Custom sheet metal cuts materials into the required dimensions to create different products. Look around and you will see sheet metal products used in daily life everywhere. Today, sheet metal cutting is used in almost everything from beverage cans and cookware to automobile frames and exhaust pipes. Its value is universal across industries, especially for small batch production.
In this article, we will provide you with an overview of custom cutting sheet metal. In addition, we will describe the main techniques, applications, and benefits. In addition, the appropriate materials and surface coatings that should be used in the manufacturing process will be described.
Custom sheet metal fabrication involves the process of forming products from sheet metal. Using sophisticated techniques, sheet metal is formed, bent, shaped, and combined to form products. This manufacturing method uses a variety of metals to create products with specific cross-sections.
In addition, this manufacturing process is suitable for different materials such as stainless steel, aluminum, brass, copper, zinc, etc. The thickness of the sheet metal is usually between 0.006 and 0.25 inches. Generally, thin sheets are more versatile, while thicker sheets are used to withstand heavy loads and strains.
In addition, computer-aided design (CAD) is used to facilitate the development of sheet metal products. CAD tools produce 3D models to obtain accurate representations of actual products. These models are converted into G-codes used by machines to cut, form, and assemble metal sheets.
Custom cut sheet metal fabrication takes different approaches. Understanding these sheet metal fabrication techniques can improve the final design and performance. Here are three common sheet metal fabrication methods.
Cutting Custom Sheet Metal
Shearing is usually the main operation in sheet metal cutting. Shearing is the process of shaping a flat sheet into a specific design. The choice of tool usually depends on the project requirements. Cutting techniques fall into two categories: conventional milling with shearing and conventional milling without shearing.
None shear cutting
Non-shear refers to cutting techniques that do not use mechanical shearing forces. These processes use heat, pressure or abrasion to shear the metal sheet. The main technologies are laser cutting, plasma cutting and water jet cutting, which are suitable for different metals and designs.
· Laser Cutting： Laser cutting uses a laser beam bar to cut and melt sheet metal. It is very precise and can make very complex shapes. It uses gases to operate on metals such as stainless steel and mild steel. For example, oxygen or nitrogen can remove the melted material and keep the cut sterile.
· Plasma Cutting： Plasma cutting uses ionized gases to melt conductive materials and metals. This method is best suited for materials such as aluminum and steel. It has high cutting speeds and accuracy, and is suitable for medium-thickness metals for commercial and special purposes
· Water Jet Cutting： Water jet cutting technology cuts the sheet metal using high pressure water which contains abrasive garnet for cutting metal sheets. This multi-process technology is mainly used for cutting soft and hard materials including rubber and carbon steel. Moreover, it is considered as a green process as compared to laser cutting as no heat affected zone is observed in the cutting area.
Shear Cutting
Shear cutting uses mechanical force to cut metal sheets into the desired size. The expected category includes techniques that utilize dies, punches, or presses to make the desired cuts. It is one of the most popular techniques in industries that handle large metal stocks and includes tools such as shears, punches, and saws.。
· Cut：In sheet metal shearing, mechanical force is used to cut sheet metal in straight lines. This is a fast and inexpensive method of scribing bulk materials such as brass or aluminum. While effective in mass production, shearing can result in sharp edges that may require post-processing.
· Punching：Punching is the process of creating shaped or circular holes in thin metal by applying force through the thickness of the sheet. It is widely used in industries that require precise cutting of shapes, such as the automotive industry. Punching is very flexible and can easily produce different contours and different patterns, or get the right shape of die.
· Blanking：Blanking is a process that uses a punch and die to cut specific small parts from a large piece of sheet metal. Part of the material is cut away, leaving only the "blank", the finished product, and the rest is waste. Blanking is often used in high-volume production because it is simple to operate and produces consistent and accurate products.
· Sawing： Sawing involves processing metal sheets or bars into thin slices using a saw blade. Horizontal band saws are good for cutting longer pieces of raw material, while vertical saws are better suited for cutting or processing small, intricate parts. Sawing is very beneficial in cutting both soft and hard metals into a variety of shapes and sizes.
Bending is achieved by bending the material while maintaining its integrity. These methods are essential in developing sheet metal for a variety of uses. The following techniques are commonly used in the forming of sheet metal.
· Bending： Bending is an efficient process for small and medium-sized productions, from the point of view of operating costs. It bends the metal to the desired angle by applying pressure. For this process, bending machines and rollers are used. In addition, bending has good compatibility with spring steel, copper and aluminum 5052.
· Rolling： Rolling uses rollers to bend or thin sheet metal. For planing, it means using a flat tool to scrape a thin layer of material off the surface of the metal. High-pressure rollers then plastically reshape the metal. It can also be done at or below room temperature (25 C), called cold rolling, or at elevated temperatures, called hot rolling. Rolling is mainly used to make components such as tubes, coils and pipes.
· Stamping： Stamping is a cold working metal cutting process. It involves cutting and forming operations to quickly produce complex shapes. Stamping machines and dies are used to form metals such as aluminum, copper, and steel. Stamping is relatively fast and economical. Therefore, it is best suited for mass production of products. However, several design changes during the process have been very cumbersome and expensive.。
· Hemming： The hemming process forms a double-walled part by bending the edge of a metal sheet to the other side. The process is usually divided into two stages: shaping the metal into a V-shaped die and then flattening the die. Hemming can also provide additional support to the edge and make the part look better. However, dimensional changes may occur due to the deformation of the material used.
· Curly： Folding rounds the metal sheet, turning it into a tubular structure. This process is usually divided into three different steps: advancing and setting the curling. Curling increases the tensile strength of the part and smoothes the surface to reduce edge sharpness. This reduces dangerous physical contact.
Welding technology in sheet metal processing
The following are the main joining methods used during manufacturing to make sheet metal parts into a single integrated component:
· Welding： Welding involves joining two metal sheets by heating and fusing them with a filler material. The process is common in the final operations of manufacturing and may include SMAW, MIG welding, and TIG welding. All of these techniques are used in different situations, but all aim to create a metallurgical bond.
· Riveting： Riveting is a mechanical fastening process where a rivet is driven through two or more metal sheets with holes in them and then expands to join the sheets together. The process is most commonly used with metals such as aluminum and copper. There are two main types of riveting: cold riveting (for thin metal sheets) and hot riveting (for metals thicker than 3 mm, such as steel). Riveting creates a strong, tight connection and is ideal for non-ferrous metals.
When it comes to custom cut sheet metal fabrication, choosing between MIG and TIG welding depends on several key factors. Here is a comparison of the two welding techniques to help you decide which method is best for your specific needs.
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PRODUCT MODEL | MIG | TIG |
POWER | DC ONLY | AC and DC, AC is suitable for aluminum |
Material compatibility | Suitable for all kinds of metals, especially for thinner sheets | Suitable for thicker metals with precise control |
Electrode Type | Using consumable electrodes | Use non-consumable tungsten electrode |
Protective gas | CO2, helium, argon or oxygen | Mainly argon, and mixed gases for special purposes |
Cooling system | Air Cooled Welding Guns | Due to the high heat generation, water cooling is used |
Welding quality | Faster but lower quality | Slower, but provides cleaner, more aesthetically pleasing results |
Application Areas | Faster process, suitable for larger projects | Slower, more meticulous processing for higher quality finished products |
Cost | Large-volume production is more cost-effective | More expensive due to higher detail and quality |
Design for Manufacturability DFM (Design for Manufacturability) is a virtual design concept that aims to prevent incorrect design decisions and enhance the product manufacturing process. In custom sheet metal fabrication, adhering to DFM standards ensures that parts are easy to produce, saving cost and time.
7 Key Factors in Sheet Metal Design
Here is a checklist you can use when designing low-volume sheet metal prototypes.
· Hole radius： Avoid using small holes in your design. They require a small punch to create and are prone to cracking. The hole diameter should be greater than or equal to the material thickness to provide the necessary strength and precision.
· Corner Relief：Bend relief refers to small localized depressions usually placed in metal sheets to facilitate the bending operation. This reduces the possibility of tearing or cracking at the bend operation point while keeping the design intact.
· Hole to elbow clearance：The distance between any two holes and an elbow must be at least 1.5 times the sheet thickness plus the radius of the elbow. This spacing allows bending without distortion.
· Sheet metal bend radius：The minimum bend radius should be set based on the flexibility allowed by the material and the tooling at hand. For flexible metals, the achievable radius is smaller than for other metals. However, the minimum radius is often tool dependent.
· Flange width：The recommended flange width for metal sheets used in the design should be at least four times the sheet thickness. In this way, appearance and design neatness can be retained along with strength and structural durability.
The main benefits of sheet metal fabrication include：
Lightweight parts manufacturing
Sheet metal cutting is very efficient and practical in cutting custom cut aluminum sheets and lightweight parts. The aerospace and automotive industries require lightweight engine parts, and custom sheet metal processing can provide quality products. It improves the fuel efficiency of aircraft and automobiles while maintaining production efficiency.。
High technology and materials
Custom sheet metal fabrication offers many possibilities for individual design. The options available are also numerous; you can get custom cut steel plates and custom cut stainless steel plates and products. Depending on the application of the end product, whether it is a structural member, housing or precision part, the choice of material is crucial.
Efficiency and accuracy
Sheet metal technology improves manufacturing efficiency because it enables rapid prototyping and improves the accuracy of the required model. For example, some laser cutters can cut parts as small as 0.0005 inches in width. Almost all sheet metal processes are computer numerically controlled, reducing human intervention and ensuring that the product is relatively free of deformation.
Multi materials are compatible with sheet metal engineering, including：
· Stainless Steel
· Hot Rolled Steel
· Cold Rolled Steel
· Pre-plated Steel
· Carbon Steel
· Aluminum Plate
· Copper
· Brass
These materials can be used to manufacture a wide range of elements and products, including automotive parts, electronic product housings, architectural elements, etc.
Surface treatment is an essential aspect of custom cut sheet metal and is both functional and aesthetic. Here are some common surface treatments used in sheet metal fabrication:
• Powder coating: Powder is applied and then hardened by heat to provide a wear-resistant protective coating.
• Bead blasting: High-pressure air blasts small beads onto a surface to clean it and leave a rough surface.
• Brushing: A major use for abrasive brushes is to provide a finely textured surface that enhances the appearance of a surface and makes it less susceptible to fingerprints.
• Electroplating: The use of an electric current to deposit a layer of metal on a surface to improve its corrosion resistance and enhance conductivity.
• Anodizing: The surface of aluminum is transformed through an electrochemical process, adding a tough, corrosion-resistant and dyeable coating.
• Laser engraving: A focused laser puts a pattern or text onto metal for decoration and engraving to add detail.
• Screen printing: The use of ink on a screen to create a pattern, logo or label on a metal surface.
Here are some basic design tips for manufacturability in sheet metal fabrication:
Wall Thickness
In sheet metal fabrication, since each part is made from a single sheet of metal, the thickness should be uniform throughout the part. Generally, the thickness of the parts ranges from 0.9 mm to 20 mm. In laser cutting, the preferred metal thickness is 0.5 mm to 10 mm. Whereas in sheet metal bending, the recommended metal thickness range is 0.5 mm to 6 mm.
Orientation of Holes and Slots
When designing sheet metal cutting parts, the diameters of holes and slots should be considered, which should not be less than the material thickness. There must be enough space between the holes. They should not be located at the circumference or edge of the sheet.
Bend Allowance and Deduction
Bend allowance determines the extra length of material required to make the desired bend on the design. Whereas bend deduction refers to the amount by which the flange length is usually trimmed to obtain a balanced appearance. Both are very important in developing a good flat pattern.
Bend Radius
The internal bend radius must be maintained at a value equal to the thickness of the material used to eliminate defect formation and distortion on the final product. Consistency in component bend radius promotes proper positioning of components and cost efficiency of sheet metal engineering.
JWB's Sheet Metal Fabrication Services
Being transparent about design requirements and affordability is critical for organizations to work with a capable manufacturer for quality sheet metal fabrication. The fabrication services provided by JWB are of the highest quality. We are an ISO compliant company, so we guarantee you a standard quality prototype or final product for your sheet metal fabrication. We provide full part inspection support to guarantee the best quality for your project. You can call or email JWB today to get an instant sheet metal fabrication quote and some feedback on your DFM results.
Custom cut sheet metal fabrication is an indispensable manufacturing technique for high-volume production. This method offers many advantages, such as increased work efficiency, accuracy, and the freedom to design lightweight components based on project needs. In addition, it is compatible with a wide range of materials and technologies. However, certain factors must be considered to achieve the best results.
