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Additive Manufacturing – Integration of Functions in EMI-Shields

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Additive Manufacturing – Integration of Functions in EMI-Shields 1 Royal Institute of Technology Master Thesis Additive Manufacturing – Integration of Functions in EMI-shields Author: Author: André JOHANSSON KUCERA Alexandra LIDHOLM Course: Course: MG212X, Degree Project in Production SE202X, Degree Project Engineering and Management in Solid Mechanics Supervisor KTH: Supervisor KTH: Amir RASHID, Bo ALFREDSSON, professor in Industrial professor in Solid Production Mechanics Examiner KTH: Examiner KTH: Amir RASHID Bo ALFREDSSON Supervisor Saab AB: Mussie GEBRETNSAE June 2019 i Abstract Additive manufacturing enables a simplified production process of components with complex geometry based on computer aided three-dimensional design. The technology of creating components layer-by-layer allows an efficient process with the ability to design parts with specific properties which can be difficult to obtain when conventional manufacturing methods are used. In this master thesis, an EMI shield was analyzed where the choice of manufacturing process was of interest. Producing the shield with additive manufacturing, instead of conventional methods, and how to integrate different materials in the process were investigated. The possibility to produce the shield and its components in the same process would result in a shorter production process with less process steps and would be an effective approach for future applications. In the current EMI shield, each component has a specific function with high demands in terms of temperature resistance, weight and EMC. These requirements must be taken into account when choosing manufacturing method and suitable materials in order to obtain desired characteristics of the shield. In the analysis of creating an electromagnetic interference (EMI) shield with multi-materials, a comprehensive literature study was conducted where different AM methods and available materials were investigated. Based on the literature research, possible concepts were generated and 3 different concepts were suggested for the final solution. A Finite Element Method software was used to verify these concepts in terms of solid mechanics, where the final design of the shield was determined based on the choice of materials in addition to optimization of the geometry. To evaluate the function and electromagnetic compatibility of the final concepts, prototypes were manufactured and tested in an experimental setup. These results were compared to the results of the original shield in order to determine whether the concepts met the given requirements or not. Concept E showed similar EMI results as the current shielding solution, whereas concept C and D resulted in a decrease of shielding effectiveness. Keywords: EMI-shield, Additive Manufacturing, composites, multi-material, FEM, product development, gasket, absorber. ii Sammanfattning Additiv tillverkning möjliggör en förenklad produktionsprocess av komponenter med komplexa geometrier utifrån en tredimensionell design. Att skapa komponenter lager för lager möjliggör en effektiv tillverkningsprocess av komponenter som skulle varit svåra att framställa med konventionalla tillverkningsprocesser. I detta arbete har ett EMI-lock analyserats där valet av tillverkningsmetod varit av intresse. Möjligheten att framställa produkten med additiv tillverkning istället för att använda konventionella processer samt hur man kan integrera olika material i tillverkningen har undersökts. Möjligheten att tillverka locket och dess komponenter i en och samma process skulle resultera i en kortare produktionsprocess med färre processteg, vilket skulle vara ett effektivt tillvägagångssätt i tillverkningen av framtida applikationer. I nuvarande EMI-lock har varje komponent en betydelsefull funktion och höga krav i form av temperatur, vikt och EMC ställs på produkten. Dessa krav måste beaktas vid val av möjlig tillverkningsmetod och lämpliga material för att erhålla önskade egenskaper hos slutprodukten. För att utvärdera möjligheten att tillverka ett EMI-lock med flera material har en omfattande litteraturstudie genomförts där olika tillverkningsmetoder och tillgängliga material undersökts. Baserat på litteraturstudien har generering av potentiella koncept genomförts där 3 koncept har föreslagits för den slutliga lösningen. För att verifiera dessa koncept har FEM-program används för att utvärdera hållfastheten. Baserat på dessa resultat har den slutliga designen av locket fastställts utifrån val av material och optimering av geometrin. Funktionen hos de slutliga koncepten och dess elektromagnetiska kompatibilitet har utvärderats genom att tillverka flera prototyper och sedan testa dessa i ett experimentellt utförande. Resultaten av detta jämfördes sedan med det ursprungliga EMI-locket för att avgöra om koncepten uppfyllde de givna kraven. Koncept E visade liknande resultat som det ursprungliga EMI-locket, medan koncept C och D påvisade en minskad skärmningseffekt. Nyckelord: EMI-lock, additiv tillverkning, komposit, multi-material, FEM, produktutveckling, packning, absorbent. iii Acknowledgement This master thesis was supported and carried out by Saab AB Surveillance in Gothenburg between January and June of 2019. The project is conducted as part of the Solid Mechanics track and Production Engineering and Management track at the Royal Institute of Technology (KTH) in Stockholm. We would like to thank Stefan Linders and Mattias Skogsberg at Saab for guidance and support throughout the work. A special thanks to our supervisor Mussie Gebretnsae who provided us with expertise, insight and knowledge. His encouragement and dedication made it possible to accomplish this project and achieve our common goal. We also thank everyone at the Gothenburg site for the welcoming atmosphere during this time. We are grateful to Mauricio Saldes, for giving us access to the Järfälla site, and Richard Ingman with the rest of the employees and lab technicians at the EW department in Järfälla for their help and support when it was needed. We thank Hans Nordström for assistance of knowledge in the field of electromagnetic radiation. It was a new subject for us to learn, but his guidance and commitment made it possible for us to create an understanding of EMI which we have conveyed in this work. We would also like to show our gratitude to our supervisors at KTH, Bo Alfredsson and Amir Rashid, for their help and dedication during this master thesis. André Johansson Kucera Alexandra Lidholm Stockholm, June 2019 iv Contents 1. Introduction.......................................................................................................................................... 1 1.1 Background .................................................................................................................................... 2 1.2 Purpose........................................................................................................................................... 3 1.3 Problem description ....................................................................................................................... 3 1.4 Delimitations .................................................................................................................................. 4 2. Method ................................................................................................................................................. 5 2.1 Data collection................................................................................................................................ 5 2.2 Technology screening ..................................................................................................................... 6 2.3 Concept development .................................................................................................................... 7 2.4 CAD ................................................................................................................................................. 8 2.5 FEM ................................................................................................................................................. 8 2.6 Prototype manufacturing and EMC testing ................................................................................... 9 3. EMC and EMI ...................................................................................................................................... 10 3.1 Electromagnetic radiation ............................................................................................................ 10 3.2 EMC and EMI ................................................................................................................................ 10 3.3 Basic shield theory ....................................................................................................................... 11 3.4 EMI shielding components ........................................................................................................... 12 3.5 EMI shield solutions on the market ............................................................................................. 15 4. Additive Manufacturing ..................................................................................................................... 17 4.1 Vat Photopolymerization ............................................................................................................. 17 4.2 Material jetting ............................................................................................................................. 18 4.3 Binder jetting ...............................................................................................................................
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