Metalworking Explained: Metal Forming, Stamping, Cutting & Joining

Metalworking is the art of shaping metals into various tools, equipment parts, and structures. It involves forming, cutting, and joining metal pieces using techniques like welding, casting, and molding. In the industrial age, metalworking has developed into a sophisticated science. The industrial revolution has led to exponential growth in the scale of modern metalworking processes, accompanied by increasingly complex technologies.

What Are the Different Types of Metalworking?

Metalworking is the manufacturing process of shaping/reshaping metals to create useful parts, assemblies, and structures.

What Is Metal Forming?

Metal forming is the metalworking category that reshapes a piece of metal into a new geometry through plastic deformation, without adding or removing material. It covers everything from large-scale bulk deformation, like forging a crankshaft, down to sheet metal forming, like stamping a car body panel. Within the forming category specifically, bulk-deformation processes are generally divided into three main categories: rolling, forging, and extrusion/drawing. See our full sheet metal forming guide for the shearing, blanking, bending, and drawing side of this category specifically.

In a bulk-deformation process, a simple part, typically a metal billet or sheet blank, is plastically deformed between tools (or dies) to achieve the desired final shape. This process transforms a basic initial geometry into a more complex one, with the tools “storing” the intended geometry and applying pressure to the material through the tool/material interface.

Bulk-deformation processes typically produce minimal to no scrap and achieve the final part geometry quickly, often in just one or a few strokes of a press or hammer. These processes are known for their significant energy and material savings.

One common bulk-deformation process is extrusion, where a heated billet is forced through a shaped die to produce a continuous profile with a constant cross-section. See our complete guide to the extrusion process for a full breakdown of how it works.

What Tools Do You Need for Metalworking?

Various tools and equipment are necessary for different metalworking processes. These can include molding, drilling, casting, welding, cutting, and more. Common tools for metalworking include a bandsaw, hacksaw, welder, angle grinder, belt sander, and drill press. It’s crucial to fully understand the safe operation of these tools before starting any project.

Is Metalworking Dangerous? Basic Safety Considerations

Metalworking carries real hazards: sharp edges and swarf, heat from welding or forging, flying debris from cutting or grinding, and noise from powered tools. Basic precautions go a long way, including safety glasses or a face shield, hearing protection, cut-resistant gloves suited to the specific task (some operations, like using a drill press, actually call for bare hands so loose gloves can’t get caught), and keeping loose clothing and long hair secured away from moving equipment. Beyond personal protective equipment, most serious metalworking injuries trace back to skipping machine guards or rushing a setup, so taking the time to understand a tool’s safe operating procedure before using it is the single best safeguard.

I ran the machine shop at Delaware Technical Community College, where part of my responsibility was making sure every student using the machines was properly trained and equipped before they ever touched one. Safety was always the top priority, and I’d rather a student ask a question than guess. My advice hasn’t changed since: if you’re ever not sure how to properly use a machine, don’t. Stop, ask, and get proper training first.

What’s the Difference Between Metalworking and Blacksmithing?

Blacksmithing is a subset of metalworking, which encompasses various methods like welding, casting, and jewelry making. It involves using a forge, hammer, and anvil to shape metals, particularly iron and steel. The origins of welding can be traced back to early blacksmithing techniques around 3000 BCE.

What Automobile Parts Are Made by Forging?

Forging is a manufacturing process that uses compression to shape metal parts. Forging is one of the oldest manufacturing processes, which dates back to well before 4000 BC. The first metals forged here were gold, iron, and copper alloys such as bronze. An area where forged parts are still used extensively is the powertrain system in the automotive industry. Several of the key components in this system require parts to be forged to be able to withstand the significant loads that will be experienced in the engine and transmission. Some examples of forged parts in a vehicle powertrain system include connecting rods, crankshafts, transmission shafts, and gears.

What Are the Advantages of Forging Over Casting?

As a result of the tight grain structure which is a result of the compressive load of forging, forged parts are stronger than cast parts. Forged parts are not susceptible to cavities, cold pour problems, porosity, or shrinkage.

What Are the Basic Types of Sheet Metal Processes?

After the metal has been flat-rolled it is usually coiled into giant rolls which then can be used to fabricate sheet metal parts. The three major categories of sheet-metal processes are shearing, bending/drawing, and forming. In the automotive industry, most sheet metal parts are either sheared or bent/drawn to achieve the final design.

What Is the Forming Process for Car Manufacturing?

Using the stress-strain diagram, automotive engineers ensure they exceed the yield stress of a material while avoiding ultimate stress. This ensures that the part is within the plastic deformation zone while stamping. The reason to exceed the yield stress of a material is to ensure that the part will hold its intended shape after the die opens up; if the yield stress is not exceeded, the part will go back to its original shape. However, automakers must be careful not to exceed the fracture stress, as this will result in a tear or crack in the sheet metal.

Common Sheet Metal Stamping Operations

“Stamping” isn’t really one operation; it’s an umbrella term for several distinct operations that are often combined within a single progressive die. The most common include:

• Blanking — cutting a flat piece (the “blank”) out of a larger sheet or coil, which then becomes the starting material for further forming.
• Punching — cutting a hole or feature into the material, where the removed piece (the slug) is scrap rather than the finished part.
• Bending — plastically deforming the sheet along a straight axis to create an angle, flange, or curve.
• Deep drawing — pulling a flat blank into a die cavity to form a hollow, cup-like shape without significant wall thinning.
• Embossing — forming a raised or recessed design into the sheet, typically for stiffness or aesthetics, without cutting through the material.
• Coining — applying very high, localized pressure to force the material into a precise final shape or thickness, similar to how coins get their detailed relief.
• Flanging — bending the edge of a part, often around a curve, to add stiffness or create a mounting surface.

Many of these operations happen in sequence within a single progressive die, where a strip of material advances station by station, with each station performing one operation, until a finished part drops out at the last station. Keeping that strip precisely positioned as it advances is critical, which is where bypass notches come in: small notches punched into the edge of the strip at each station that a pilot pin or sensing feature can reference to confirm the strip has advanced correctly. If the strip mis-feeds or a bypass notch doesn’t line up as expected, the press can stop automatically before the next station forms a defective (or die-damaging) part. In short, bypass notches exist for strip control and quality assurance, not to shape the finished part itself.

For a deeper look at how these tradeoffs play out in real part design, see our sheet metal design guidelines, or our full sheet metal stamping and forming design guide for a deeper dive into metal forming specifically.

What Is the Machining and Finishing Process?

Usually, most companies stamp, forge, or cast the majority of their parts before conducting any machining or finishing operation. If machining or finishing is required, the cost of the part skyrockets, especially as the dimensional tolerance gets tightened up. For this reason, many companies try to design around these manufacturing processes.

Machining is the process of cutting or removing material from the workpiece. The most common types of machining operations are turning, milling, or drilling. During the finishing process, less material is cut or removed from the material, when compared to milling, so the part ends up with greater tolerances and a nicer surface finish. Many times, finishing is done to improve the appearance or the feel of a part.

Heat treatment is a type of property modification process in which metal or metal alloy is heated to enable recrystallization of the metal and thus alter its material properties. Recrystallization occurs when the temperature is increased to the point where the material is glowing red hot but prior to reaching its melting point. The metal is then cooled in a controlled way to obtain the desired mechanical properties. As can be seen in the graph below, the hardness and strength of a material are inversely related to the ductility of the material.

What Are the Different Types of Surface Heat Treatment?

Surface heat treatment is a type of heat treatment where the outer layer of a part has a higher hardness requirement than the core of the material; one reason for needing this is for more wear resistance. See a list below of various types of surface hardening.

In conclusion, metalworking is a versatile and essential skill that encompasses a variety of processes, including metal forming, stamping, cutting, and joining metals. Understanding the basics of metalworking, such as the tools and techniques involved, can open up a world of possibilities for creating useful and precise parts. Whether you’re studying sheet metal stamping for an automotive program or working through the fundamentals for the first time, learning the core processes is the first step toward understanding how nearly everything metal actually gets made.