16.810: Team M4Final SpecificationsFinal SpecificationsDesign RationaleManufacturingAssemblyCost EstimateFuture WorkFinal ConclusionsLessons LearnedLessons Learned16.810: Team M416.810: Team M4Optimizing Roller AssemblyOptimizing Roller AssemblyIAP 2007IAP 2007Ryan McLinkoRyan McLinkoCarolyn OCarolyn O’’BrienBrien• Roller assembly moves climber up ribbon• Rollers, plates, and sidebars all have extra mass• Purpose– Less power needed to climb– Increased scoreMotivationMotivation• Minimize climber weight• Minimize climber cost• Minimize time to attach climber to ribbon– Must be < 4 min• Maintain von Mises Factor of Safety > 2RequirementsRequirements• Climber must survive a 2 m drop test• Climber must lift own weight• Average speed > 2 m/s• Material unaffected by 5.8 GHz microwaves• Climber unaffected by water• Climber must resist 11.5 mph windsConstraintsConstraintsInitial SketchInitial Sketch• Initial design was given• Holes placed in strategic locations• Refined with FEA softwareDesign ChoiceDesign ChoiceCAD Model: Side PlateCAD Model: Side PlateCAD Model: Side BarCAD Model: Side BarCAD Model: Drive RollerCAD Model: Drive RollerCAD Model: Guide RollerCAD Model: Guide RollerFEA Analysis: Side Plate LeftFEA Analysis: Side Plate LeftForcesForcesFOSFOSDisplacementDisplacementmin: 20min: 20max: 5.8emax: 5.8e--5m5mFEA Analysis: Side Plate RightFEA Analysis: Side Plate RightForcesForcesFOSFOSDisplacementDisplacementmin: 17min: 17max: 6.1emax: 6.1e--5m5mFEA Analysis: Side BarFEA Analysis: Side BarForcesForcesFOSFOSDisplacementDisplacementmin: 2.2min: 2.2max: 9.8emax: 9.8e--4m4mFEA Analysis: Side Bar BelayFEA Analysis: Side Bar BelayForcesForcesFOSFOSDisplacementDisplacementmin: 2.3min: 2.3max: 1.5emax: 1.5e--3m3mFEA Analysis: Drive RollerFEA Analysis: Drive RollerForcesForcesFOSFOSDisplacementDisplacementmin: 2.1min: 2.1max: 4.9emax: 4.9e--4m4mFEA Analysis: Guide RollerFEA Analysis: Guide RollerForcesForcesFOSFOSDisplacementDisplacementmin: 2.1min: 2.1max: 5.7emax: 5.7e--4m4mMachined Part: Belay Side Machined Part: Belay Side BarBarMachined Part: Side PlateMachined Part: Side PlateFinal SpecificationsFinal SpecificationsRequirementsMinimize WeightResultsSide Bar Cross (x10)0.124 lbs0.051 lbsSide Bar Belay (x2)0.121 lbs0.055 lbsSide Plate Left (x2)0.89 lbs0.70 lbsSide Plate Right (x2)0.96 lbs0.65 lbsDrive Roller (x4)1.32 lbs0.63 lbsGuide Roller (x2)0.91 lbs0.47 lbsTotal33.7 lbsDifference:.073 lbs.066 lbs.19 lbs.31 lbs.69 lbs.44 lbs5.5 lbsFinal SpecificationsFinal SpecificationsRequirementKeep Cost LowClamp TimeFOS>2ResultCost to team: $100Kept clamp simpleFOS: Belay Side Bar-2.3Side Bar-2.2Roller-2.1Side plate (left)-20Side plate (right)-17Design RationaleDesign RationaleFocusMinimize weight in order to aid in speeding up the climberCost was less important, but didn’t use strange materialsWanted something simple and effectiveManufacturingManufacturing• Side Bars and Belay Side Bars– Water jetted out of ½’’ polycarb– Milled holes for screws• Side plates– Water jetted– Milled holes for axles and screws• Rollers– Cut on bandsaw– Lathed– Drill pressed holes for screwsAssemblyAssembly• Side Bars and Belay Side Bars– Screwed into the slots on the side plates– Belay hook will be added to the central two holes– Side bars will be mounted to the motor• Side plates– Attached to the motor, side bars, rollers, and clamps by screws or simply pressed together• Roller– Attached by screws and an axle to the side platesCost EstimateCost EstimateSection Rate Qty Total CostI. Design and EngineeringLabor Rate for Each Designer $75/hour 5 375Labor Rate for Each Cad/Cam Machine $40/hour 4 160II. Materials CostPolycarbonate Sheet $19.47/sqft 3 58.41Polycarbonate Rod $62.50/ft 2 125III. Waterjet ManufacturingLabor Rate $55/hour 1 55Machine Use Rate $100/hour 1 100IV. Other MachiningLabor Rate $35/hour 4 140V. Assembly RateAssembly Work Labor Rate $55/hour 2 110Miscellaneous Test Rate $55/hour 4 220Hours CostTotal 21 1343.41Future WorkFuture Work• Not everything could be completed during IAP– Work will continue after the class ends• The side plates will be finished• Rollers will be hollowed out• Side bars will be created• After all this occurs, the new pieces will be put together and tested as a new recursion of the climberFinal ConclusionsFinal Conclusions• The weight drop is significant• Will alter the performance of the climber for the better• Cut large pieces out of the materials while maintaining a good FOS• Further iterations of this process will be necessary to achieve the ideal parts– Continued shaving off of material may occur– Many of the pieces achieved a radical new design• Sign of the evolution of a projectLessons LearnedLessons Learned• Do not trust random other students regarding the operation of machinery• If it can go wrong, it will—over and over again.• The iterative process is effective and can be repeated infinitely– There’s always something better out there• -Double checking position of hole before optimizingLessons LearnedLessons Learned• Peel the plastic off before water jetting• When doing large water jet parts, pause water jet periodically to make sure the piece hasn't shifted• Standard truss ribs are very inefficient for side bars, ribs connecting forces make much more