An introduction to the fabrication of metal parts
Metals like aluminum, titanium, iron and nickel are the building blocks of modern society – constituting countless objects that are part of our daily lives.
From extremely hard to very malleable, these elements have different properties that require specific technologies and manufacturing approaches. These are also known as metal fabrication.
By a simple definition, metal fabrication is the manufacturing process of shaping metal into parts and finished products. From connecting parts like technical attachments to big machines like airplanes, metal fabrication is responsible for items in almost every industry and every area of our life. Likewise, metal fabrication shops around the world dedicate their expertise to everything from mass-produced products to custom parts.
There are several processes involved in metal fabrication, the ease of use of which depends on the type of metal and product. Each process often falls into one of two main categories: removal and deformation. Below, we’ve compiled a detailed look at some of these various processes and their importance.
One of the main methods of making metals is to remove a significant portion of a metal part. Different elimination processes produce different results. Some of them include:
Considered the foundation of metal fabrication, machining is a subtractive shaping process that removes leftover metal to create a shape. Over the past 150 years, machining tools have evolved from raw pulley and steam mechanisms to today’s ultra-precise and advanced Computer Numerical Control (CNC) machining equipment.
There are several different methods that produce CNC parts, such as milling, drilling and turning. Milling is one of the most common methods, which involves multi-point cutting tools that remove metal from the workpiece.
Punching is used to make cuts of different shapes. A punch and die tool works the same way as a large pair of scissors; it uses pressure to produce the desired shape and remove excess material. The method can be used to create various shapes and sizes, but the drilled holes are most often geometric shapes like circles, squares, or rectangles. Once cut, the shape is discarded and the sheet is kept as the final product.
If, on the other hand, the cut part is to be used for the drawing, the method used is cutting. This method is often used to produce multiples of the same shape from a larger sheet of metal. Such examples include the creation of jewelry, watch components, and clockwork gears.
Cutting involves separating a piece of metal – partially or entirely – into two or more sections and is one of the most versatile manufacturing processes. It is known to produce clean, straight cuts through the metal part.
On the surface, it may appear that the method involves nothing more than cutting large chunks of metal into smaller pieces – but it’s a rather complex process that involves lasers, electric scissors, jets of water. and plasma for the production of precise sections.
Unlike removal, deformation alters the material instead of removing its parts. As such, it is often used to create 3D shapes. Some of the ways that metallic materials can be deformed are listed below.
The bending process – which changes the shape of the material – is often carried out with a hammer whose large, flat head is adapted to the deformation of the part. While some hammers are portable, others are connected to a machine. The latter type, also known as a power hammer, is used to apply more force to metal.
Bending can also be done using a press brake – a machine that is used specifically for bending metal parts like sheet metal.
Extrusion is a process that produces objects with a fixed cross section shape, in which metal (hot or cold) is forced through a die with the desired cross section.
Its main advantages over other manufacturing methods are its ability to form complex cross sections and do so with rigid materials because the material is subjected to high compressive stress. It also gives a high quality surface finish and allows great freedom in the design process.
This process is often used for more malleable metals such as copper, aluminum or brass. Deep drawing will stretch the material as a tool applies pressure to the sheet; the result is a cup-shaped material. Tin cans, pots, cups, kitchen sinks, and fuel tanks are all examples of deep drawing metal fabrication.
Spinning, or extrusion forming, is a process in which a metal disc or tube is rotated at high speed to form an axially symmetrical part. It can be done by hand or using a CNC lathe. Common spinning applications include cookware, satellite dishes, musical instruments, and rocket nose cones.
Due to its complexity and versatility, metal fabrication has many applications in all products and industries. However, it is imperative that manufacturers fully understand the processes and materials involved due to their unique and detailed characteristics.
Generally, metal fabrication methods fall into one of two groups: removal and deformation. The processes that incorporate material removal include machining, punching, punching and cutting. On the other hand, deformation processes alter the shape of materials with methods such as bending, extrusion, deep drawing and spinning, among others.
This introduction should give you a first idea of how these methods work and how they are used.