A French manufacturer of high-speed optical transceivers used in data centres was developing a compact QSFP module. The design required a tiny wave spring to preload a heat sink against a sensitive photonic chip. The spring needed to fit within a 7mm diameter pocket and deliver a precise 4N load at a working height of just 0.8mm.
The Challenge
Standard wave springs available from catalog suppliers could not meet the combined requirements of the small diameter, low working height, and specific load. The French team approached several European spring manufacturers but received either high minimum order quantities or quotes with 6-week lead times. With only 600 pieces needed for the initial design validation, they needed a flexible partner.
Our Solution
Tingfeng Hardware reviewed the 3D model and load specification. We proposed a custom flat wire wave spring produced on our CNC coiling equipment. By using 0.15mm thick stainless steel 301 flat wire, we achieved the required 4N load within the 0.8mm working height. The spring design included three waves with carefully calculated amplitude to ensure uniform force distribution across the heat sink surface. We produced the 600 springs in one week, and each spring was tested for load at the specified height.
Outcome
The springs fitted precisely into the module and provided consistent thermal contact. The French client completed their validation on schedule and has since ordered 8,000 additional springs for the production ramp.