Metal fabrication manufacturing refers to the various processing and treatment techniques carried out on metal raw materials to produce products. There are many types of metal fabrication manufacturing, and there are many classification methods as well. Generally, metal fabrication manufacturing can be divided into "metal fabrication manufacturing that shapes" and "metal fabrication manufacturing that alters properties." The former involves processing materials such as sheets, bars, or molten metal to create product shapes. The latter involves heat treatment or chemical treatment to increase metal hardness or enhance rust resistance.
Mechanical processing includes cutting, grinding, and special processing methods.
Cutting Processing
This is a method of shaping by cutting and removing unnecessary parts of the workpiece using cutting tools. It is the most commonly used processing method due to its wide applicability to various materials, balanced precision and cost, and high versatility. The most representative equipment used in this method includes lathes, milling machines, machining centers, and drilling machines.
A lathe processes the workpiece clamped onto a chuck, allowing it to rotate, while a cutting tool called a lathe tool is attached to the workpiece for cutting. It can process cylindrical surfaces and thread tapping.
Milling machines and machining centers fix the workpiece on a workbench and use a rotating milling cutter to cut the workpiece.
Drilling machines also fix the workpiece on the workbench and use drills, taps, and other cutting tools for drilling and tapping operations.
Lathe processing and milling processing are very common methods and are widely used in various products, such as household appliance components and automotive parts.
Grinding Processing
This method involves removing unnecessary parts of the workpiece using grinding wheels. It is similar to cutting but uses grinding wheels for higher precision. However, it has a lower material removal rate per unit time and higher costs and processing time. Typically, cutting is used to rough out most of the shape, and grinding is used only for precision areas.
The most representative equipment includes cylindrical grinders and surface grinders. Cylindrical grinders process cylindrical outer surfaces, while surface grinders process flat surfaces to improve flatness, roundness, and surface roughness. Grinding is commonly used for automotive parts and machine tool sliding parts requiring precision surfaces.
Special Processing
Special processing methods not classified under cutting or grinding fall into this category. Representative methods include electrical discharge machining (EDM) and laser processing.
Electrical discharge machining applies voltage between the workpiece and electrode, causing discharges that generate heat to melt the material into the desired shape. The electrode can be a carbon electrode matching the processing shape or a fine wire electrode. This method is capable of high-precision fine processing and can handle materials too hard for cutting.
Laser processing uses high-energy laser beams to melt and evaporate materials into the desired shape. Its advantage lies in its ability to perform very fine and precise processing.
EDM is often used for engraving die cavities, precise cutting of thin plates, and key slots, while laser processing is used for precision cutting of thin plates and micro-drilling.
Plastic deformation processing includes stamping, forging, and rolling.
Stamping Processing
This method uses tools or dies to press on sheet workpieces with large force, cutting or shaping them according to the die's shape.
Equipment used includes shearing machines, stamping presses, and turret punch presses. This method provides precise shaping of sheets and is widely used in various products. Sheet metal processing is considered a broad category of stamping processing, widely used for vehicle body shells and household appliances.
Forging
This method uses large force applied by hammers or dies to press or hammer the workpiece, shaping it according to the die's shape. Workpieces are often preheated to facilitate deformation, classified into hot forging, warm forging, and cold forging based on temperature. Depending on the use of dies, it can be classified into die forging (with dies) and free forging (without dies).
Die forging uses air hammers or hydraulic presses, while free forging uses crank presses, etc.
Forging imparts high strength to workpieces, making it suitable for engine parts and tools requiring high strength, like wrenches.
Rolling
This method uses a tool called a rolling die to press on cylindrical workpieces, forming them into the die's shape. Since it involves rotating or rolling the workpiece during shaping, it is called "rolling." It is commonly used for external thread processing, such as bolts and screws found in everyday household items.
Cast Processing
Some metal fabrication manufacturing methods do not fall into these main categories. Powder metallurgy and metal 3D printing are relatively new processing methods enabling complex shapes and geometries not achievable by traditional techniques.
Powder Metallurgy
This method involves pressing metal powder into product-shaped molds and heating it in a furnace to bond the metal particles together, forming the product. Although rarely used, it can produce products with special properties unattainable by other processes, such as energy-saving gears and special bearings that require no lubrication.
Metal 3D Printing
A recently popular method, this involves building the required parts layer by layer to form the final product. It has fewer constraints on tool paths and shapes, enabling unique shapes not possible with traditional methods. Previously used for rapid prototyping, it is now also used for low-volume, high-value production. Despite its relatively short development history, it is used in manufacturing jet engine blades and luxury car brake parts.
