Fräsning i varma material
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Gestamp Hardtech manufactures safety components for the automotive industry. The forming dies used for press hardening at Gestamp Hardtech in Luleå are manufactured by milling in CNC-machines. Some forming dies are used to create soft zones at the pressed crash safety components. This means that the specific forming dies are heated while in use. When the forming dies are heated the form is changed because of the heat expansion. To give the forming die the right form the expansion is simulated and compensated while milling. The problem is that the simulation often proves wrong, the scanning of the forming die often shows that the tolerances haven’t been reached which means a new simulation and a new milling process has to be executed. This is a process that takes a lot of time and money for Gestamp Hardtech. The purpose of this master thesis has been to develop a method that allows soft zone forming dies to be milled while heated and in such way achieve the right tolerances right away.The goal with this work has been to perform a test to investigate if it is possible to mill forming dies while they are heated without losing the tolerances or risk that the milling machine or any human get hurt.Many concepts have been developed to solve the cooling, the wiring, the protection of the equipment and more. The work continued with detail design with the concept that received the highest score in the concept selection matrix. The constructed parts were then manufactured to be used in the tests of hot milling that were performed.Two tests have been performed where a heated forming die have been processed according to the developed concept. No visible defects were spotted after the hot milling process. To analyze the achieved tolerances the forming die were scanned before and after the milling with a result showing that the desired tolerances were not achieved. The deviation depends on that the heat distribution was uneven in both the forming die and the cooling plate and also that the performed scanning was not accurate enough. The temperature in the chuck gave no risk of bearing failure and the temperature in the cooling plate gave no risk of fire in the working table during milling of a heated forming die. The goals with the tests of heated milling that were stated in the project are completed. To make it possible for Gestamp Hardtech to use hot milling in their production it is recommended to manufacture a new heat shield that can handle all types of tools, install connections for water and electricity to standardize the wiring and to install a water chiller to be able to get the same temperature of the cooling water when milling as when pressing.
Place, publisher, year, edition, pages
2015. , 49 p.
Teknik, Fräsning, varmfräsning, Olof Johansson
IdentifiersURN: urn:nbn:se:ltu:diva-58550Local ID: f21fd913-aff5-46bf-8a49-9b125e85ce34OAI: oai:DiVA.org:ltu-58550DiVA: diva2:1031938
Subject / course
Student thesis, at least 30 credits
Mechanical Engineering, master's level
Validerat; 20150609 (global_studentproject_submitter)2016-10-042016-10-04Bibliographically approved