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Optimization of Sprue Design for Advanced Investment Casting Through FEA Analysis

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Optimization of Sprue Design for Advanced Investment Casting Through FEA Analysis TPC Components AB School of Innovation, Design and Engineering Optimization of sprue design for advanced investment casting through FEA analysis Bachelor thesis work Basic level, 15 points Product and Process Development Kanthee Prathan Mälardalens University, Academy for Innovation, Design and Engineering Supervisor, TPC AB: Daniel Kuivamäki Supervisor, university: Barrett Sauter Examinor: Janne Carlsson Presentation day: august 27th, 2020 ABSTRACT Investment casting is a complex manufacturing method with many challenges that must be solved before components of the right quality can be produced. TPC is a company that utilizes investment casting to produce a variety of products, lately the company has higher ambition in wanting to cast higher technical demanding component like heat resistant gas turbine blades. This requires a sprue that can control the filling process, by allowing the fallen stream of molten metal to enter the moulds cavity in a laminar manner. This study has implemented the product development process by (Ulrich, 2012) to develop the requested sprue. The primary support for this study is study material given by the company also known as "PMG running spreadsheet TPC" base on theory and equations from (Jolly, 2002), which is believed to have origin in sand casting manufacturing process. The project began with recreating the textbook model after establishing a number of control parameter such as critical velocity. Then simulation software Nova flow was used to evaluate the velocity and FEM in Solidworks to study if the dimension of the model can be directly use for investment casting process. The results show that it was not possible, therefore in the concept generating phase only theory of casting was used to create new concept. Then 3 existing sprues were chosen for benchmarking to gain deeper understanding about their design intension. One of the concepts was inspired by the CEO Mark Irwin “concentric pipe design” and in total 10 concepts were created of which 6 were tested for both flow and FEM analysis. 2 concepts were chosen for further development which also became 2 final concepts, after 3 iterations of improvement. These concepts show that many improve in terms of laminar filling and higher yield than the existing benchmark sprues. Although further development is required. The analysis shows that every step in the project has its own flaws, but that is the nature of being an engineer, as long as the problem encountered can be viewed with critical and analytical eyes. A well-considered and balanced solution can be provided, although nothing of this can be certain before a trail of test can provided to confirm any assumptions which is not included in this work. The discussion section processes the thoughts, experience, and doubts about the project in general and the decision making leading to this report and what could have been done differently. The most significant lesson learn from this is that section is when solving a complex issue there must be very clear delimitations and well-defined goals to every specific solution. Otherwise the workload will be extensive and cause more harm than necessary. The conclusion of this project shows that two concepts generated with the help from the product development process work better than the case study, which can be found in section 4.3, that was based on “PMG running spreadsheet TPC” calculation model, from the velocity perspective. To achieve this, the sprue uses its own geometry constrain and constricts the flow by collecting the molten metal in a “well” before the calmer stream could be distributed throughout the whole cavity. Indirectly this means that the studied material given from TPC AB could not be directly implemented into the investment production process. The given material should be seen as a complement and guidance when creating new sprues. Concerning the FEM analysis tool, it was helpful in this project in evaluating the sprues geometry expose to the assumed force in the production process to avoid unnecessary failure and therefore waste. Although if the company do not intend further work with the development of other sprues then this method is not necessary and would not have significant value to their current manufacturing process. 2 (84) ACKNOWLEGEMENT I would like to thank everyone, friends and family who supported me in this project during this last few month and who showed great understanding for my absence from all the important events. Many thanks and appreciation to my supervisor(s) in helping me to understand the many issues in this work so that appropriate solutions could be provided. Also, great thanks to TPC AB, especially Mark Irwin for giving me the opportunity to conduct this study and to learn so much about their process and the casting industry. This have been a great lesson-learn journey without them this would not have been possible. Special thanks to my better half who has been supportive in both time and effort by reading this report countless times and correcting my mistakes. Without her this study would not have been possible. 3 (84) CONTENTS 1. INTRODUCTION ......................................................................................................................................... 10 1.1. BACKGROUND ......................................................................................................................................... 10 1.2. PROBLEM FORMULATION ......................................................................................................................... 10 1.3. PURPOSE AND RESEARCH QUESTIONS...................................................................................................... 12 1.4. DELIMITATION ........................................................................................................................................ 12 2. METHODOLOGY ........................................................................................................................................ 13 2.1. PRODUCT DEVELOPMENT PROCESS .......................................................................................................... 13 2.1.1. PLANNING ........................................................................................................................................... 13 2.1.2. CONCEPT DEVELOPMENT .................................................................................................................... 13 2.2. INFORMATION GATHERING...................................................................................................................... 15 2.2.1. LITERATURE STUDY ............................................................................................................................ 15 2.2.2. OBSERVATION ..................................................................................................................................... 15 2.2.3. CONFERENCE CALL ............................................................................................................................. 16 2.2.4. DISCUSSION ........................................................................................................................................ 16 2.2.5. CASE STUDY ....................................................................................................................................... 16 2.2.6. BENCHMARK ....................................................................................................................................... 16 2.2.7. FEM ANALYSIS ................................................................................................................................... 17 2.2.8. SOFTWARE .......................................................................................................................................... 17 2.3. 3D-PRINTING .......................................................................................................................................... 17 3. THEORETICAL FRAMEWORK ............................................................................................................... 18 3.1. WHAT IS CASTING? ................................................................................................................................. 18 3.2. INVESTMENT CASTING ............................................................................................................................ 18 3.3. SAND CASTING ........................................................................................................................................ 19 3.4. CASTING RULES ...................................................................................................................................... 20 3.5. GATING SYSTEM ..................................................................................................................................... 21 3.6. LAMINAR FLOW ...................................................................................................................................... 22 3.7. COMPANY ANALYSIS .............................................................................................................................. 23 3.7.1. THE CASTING PROCESSES ................................................................................................................... 24 3.7.2. CONCENTRIC PIPE DESIGN .................................................................................................................. 24 4. EMPIRICS ....................................................................................................................................................
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