What’s the Difference Between Metal Fabrication and Metal Machining

Metal fabrication and machining are two popular terms used by parts manufacturers and engineers. While both techniques are distinct, they share some similarities, such as creating metal parts and structures. This article explores each operation, providing a comprehensive review of metal fabrication and machining operations. Read ahead!

What is Metal Fabrication?

Metal fabrication involves creating metal structures and components through various methods, including cutting, bending, and assembling. This process transforms raw metal materials into finished products for use in various industries, such as automotive, aerospace, construction, and manufacturing. 

M etal fabricating  involves a series of techniques, including CNC machining, sheet metal fabrication, metal casting, and even advanced methods like 3D printing. Each method serves a unique purpose and is selected based on the desired properties and specifications of the final product. 

While CNC machining provides precision and repeatability, sheet metal fabrication allows for creating lightweight and durable parts, metal casting is ideal for producing complex shapes, and 3D printing is used for rapid prototyping and customization. 

Processes Involved in Metal Fabrication 

As mentioned earlier, fabricating metal partsincludes different manufacturing operations. Below, we examine some of the standard processes used for metal fabrication.

CNC Machining

CNC machining is one of the manufacturing industry’s go-to processes for creating precision-focused parts. This technique uses computer codes and programs to control cutting tools as they maneuver a workpiece, performing operations like cutting, milling, turning, and drilling.

After the machinist or operator has configured the device, the machining process is typically automated. This feature accounts for the high precision and speed of CNC machining, as the device operates with minimal human intervention.

3D Printing

3D printing is an additive manufacturing process that involves building the parts layer by layer. It is an innovative metal fabrication process that allows the metal fabricator to build the metal parts in layers from a digital file. 

This technology enables the creation of highly complex and intricate shapes that would be challenging or impossible to achieve with traditional fabrication methods. Metal 3D printing processes, such as Selective Laser Melting (SLM), use high-powered lasers to fuse metal powder particles together. The process is more common for rapid prototyping and custom fabrication of low-volume parts with high precision and minimal material waste. 

Sheet Metal Fabrication

Sheet metal fabrication involves forming and shaping metal sheets into specific designs and structures. This process integrates techniques, such as cutting, bending, and assembling, to produce metal products or components. Manufacturers use laser cutting, shearing, or waterjet cutting, while bending typically involves press brakes. The metal sheets can be shaped into various forms, from simple brackets to complex enclosures. Sheet metal fabrication is a cost-effective method for creating durable parts with uniform thickness and good surface finish.

Metal Casting

Metal casting is the process of heating metal into a molten state at high temperatures. The liquefied metal is then poured into a pre-made mold cavity, bearing the intended shape and structure of the parts. There, the metal cools and solidifies, taking the shape of the mold.

This process is ideal for producing complex shapes that would be difficult or impossible to achieve through other fabrication methods. Metal casting can be done using various methods, such as sand casting, die casting, and investment casting. Each technique has its advantages, depending on the size, shape, and type of metal being used.

What is Metal Machining?

Metal machining is a subtractive manufacturing process that removes material from a metal block until the intended part, shape, or finish is achieved. This process is an example of metal fabrication, though one of the most common. Machining operations typically use precision-based tools and machinery like lathes, mills, and drills, many of which are equipped with CNC capabilities, enhancing their precision.

The technique creates parts and components with high precision and tight tolerances, making it suitable for applications where accuracy is critical. This technique is a mainstay in various industries, such as aerospace, automotive, and medical device manufacturing. The go-to machining operations include turning, milling, and drilling. However, it includes other operations involving cutting off pieces of a workpiece. 

Unlike other forms of metal fabrication, machining focuses specifically on shaping and finishing the metal through controlled material removal. This reason accounts for the exceptional precision, surface finish, and customization for intricate designs and complex geometries it offers.

Processes Involved in Metal Machining 

We already briefly mentioned the standard processes associated with metal machining. Below, we discuss some of these operations. 

Milling

Milling is a machining process that uses rotating cutting tools to remove material from a metal workpiece. It is highly versatile and can be used to create various shapes, including slots, holes, and complex 3D contours. Milling can be performed on different types of machines, such as horizontal or vertical mills, and can handle a wide range of materials, including aluminum, steel, and titanium. The process is ideal for creating parts with precise dimensions and intricate details, making it popular in the automotive, aerospace, and manufacturing industries.

Turning

Turning is a machining process in which a single-point cutting tool moves linearly while the workpiece rotates against the tool. The process typically removes material from the outer diameter of a workpiece, creating a rounded structure, often in the form of a cylinder or a cone. This process is commonly performed on a lathe and is used to create parts such as shafts, bushings, and bolts.

Drilling

Drilling involves creating round, precise holes in a workpiece using a rotating drill bit. It is one of the fundamental machining operations used to make holes of various sizes and depths. Drilling can be performed on various machines, including drill presses, CNC, and milling machines. This process is widely used in metal fabrication for producing holes for fasteners, such as bolts and screws, or for preparing parts for assembly.

Grinding

Grinding is a precision machining process that uses an abrasive wheel to remove small amounts of material from the surface of a metal workpiece. It is typically used for finishing operations to achieve a high degree of surface smoothness and tight dimensional tolerances.

Electrical Discharge Machining (EDM)

Electrical Discharge Machining (EDM) is a non-traditional process that uses electrical discharges or sparks to erode material from a workpiece. This process is beneficial for machining hard materials or complex shapes that are difficult to produce with conventional machining methods. 

Metal machining is fundamentally a subtractive manufacturing process, meaning it involves removing material from a solid block (or workpiece) to create a desired shape or form. This process encompasses various operations, including size reduction, cutting, sawing, planing, and broaching. Each operation is designed to shape or fabricate a metal workpiece by removing excess material. On the other hand, metal fabrication can take any form, including machining, welding, and 3D printing, which is an additive process.

Differences Between Metal Fabrication vs Metal Machining

The table below summarizes the differences between metal fabrication and machining.

Feature	Metal Fabrication	Metal Machining
Definition	A broad range of processes that involve cutting, bending, forming, and assembling metal materials into a final product.	A subtractive process that involves removing material from a solid block to achieve the desired shape and dimensions.
Process	Includes metal machining, 3D printing, sheet metal fabrication, metal casting, forming, bending, and welding.	Includes various machining operations, like milling, turning, drilling, grinding, and EDM.
Applications	Used for large-scale structures, frames, enclosures, automotive bodies, aircraft panels, and industrial equipment.	Used for producing small, complex, and detailed components such as gears, bolts, engine parts, and medical devices.
Tooling and Equipment	It requires various tools and equipment, such as various CNC devices, welders, laser cutters, casting machines, and 3D printers.	Requires specialized machinery, such as CNC mills, lathes, drills, grinders, and EDM machines.

Conclusion

Metal fabrication and machining are manufacturing processes, each offering unique advantages and serving distinct purposes. However, we must emphasize that machining is a form of metal fabrication. Therefore, the latter is a broader term, encompassing the former, among other manufacturing operations.