Transcription
M2794.006900DESIGNFOR MANUFACTURINGWeek 2, September 14Design for Manufacture (DFM):ConceptFall 2017Professor Sung-Hoon AhnDepartment of Mechanical and Aerospace EngineeringSeoul National University
2What is Manufacturability?Do you know how to make these parts?
3More important questions? How much does it cost?How long does it take? These issues are influenced by: Manufacturing processAvailability of machinesMaterialBatch size (how many parts)Etc.
4Model for manufacturing?“When we mean to build,we first survey the plot,then draw the model”William Shakespeare (1564-1616)
5Problems in traditional manufacturingCommercial CAD (CATIA, ProE, I-DEAS, ringTime lost inredesignOuch, it’s notMachinable
6Definition of DFMProcess of proactively designing products to: optimize the manufacturing functions Fabrication Procurement Assembly Service Test Repair assure the best cost, quality, reliability, safety, timeto-market, and custom satisfaction”(D. Anderson) Also, Design for manufacture, manufacturing,manufacturability
7Cost in product development 80% of cost iscommitted atdesign stageIncurred cost fordesign is lessthan 10%
8Importance of DFM1. Design decision affects manufacturing cost andproductivity2. Designers play important role not only shaping,but also in manufacturability, cost, life cycle ofproducts
9History of DFM (1) Eli Whitney (19C ) Musket (gun) manufacturer Redesigned a limited tolerance*Used fixtures, gauges, andspecially developed machines Each part could be made by semiskilled workers at a faster andcheaperChanged process from sandcasting to forging increasedaccuracy
10Tolerance Engineering tolerance isA machine's potential to cope with changesin the following elements of itssurroundings and remain functioning
11Whitney’s Musket
12History of DFM (2)Henry Ford (1907) Standard parts Simple design Conveyor system Price reduction 2000/car - 350/car1908 1927: 15 million soldCadillac, General motors (1909)T-model (Ford)Charlie Chaplin – Modern Times; Factory Work
13DFM category1.2.3.4.5.General rulesProcess specific rulesProduct specific rulesDesign for Assembly (DFA)DFX EnvironmentRecycleQualitySix sigmaEtc.
141. General rules of DFM Minimum number of partsStandard partsModular designMulti-functional partsThe same parts to various productsMaximum surface roughness and toleranceAvoid secondary processUse materials easy to manufactureConsider number of parts to be manufacturedAvoid many componentsMinimize handling of partsFeasibleBetter
15Manufacturing Time vs. Surface RoughnessSurface roughness vs. Relative manufacturing time depend onSurface finishing methodRelative manufacturing timeCylindrical grindingSurface grindingEnd millingReamingTurningFlexibility millingShaping & PlaningDrillingSurface roughness ( )
16TolerancesRelationship between relativemachining cost and tolerance.Source: S. Kalpakjian, Manufacturing Engineeringand Technology, 3rd ed. Addison-Wesley, 1995
17Per Part CostThe relation among an output, selection of machine tools, andeconomical efficiency of production making.The cost of each partsGeneral purpose Special-purposemachine toolmachine toolsHand workNC machine toolsThe cost of materialsThe number of parts
18Product Development Time
192. Process specific rules: MachiningAvoid thin wallAvoid thin and longboring beamAvoid turing processing ofthin and long component.Short and firm componentdoes not require tailstock.
20Process specific DFM: DrillingThe drill enters andcomes out with thedirection which isvertical to the drill’saxis.The drill slipsto the left.WorstThe drill slipsto the right.BadGood
213. The Assembly from Heaven Can be assembled one-handed by a blind personwearing a boxing gloveIs stable and self-aligningTolerances are loose and forgivingFew fastenersFew tools and fixturesParts presented in the right orientationSnap-fit principleParts asymmetric for easy feedingParts easy to grasp and insert(Dr. Peter Will, ISI)
22The Assembly from Hell - iPhone 4 The opposite in each case from the previous slideVSAssembly components of iPhone 4 Number of screws: 52*Number of components : 14*Assembly components of Galaxy S3 Number of screws: 11*Number of components : 8** Number of screws and components are assumed values.
23Assembly Issue of iPhone“The iPhone 5 is the most difficult device thatFoxconn has ever assembled. To make it lightand thin, the design is very complicated,” said anofficial at the company who declined to be named.“It takes time to learn how to make this new device.Practice makes perfect. Our productivity has beenimproving day by day.”- The Wall Street Journal, October 17, 2012
24Assembly of iPhone 4http://www.youtube.com/watch?v Q67gLwbpQao
25Assembly of Galaxy S3http://www.youtube.com/watch?v efXxYbz8DXs
26Design for Assembly-bad designA main assembly for the Epson printer.The No. of parts:49 partsAssembly work:57 timeAssembly time:552 secThe labor costs: 3.83(Ref.: Assembly Engineering. January 1987)
27Design for Assembly-good designA main assembly for IBM printer.The No. of parts: The No. of parts:IBM printerEpson printer32 parts49 partsAssembly work:Assembly work:32 time57 timeAssembly time:Assembly time:170 sec552 secThe labor costs:The labor costs: 1.18 3.83(Ref.: Assembly Engineering. January 1987)
28Straight MovementPin for taking locationSpring clipHole for taking locationBadGood
29Self LocationThe pipe is connectedto flange.One part is connected at the other part using boltStepBadGoodThe cylinder inserts There is the chamferingat the hole.at the edge.The cylinder having step inserts at the hole.
30Design for no-assembly
31Design for no-assemblyWindshield WiperManufactured in one single step,drastically reducing manufacturing costsMicro-compliant compliantmechanism for four-barMicro-compliant compliantmechanism for crimpingAnalog Integrated Circuits and signal processing 29 7 7-15 2001
32Design for no-assembly 4D printingSpeed X4Folding-unfolding process of the prototype of deployable mirror(Wei Wang, IDIM, SNU)Robotic bees take flight(Harvard U.)
33DFA - Modular DesignExisting mode Cockpit moduleExample: Lego –building block
34Modular Design: example Google’s modular smartphonehttp://www.youtube.com/watch?v fEC6myN2mXg
35Modular Design: example Volkswagen modular platformMQB(Modulen Quer Baukasten): Modular Transverse Matrix
36Modular Design: example Volkswagen modular platformMQB(Modulen Quer Baukasten): Modular Transverse Matrix
374. Product specific rules: DFM Air intake manifolds Original : Cast AlRedesigned : moldedthermoplastic compositeExample: GM 3.8 liter V6 engineK T Ulrich & S D Eppinger, Product design and development 2nd edition
38Manufacturing cost
39DFM process5 steps of DFM Process1.Estimate the manufacturing cost2.Reduce the cost of components3.Reduce the cost of assembly4.Reduce the cost of supportingproduction5.Consider the impact of DFMdecision on other factors
40Effect of process change
41Cost of original intake manifold
42Cost comparisonCustom component for the original intakemanifoldAssembly cost estimation For the PCV valve assy.of the redesigned intake manifold
43Redesigned intake manifoldThese were:24.0314.4838.51If they sell 1 million cars, cost saving can be 16.58 million just from the manifold43% reduction of cost
44“Design” applying the DFM principle“Plot”“Design” applying the DFM principle
45DFM vs newparadigmBack panelIncreasing degree of freedomfor design by expansion ofmanufacturing processesReduction of degree of freedom fordesign by limitation ofmanufacturing processesEdge (Glass process)DisplayFlat cellphoneSimple design withconsideration of assemblyProblems Design and manufacturing processesfocused on cost and productivity Limitation of material and its propertyCurved display designCurved displayHigh added-valueHow?Hybrid processes
46Expanding Manufacturing Domain
Design Manufacturing Over-the-wall manufacturing. 6 Definition of DFM Process of proactively designing products to: optimize the manufacturing functions assure the best cost, quality, reliabil
