Development and Deployment of Involute Splines Cold Forming Process for Gear Manufacturing

A dynamic simulation model for cold forming of involute splines through a rolling process is presented. The model identifies a unique rolling methodology which consists of various phenomenon to illustrate the forming process in detail. Mass produced involute splines on four loose gears in a six speed manual transmission are developed from forgings to the final part. A new standard has been set for manufacturing of spline rolled gears. The final vehicle applications comprised of various automotive model variants. It is a report that provides a background into the theoretical and practical principles of cold metal working otherwise known as cold forming. Splines are formed on gear surfaces through an axial rolling cold forming process. In addition, it addresses all the concept, design, manufacturing and quality processes involved. State of the art technology in gear manufacturing is clearly demonstrated. Furthermore, in depth analysis of results from critical dimensions that constitute the major and minor characteristics of involute splines are reviewed. Finite element modelling and simulation aspects are all covered. The modelling of contact between the tool (die) and a gear blank is presented in detail which fundamentally demonstrates the understanding of material flow during the manufacturing of cold formed involute splines. The effects of stress, plastic strain and temperature on the material is understood and shown in the model development. The splines in this project are manufactured in the fourth process of seven different gear manufacturing processes and procedures. Additionally, the finished parts are internally assembled into a sealed transmission case comprising of meshed components that sit in chronological positions known as ratios. Individual gear manufacturing operations are also captured in this report as they respectively influence the geometry and tolerance criteria of the finished cold formed spline. An established failure mode effect analysis report, drawings and control plans are revealed. These validate the phases that led to achieving design intent and final product ii specification. Factors such as machines and automations installation, process and design capability studies are presented. Core effective manufacturing criteria such delivery, cost, cycle time and statistical process controls are identified. Part clamping and tooling trials were completed in respect of the mechanical and material deformation observed during the simulated and actual rolling processes. All these aspects formed integral parts of the process development stages. For the cold forming process, quality standards were reviewed for various spline classes to institute the correct geometric tolerances for the measurement processes. Within the 80 year history of the establishment, splines were always manufactured by cutting which had significant cost implications hence a different approach was investigated to enhance quality, reduce waste, increase efficiency and product reliability