Common Metal Fabrication Methods

Extrusion

Bending

Shearing

Milling

Laser Cutting

Metal fabrication includes several processes of manufacturing metal components by changing the raw metal material using various tools. Metal fabrication processes can be classified as cold, warm and hot working depending on the temperature at which the material is processed. 

Most of the objects around us such as paper clips, computers, bolts, nails, automobile parts, parts used for instruments and machinery and countless other products are transformed by metal fabrication processes such as bending, punching, drilling, turning, grinding, threading etc. The factors influencing the metal fabrication process included the type of material being machined, the rate of production, the desired geometry, and other physical requirements of the part.

Metal fabrication can be divided into the following categories.

Metal Forming

• Forging: Forging involves plastic deformation of the workpiece by compressive forces. Parts such as crankshafts, connecting rods, gears, bolt heads etc., are made by forging.
• Rolling: Rolling is a process of reducing the thickness of a long workpiece by compressive forces using a set of rolls. Plates used for Machine structures, vessels and sheets used for automobile and aircraft bodies, appliances and furniture etc are made by rolling.
• Extrusion: During extrusion billets are forced through one or more dies by a compressive force that is applied to a ram. The extruded piece that emerges has the desired shape. In general, extrusion is used to produce cylindrical bars, hollow tubes and more complex shapes.
  
• Drawing: Drawing is a process of forming sheet metal into shapes such as cups and trays.
  
• Deep Drawing: Deep Drawing is a type of drawing where the depth of the part can be greater than its diameter.
  
• Bending: During bending, the workpiece is bent to form flanges, contours, curls, seams, corrugations and other geometries by means of applying force through hydraulic, pneumatic and electrical machines. 
• Spinning: Spinning is a process of forming axially symmetrical shapes.

Shearing

• Conventional shearing: Shearing is a metal cutting process through which flat surfaces cut using a scissors-like action, usually in straight lines.
  
• Turret Punching: Turret Punching creates shapes in sheet material by successively punching a series of basic shapes. Edges are cut by the shearing action of a punch and die.
• Blanking: During blanking, different shaped parts are created in sheet metal by applying a punch and die.

Material Removal

• Sawing: Sawing is a type of cutting in which the cutting tool is a blade that has a series of  teeth, with each tooth removing a small amount of material. Sawing is typically used to shape raw material to the approximate size of the part, prior to additional processes.
  
• Tapping: Tapping produces internal threads in the workpiece. This involves use of a tool with multiple cutting teeth.
• Broaching: Broaching involves use of a long multitooth cutting tool that makes successively deeper cuts. Broaching is used for machining internal and external surfaces such as key slots.
  
• Boring: Boring produces circular internal profiles in hollow workpiece or on a hole made by drilling or another process.
• Turning: Turning rotates the workpiece about its axis while applying cutting tools to create a desired shape.
• Drilling: Drilling produces holes in a workpiece using a fluted cutting tool.
• Milling: Milling removes small chips using a rotating cutter that moves in three axiis.
  
• Grinding: Grinding is a chip removal process in which the cutting tool is an abrasive grain wheel. Different types of grinding include Surface grinding, Cylindrical grinding, Internal grinding and Centerless grinding.

Advanced METHODS

• Laser Cutting: Laser cutting involves focusing a beam of high density energy on the surface of the workpiece. The beam evaporates portions of the workpiece in a controlled manner.
• Electro Discharge Machining: Electro discharge machining is based on erosion of metal by spark discharges. This process can be used for machining any material which is an electrical conductor.
  
• Wire EDM: The wire EDM or Electro Discharge Machining produces part shapes by cutting a metal work piece with a continuously moving wire by means of rapid, repetitive spark discharges. This process is used to cut thin and thick metal and is often used to make punches, tools and dies from hard metals.
  
• Waterjet Cutting: In this process, the force of a water jet is used to cut material. The water jet acts like a saw and cuts a narrow kerf in the workpiece. Most of metals, plastics, fabrics, wood products, rubber, insulating material, leather, brick and composite materials can be cut using the waterjet process.