En undersökning av framtidametoder för att säkra förband i produktion

Sammanfattning: The thesis is an examination of the methods that are appropriate and long-term choice to obtain clamping force and secure screw joints in production. The employer, Scania CV AB, transmission manufactures axle gears to all trucks produced in Södertälje. One of the most common assembly elements is screw joints, where the clamping force is essential to achieve a secure joint. Current methods to secure the joint is due much of the friction effect and is an indirect method to measure the clamping force. The clampforce accuracy becomes more widely with torque angle control. Scania is working with continuous improvements in order to always keephigh quality and customer focus and the purpose of this study is to evaluate the future means to secure the clamping force of screw joints to keep the best quality. Potential methods to be examined is ultrasound technology and gradient yield control and their accuracy compared to current method. The study also aims to examine the economic impact of deviations in production of axle gears. Scania already runs development projects in secure units for engine assembly and benchmarking in the enterprise is therefore one of the methods of investigation. The work consists of three parts where theory and experiment section aims to explain and prove the methods of securing screw joints and to advance the author on the subject. The second part is the economic study that seeks to demonstrate how much the current method costs Scania compared with investment costs for new methods. The final part is to analyze the new methods and results of the study and performed experiments. For Scania axle gear assembly and the selected unit does ultrasound method more accurate and direct measure the clamping force. It convinces the future of clamping force control as a method of securing screw joints. As the method gives a more reliable control of clamping force and may be for joints that are affected by subsidence ensure quality to customers. The ultrasonic method is a long termsolution for Scania critical joints and gives them the most accurate quality to compete with on the market.