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Top five pieces of advice for sheet metal folding


Sheet metal folding is a precise and intricate process. To achieve optimal metal folding results, it is important to have the right knowledge, techniques and tools available.

What is metal folding?

Sheet metal folding is a key stage within the sheet metal fabrication process. It takes place after the metal cutting stage and involves the material being formed around the edge or face of a tool by applying pressure.

The machines used for the metal forming process include manual press brakes, automated bending cells or panel bending machines. Once folded and checked, the part will then move onto the next process in the manufacturing schedule.

Do you need metal folding advice?

Keep reading to discover KMF's expert tips for metal folding:

Choose a suitable sheet metal bending technique

There are several techniques for sheet metal folding, all suitable for different products and purposes. Some of the most commonly used methods include:

Air bending

Air bending relies on a V-shaped punch and a die (a specialised machine tool used to form sheet metal into a desired shape). Using a press brake, a bend angle is formed by driving the punch into the sheet metal to a specific position within the die opening. The metal is formed without touching the tooling surfaces, leaving space (or air) underneath the sheet offering a high bend angle control. This method is ideal for a wide range of bending angles.

Bottom bending

This method uses a bottom tool (known as V-die) to bend the metal over a stationary die block. This type of bending involves deforming the sheet metal in the bend region by applying additional force through the tip of the punch. Bottom bending provides consistent and accurate results and is suitable for large parts and high-volume production.

Folding machines

Automated folding machines are ideal for complex and repetitive bending operations, offering speed, accuracy and consistency of parts. For companies that require a high volume and variety of parts, automated machinery can help them to meet their manufacturing requirements.


In coining, sheet metal is pressed between the punch and the die to produce a sharp fold. Coining uses up to 30 times more pressure to bend the sheet metal in comparison to air bending. This type of bending can be used for thick metal to create precise and intricate bends.

Utilise automated technology

Automated technology has become increasingly prevalent in the sheet metal folding process as it improves the efficiency, accuracy and complex bending capabilities.

Whilst the initial investment into robotic machinery may be high, high-spec machines can reduce labour costs making it a strong investment. Removing the need for manual, repetitive bending tasks, puts workers in safer and more skilled jobs.

One example of industry-leading and reliable automated bending machinery is the TRUMPF Trubend. This fully automated bending cell features automatic part scanning and picking. The robotic arm picks up material, feeds it into the folding tool and then applies pressure to fold the part. This ensures that parts are bent with ultimate accuracy, cost-effectively and at a high capacity.

Consider the material thickness

Before the folding process begins, it's crucial to understand the material that is being worked with. Different metals have varying thicknesses and toughness which can significantly affect the bending process. A thinner-guaged metal is easier to bend, while a thicker material requires more consideration to retain the bend and meet precise tolerances.

The bend radius refers to the inside radius of the bend. The minimum bend allowance represents the minimum amount of material needed for a successful fold. As thickness increases, the required bend radius also rises and the minimum bend allowances become larger.

Thicker metal is generally heavier and harder so requires more effort to manipulate. Increased weight also impacts the choice of equipment and machinery used for bending.

Thicker materials have a greater resistance to deformation, making it more challenging to achieve tight bends without exceeding the metal's elastic limits. It may require multiple passes or adjustments in the process to achieve the desired angle.

Partner with metal folding experts

Partnering with a reliable manufacturer for sheet metal folding ensures high-quality results, access to advanced technology, scalability and excellent customer support.

As a leading supplier of sheet metal folding and fabrication services, KMF Group uses state-of-the-art bending technology and can manufacture all manner of metal-formed products. From small parts with a single bend to larger complex parts with multiple folds and flange lengths, KMF delivers a system that enables outstanding operational performance for any metal folding operations.

Do you require metal folding advice?

Contact KMF Group to discuss how its one-stop-shop metal fabrication solution can benefit your business.

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