Various fabrication manufacturing processes are available that vary depending on part’s geometry, the product’s intended purpose, and the materials used in crafting it.
FREMONT, CA: Metal fabrication refers to the process of building structures and structures from raw metal materials that involve cutting, shaping, welding, machining, molding, and assembly to create the final product. Unlike assembling ready-made components to create an end product, fabrication creates an end-product from raw or semi-finished materials. Various fabrication manufacturing processes are chosen in a way to suit a project depending on part’s geometry, the product’s intended purpose, and the materials used in crafting it. Conventional custom metal fabrication processes include the following.
Casting
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When molten metal is poured into a mold or die and allowed to cool and harden into the desired shape, it creates an identical product. It is of three types, namely Die Casting, Mold Casting, and Sand Casting. In die casting, workers force the liquid metal into a die instead of mold and the applied pressure keeps it in place. In permanent mold casting, they pour the molten metal into a mold. Permanent mold casting can create stronger castings than die casting, but they can be difficult to remove from the final product. With sand casting, casts are made by pressing a pattern into a fine mixture of sand, which itself forms a mold for the molten metal to be poured into.
Cutting
One common type of fabrication involves cutting a metal workpiece into smaller sections and is the first stage in the longer fabrication process. Modern methods like laser cutting, power scissors, waterjet cutting, and plasma arc cutting replace the traditional sawing methods.
Drawing
Drawing uses tensile force to stretch metal into a thinner shape using a die. The process is usually used with sheet metal fabrication to turn sheets of metal into hollow cylindrical or box-shaped vessels.
Folding
Folding shapes the sheet metal, which is manipulated to bend at an angle. Most commonly, a brake press is used to create a crease in the metal by pinching it. The workpiece to be folded is held between a punch and a die and forced to crease with pressure from the punch.
Forging
Forging uses compressive force to shape metal. It employs a hammer or a die to strike the workpiece to form the desired shape.
Extrusion
Extrusion is the process of forcing the workpiece through or around an open or closed die. It reduces the diameter of the workpiece to the cross-section of the die. By pressing around a die, a cavity is formed within the workpiece. For both processes, a metal slug or cylinder is used.
Machining
In this process, the workers shape the metal by removing the unwanted material from it involving different mining processes, including drilling, turning, and milling. While drilling cuts a hole in the material using a rotary cutting tool, turning uses a lathe to rotate the metal when a cutting tool removes metal along the diameter in a linear motion, thereby creating a cylindrical shape. Use a CNC machine when precise measurements are needed. Miling is a finishing process that uses multi-point cutting tools to progressively remove material from the workpiece to achieve the desired shape.
Punching and Stamping
CNC punch presses make holes in the piece of metal for fastening purposes. Most punch presses are mechanical but smaller, and simpler punches can be hand-powered. Here, uniquely shaped turrets on a punch press hit the metal through or into a die to create holes.
Stamping is similar to punching, except the press doesn’t create a hole in the metal but an indentation. The process forms shapes, letters, or images in a metal panel or sheet. Mechanic and hydraulic stamping presses perform stamping.
Welding
With heat and pressure, welding joins two or more metal pieces of any size and shape. Four widely used welding procedures include Stick or Arc Welding, MIG Welding, TIG Welding, and Flux Cored Arc Welding.
Stick welding employs an electrode stick that produces an electric current forming an electric arc when in contact with metal. Metal Inert Gas Welding (MIG) uses a gas supplied externally along with a continuous solid wire electrode to protect the metal from reacting to environmental factors so that the process can be faster. Flux Cored Arc Welding is similar to MIG except for the fact that it does not require any secondary gas source as the wire electrode employed contains a core that produces shielding gas. Tungsten Inert Gas Welding (TIG) uses a tungsten electrode rod applied for heavy fabrication, and the process requires a skilled welder.
