of sheet metal parts is to increase corrosion resistance, wear resistance, and decorative properties. The type of electroplating treatment varies depending on the material. Firstly, the representative non electrolytic nickel plating in SPCC electroplating processing has excellent corrosion resistance and wear resistance, and is easy to maintain a constant film thickness. Therefore, it is commonly used in precision equipment. Iron tetroxide protective film, commonly known as "blackening", is suitable for precision instrument parts due to its thin film and small size changes. However, after using oil, it will accelerate the rusting process, so attention must be paid to the usage area.
Trivalent chromate can be divided into white and black, and is an environmentally friendly electroplating method. The surface of white chromate turns white, while the surface of black chromate is black. Sometimes, considering a certain degree of corrosion resistance, stainless steel is chosen, and stainless steel sheet metal parts are rarely electroplated in subsequent processes. Due to its difficulty in electroplating, if you really want to improve corrosion resistance, you can consult a professional surface treatment company.
Anodizing
Anodizing is a surface treatment that artificially forms an oxide film on the surface of aluminum alloy. Anodizing can only be applied to improve corrosion resistance and wear resistance when the material is aluminum alloy. Usually white anodized and black anodized, but professional suppliers can also add colors such as blue, green, and red.
Laser marking
Laser marking can not only decorate by illuminating the surface with weaker laser, but also add product numbers and barcodes and other information. In the genre of laser processing, it is classified as "surface modification", as information is directly written on the material surface and will not disappear unless erased by polishing. In recent years, the demand for identification information such as traceability of parts and manufacturing batch numbers has been increasing, and the need for this information is also increasing.
Design techniques for sheet metal parts
When designing sheet metal parts, consideration must be given to machinability, including the possibility of machining. There are many factors to consider when designing, and here we mainly discuss three precautions.
If it cannot be unfolded into a board, it cannot be processed
Sheet metal parts are made by cutting or bending a plate, so if the drawing is not originally a plate, it cannot form a part. Therefore, in the sheet metal processing plant, in the preparation process of processing, "unfolding" operations will be carried out, which means removing the bending, welding and other processing of the drawing and restoring it to the original plate. If you use 3D CAD for design, it will be difficult to notice these, so it is recommended to unfold them in your mind before finalizing the drawings.
Consider processing limits
Due to the fact that sheet metal parts are formed by bending a sheet metal, the range of processing that can be done may be limited by the size of the bent part and the distance from the end face of the product. For example, the machining of holes near the bent part, the minimum distance between the hole and the end face, the minimum distance between the bent part and the end face, and the maximum bending angle may also be limited by the equipment. There are also situations where even if it can be achieved on CAD, it cannot be processed in reality. It is best to confirm the processing restrictions of the processing plant in advance for design, to avoid rework due to inability to process after ordering.
During bending processing, sometimes the product may interfere with the mold, please note
In cases where the long side is longer than the short side due to U-shaped or box shaped bending, the processed product may interfere with the mold during sequential bending. If there is interference, it may not be possible to process, so attention should be paid during the design phase.
Miesmi's MEVIY can provide real-time quotes and processing for sheet metal parts, and has the function of analyzing interference during bending processing. If interference with the mold is found after analysis, a message will be displayed on the quotation screen, and the interference area can be checked by double clicking. By fully utilizing these features, sheet metal design can be efficiently carried out.
