“In sheet metal fabrication, aluminum bending is the most commonly employed technique for large-scale production. The fidelity of aluminum lies in its ease of fabrication and formability.”
Bending of aluminum is an adaptable metalworking, or molding an aluminum sheet into the desired geometry. It’s not as simple as it sounds, as there are various challenges associated with the process. Bending requires certain things to consider, for instance, the grade you are working with and the optimum bend you are looking for.
Why Aluminum is the most preferred metal to utilize for bending purposes? The answer lies in its superior formability. It is known for its exceptional flexibility, lightweight nature, and tremendous machinability.
The benefit and required output, mostly depend upon the grade you bring for bending purposes. Aluminum alloys come in various types and grades and can be bent in certain ways but it needs careful consideration and expertise as sometimes, it may require some more bendings over the same bend.
To avoid these mistakes, keep reading the blog that highlights how metal fabrication industries bent sheet metal to gain desired geometries. Moreover, we will discuss efficient techniques for bending aluminum sheets into the required shape.
Aluminum Sheet Bending: The Process
Aluminum Sheet Metal Bending
The process of bending starts by selecting the die and determining the actual bend requirements. Fabricators calculate the critical design parameters; for instance; the required bend allowance, bend radii, material thickness, force, and the point from where to bend the sheet. Moreover, the die used is also a key important to consider. The most commonly used die includes 90° dies, acute angle dies, etc.
After careful consideration of these key factors, the setup of the CNC brake press starts afterward. There are multiple ways to bend depending on the design complexity, material, and optimal bedding requirement. The choice of the right die and tool is considerably important for operating the brake press. The CNC information is inputted into the brake. This helps the machine to test the force required for bending.
Then align the flat aluminum sheet between a tool and a die. Operate the machine and it will bend the AI sheet according to the required output bend. Lastly, remove the sheet and send it for further processing.
Note: The dies used are commonly made of carbides and steel material.
Related To: The Basics of Sheet Metal Fabrication
Sheet Metal Bending: YouTube
Next, we will discuss the most commonly employed fabrication techniques for aluminum bending:
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Effective Techniques To Bend Aluminum Sheets
For precision bending, normally, there are five techniques that most manufacturers exploit for desired bending. Let’s figure out how these apply to aluminum metal.
1. Press Brake
Press bending uses a press to bend aluminum into the desired geometry. A brake press is usually implemented for linear bends and folds. This vital technique is arrayed with a folding tool, named a die which is placed on the press. Press brakes can accommodate material thicknesses from 0.5 to app.15mm, due to high hydraulic pressure assembly.
Brake press for bending metal sheets
An aluminum sheet is placed between the two dies and press strikes it to create bends. The core advantage of using a press brake lies in its precision. It helps in shaping flat, square sheets of aluminum.
2. Coil Bending
Coil bending is also known by the name roll bending or three-roll bending. This approach uses a cylindrical rotating roller to bend aluminum into curved and rounded forms. These rollers apply pressure to the aluminum sheet to turn it into the desired shape.
The rotating cylinder can be adjustable and positioned to attain even tighter tolerance with minimal turnaround. This technique is favored for curved shapes and achieves tighter tolerance up to + 0.01- 0. x.
3. Rolling Machine
Rolling machines are also titled by other names rolling mills or rolling forming. These machines come in two forms; manual-operated and automated-operated. The choice depends on the production volume and desired bending curvature. During its working, the material (aluminum sheet) is deformed to get the desired output.
Rolling Aluminum Bending
In addition to their pros, these machines are well suited to shape conical or cylindrical bends in aluminum sheets. For instance, tubes, air tanks, and chimneys are some key applications of rolling machines.
Capacity-wise, it usually bends aluminum sheets of multiple thicknesses ranging between 1 mm to 50 mm approx.
4. Sheet Metal bending
The sheet metal bending technique employs metal brakes to create bends in aluminum sheets. It contains two beams that are elongated parallel towards each other to create a bend or desired shape from an aluminum sheet.
Design manufacturers are mostly preferred for shaping rounded or tapered shapes or projects that require repetitive bends. Moreover, This bending methodology is implemented on large aluminum sheets.
5. Compression Bending
This bending uses a die or punch to apply mechanical stress on an aluminum sheet to make a bend. How does it perform bending operations?
First of all, the technician places the aluminum sheet between a punch and a die. Then, they operate the machine and ultimately, punch applies pressure to bend the sheet to the desired form.
Compression bending is used for smaller to medium-thickness metal sheets. However, it’s difficult to make bends in higher-thickness sheets by using this technique.
Best Aluminum Alloys Use For Bending Applications
Aluminum Alloys for Bending
During the selection of aluminum alloy, various factors need to be considered. For instance; formability, elongation percentage, workability, and thermomechanical treatments. Among aluminum grades, mostly aluminum 3xxx series alloys are used in bending applications due to their high formability.
Here are examples of some sound aluminum grades known for their excellent manufacturability.
Aluminum 5052
- Aluminum 5052, is a high-strength aluminum grade widely employed for bending.
- This alloy is primarily used along with magnesium.
- AA5052 is known for its high elongation percentage.
- This alloy is used in marine equipment, medical tools, and signages, for its highest corrosion resistance ability.
Aluminum 3003
- Al 3003 has excellent workability, weldability, and a good elongation percentage.
- These alloys are enriched with manganese content. Magnesium imparts structural abilities to make them sound for bending applications.
- You can twist these alloys with minimum force or pressure.
- Common uses of these alloys are; siding, storage tanks, roofing, and chemical machinery.
Aluminum 6061
- AA6061 is composed of magnesium and silicon and usually comes in two forms; 6061-T4 and 6061-T6.
- It shows superior structural strength and rigidity along with a good elongation percentage. This rigidness of AI6061 results in cracking when used in bending operations.
- It possesses lower bendability than AA3003 & 5052.
- Aluminum 6061, finds its diverse applications in structural sectors of automotive, and aerospace industries.
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Aluminum Sheet Bending: Things to Consider
In sheet metal fabrication, some key aspects should be considered to get the best possible bends and geometries.
1. Formability
Formability refers to the flexibility or elasticity of metal aluminum when it undergoes deformation or compression without being dented. Aluminum formability varies from grade to grade. The factors depend upon thickness, temper, temperature, and hardening of work.
2. Bending Direction
Bending direction plays a pivotal role in aluminum sheet bending. It is considerably perpendicular to the metal sheet direction to avoid cracks related problems. The parallel direction poses the problem of cracks on the targeted material bend.
3. Clearance of Bending
To avoid bending failures, there must be a gap between the punch and the die. If there is no bending clearance, interference can occur.
4. Bend radius and thickness
The degree of bending dictates the thickness of the aluminum sheet. Mostly, people get confused about the rule of thumb between radii to bending ratio. Both of these have inverse relations. It means that the higher the thickness, the smaller the radii will be. Similarly, thinner aluminum sheets possess small radii. Normally, thicker aluminum sheets with smaller radii require higher force to bend as compared to thinner sheets with small radii.
5. Level of Elongation
The elongation percentage determines the braking ability of the aluminum sheet. It usually represents the elasticity of sheet metal. The higher the elongation percentage, the easier it will be to bend aluminum sheets.
Common Problems Encountered During Aluminum Sheet Metal Bending?
In sheet metal bending of aluminum, fabricators often face several problems during bending operation. Some common issues include; burr formation, cracking, bending interference, indentation, slippage, and bulge. Let’s figure out these common bending issues in detail;
1. Cracking
Bending cracks appear due to misalignment of metal sheets, smaller bending radii, tensile surface, inadequate pressure, and unremoved burr from the part edges. To avoid these cracking issues, fabricators must employ holes or grooves to make the bending operation smooth and crack-free.
2. Bending Interference
The problem is caused by certain determinants. For instance; the shape and size of the part, and the selected die. These issues can be minimized by considering bending die designs, the sequence, and the dimensions of bends.
3. Bending indentation
Bending indentation often occurs on the inner surfaces of metal sheets. Normally, the strong press against the sheet metals creates friction that ultimately leads to noticeable marks on the sheet. To prevent this, anti-indentation rubber balls or ball bearing dies can be used. These anti-indentation balls eradicate the issue through physical isolation.
4. Splits and Wrinkles
Aluminum metal sheets in some cases have experienced necking or splitting issues. These issues are caused due to excessive bending when thin aluminum sheets are pushed above their limit of workability. To avoid these issues, operators must examine the thickness, and sheet radii, before starting the bending process. Conversely, wrinkles are caused by applying high stretch or compression strain to aluminum sheets.
Advantages of Using Aluminum For Custom Bending Parts?
Aluminum comes with various advantages when utilized for bending applications and custom intricate parts. Here are some of the notable advantages of aluminum;
- High Durability: Aluminum is highly durable and flexible when being bent for different intricate geometries. Its malleability features make it sound to bear high mechanical stress. Moreover, it has a distinct property of non-corrosiveness.
- Economical Alloy: Aluminum offers several economical pros when used in bending applications. It produces no waste during bending operations. Alongside, it comes with a minimum cost when compared with other metal alloys such as steel, cast iron, titanium, and brass.
- Lightweight property: Lightweightness of aluminum is its prime feature. Its lightweight property adjacent to high strength and machinability makes it an ideal choice for bending applications.
- Workability: When it comes to workability, aluminum is at the top list. It’s quite easier to cut aluminum than steel. Its high adaptability and malleability properties make it sound for fabricators to make simpler to complex bends.
- High heat tolerance: When compared to other metals, aluminum has gained significant attention due to its high heat tolerance. Parts made of aluminum can withstand high heat rates and tight tolerances are notably important.
- Versatility: Metals ductility plays a key role in bending. It determines how well the metal can bear shear and mechanical stress. Aluminum for its high ductility is well suited for bending jobs. Moreover, it bears high thrusts without being damaged.
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Read more:
- What is manual sheet metal fabrication
- Stainless Steel Sheets for fabrication Projects
- Notches & Tabs In Sheet Metal Fabrication
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Summing Up
Sheet metal bending is a versatile metal fabrication process. It offers unique and economical pros when employed for medium to large volumes of production. However, several key determinants need to be considered for smooth and accurate bends.
The core edge of this tremendous technique is that it does not require any tooling or mold for its operation. In addition to the applications of aluminum sheet, it’s widespread across the globe from automotive, aerospace, and consumer products to custom manufacturing appliances.
Although, there are some challenges associated with its operation. But, keeping their alternate solution or information provided in this guide will help you make your bending process more uniform and with relatively no error. Moreover, this article entails the grounding knowledge on sheet metal fabrication and helps you through bending operations.
To get the best optimal output for your bending requirements, the best approach is to consult with professionals to optimize the performance intended for your desired applications.
FAQs
Q1. Types of sheet metal fabrication?
There are certain types of sheet metal fabrication commonly practiced in manufacturing industries; such as; sheet metal blanking, sheet metal bending, piercing, and punching.
Q2. What metals are commonly used for metalworking?
Mostly, steel, aluminum, brass, and carbon, are used in metal fabrication industries. These materials are well suited for cutting, shearing, and piercing applications.
Q3. Why is aluminum highly used for fabricating use?
Aluminum due to its exceptional formability and lightweight properties is considered best for metal fabrication applications.
Q4. What is elongation of aluminum alloys?
The level of elongation for aluminum sheets indicates the highest level of stretch till the deformation of aluminum sheets. The more elongation, the higher will be the bending efficiency.
Resources
- A-Pradeau (2016), Prediction of failure in bending of an aluminum sheet alloy, International Journal of Mechanical Sciences, Volume 119: Retrieved From: Science Direct
- Ida Westerman (July 1, 2011): Three Point Bending of Aluminum Alloys: Influence of Microstructures and Textures on Bendability and Fracture Behaviour: Retrieved From: Springer
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