In the aerospace industry, every technological leap forward embodies the relentless pursuit of higher efficiency and lower costs. Quintus, an industry pioneer in sheet metal forming technology, has once again showcased its unique advantage in complex component production with its superior forming solutions. By leveraging its innovative single-step forming technology, Quintus has successfully transformed the production process of helicopter jet engine exhaust ducts, achieving a significant cost reduction of up to 50%.

Quintus' strength lies in its profound technical expertise and continuous process optimization. By seamlessly integrating rigid molds with flexible rubber diaphragms and precise control via a high-pressure hydraulic system, Quintus achieves unparalleled precision and efficiency in complex part forming. This flexibility and cost-effectiveness revolutionize the production of helicopter jet engine exhaust ducts. By reducing production steps from nine to five, Quintus not only significantly shortens the production cycle but also drastically cuts costs, making it an ideal solution for small-batch, multi-variety component production and setting a new benchmark for the aerospace manufacturing industry.

Higher Pressure, More Advantages

Quintus' Flexform press elevates single-die sheet metal forming technology to new heights, with its core strength lying in its operation under unprecedented high pressure conditions—up to 1,400 bar (equivalent to 20,000 psi), far surpassing the 200-300 bar (3,000-4,350 psi) range of older and newer low-pressure equipment prevalent in the market.

Figure 1: Quintus Hydroforming Press

Equipped with an adjustable ram, this deep-drawing press precisely adjusts the forming pressure based on the depth of the draw, making it particularly suitable for manufacturing deep, complex metal parts. By integrating advanced deep-drawing stations with classic forming stations, the press further expands its processing capabilities.

Thanks to its ultra-high working pressure and refined pressure control technology, coupled with innovative mold design, Quintus' Flexform press enables complex shapes that would otherwise require multiple pressing steps and intermediate heat treatments to be produced in just one or two steps. Notably, despite the significant increase in pressure, the use of a flexible rubber diaphragm as a pressure transmission medium ensures a gentle forming process, effectively reducing the risk of material cracking or other damage.

The high-pressure environment of the Quintus Flexform press also significantly reduces common springback phenomena, making it easier to control part dimensions within tolerance limits. Additionally, the high pressure leads to more predictable processing results, significantly reducing variations in forming tolerances. In conjunction with modern simulation software, engineers can accurately predict springback and make precise compensations during mold design, often eliminating the need for subsequent corrections, thereby enhancing production efficiency and final product quality.

Project Example: Helicopter Jet Engine Exhaust Duct

The Quintus case study focuses on a critical component of helicopter jet engines—the exhaust duct. Produced consistently for years, this duct is crafted from 0.76 mm (0.030 in.) thick Inconel 625, renowned for its exceptional high-temperature and corrosion resistance.

This complexly designed exhaust duct part features a three-dimensional curved shape, forming the outer half-shell of the final exhaust duct structure. During production, these half-shell components undergo precision machining before being seamlessly welded together to form the complete exhaust duct structure, as depicted in Figures 2 and 3.

Figure 2: Typical Location of Such Components

Figure 3: Component Geometry

The original manufacturing process encompassed nine steps, from initial blank preparation to three final precision pressing operations shaping the material into its intended form. Due to work hardening during pressing, which can compromise subsequent processing, an intermediate heat treatment was incorporated before the final forming stage to soften the material, restore its workability, and ensure precision and quality in subsequent operations.

Figure 4: Original Manufacturing Process

Recognizing the potential for process optimization, Quintus' application experts initiated a project to create a demonstration model. Drawing on extensive mold design expertise and the capabilities of modern simulation software, Quintus engineers swiftly developed a new mold and pressing cycle, reducing the forming stages from three to one.

Figure 5: Simulation enables accurate prediction of forming results, including springback, significantly accelerating the development process

Accurate simulation of the forming operation is crucial for ensuring a rapid and cost-effective development process. By testing and validating in simulation software, traditional trial-and-error costs are minimized.

Quintus' engineering team explored a novel mold design with rounded edges outside the trimming line instead of fillets, aiming to further reduce forming steps. Simulations validated this concept, demonstrating that the new mold could achieve flawless forming in a single press with a smooth surface free from cracks or wrinkles. As shown in Figure 6, the forming limit diagram clearly indicates that all strain values are well below the threshold, with material thickening concentrated outside the trimming line, not impacting overall quality.

Figure 6: Simulation of material strains shows that pressing steps can be reduced from three to one without cracks or wrinkles

Simulations also revealed minimal springback and thinning well below the specified 20% limit within the trimming line, as shown in Figure 7 below.

Figure 7: Simulation shows limited springback and thinning

Simulation software allows Quintus engineers to optimize the drawing curve (pressure vs. stroke) and blank shape directly in the software, saving time on physical trials.

New Mold Design: Single-Press Forming

The original forming process required two sets of pressing dies for the three pressing steps: an initial pressing die and a deep-drawing die for the final two steps.

Quintus designed a new mold leveraging the capabilities of modern Quintus presses, enabling final part forming in a single press with a single die, significantly optimizing production, shortening lead times, and reducing costs.

Figure 9: Left: Original mold forming with corners; Right: New mold forming without corners

The key difference between the original and new molds lies in the new mold's rounded, corner-free design. Sharp-edged geometries pose processing challenges due to stress concentrations, increasing crack and wrinkle risks. The old mold's sharp corners necessitated repeated blank pressing to prevent wrinkles.

Another significant improvement is the introduction of a flat-designed draw bead in the new mold, contrasting with the old mold's draw beads with varying radii grooves, which caused unnecessary radial stresses.

The third enhancement is material-based, as the new mold is crafted from tool steel instead of bronze, reducing costs and significantly enhancing wear resistance, thereby extending mold life.

Lastly, the new mold features a groove designed to facilitate precise blank positioning (as shown in Figure 10), enhancing operator convenience and accuracy.

Figure 10: New mold with groove for easy blank positioning

Process Validation of the New Mold

Quintus tested the new mold on a Quintus QFM 1.1 - 800 press, identical to the one used in the original process at 800 bar. After eight pressing cycles and less than a day of parameter experimentation, the process achieved the desired results. Measurements revealed a maximum thinning rate of 12.1%, well below the 20% allowable thinning tolerance.

Cost and Time Savings with the New Mold

The project validated the optimized exhaust duct production process, reducing steps from nine to five. While both processes produce satisfactory parts, the new process significantly saves time and costs, representing an innovative and efficient mold design.

Figure 11: Pressing with the original mold (left) and the new mold (right)

Advantages of the New Mold Design

More Cost-Effective

? A single mold is sufficient for the operation.? Reduced press wear—fewer pressings per part (from three to one), lowering maintenance costs.? 50% reduction in degreasing and heat treatment costs—only one round of each required in the new process.

Faster Production

? Pressing cycles reduced from three to one, freeing up significant press capacity. At current output, press utilization drops from 58% to 9%, a decrease of 84%.? 50% reduction in degreasing and heat treatment time.? Substantial savings from reduced handling, transportation, and storage between operations.? Faster operator preparation as polyurethane plates and aluminum sheets are no longer required for extra support at certain blank locations during pressing.

Three Key Factors Enabling Optimization

? Quintus Flexform press's precise pressure control and high-pressure environment.? Accurate computer simulations during process development.? Innovative mold design based on expert application knowledge.

By optimizing the original forming process with the new mold, production steps were reduced from nine to five. In addition to freeing up substantial press capacity, the potential cost savings for this specific part alone are estimated at over 50%!

Accurate Simulations Reshape Process Development Experience

In the new era of process development, simulation software has become an indispensable tool, enabling precise prediction and simulation of forming processes. This shift from traditional, costly, and time-consuming trial-and-error mold design to a more efficient approach is transforming the industry.

Through simulation technology, engineers can quickly assess mold design performance in terms of springback and material thinning, optimizing designs and ultimately boosting productivity and cost savings.

Comprehensive Application Expert Support for Production Optimization

To harness the advanced capabilities of Quintus Flexform presses, such as increased pressure limits and refined pressure control, mold designers must consider these factors early in the forming process and mold design stages. Quintus offers comprehensive support from strategic advice to complete mold design and access to its high-pressure application center for customer trials.

With decades of industry experience, Quintus can engage in the early stages of production process optimization, particularly supporting low-cost, high-efficiency suppliers during contract bidding phases. Quintus shares design strategies and insights for achieving high quality, efficiency, cost-effectiveness, and productivity. Quintus' application engineers, experts in Flexform stamping simulations, provide professional support every step of the way, from simulation analysis to mold design!