Metal forming is one of the fundamental processes in manufacturing. It uses various mechanical methods to change the raw metal material into various shapes and provide necessary components for many industries. In sheet metal fabrication, the main process includes press brake vs stamping.
The press brake can achieve the partial bending and deforming of the material, which is used for straight sheets or slice materials. Via simple operation, an ideal bending shape can be produced. This costs a little and is very convenient for simple and single parts.
The stamping adopts the integral forming principle, which simultaneously moves up and down through the die and stamps the material into the required forms. This brings higher accuracy and achieves more complex three-dimensional modeling. However, the cost may be high.
Choosing the way of proper metal forming is closely related to the success of products. Our passage aims to make a comprehensive comparison between the two main metal forming processes, press brake vs stamping, which can offer a reference for readers to choose the ideal process.
What Is Press Brake
The press brake is a machine tool used to bend metal sheets. It can be bent through clamping the workpiece between the matched top punch and bottom die. The bending process involves two C-shaped frames, which are made up of the side of the press brake and can be connected to the bottom workbench and top movable beam. The bottom dies are installed on the workbench, and the top punches are installed on the upper beam.
The press brake features two main types: hydraulic and electronic. The hydraulic press brake utilizes the bending force produced by hydraulic cylinders and pumps. It is driven by the mechanism to produce reliable metal bending. The electronic press brake adopts servo motors and advanced digital control devices. It can provide programming bending sequences and higher accuracy.
Process Overview:
- Preparation: The metal sheet, typically composed of materials like steel, aluminum, or stainless steel, is readied for the bending operation.
- Setup: The metal sheet is placed between the punch (upper tool) and the die (lower tool) on the press brake machine, ensuring proper alignment.
- Clamping: The press brake secures the metal sheet firmly between the punch and die, ensuring it remains stable throughout the bending process.
- Bending: The machine applies hydraulic force through the punch, shaping the metal sheet to match the profile of the die.
- Release: Once the desired bend is achieved, the clamping force is released, allowing the formed metal sheet to be carefully removed from the machine.
Advantages
- High efficiency: the press brake can reduce the workers’ operation time and improve working efficiency. Due to the machine's higher automation, simple adjustments and monitors are needed for mass bending production.
- High accuracy: the press brake can achieve high-precision bending operation, significantly improving the press brake's quality. It features high speed and high precision position during the movement, thus realizing the bending effortlessly.
- High automation: the press brake features high automation, which can achieve one essential operation, thus reducing the workers’ operation burden. Besides, the machine can also perform automatic material distribution, positioning, feeding, clamping, bending, fine adjustment, material withdrawal, cleaning, etc., achieving human-machine collaborative operation.
- Strong stability: the press brake can achieve bending operation through strict procedures. Many problems are generated during manufacturing because of improper operation and other reasons, such as deformation and bending angle deviation. The large press brake can handle those problems quickly.
Disadvantages
- High cost: compared with traditional manual operation and common mechanical equipment, the press brake is expensive.
- High technology: the CNC press brake requires elites to operate the machine. If the company can’t hire the proper workers, the working efficiency may not be generated entirely.
- High-difficulty repair: due to the complex structure of the press brake, the difficulty of repairing and maintaining the machine is relatively high. If the components require fixing, the high-technology maintenance worker needs to handle them. Otherwise, the equipment will not work correctly.
Types of Press Braking
- Air Bending: This method involves partial contact between the metal sheet and the die, allowing flexibility in adjusting the bend angle.
- Bottom Bending: The punch fully penetrates the die, creating a precise bend angle.
- Coining: This technique uses significant force to conform the metal to the exact angle of the punch and die, often resulting in metal thinning.
The press brake is widely applied in many manufacturing. The automotive relies on it to form the body components and chassis. The electrician manufacturing relies on it to bend metal panel cabinets. Also, the press brake can be applied to the HVAC, electronics, and aerospace industries to shape ductwork, enclosures, and structural components. Its flexibility makes it a versatile solution for metal manufacturing.
What Is Stamping
Stamping is an essential process in metal fabrication, which refers to forming metal parts by pressing or "stamping" them between top and bottom dies. This involves a high-speed metal forming process that uses a punch press, a machine equipped with dies to operate a punching operation.
There are various types of press, and each type is customized for specific tasks; the common use is as follows:
Mechanical press: it uses a mechanical flywheel to store the energy and transform it to the punch, then be operated when transported to the die.
Hydraulic press: it uses hydraulic oils and a series of hydraulic cylinders to produce compressor force.
Servo press: this innovative machine uses servo motors to drive the punch. They combine the advantages of mechanical press and hydraulic press to offer speed and control.
Over the years, metal stamping has been regarded as the top reference process for its easy access and economical, which has the advantages as follows:
- Short cycle time: the stamping process usually can finish the production of the parts, thus improving the working efficiency.
- Generate the complex parts: metal stamping can produce difficult parts with high shape control, thus meeting various demands.
- No need for skilled operators: compared with other manufacturing processes, metal stamping features high automation, thus no need for highly skilled operators, reducing the labor cost.
Here are the disadvantages of the stamping:
- Can’t produce long components: metal stamping can not make long-size components because it can be easily influenced by the rebound, thus leaving tooling residues and marks on the workpiece.
- Die cost increased: when multiple different lengths of the same profile are required, and each size requires a different stamping die, the manufacturing cost of the die will be increased.
- Difficulty in changing stamping patterns: once the stamping mode is set by the stamping tool, it is difficult to flexibly change it, which may limit the diversity of production.
- High cost for long components: the tools for producing the long pieces may be expensive. Thus, the price will be increased.
As for application, stamping is everywhere in many industries. The automotive relies heavily on it to produce large quantities of uniform parts such as fenders, hoods, and other panels. Electronics manufacturers use stamping to create complex components in devices. Even the daily goods, from cabinet tools to metal clips, you can see the footprint of the stamping process.
Key Differences: Press Brake vs Stamping
In the realm of metal fabrication, the press brake and stamping have their own characteristics. Here are the main differences between them:
Production Volume
Press brake: this is specially designed for low-medium production tasks. As for the mechanism and the accuracy they provide, the press brake is usually chosen for specific tasks, in which each part has its distinctive specific. Also, it can be applied on a small scale.
Stamping: this process is the top reference for high production. Its ability to quickly produce mass and even parts makes it an ideal choice for mass production.
Precision
Press brake: one of the apparent characteristics of press brake is its high accuracy. It can bend precisely and ensure that each workpiece is being made exactly. This precision is vital for tasks. Even a little deviation may cause functional or beautiful problems.
Stamping: although the sheet metal stamping itself is precise, especially when producing the uniform parts, it could not match the press brake with the tasks of the same detailed levels.
Speed
Press brake: the speed of the press brake is relatively slow because of its attention to precision and access to low-medium production.
Stamping: stamping stands out in speed. Its high-speed sheet metal forming process and mass-scale production ability can make the speed faster, especially for mass production.
Cost
Press brake: each workpiece produced by press brake may be expensive, especially for specific tasks and small scale.
Stamping: owing to its efficiency and speed, stamping will lead to the lower cost of a single workpiece when handling mass-scale production. The initial tooling costs may be expensive, but the unit costs will drop significantly when mass-produced.
Mechanism
Press brake: it is operated by clamping the metal sheet between the matched punch and die. Then, press the piece of sheets into the die to bend it into the required shape.
Stamping: stamping uses mechanical press and dies with specific and custom designs to cut, stamp, or rebuild metal sheets. Through pressing between the top punch and bottom die or “stamping” the sheets to form.
Flexibility and Adaptability
Press Braking: it offers high flexibility, allowing quick adaptation to different part designs and production requirements. This is particularly beneficial for custom orders, small-batch production, and projects requiring frequent changes.
Stamping: it is less flexible due to the need for custom dies but highly efficient for producing large volumes of identical parts. For manufacturers with stable, high-volume production demands, the initial investment in stamping dies is justified by long-term cost savings and production efficiency.
Material Utilization and Waste Reduction
Press Braking: known for optimizing material usage, press braking process involves bending sheet metal without significant material removal, thus reducing waste. Additionally, the ability to produce complex shapes using standard tooling enhances material efficiency.
Stamping: while stamping can generate more waste, especially during initial setup and die-cutting, careful planning and design optimization can improve material utilization. Advanced technologies like progressive dies can minimize waste by performing multiple operations on a single piece of material.
Part Size and Complexity
Press braking: the press brake is designed for small to medium-sized parts. While the bending machine can handle a variety of part sizes, very large parts might require multiple bends or repositioning, which can increase complexity and reduce efficiency. It is well-suited for parts with simple to moderately complex designs, such as basic bends, flanges, and channels.
Stamping: it is versatile in handling both small and large parts. For larger parts, stamping is often more efficient because it can produce numerous parts simultaneously using large die sets, reducing production time and cost per part. It excels in producing parts with intricate and complex shapes, including features like holes, embossing, and detailed contours.
Material Integrity
Press braking: it involves bending the metal sheet gradually, which helps maintain the material's integrity. The bending process can create localized stress points, but the overall impact on the material's structural properties is minimal. This method is particularly advantageous for materials that are prone to cracking or those that require maintaining their mechanical properties throughout the process.
Stamping: it involves significant deformation of the material as it is shaped by the die and punch. This can lead to work hardening and changes in the material's microstructure, potentially affecting its strength and durability. The high-speed impact and pressure exerted during stamping can introduce micro-cracks and residual stresses, which may compromise the material's integrity over time.
How to Choose the Appropriate Manufacturing Method
1. Size of Workpieces
Workpieces of different sizes and volumes require different manufacturing costs. The manufacturing cost of small workpieces is lower than that of large workpieces. In the manufacturing process of workpieces, different manufacturing technologies can be used. Shearing machines and laser cutting machines can be used to cut sheet metals, which can then be processed with a stamping machine or bent with a press brake.
2. Material Types
Different manufacturing processes are suitable for different materials. The ductility and tensile strength of materials vary, which influences the suitable manufacturing process. Press braking and roll forming are suitable for materials with low strength.
High-strength materials have poor ductility, making it difficult to bend and roll form. Using unsuitable materials will generate a significant amount of waste and damage the tooling.
3. Workpiece Design
Certain workpiece designs, such as holes and embossing, are more suitable for stamping. The cutting edge of laser cutting will be smoother, whereas the edge of stamping will have many cracks. The shape and complexity of the workpiece also affect the choice of the metal forming method. Roll forming can form complex linear shapes in a single pass, while bending requires multiple passes.
4. Cost
Ultimately, all choices aim to reduce costs while maintaining quality. The labor cost of stamping automation is lower than that of manual bending. There is little difference in tooling cost between roll forming and press braking. The roll forming process can save costs for the mass production of large workpieces. Press braking is more suitable for small workpieces and small-batch manufacturing.
Conclusion
In the intricate realm of metal fabrication, the choice for press brake vs stamping is a critical factor that can influence the result of programs. Both of them have their advantages for specific and custom requirements.
The press brake is renowned for its precision and suitable for low-medium production.
Each workpiece may have its distinctive specification or custom production shape.
Its flexibility and ability to handle designs make it a precious tool for metal manufacturing.
On the other hand, the stamping is famous for its efficiency and speed.
It is specially designed for high production and is skilled in generating mass-scale and even components.
Its ability to produce uniform and even parts makes it the first choice for mass-scale production.
Above all, the press brake will be the first choice for customized and low-medium batch projects, and the stamping will be a good choice for mass-scale production.
