Development of Mechanical Joining Technology for Light Weight Car Body Concepts

Important results from the project

The goal of the project is to enable the implementation of multi-material design of next generation cars in order to reduce weight and maintain or increase the stiffness and the strength of the car design. The project will focus on: Evaluation of process capability of different types of possible adhesives in combination with mechanical joining. Studies of the impact of joining speed on joint quality. Specific support for product related mix-metal solutions driven by Product Development, e.g. hybrid closures (Hood, Trunk lid/Tailgate, Doors), aluminum application in BIW, aluminum intensive closures. Project will deliver basic process knowledge about new material combinations and process conditions in order to support product development of new concepts. Another result of this project will be that more flexible and cost effective equipment solutions can be devised for implementation in our assembly production lines and give better opportunity to optimize joining of different light weight applications.

Expected long term effects

The main advantage of this project will be the process driven product concept which will meet requirements for both lower weight and cost effective production. The project will deliver these main results within the process area mechanical joining: Recommended adhesives for mechanical joining, clinching and SPR. Evaluation of advanced software, the impact of the available joining parameters on quality of the joint, such as joining speed, direction choice for some selected material combinations and adhesives. Evaluation of mechanical parameters of el-servo equipment. Possibility to develop the technique together with equipment supplier Increased understanding of possibilities to use el-servo as application in assembly operations with environmental benefits. The project also supplies product development with mechanical joining technique competence towards CO2 targeted product projects: Development of mechanical joining concept for Mix-metal door Development of mechanical joining concept for Aluminum Intensive door In addition to those specific projects we are also expecting to support other national lightweight car body-related activities with a certain tests and prototyping.

Approach and implementation

The project will be divided to several work packages which are briefly described below. The project group will in detail specify every activity in each work package in order to set conditions for the test set-ups and refine and adjust time table according to Volvo Cars needs and prioritization. WP1: Parameter studies for el-servo clinching equipment for coming tailgate steel-concept. Target: Find the joining parameter window for cost effective solution with help of advanced software. WP2: Mapping of suitable adhesives for mechanical joining and steel-aluminium joints. Clinching Target: Mapping of suitability and recommendations for different adhesives for hybrid mechanical joining - clinching WP3: Basic knowledge build-up about the impact of joining speed impact on joining quality - clinching Target: Understanding how the speed as a parameter of joining process influences quality of the clinch joint. Only basic knowledge about joinability with approved joints. Only the process aspects will be studied, not strength-related performance. WP4: Mapping of suitable adhesives for mechanical joining and steel-aluminium joints - self piercing riveting (SPR) Target: Understanding of how the adhesive as an additive material influences the quality outcome. Mapping of suitability and recommendations for different adhesives for hybrid mechanical joining - SPR. WP5: Basic knowledge build-up about the impact of joining speed on joining quality - SPR Target: Understanding of how the speed as a parameter in joining process influences the quality outcome. Only basic knowledge about join ability with approved joints from the process point of view, not strength-related performance. WP6: Conceptual development - Hybrid door concept and Al-intensive door concept Target: Quality assurance of hybrid (adhesives) mix-metal joining for Hybrid door concept and Aluminum intensive door concept. WP7: Conceptual development - other light weight concepts Target: Manufacturing Engineering support to conceptual development of other light weight concepts