Copyright 2003 Joseph Greene All Rights Reserved 1 MFGT 124 Solid Design in Manufacturing The Design Process Professor Joe Greene CSU, CHICO Reference: The Mechanical Process, 3 rd Edition, David Ullman, McGrall Hill New York (2003) MFGT 124

Copyright 2003 Joseph Greene All Rights Reserved 2 Chap 3: Problem Solving Topics –Introduction –Overview of Design Process –Designing Quality into Products –Simple Design Process Examples –Complex Example –Communication during the Design Process –Sample Design Problem

Copyright 2003 Joseph Greene All Rights Reserved 3 Introduction The design process –Varies from product to product and industry to industry –Generic diagram of activities that must be accomplished for all projects. Figure 4.1 –Project definition and planning »Establish need for product –Specification definition »What should product do and how will it be tested? –Conceptual design »Build a prototype to prove concept is manufacturable –Product development »Build production parts and a system for mass production –Product Support »Provide means for product to be used »Provide spare parts for returns.

Copyright 2003 Joseph Greene All Rights Reserved 4 Introduction The design process –Always have market input New type of part that is new to market. Use consumer focus group testing. Develops business case Example, –Stick it notes or walkman or CD burners –Most designs are redesigns of existing products Cars have major design changes every 5 to 7 years. Cars have minor changes to fascias, lighting, every 1 to 3 years. Computers are redesigned every 6 months. Make products less expensive and more features. Fix problems with current designs –Cars have changes in the first year of production. »Often times prototype tooling is used at start of production

Copyright 2003 Joseph Greene All Rights Reserved 5 Introduction Break part into major systems and subsystems –Car has 6 major systems Designed by about 300 designers for GM. Lowers, uppers, engine, transmission, interior, and exterior panels. Assembly plant is laid out in order of build of 6 major systems. Design of car is broken into 6 major systems. –Each system is proken down into subsystems and assemblies and subassemblies. –Example, space shuttle, Fig 4-2 Rocket booster, Fig 4.3 Major systems –Sub systems

Copyright 2003 Joseph Greene All Rights Reserved 6 Major Systems Space Shuttle is broken down into smaller components. –Major Systems –Tree Diagram Each sub system is broken down further to major assemblies. Each major assembly is broken down further to sub-assemblies. Each subassembly is broken down further into individual parts. –Engineers are typically responsible for a sub-assembly or two and several parts. –Designer is given a few parts to design. All parts and assemblies have to be designed to fit together to form major assemblies and systems. –Problems can occur if a redesign in on part does not get changed in another mating part in the subassembly. One designer has an older subassembly information than another designer. Example, GM Camaro bumper beam not fitting with rails changes, –Solution: Use product data management to coordinate versions of parts. Designer is automatically sent the latest drawing information when the designer opens the model.

Copyright 2003 Joseph Greene All Rights Reserved 7 Project Planning Example of Redesign –Shuttle has reusable boosters Before each launch –Booster is disassembled, repacked with fuel, shipped to launch site, and assembled in field. –Field joints were used to fasten segments together. –Changes in materials or design have to be updated to master design. Project planning –Process- Fig 4.1 –Planning is important Chief engineer and product development team meet every week and major systems groups give status report (timing, budget, performance) Resource requirements –What funding and personnel are needed in near future. Timing and Cost –15 people worked on design of field joints of rocket boosters for 1 year. –Hundreds of GM engineers work on a car program over 4 years.

Copyright 2003 Joseph Greene All Rights Reserved 8 Specs Definition –Federal requirements Bumpers must be 2.5 MPH for cars and 0 MPH for trucks. Canadian requirements are 5 MPH with some damage OK. –Customer requirements Want no damage to vehicle in low speed collisions (< 10 MPH) –Company requirements Bumpers must survive 5 MPH impact with no damage for cars and 2.5 MPH for trucks. –Specifications are written to meet the company requirements. Bumper must maintain defection less than 130mm and maintain a load of 8,000 pounds without breaking. Bumper must survive two car hits at 5 MPH and one crash into the wall at 5 MPH. Bumper must survive room temperature impact and one at –40  F.

Copyright 2003 Joseph Greene All Rights Reserved 9 Conceptual Design Most designs start with a conceptual design. –Designs can start on paper with a back-of-the-napkin design or in CAD in sketch mode. Brainstorming session proposes several designs. Designs are ranked in order of those best meeting requirements. Conceptual design is developed to prove that idea works and is best. –Functional prototype is produced and tested with some of the important functional requirements. –Quality is estimated. –Costs are estimated. –Timing is estimated to produce part. –Conceptual design will lead to a Go – No Go decision. Go decision- money is requested and approved, resources are identified, timing is established, project requirements are finalized. No-go decision- Project is shelved and no resources are provided. –Example, GM Camaro program was cancelled in 1985 and then restarted in –It takes 5 years to design a car. 4 years after car program is approved.

Copyright 2003 Joseph Greene All Rights Reserved 10 Product Development Puts concept into production. –Develops the part into a production system. –GM has 4 phases to develop a car or truck Phase 0- develop functional prototype that meets performance on a per part basis. –Business case is developed and $$ are approved for programs, typically $300M to $5 Billion. –Tools are ordered. Steel stamping dies take 12 months to make; plastic molding tools take 6 months to make. Phase 1- develop systems that meet performance requirements on production tools and materials. –Production plant is identified and production parts are produced in small batches. –Cars are tested for final safety testing. Phase 2- develop plant production system to produce car in the assembly plant. –Layout of assembly plant is changed to new car or truck line at costs of $200M to $800M. –Limited cars are produced and market tested. Phase 3- start of production at line speed of 1 car per 60 seconds. –Get first saleable vehicle.

Copyright 2003 Joseph Greene All Rights Reserved 11 Product Support Support is needed for the design. –Manufacturing and assembly support. Meeting quality targets like ISO Quality workshops and clinics. Design changes in production plants. –Sales and marketing support. Parts are provided for early showroom and customer clinics. –Spare parts and warranty support. Provide parts and design for years after production stops to supply spare parts to customers wanting to repair or replace item. –GM requires vendors to supply parts up to 10 years after car program ends. –Engineering support Engineering changes during production that make the part cheaper or have higher quality.

Copyright 2003 Joseph Greene All Rights Reserved 12 Product Quality Designing quality into parts –Quality cannot be manufactured or inspected into a product, it must be designed into it. Old school: –Quality was to measure the quality by inspecting the parts and see what the problems are and then make changes to production system. New school: –Quality is designed into the part by having concurrent engineer where the design is approved by a cross-functional team. More effective to design quality into a product than measure it later. Better to make design changes early in product development than later. Example, –US car makers versus Japanese car makers. –Figure 4.5 –Best practices in design. Table 4.1

Copyright 2003 Joseph Greene All Rights Reserved 13 Simple Design Example

Copyright 2003 Joseph Greene All Rights Reserved 14 Complex Design Example

Copyright 2003 Joseph Greene All Rights Reserved 15 Communication