Metal stamping and forging are among the pillars of metalwork globally and are crucial yielders of metal parts and essential machinery components. These processes date back to the medieval times when metal was minimalist and straightforward. They’re usually subtly nuanced, and it’s typical to confuse one for the other. However, there’s a considerable difference, often not so challenging to point out.
Stamping uses extreme die pressure with high precision to shape blanks. Conversely, forging involves heating and hammering metals to deform them to desired shapes. However, forging still happens at ambient temperatures but applies extreme physical hammering force. Unlike stamping, which uses dies, forging uses hammers and anvils.
The two processes include more than meets the eye, mainly including the nuances setting them apart. I’ll offer insight into the two processes to help you understand the two processes more in this article.
Stamping Vs. Forging: Process Overview
Over time, forging has become a typical metal-forming process since the stem of blacksmithing in the medieval 4000 BC. On the other hand, metal stamping became a thing in the mid-17th¬¬ century. The two approaches aren’t far apart from each other. However, their products exhibit varied characteristics in metal structures, although none are comparably weaker than the other.
Metal stamping and forging have become a staple in the modern world thanks to their products’ durability, strength, and workability. Numerous industries rely on these metalwork products for various functions, including automotive, aviation, and everyday home appliances. As much as both rival each other, there’s no denying that both are essential in their various parts.
The Collective Reasons for Forging and Stamping
Metal stamping and forging serve a single purpose: to produce quality metal parts, components, and other varied products. However, manufacturers choose to niche on a single process or prefer one to the other because of the tiny differences they make. Both metals produce sturdy parts, but the inclusions, the scale of production, or the overall material density might be determining.
Inclusions for both processes are usually different, and the strength varies to some extent. I wouldn’t flaw either of these processes, but forged metal parts have lower inclusions since they mostly use alloys, and the process distributes the impurities in their structural forms. That makes them more resistant to stress and tear compared to stamped metals. Stamped materials are still sturdy and incredibly workable, but that typically depends on the blank material.
The Metal Forging Processes
Forging has become incredibly advanced and more efficient. Standard forging processes no longer use hand tools, and the process has scaled up to industrial-scale production that utilizes electricity and hydraulics. And as far as you guessed, the process isn’t one-way traffic but tags along with various techniques and types. Ideally, the two main forging types include:
Hot forging uses heat in its metal and component formation. The process involves subjecting metals to extreme temperatures, reaching up to 25000 F, before hammering and deforming them into the desired shapes. It’s an essential process that helps eliminate chemical inconsistencies, making the final product incredibly sturdy. Besides, heating makes these metals malleable and ductile. Hence shaping them becomes a piece of cake.
Unlike hot forging, cold forging processes involve shaping metals in ambient temperatures. However, it borrows and combines a series of metal stamping techniques, including cold drawing, bending, extruding, and coining. This process edges out hot forging since its products’ dimensions are usually spot on, the surface finishing impressive, and the uniformity more even. However, it’s not fit for stone-cold metals like steel, which require some form of annealing before shaping.
The Metal Stamping Process
Metal stamping involves deforming metals in ambient temperatures, with a bit of change in metal thickness. This process is almost similar to cold forging since it uses the same techniques, such as bending and coining. However, it also adds more to embossing, blanking, and punching. Stamping uses mechanical or hydraulic forces and is ideal for getting the desired dimensions and the correct indents. However, the material might not be as sturdy as those resulting from forging due to chemical inconsistencies.
Stamping Operation Types
Metal stamping uses various processes but sometimes results in similar products. The difference is usually the procedures used; some yielding adequately finished metal parts while others may still require more surfacing and trimming touches. Here are the various types of stamping operations.
Progressive Die Stamping
The stamping machines in progressive die stamping usually feature a series of stamping stations aligned for the sheet to undergo stamping, punching, cutting, and trimming simultaneously. Here the long metal sheet gets fed into the stamping die, gets stamped, and gets pulled to the nest station in the line to perform a different operation, hence, appearing as progressive. The finished product later emerges from the other end when ready for use.
Transfer Die Stamping
Like progressive die stamping, this process includes stamping in different stations but conveys the sheet and stamped materials using conveyor belts. It’s a standard process used in large-scale metalwork production and helps transfer large stamped metals from one station to the other for further touches and finishing.
Fine blanking is ideal for achieving high precision products, especially at the edges. They include clamping the black in place, performing the blanking, and ejecting the finished part from the machine. Usually, it combines hydraulic or mechanical presses or uses each one solemnly. The most significant difference with this process is that it uses excessive forces to achieve such high pinpoint accuracy levels and smoother edges.
This process produces more complex parts with sophisticated bends and twists. They use two verticle slides instead of one to conduct various shaping and deformation. The slides usually strike the blank horizontally to deform it and create complex indents and designs. And since it allows the attachment of multiple tools on each slide, it makes it a low-cost and efficient metal deformation choice.
Stamping and Forging Similarities
Not all metalwork operations are similar since the techniques used to alter the material blank differently, changing their physical and chemical properties. However, given their operations’ nature, a few similarities exist between stamping and forging. These similarities sometimes make these two metal forming processes operational concurrently in the same manufacturing companies and include the following.
They Both Use Blanks for Shaping
Blanks are metal sheets shaped into metal parts to form the end products of metal stamping and forging. Both processes use blanks in unique ways, with stamping deforming them without altering their chemical properties – or perhaps less than forging. The blanks used in forging are manly metal alloys having high melting points, heated intensively before shaping and deforming. Blanking uses pure metal sheets, for the most part, mainly copper, steel, and aluminum. However, some manufacturers prefer using metal alloys as well.
Altering the Metal’s Physical Properties
Forging changes the impurity distribution and eliminates inclusions that make them more resistant to shear stress. That makes them incredibly sturdy and highly resistant to tearing and breaking. Stamping also alters the physical capabilities of blanks by stretching them, reducing their overall thickness, and making them less sturdy than they were. However, the changes don’t include altering the melting points or electrical conductivity, but those that change their even heat treatment responses.
Cold Forging and Stamping Occur at Room Temperature
Unlike hot forging, cold forging happens at room temperature, and its deforming processes use almost similar techniques. They include coining, bending, and cold drawing, similar to metal stamping. However, the only difference is the tools used to shape the blanks. Deforming metals requires extreme forces and pressure since the metals still have their natural properties. That means immense forces need to deform these blanks and mechanical or hydraulic forces need to tag along.
Annealing Can Happen for Both
Although not entirely, annealing can happen for metal stamping as much as in forging (hot forging). Annealing helps “soften” metals and makes them more vulnerable to physical stress. That helps make them easily deformable, and shaping them becomes less stressful. However, this annealing is usually different from forging because the metal gets shaped through hammering while still red hot. After heating, the metal blank first cools down for exceptional stamping cases to compromise its structural properties before deforming. That improves their material flow, thus possibly resisting tearing and breaking.
Despite their similarities, these two metal-forming work differently, which sets them apart. Here are the variations between these processes.
Different Tools Used
Forging uses hammers and anvils to shape red hot blanks blazing at temperatures beyond their crystallization points. That makes them easily malleable and more ductile, reducing the force for deforming. On the other hand, stamping uses dies under intensive mechanical or hydraulic forces. These metal blanks are usually touched to shape and deform, given their sheer resistance to pressure, and more intensive forces need to be operational.
The Rigidity of the End Products
Metal products from forging possess a plethora of properties depicting a high resistance to shear pressure. Their structural reliability is top-end since they usually don’t have internal gas pockets that compromise their structural integrity. Therefore, they never cave into extreme pressure, impact or stress. On the other hand, metal stamping products have lower structural integrity. And given the powerful forces they get subjected to, they tend to be somewhat weaker than the original blanks.
Concurrent Shaping, Cutting, and Branding
Forging is minimalist, meaning that metals get shaped using hammers and anvils before being branded separately. However, stamping usually combines the processes in a single ram, making it more manageable. That’s even true for progressive die stamping, which refines the stamping products in a single operation. Although branding and creating shapes and smoothed-up edges are possible in metal forging, it has to occur separately. The initial hammering usually shapes the metal blank before it’s ready to undergo further processing.
Precision and Efficiency
Achieving high precision and efficiency is easier in stamping than in general forging. However, it’s still possible for further processing and refinement processes, collectively known as precision forging. Conversely, stamping ensures high pinpoint accuracy and efficiency in a single operation, creating products ready for use. In some cases, stamped products undergo deburring to remove shards of curt materials or to grind the sharp edges. However, that won’t be necessary if the stamping machine is proficient enough.
Advantages and Disadvantages of Stamping and Forging
Like every metal forming process, stamping and forging have strengths and weaknesses. The advantages and disadvantages of both approaches include the following.
- Low secondary costs – stamped products require little finishing due to the process’s high precision and accuracy. That, therefore, doesn’t prompt costly secondary costs like other metal forming processes, including forging.
- Lower die costs – metal stamping dies only require simple milling, computer-aided machining (CAM), and designing. Unlike the dies for most metal forming processes, stamping dies are relatively cheaper to produce.
- Machine automation – stamping machines are easy to automate using top-end computer programs, which also lower the cost of labor.
- The need to change dies – unless dealing with progressive die stamping, replacing dies for different operations on the same machines can be daunting.
- Higher cost of presses – pre-production processes such as creating custom dies and acquiring milling machines can be costly. Besides, they usually take more time and can be a problem if there’s none.
- Sturdier products – undoubtedly, fording eliminates material inclusions, distributing metal impurities throughout the metal structure. That makes them resistant to impact and stress.
- No specialized skills needed – unlike stamping, which requires well-versed operators, forging doesn’t. That makes them easy to produce.
There are low operating costs due to its incredibly minimalist metal forming approach.
- Forging doesn’t produce complex shapes – unlike stamping, forging produces simple shapes that require costly processing and finishing, especially in hot forging.
- Brittle metals are unsuitable – given the constant hammering in hot conditions, brittle materials cannot withstand the stress and can break quickly.
- Costly operations in large-scale forging – industrial-scale forging can be cost-intensive and initial costs can be overwhelming.
Metal stamping and forging aim to produce usable and workable metal parts for a plethora of industries. And regardless of this similarity, the two processes are isolated and operate differently. Both approaches are equally practical and have their strengths and weaknesses, and in my opinion, none edges out the other. But hopefully enough, this article will help you decide which of the two suits you best.