ME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 1 Topical Course Review No warranty as to completenessME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 2ME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 3 Topics for final exam • Casting • Deformation processing – forging – extrusion • Sheet Metal Bending • Machining – traditional – non-traditional • Polymer Processing – injection molding – extrusion • Joining – fusion – non-fusion • Rapid PrototypingME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 4 Casting Temperature time initial melting solidification pouring removalME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 5 Casting • Heating and melting – energy required (temperature rise and phase change) • Pouring – fluid flow (Reynold’s number, Bernoulli’s equation, conservation of flow) – aspiration, bottom-gated molds • Cooling and solidification – cooling time limits pouring time – insulating vs. conducting molds – risers – cooling below solidification • Gas bubbles and voids – where they come from – how to eliminate themME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 6 Deformation processing • Forging • ExtrusionME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 7 Models • Which mechanics model? – plane strain – not plane strain • Cold – strain hardening • Hot – strain rate • Plasticity, no elasticityME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 8 Forging • Plane strain (rectangular) or not plane strain (cylindrical upsetting) • Hot or cold • Sticking or sliding or both • Open or closed (flash) • Key additional limitation – die pressureME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 9 Extrusion • Direct, indirect • Large angles – energy balance analysis – dead zone • Hot or cold • Key limitations – die pressure – powerME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 10 Sheet Metal Bending • Elasticity and plasticity important • Springback – various material models • Key limitations – tearing of metal (necking) (maximum strain) – in plastic zone?ME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 11 Machining • Orthogonal cutting • Oblique cutting • Cutting forces, torques from cutting power: – material removal rate – specific cutting energy • Cutting temperature – friction – shearME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 12 Machining • Tool life limited by temperature, diffusion – Taylor’s equation • Cutting economics – single point cutting – minimum cost – maximum production rateME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 13 Polymer processing • Extrusion – continuous flow from screw through die • Injection molding – two part process • shot production • mold filling – part cooling in mold • mold filling time must be shorter than cooling timeME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 14 Polymer processing • Screw equation – drag flow (forward) – pressure driven flow (backward) • Die or mold equation – pressure driven flow (forward)ME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 15 Polymer processing • Extrusion – equate screw and die equations – flow rates must be equal – pressure rise in screw must equal pressure drop in dieME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 16 Polymer processing • Injection molding – shot production • screw equation • back pressure gives “dp” term • flow rate determined by time allowed (cooling) or degradation – filling of mold • pressure driven flow into mold • minimum time determined by degradation • maximum time determined by solidification/cooling timeME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 17 Joining • Fusion – melting of base material and filler – welding • oxy-acetylene • oxygen (oxy-fuel) cutting • thermit • resistance • arc • laser • electron beamME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 18 Joining • Non-fusion • Filler material may melt or be liquid – ultrasonic – friction – friction stir – soldering / brazing – adhesivesME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 19 Rapid Prototyping and Manufacturing • Additive fabrication – material is added, not removed • Direct fabrication from a CAD file • Layered manufacturingME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 20 Rapid Prototyping and Manufacturing • Stereolithography (SL) • Selective Laser Sintering (SLS) • 3-D Printing • Light Engineered Net Shaping (LENS) • Fused Deposition Modeling (FDM) • Solid Base Curing • Laminated Object Modeling (LOM)ME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 21 Types of Questions • Single equation • Multiple equations - Puzzles – Requires modeling (abstraction) of the problem – What is given? – What is asked for? (can be starting point) – How do the parts of your model fit together? • N.B. - Equations are relations between variablesME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 22 Question Format • Ranges: – Upper – Lower • Show me you truly understand question and process, rather than just choose some equations to fill in.ME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 23 Modeling is key • Assumptions • Can you do it? • Material modelsME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 24 Model assumptions • What is happening? • What are the assumptions? – Plane strain – Fully plastic – “Cold” vs. “Hot” temperature – Frictionless • What limitations do they impose?ME 4210: Manufacturing Processes and Engineering - Prof. J.S. Colton © GIT 2011 25 Limitations – can you do it? • Time • Speed • Power • Force • Torque • Material