At LEW, our fully automatic main eye rolling process is designed to perform all required forming operations in a single heat cycle, ensuring efficient processing, consistent eye formation, and improved dimensional accuracy. This integrated process minimizes repeated heating, supports uniform quality and repeatability, and contributes to the strength, durability, and reliability of leaf springs in line with specified engineering requirements.
Our semi-automatic second eye forming and bending process ensures accurate forming of leaf spring second and third leaves along with precise bending to meet specified design requirements. We manufacture Full Military Wraps, Half Military Wraps, V-Cuts, Diamond Cuts, Spear Head Cuts, Keyway Grooved Ends, OSBs and BSBs combining controlled machine operations with operator expertise, this process supports dimensional consistency, repeatable quality, and reliable performance, contributing to the durability and precision of our automotive leaf springs.
We utilize fully temperature-controlled, PLC-operated batch-type hardening furnaces supplied by SMT to ensure precise and consistent heat treatment of leaf springs. During the hardening process, the steel undergoes a metallurgical transformation from Austenite to Martensite through controlled quenching. This critical process helps achieve the required hardness, strength, and mechanical properties, supporting the durability and reliable performance of our automotive leaf springs.
At LEW, our latest computerized continuous tempering furnaces ensure precise control of temperature and processing time to achieve the required metallurgical properties of hardened leaf springs. Equipped with a Temperature Override System, the furnace temperature is closely monitored and controlled to maintain process stability and ensure consistent heat
treatment quality.
The conveyor speed is carefully adjusted according to the metallurgical requirements of the transformation from Martensite to Tempered Martensite, ensuring the appropriate tempering cycle for the desired mechanical properties. This controlled process reduces brittleness, improves toughness, and optimizes the balance between strength, hardness, and flexibility.
Through precise temperature regulation and controlled processing parameters, LEW achieves a final microstructure comprising approximately 99% Tempered Martensite, supporting consistent quality, enhanced durability, and reliable performance in demanding automotive suspension applications.
Taper rolling at LEW is a precision-controlled process in which the thickness of the leaf spring is gradually reduced towards its ends to achieve the specified tapered profile. This process ensures uniform thickness transition, optimized material distribution, and the required flexibility and stress characteristics, in accordance with engineering design specifications. Taper rolling involves heating the leaf spring ends and then rolling the heated end between two heavy duty rollers. This gradually reduces leaf spring thickness towards the ends to achieve the required stress distribution, flexibility, and uniform bending characteristics.
Tapered leaves have fewer spaces (or gaps) between them so there is much less inter-leaf friction. This gives a much smoother, more comfortable ride that feels closer to coil springs. Moreover, Tapered end leaf springs are significantly lighter—often cutting around 30% to 50% of the weight. This lowers the un-sprung weight of the vehicle. Apart from that, tapered leaf springs offer a progressive spring rate that is they flex easily for comfort when unloaded, and stiffen up as more weight is added.
At our production line shot peening is a critical surface treatment process used to increase the fatigue life of leaf springs and enhance their long-term durability. During this process, shots are propelled at high velocity onto the tension side of the leaf spring, inducing beneficial compressive residual stresses on the surface.
These compressive stresses help counteract tensile stresses developed during service, reducing the likelihood of fatigue crack initiation and propagation under repeated loading cycles. This improves the spring's resistance to fatigue failure and supports reliable performance under demanding automotive suspension conditions.
By maintaining controlled shot peening parameters and consistent process quality, we enhance the fatigue strength, durability, and service life of its leaf springs in accordance with the required engineering specifications.
At our highly specialized OE production line we perform stress peening on several leaf springs. Stress peening is performed by applying a predetermined bending stress to the leaf spring while shot peening is carried out on its tension side. The high-velocity impact of the shots induces compressive residual stresses, improving fatigue resistance and extending the spring's service life.
At LEW, every leaf spring undergoes Brinell Hardness testing to verify compliance with specified hardness requirements after heat treatment. This ensures consistent metallurgical quality, strength, and durability in according to set process standards.
All leaf springs produced at LEW undergo controlled scragging, whereby a predetermined load or deflection is applied to stabilize the spring’s arch and minimize subsequent permanent deformation during service. Load setting ensures the required load-deflection characteristics are achieved at the specified kerb (curb) load.
At LEW, we operate four different categories of load testing machines capable of applying both heavy-duty and light-duty static loads for suspension testing. These arrangements verify leaf spring load-deflection characteristics and ensure compliance with specified performance requirements and engineering standards.
At LEW, our dedicated paint booth supports the application of protective coatings designed to meet at least 460-hours Salt Spray Test (SST) requirements, providing enhanced corrosion resistance and long-lasting surface protection in accordance with industry standards.
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