The choice depends on numerous factors, including the tube diameter, material used, wall thickness, required bending radii, and the complexity of the geometry to be produced.
These parameters are common to any tube bending process, but in the aerospace sector they take on particular importance due to the alloys used. Materials such as titanium, Inconel, or other special alloys have mechanical properties that make processing far more complex than in traditional industrial applications.
For this reason, components that may appear geometrically simple—for example, featuring a single bend and a relatively low degree of geometric complexity—can become a demanding technological challenge when intended for aerospace applications.
One of the indicators commonly used to evaluate bending difficulty is the DR (Difficulty Ratio). However, this parameter only considers the geometric aspects of the bend and is calculated as the ratio between the square of the diameter and the product of wall thickness and bending radius.
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In the aerospace sector, wall thicknesses tend to be particularly reduced to limit the part weight, consequently increasing the criticality of the process. However, this does not make the DR sufficiently representative of the bend to be produced, for two main reasons:
The first is that the DR does not take into account the bending angle, which directly affects the complexity of the operation: the greater the required angle, the more difficult it will be to achieve the desired result without defects.
The second is that the DR does not take into account the tube material. Materials typically used in the aerospace sector, such as titanium alloys, high-strength aluminium alloys and special stainless steels, are very rigid, with a very low percentage of elastic elongation and are therefore difficult to deform at room temperature, and consequently difficult to bend.
All of this is further compounded by another fundamental requirement, which is not considered by the DR: surface quality.
In the aerospace industry, it is not sufficient to produce a dimensionally correct bend; it is also essential to preserve the integrity of the material and the surface quality. Any surface imperfection, scratch, or mark, whether on the inside or outside of the tube, can become a potential point for fatigue phenomena or a reduction in the mechanical strength of the component. Under extreme operating conditions, such as those typical of aerospace applications, these defects represent an unacceptable risk factor.
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To address these challenges, it is necessary to have maximum control over every stage of the bending process. The most important general rule is to choose a new-generation fully electric (all-electric) tube bending machine.
These systems are designed to provide the highest level of process control and make it possible to meet the extremely strict tolerances required by the aerospace sector.
Today, several manufacturers are able to offer high-performance all-electric machines. However, choosing a manufacturer with long-standing specific experience in tube bending can represent a decisive advantage.
BLM GROUP has been developing all-electric tube bending machines for over twenty years. The company’s first fully electric tube bending machine dates back to 2002. Over this long journey, hardware and software solutions have been developed that can make a real difference in aerospace applications.
Among these, VGPNext stands out as one of the most advanced CAD/CAM software solutions for tube bending machine programming available on the market. The platform integrates advanced features that simplify the operator’s work and make it possible to maintain optimal control over the entire production process.
Among the advanced features of VGPNext and BLM GROUP tube bending machines that are particularly appreciated in the aerospace sector are:
B_Tools, which automatically compensates for material springback after bending.
Adjustable torque control, which dynamically regulates the clamping force applied to the tube, improving surface finish and preventing slipping phenomena.
Adjustable booster, which optimizes the push force applied during bending to reduce extrados thinning and preserve the mechanical properties of the tube.
Other compensation and control strategies that allow the machine to adapt to the specific characteristics of the processed material, in addition to numerous process control strategies and dedicated hardware solutions, such as clamping pads and tooling made with specific materials for applications.
All these features contribute to one of the most important results for the aerospace sector: the drastic reduction of production scrap. A fundamental factor when processing high-value materials such as titanium alloys, Inconel, and other superalloys used in aeronautical and space applications.
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Another typical characteristic of the aerospace sector is small-batch production. In these contexts, the time required for production changeover becomes strategically important.
In tube bending, production changeover largely coincides with tooling change. To ensure efficiency, repeatability, and reliability, BLM GROUP has developed Plug & Bend, an innovative quick tooling change system that completely eliminates manual adjustments.
The operator simply has to insert and lock the components using quick couplings. No additional adjustments are required. Plug & Bend eliminates the risk of errors or settings differing from previous productions.
The result is consistently precise and repeatable production, independent of the individual operator’s experience.
Would you like to learn about one of the customers that chose BLM GROUP for these applications? Read the story of MundoTech, which works for the most important companies in the aerospace sector.
In the aerospace sector, the choice of a tube bending machine cannot be based solely on the ability to produce a specific geometry. It is necessary to consider process control, achievable surface quality, management of special materials, scrap reduction, and repeatability of results.
In this context, BLM GROUP’s latest-generation all-electric tube bending machines, combined with the advanced features of VGPNext and innovative tooling change solutions, provide the level of control, repeatability, and reliability required by the most demanding aerospace applications, helping to reduce scrap and ensure the quality of the finished component.