ME/MECA 238A1 ME/MECA 238A - Mechanical/Mechatronic Design Project I Course notes prepared by G.A. Kallio, based on The Mechanical Design Process, by D.G. Ullman

ME/MECA 238A2 Product Design Phase (Ch. 9-12) Refine concepts into quality products (i.e., hardware design) Generation-evaluation: closely entwined and iterative Concurrent engineering: DFX

ME/MECA 238A3 Elements of Product Design Modeling & analysis Material selection Manufacturing methods Economics Assembly Safety, reliability, environmental impact

ME/MECA 238A4 Importance of Drawings Store and archive information Communication Analysis & simulation Completeness check Synthesis

ME/MECA 238A5 Types of Drawings Layout Drawings –scaled, working drawings of entire product –shows interfaces with existing hardware –basis for Detail and Assembly drawings –important dimensions shown –no tolerances

ME/MECA 238A6 Types of Drawings, cont. Detail Drawings –individual components –used to communicate product to manufacturer –fully-dimensioned & toleranced –sufficient views to show entire shape and all dimensions –signature block

ME/MECA 238A7 Types of Drawings, cont. Assembly Drawings –shows how components fit together –exploded view is common method –components identified with a number and keyed to a parts list, or Bill of Materials (BOM) –multiple views may be necessary –reference to assembly instructions –signature block

ME/MECA 238A8 Types of Drawings, cont. Diagram Drawings –type of assembly drawing –not drawn to scale or real to form –usually for electrical wiring & piping –standard symbols with component specs –may include signature block & BOM

ME/MECA 238A9 Bill of Materials Typical information: –item number (keyed to Assembly Drawing) –part number (indexed to a company system) –quantity –name or description –fabrication material –source (if made by outside vendor)

ME/MECA 238A10 Dimensions and Tolerances Dimensions may describe size, location, orientation, and form Tolerances define the allowable dimensional variation based on loss of function –sensitive dimensions –robust dimensions –unrelated dimensions

ME/MECA 238A11 Tolerancing Drawing tolerances should depend upon fabrication method, cost, and function Fabrication methods produce a random, statistical variation on all dimensions Be aware of tolerance stack-up Geometric Dimensioning & Tolerancing (GD&T)

ME/MECA 238A12 Product Generation (Ch. 10) Form generation –Spatial constraints, relative arrangement, interfaces, developing components, refining & patching Materials & Process Selection Vendor Development

ME/MECA 238A13 Product Evaluation for Performance (Ch. 11) Physical Testing (Spring 2002) Modeling & Simulation Robust Design (Taguchi’s method)