It is not uncommon to find people using the words ‘metal fabrication’ and ‘metal welding’ interchangeably. In engineering, the words are two distinct concepts. Metal fabrication is a comprehensive term that involves all processes that convert raw materials into finished components. However, metal welding is more specific and refers to the joining of two or more metal pieces.
As a newbie or professional, it is important to understand the differences between metal fabrication and metal welding to make informed decisions. This article will explore what metal fabrication and metal welding are and how they differ.
Is Metal Fabrication the Same as Metal Welding
No, metal fabrication is not the same as metal welding. In manufacturing, both words are not synonymous and have different meanings. Metal fabrication is a broader term that involves cutting, shaping, and joining metal raw materials to create a finished product. On the other hand, welding refers to the process of fusing two or more metal parts using heat, pressure, or both. Welding comes under metal fabrication and is just a part of it. In simple terms, all metal welding processes are indeed metal fabrication processes. However, not all metal fabrication operations will involve welding. For easier understanding, let’s look at what metal fabrication and metal welding are in detail.
What is Metal Fabrication
Metal fabrication encompasses a lot of processes that deal with the creation of useful components from a metal material. It involves cutting, bending, and shaping metal workpieces with special tools to get a final part. Four broad manufacturing categories fall under metal fabrication.
- CNC Machining
CNC machining is a subtractive manufacturing process that uses preprogrammed software to control the movement of complex tools and machinery. It is an automated technique and can be used to produce parts with complex shapes and designs. CNC machining works by creating a 2D or 3D model of the final design using CAD software.
You then convert the CAD model to programming languages in the form of G-code and M-code. The final step entails configuring the machine and running the program till the end. CNC machining creates high-quality parts with superior surface finish. The following are some of the common processes and operations that come under CNC machining
CNC Milling
Milling is a type of CNC machining technique that involves mounting the cutting tool on a rotating spindle. Here, the workpiece is stationary while the tool engages and disengages for a cutting action. CNC milling machines come as 3-axis, 4-axis, or 5-axis depending on the number of axes of motion.
CNC Turning
In CNC turning, the workpiece rotates at a high speed while you feed in the cutting tool to remove excess material. CNC turning operations can either be specific or nonspecific. Specific CNC turning processes include facing, grooving, and parting. Drilling, threading, and knurling come under non-specific CNC turning operations.
CNC Cutting
You can also control laser cutters, plasma cutters, and water jet cutters using CNC technology. This process is known as CNC cutting. It is different from using physical tools to divide the metal workpiece. Rather, you use a high-power laser beam, plasma arc, and high-pressure water jet to cut through materials.
- Sheet Metal Fabrication
Sheet metal fabrication comes under the umbrella term metal fabrication. As the name implies, what you work with are sheets of metal 0.02 to 0.250 inches thick. Furthermore, most sheet metal fabrication processes are automated making it easy to create accurate and precise parts. The conversion of metal sheets to useful components requires cutting, forming, joining, or a combination of all.
Cutting Sheet Metal Fabrication
Cutting is usually the first step in sheet metal fabrication. It is the process of removing material from a workpiece to create the intended design. You can carry out cutting with or without a shear force. Cutting with shear involves sawing, blanking, and punching the metal sheets. However, cutting using heat, pressure, and abrasive materials is also possible.
Forming Sheet Metal Fabrication
Forming sheet metal techniques do not remove or add any material. Rather, they change the shape of metals for various reasons while retaining them while in their solid state. In forming, you can bend or roll metal sheets to reduce thickness. Additionally, it is possible to stamp or curl the tip to conceal burrs.
Joining Sheet Metal Fabrication
Welding comes under this category of sheet metal fabrication. You use heat to create a permanent joint by melting the edges of the workpiece. Riveting is another type of sheet metal joining. It is a temporary technique and the riveted parts can withstand stress and vibrations.
- Metal Casting
Metal casting describes the process of heating a material and pouring it into a mold that contains a negative impression of the final part. As the molten metal cools and solidifies, it takes the shape of the mold. Metal casting is a versatile process and you can use it for many types of metals. There are three main types of metal casting; sand casting, die casting, and investment casting.
Sand Casting
Sand casting is one of the oldest casting techniques available. The mold here is made of sand that is broken to remove the part. This process is cost effective and you can use it for complex shaped components.
Die Casting
In die casting, the molten metal fills the mold under pressure and at a high speed. The molds used in die casting are usually created using steel and are reusable. This allows you to create dimensionally accurate and consistent structures.
Investment Casting
Investment casting is slightly different from the two processes previously described. The first step is to create a wax pattern using a die. You then dip the pattern into a refractory ceramic slurry and allow it to dry. The wax is melted out to get the final mold used to produce parts.
- 3D Printing
3D printing is an additive process you can employ to make a part from a digital file. Selective laser melting (SLM) and direct metal laser sintering (DMLS) are the two processes suitable for printing metal parts. SLM and DMLS work in similar ways. To carry out SLM, you first create a model of what you want to produce and send it to the printer. You then use a high-power laser to melt metal powders layer by layer. The laser simultaneously fuses the layers of metal powders to provide a strong part. Unlike SLM, the DMLS technique sinters and does not completely melt. Parts are produced without reaching the metal’s melting point.
What Is Metal Welding
Welding is just a process under metal fabrication. It refers to the joining of two or more metal workpieces to form a weldment. The workpieces are heated at a high temperature above their melting points. They fuse as they cool and solidify. There are different categories of welding you can use in metal fabrication. The most common are laser welding, TIG welding, and MIG welding.
- Laser Welding
Laser welding uses a high-energy laser beam to fuse metal parts. The joint absorbs the energy and becomes molten. When laser welding, CO2 and fiber lasers are the ideal laser types for joining metal parts. The energy is concentrated on a small spot and does not affect the surrounding material. Laser welding is fast and reliable. However, this technique comes with a high cost of purchase and operation.
- TIG (Tungsten Inert Gas) Welding
TIG welding is an arc welding process that uses a non-consumable tungsten electrode to create high-quality welds. As the electrode gets in close contact with the workpiece, an electric arc is formed. The arc heats up and melts the metal forming a weld pool. The pool solidifies to form a strong bond. TIG welding is versatile and you can use it for thin metals. The final welds are clean and aesthetically pleasing.
- MIG (Metal Inert Gas) Welding
MIG welding is another arc welding process. It works with a continuous wire electrode and electric current to join two pieces of metal. MIG welding does not need an additional filler material as the electrode acts as one. This technique is fast and suitable for metals of varying thickness. During MIG welding, it is compulsory to use an inert gas, usually argon or helium. The gas protects the weld pool from contamination.
Differences Between Metal Fabrication and Metal Welding
Metal fabrication and metal welding have different meanings. Furthermore, they have distinct objectives and produce unique results. Let’s look at their differences in detail
- Scope
Metal fabrication refers to a wide range of operations from designing to finishing. It includes every process that involves turning metal raw materials into functional components. On the other hand, metal welding is restricted to techniques that join metal pieces using heat and pressure.
- Techniques and Tools
The techniques and tools in metal fabrication are broader. You use techniques like cutting, stamping, machining, and bending with tools such as lathes, presses, and cutters in metal fabrication. The tools in metal welding are different and include welding guns, touches, and electrodes.
- End Products
The end products of metal fabrication and metal welding are somewhat different. The result of metal fabrication is a metal component or assembly of auto parts, medical devices, and enclosures. For metal welding, the end product is two or more pieces fused to make a whole.
Conclusion
Fabrication and welding are closely related processes but are not the same. Welding is only one part of the entire metal fabrication process. The purpose of metal fabrication is to create a finished product from a raw material that can be in any state. On the other hand, welding aims to permanently join solid metal pieces through a strong cohesive bond. Still confused? Reach out to a renowned metal fabrication shop for all your questions and clarifications.