授章节教师：杨宏智教授.pptVIP

授課教師：楊宏智教授 * 【本著作除另有註明外，採取創用CC「姓名標示－非商業性－相同方式分享」台灣3.0版授權釋出】 【本著作除另有註明外，採取創用CC「姓名標示－非商業性－相同方式分享」台灣3.0版授權釋出】 【本著作除另有註明外，採取創用CC「姓名標示－非商業性－相同方式分享」台灣3.0版授權釋出】 楊宏智（台大機械系教授） * Chapter Outline Introduction Design Considerations in Casting Economics of Casting Introduction Successful casting practice requires proper control of a large number of variables Flow of the molten metal in the mold cavities, the gating systems, the rate of cooling, and the gases evolved would influence the quality of a casting Design Considerations in Casting All casting operations share the characteristics of phase change and thermal shrinkage during the casting cycle But each process will have its own design considerations Sand casting will require mold erosion and sand inclusions in the casting Die casting will not have this concern Defects frequently are random and difficult to reproduce Design Considerations in Casting:General Design Considerations for Castings 2 types of design issues in casting: Geometric features and tolerances incorporated into the part Mold features that are needed to produce the desired casting Design Considerations in Casting:General Design Considerations for Castings Design of Cast Parts Corners, angles, and section thickness Flat areas Shrinkage Draft Dimensional tolerances Lettering and markings Finishing operations Design Considerations in Casting:General Design Considerations for Castings Locating the Parting Line Parting line is the line or plane separating the upper (cope) and lower (drag) halves of molds Parting line should be along a flat plane rather than be contoured Location is important as it influences mold design, ease of molding, number and shape of cores required, method of support and the gating system Parting line should be low for less dense metals and located at mid-height for denser metals Design Considerations in Casting:General Design Considerations for Castings Locating and Designing Gates Multiple gates are preferable Gates should feed into