This Article takes an In-depth look at Metal Stamping
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The evolution of metal stamping took off during the industrial revolution as a cost-effective cold-forming technique, initially applied to crafting bicycle frames and handlebars. Originating in Germany, this process has matured into a crucial component across various industries, enabling the production of diverse parts and components. The early auto industry transitioned its part manufacturing from forging to metal stamping, primarily due to the reduced expenses associated with the stamping method.
Metal stamping is a straightforward process where rolled or sheet metal, termed a blank, is placed into a pressing machine equipped with a die shaped as the desired part. Through force and compression, the die forms the metal. After a specific duration, a partially formed component is extracted. While this might appear simple, the process involves multiple stages, including trimming and finishing, among other tasks, to produce the completed part.
Despite metal stamping's century-old roots, it has significantly advanced over the years, incorporating cutting-edge technology. This is evident with the adoption of computer numerical control (CNC), where designs are conceptualized and trialed digitally before being executed by CNC metal stamping machines.
Metal stamping provides multiple benefits. As a cold-forming technique, it eliminates the need for heating, thus lowering costs. This method additionally supports the creation of complex, detailed designs that might be difficult to accomplish using alternative techniques. Moreover, the precision and accuracy of metal stamping make it the go-to method for manufacturing intricate parts.
The metal stamping process involves transforming a flat metal sheet into a specified shape. Despite its complexity, the process includes many sophisticated techniques. From automotive and aerospace sectors to medical and electronics industries, metal stamping plays a pivotal role in producing cost-efficient, high-quality parts and components. Metal stamping encompasses a variety of techniques such as punching, blanking, embossing, coining, bending, and flanging.
Punching involves extracting a scrap slug from the workpiece upon the punch's entry into the die. Though typically performed on sheet materials, rolled metals can also be utilized. This process results in a hole reflecting the design's precise dimensions, consistently producing holes of varied shapes and sizes.
Sheet metal blanking is a shearing and cutting methodology where a "blank" is cut from a larger metal sheet. This blank is configured to reflect the final part's designed shape, typically involved in 2D forming processes.
Embossing crafts a raised or recessed design by pressing the blank against a die shaped like the intended pattern. When pressed into the embossing machine, a tool creates a raised design on the blank's opposite side. By positioning the blank on a rubber or foam pad, it achieves a smooth embossed finish.
Coining is necessary for smoothing the edges of stamped parts, delivering finer detail and strengthening the workpiece. Coining minimizes the need for additional finishing like deburring or grinding. This process requires immense pressure to achieve the desired plastic deformation.
Bending involves shaping metal into L, U, or V profiles through deformation. A press brake uses a punch and die to perform the bending. Varied bending approaches include mechanical, pneumatic, hydraulic, and CNC methods. The bending process deforms metal above the yield strength but remains below its tensile strength, occurring around a set axis.
Flanging involves a technique of crafting flares or flanges in metal using a die, press, or a dedicated flanging machine. This process produces a 90-degree bend in the metal. When the bend's breakline exceeds the trim line, it's called a stretch flange, whereas a shorter breakline than the trim line is a shrink flange.
Metal stamping machines employ cast, punch, deformation, and bending methods using computer programming or CNC machines for exceptional precision. The advanced metal stamping process facilitates the rapid creation of exact metal shapes with unparalleled precision and accuracy. These innovative tools offer custom solutions for 300 distinct raw material types. The economical nature of stamping renders it a cornerstone in producing essential items that simplify life.
Metal stamping machines are crucial in the United States and Canada for efficient, cost-effective mass production of metal components. These machines play a key role in various industries, including automotive, aerospace, electronics, and medical, driving technological advancements and economic growth. Below, we explore a range of these machines and highlight the features that have made them popular.
The Komatsu E2W series presses stand out for their precision, dependability, and energy efficiency. Featuring advanced servo-driven technology, these presses offer precise control over the ram’s movement, ensuring consistent and accurate stamping. Their design focuses on minimizing energy usage and reducing operational costs, making them a favored choice for diverse metal stamping needs.
AIDA's NC1 series presses are celebrated for their durable construction, exceptional speed, and versatility. Designed with cutting-edge controls and automation capabilities, these presses ensure swift and efficient production. Renowned for their precision, the NC1 series adeptly manages a diverse array of stamping applications, making it a preferred choice for metal stamping enterprises.
The Bliss C1 Straight Side Press is celebrated for its exceptional durability and rigidity, ensuring stable and precise stamping operations. Its straight side design offers easy access to the working area, making die changes and maintenance straightforward. Known for its capability to handle heavy-duty stamping applications effortlessly, this press is a reliable choice for demanding tasks.
The DSF Series Servo Presses from SEYI are renowned for their precision and high-speed performance. By harnessing servo motor technology, these presses ensure precise control of the ram’s movement, leading to lower energy consumption and enhanced productivity. Ideal for tasks involving complex forming and intricate shapes, the DSF Series is a top choice for demanding applications.
Metal stamping refers to several types of forming processes each of which performs a special type of operation. The type of stamping method depends on several factors from the design of the part to the number of required stamping operations. The choice of procedure is normally defined and specified by the engineer or designer.
Normally, stamping refers to a single operation where a portion of a part is formed in one machine before being moved on to another machine or set of machines. The process requires multiple dies on several pieces of equipment. Finishing and shaping are separate operations performed after the part has been through the various machines. Progressive stamping removes the need for multiple machines performing several functions and handling of the workpiece in a single set of operations. A strip of rolled metal unrolls into a single die press with a number of stations that perform individual functions. Each station adds to what has been done previously resulting in a completed, finished part.
Progressive stamping simplifies the production of complex and intricate parts decreasing production time while increasing efficiency. Movements must be precisely aligned since the part is still connected to the metal roll. The first station separates the fabricated part from the rest of the metal. Progressive die stamping is ideal for long runs since the dies last longer and do not sustain any damage as a result of the process. As with several stamping processes, progressive stamping is repeatable. Each station performs a different cut, bend, or punch to gradually achieve the desired end shape and design. Progressive die casting is faster and has limited waste scrap.
Transfer die stamping uses a mechanical transport system to move the part from station to station. It is used for tube applications, frames, shells, and structural components. A die can be a simple single die or part of several dies lined up in a row. To perform transfer die stamping, the part is removed from the metal strip as it transfers between stamping stations. Transfer die stamping was developed to produce large parts and workpieces with the additional benefit of lower tooling costs.
Four slide, multislide, or four way stamping shapes the workpiece horizontally sliding it between four different tools. As the workpiece feeds, it is bent by each tool using a smooth set of processes. Each slide is driven by a shaft controlled by the rotations of a cam. The shafts are connected by a bevel gear with one electrical motor to power the shafts. The workpiece may be shaped with all tools working at once or in succession. The key to four slide stamping is the shafts, which allows the work piece to be shaped on all four sides.
Fine blanking is a special type of stamping that produces flatness and a sheared edge that is impossible with traditional stamping. Any secondary machining of parts is not required since profiles, web sections, and holes are completed in one process. To achieve the perfection of fine blanking, the blank is compressed between the upper and lower punches allowing the process to hold a very tight tolerance. The process is known for its high accuracy and smooth edges. It is done with hydraulic or mechanical presses or a combination of the two.
The blanking process involves three key movements: clamping, blanking, and ejection. Fine blanking presses operate under high pressures, necessitating tools that can endure these conditions. This entire process is executed in a single cold stamping step.
The normal categories for stamping presses are mechanical, hydraulic, and mechanical servo. Feeding is done automatically either in sheets, coils, or perfectly sized blanks. The type of feeder depends on the thickness of the sheets. The reel type is used for thinner sheets while thicker metal sheets are fed individually. With roll metal feeders, as the metal unrolls, it is straightened to remove any residual effects.
Mechanical milling is a method for preparing and reshaping metals without the use of heat or chemicals. Its function is to remove metal from a workpiece by using a cutter where the metal has a flat, rough, or irregular surface, and the workpiece is fed into the cutter. Mechanical milling requires a high powered motor to rotate the cutter to break down the structure of the workpiece. The size of the cutter and speed vary depending on the type of machine. Most mechanical milling equipment weighs several tons and is designed for heavy duty operation. They have been a major part of manufacturing and product production since the industrial revolution.
Hydraulic milling machines use the force of hydraulic power to compress the workpiece onto the die. This form of milling is widely used because of its accuracy and cost effectiveness. Pressure applied to the die is more uniform than produced by mechanical milling machines. In many cases, the hydraulic milling machine‘s process is referred to as stamping since the workpiece is stamped into the mold or die. The workpiece is fed into the machine and aligned with the die where pressure is applied. The amount of pressure and speed can be adjusted to fit the type of metal. As with all milling equipment, hydraulic machines come in several sizes to fit the type of manufacturing.
Until recently, the only way to increase tonnage on a press was to build a bigger press with a larger motor or flywheel, an expensive process. Press designing engineers decided to build a better press by removing the motor, flywheel, and clutch and replacing them with a servo motor focused on needed energy.
Servo presses offer greater flexibility by allowing precise adjustments to stroke and slide positions. Unlike traditional presses that use a flywheel, servo presses utilize a servo motor to deliver torque through a controlled and programmable system. This innovation enables exact control over speed, making it possible to adjust velocity, dwell time, and stroke length to meet the requirements of various applications.
Using high capacity motors, mechanical servo presses can create complicated stampings at a faster rate than hydraulic presses and are powered by a link-assisted drive system or a direct drive one. Of the three types of presses listed, the mechanical servo press is the newest and most expensive. Regardless of the drawback of cost, several manufacturers have installed mechanical servo presses and have found them to be more efficient and cost effective.
Stamping dies are precision tools specially designed to cut and form metal sheets into a specific shape or profile. Dies are made from hardened steel called tool steel, a variety of high-hardness and abrasion resistant steel. Included in a die can be cutting and forming sections made from other metals that are hard and wear resistant. Dies for metal stamping can be either single-station or multiple-station.
Dies used for single station operations can be compound or combination . Both perform multiple operations in a single function. The main difference between them is their design and the type of stamping they do where a compound die mainly cuts and a combination die does both cutting and non-cutting processes.
Compound dies are designed to execute multiple cutting operations in a single press, such as those required to manufacture a simple steel washer. They can produce a part every three seconds, which minimizes labor costs and shortens lead times. By cutting complex parts in a single stroke, these dies ensure precise accuracy for each piece. The high precision of compound dies also reduces material waste, contributing to additional cost savings.
Combination dies feature both cutting and non-cutting tools, allowing them to reshape materials in a single operation. This integrated approach enables simultaneous processes such as cutting, drawing, and bending. One of the key advantages of combination dies is their efficiency and cost-effectiveness for large projects. They streamline die setup, reduce waste significantly, and can perform tasks like creating holes and flanging with a single cut.
Multi-station dies employ progressive milling to automate the movement of the workpiece through various stages. Raw metal is introduced into the machine, where it undergoes processes such as cutting, bending, coining, or punching, based on the system’s programming and the part’s specifications. Each station within the die can perform one or multiple functions, streamlining the manufacturing process.
Steel rule dies, also referred to as knife dies or cookie cutter dies, were first used to cut softer surfaces such as plastics, wood, cork, felt, fabrics, and paperboard. Though they are not as sturdy as steel dies, they have found use in the cutting and shaping of thin non-ferrous metals such as aluminum, copper, and brass.
Steel rule dies are made of high grade, high density, and hardwood plywood with steel strips added. Slits are cut into the flat plywood. Steel rule, which is similar to a razor blade, is inserted into the slits. Rubber is glued to the flat side of the plywood to help eject it after the cutting process and prevent it from sticking to the metal press. Steel rule dies come in several thicknesses depending on the application.
The steel strip material used for the cutting surface is designed to match the desired shape. The characteristics of the workpiece, such as thickness and hardness, help determine the steel rule thickness to be used in the cutting blade. Steel rule dies can be used to cut exotic materials, thick foam, carpet, and rubber. It is an inexpensive and effective method of cutting thin sheet metals.
Stamping involves a detailed understanding of metals and their manipulation. The choice of metal for a project is crucial and depends on the desired result. While metal is typically used for stamping, non-metal materials like paper, leather, and rubber can also be shaped through this process. DIY enthusiasts and hobbyists often use hand-operated stampers for home projects and for shaping non-ferrous metals.
Though there are thousands of metals that can be stamped, there are two general categories - ferrous and nonferrous where ferrous metals have iron and nonferrous do not. Nonferrous metals that are commonly stamped are aluminum, brass, bronze, gold, silver, tin, and copper. One of the factors that determines the formability of a metal is its carbon content, though carbon is only one of many factors.
Alloys, a compound of two or more metals, are commonly used in metal stamping. Each alloyed metal has special characteristics that has to be considered when being used for metal stamping. For example, non-standard alloys, such as beryllium nickel and beryllium copper, are excellent for metalworking, forming, and shaping musical instruments and bullets.
The art of shaping and forming precious metals has deep roots, stretching back to ancient civilizations such as the Romans, Greeks, and Egyptians. What was once the domain of skilled artisans has evolved with the advent of modern stamping machines. Today, silver, gold, and platinum can be crafted into elaborate designs using advanced dies and cutting tools. While the craftsmanship of yesteryear has been largely replaced by technological innovation, the essence of metalworking continues to thrive through these sophisticated machines.
Ferrous metals are excellent for manufacturing components thanks to their durability, high tensile strength, and hardness. Low carbon steels, in particular, offer exceptional formability, making them suitable for creating hardened machine parts and various other versatile applications.
As with any industrial process, careful planning and preparation are necessary when using metal stamping. The selection of the correct metal and the quality of the final product depends on the type and quality of the materials for the process.
When a workpiece has completed the stamping process, it may require other processes to remove any imperfections, deformities, or excesses as well as the addition of other parts and applications. This is performed during post stamping production operations, which include deburring, tapping, reaming, and counterboring.
After stamping, workpieces may have rough, sharp, or jagged edges known as burrs. The process of eliminating these imperfections is called deburring. Various methods can be employed for deburring, including manual techniques, electrochemical processes, and thermal treatments. Burrs can form not only on edges but also in seams, meaning multiple sections of a workpiece may need deburring.
Deburring improves the quality, aesthetic value, functionality, and appearance of a workpiece. Also, there is the matter of safety where a small notch or deformity can catch on a piece of equipment or cause personal injury. More difficult burrs may need to be flanged over to produce a smoothed edge and direct the burred edge to the inside fold where it will not cause injuries or be noticed.
When a design is created using CAD, onscreen results and calculations give the impression that what has been produced is perfect and flawless. What may be ignored are some of the limitations to processing and types of material, which can lead to the production of parts that do not perform as they were designed. Thickness, formatting area, grain direction, and hardness all have an influence on the design of a part and the stamping process.
Design flaws can compromise the quality of the final product. One such flaw is overly narrow projections, which can distort the workpiece.
Designs are tailored to match the manufacturer’s existing equipment, tools, dies, and materials. Utilizing custom dies or special equipment raises both manufacturing and fabricating expenses, ultimately increasing the cost of the final product.
Special consideration is necessary regarding sharp edges, corners, and bends in a design to help in the reduction of burrs and other deformities since they will require special finishing and other secondary treatments. Sharp bends or corners may cause cracking due to increased stress on the workpiece. Increased stress can lead to failure of the part.
During the design phase, precise adjustments are necessary to accommodate the folds on edges, flanges, and material removal, ensuring the product fits within the width and length constraints of the workpiece.
Large stampings require a stamping press with a large bed and higher tonnage. When larger machines are not available or practical, production can be completed by using multiple steps that are later joined together.
Punching is a cutting process used to modify and deform a metal blank where shearing force is applied. It is similar to blanking with the exception of the piece being removed, slug, is scrap. Punched holes are in simple geometric shapes either individually or combined. Holes formed from punching normally require secondary finishing since burrs are left around the edges of the hole. The punch is driven into the workpiece at high speed. CNC punch presses can be hydraulic, pneumatic, or electrical able to deliver over 500 punches per minute. Most punches have a turret that can hold close to 100 different styles of punches.
Bending is applying force to the workpiece causing it to bend at an angle to create a desired shape. The operation is performed along one axis, but a set of operations are possible for complex pieces. Parts can be as small as a bracket or several feet. Bending creates both tension and compression in the workpiece. The outside part will have tension while the inside, as it shortens, experiences compression. In some cases, it may be necessary to overbend to account for any springback.
When milling holes by punching or drilling, ensure that the holes are spaced at least twice the sheet thickness apart. This distance is crucial for maintaining the metal's strength and preventing deformation. For holes positioned near the edge of a workpiece, they should be placed at a distance equal to the thickness of the workpiece from the edge. Additionally, the space between holes and bends should accommodate the bend radius and be sufficiently far from the bend to avoid compromising the structural integrity.
Metal stamping is a versatile method for reshaping and deforming metal sheets, allowing for the creation of highly intricate and complex designs that other processes cannot achieve. This technique can transform a simple flat piece of metal into a functional and practical shape with ease.
There are several benefits to metal stamping, which include lower costs for dies and any secondary factors. Modern era stamping machines are automated and work with little need for any handling of the workpiece. The dies and tools required for stamping are inexpensive and can be used multiple times. Cleaning, plating, and other secondary processes are less expensive since many products are nearly finished after being pressed. Automation processes for stamping machines are uncomplicated and adaptable. Various computer programs offer precision, control, and precise dimensions for the completion of a product providing quicker turnaround times. An added benefit of automation is a significant decrease in labor costs.
One of the drawbacks to metal stamping is the cost. Upfront cost of equipment, tools, and dies are high and require a significant investment. For custom parts or designs, a special steel die has to be created leading to longer pre-production and extended turn around times. Changing dies during production due to design flaws can be difficult and time consuming.
Metal stamping is rapidly emerging as one of the fastest-growing production techniques globally. Over the next decade, the stamping market is projected to reach $300 billion worldwide. While this figure might seem ambitious, it becomes more understandable when you consider the wide range of industries that rely on stamping for their manufacturing processes.
The process of metal stamping is used by industry to produce parts and products with high precision, accuracy, and speed. Products produced using stamping methods have lower errors per production cycle than any other process, which eliminates flawed or faulty products.
Several industries rely on stamping to produce products. The automotive industry uses it for structural components such as body frames, electrical systems, and steering systems. The aerospace industry requires parts that need to meet strict manufacturer specifications to ensure safety and maintain certifications. The medical industry has requirements similar to aerospace and depends on metal stamping for its accuracy and reliability.
Computer and electronics manufacturers use metal stamping to create their internal components. Technical parts have special shapes and dimensions requiring precision manufacturing and production methods. The stamping process plays a critical role in the fabrication of these modern conveniences.
The metal stamping industry has played a part in the production of most of the items found in homes, schools, business, and offices. It has become an essential part of 21st Century advancements. It is highly likely industry will continue to depend on it for many years to come.
Stamping is a major part of manufacturing and part production. It is very likely that it will continue to play an important role in the production of future parts for innovations and inventions that are presently on the drawing board or in the imaginations of engineers. For more information on milling and stamping companies consult ÌÇÐÄVlog for a complete listing of local and national fabricators, processors, and producers who can meet your production requirements.
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