detailset DESIGN
Designing Holes in Iron JITEN SHAH, PRODUCT DEVELOPMENT & ANALYSIS, NAPERVILLE, ILLINOIS
various times over the years in this column. When, where and how are answered based on the specifi c needs and application
W
Case 2: Opener Mount Casting Some holes can be cored, others are incor- porated as part of the mold.
• T e series of holes at the top could not be molded because its orientation was not perpendicular to the parting plane, so the metalcasting facility used a slab core, which could be used in diff erent pitches for diff erent mounting locations.
• Holes located parallel to the parting plane were achieved without using additional cores by incorpo- rating them as part of the green sand mold.
• T e key factors driving as-cored vs. as-cast solid holes are hole diameter to thickness/depth, the pitch or inner distance between them, parting plane orien- tation and the type of molding process.
of each part. Included here are specifi c examples of sand cast iron components and how the designers decided to achieve the holed features.
Case 1: Engine Bracket for John Deere 7R Series Tractor The location of an as-cast hole reduces weight without weakening the component for structural strength.
• By designing locations strategically with reference to the parting plane, it is possible to achieve as-cast cored pockets using the cope and drag pat- tern; no corebox tooling is required.
• By strategically designing cored fea- tures, typically in low stress areas, it is possible to optimize the casting unit weight vs. other manufacturing pro- cesses such as fabrication or milling.
hen should a design incorporate a hole and when should it be machined? Where should the hole go? What’s the most economical way to achieve a hole in a design without sacrificing quality? The answers to these ques- tions are never straightforward, but have been addressed
18 | METAL CASTING DESIGN & PURCHASING | Mar/Apr 2016
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60