Senior Design - Surgical Drill Shaft

MultiMulti--Angular Drill ShaftAngular Drill ShaftTuesday, May 31, 2005Tuesday, May 31, 2005

Chester BennettChester BennettJoslynJoslyn BradleyBradley

Scott RussellScott RussellRyan SchlotterbackRyan Schlotterback

Mark Mark SvendsenSvendsen

Tuesday, May 31, 2005Tuesday, May 31, 2005 Zimmer/IUPUI Zimmer/IUPUI 22

Project BackgroundProject Background

Purdue Mechanical Engineering program Purdue Mechanical Engineering program recently rated 7th best Mechanical recently rated 7th best Mechanical Engineering program in the nationEngineering program in the nation

Zimmer Holdings, Inc. the largest Zimmer Holdings, Inc. the largest orthopedic engineering company, based orthopedic engineering company, based out of Warsaw, INout of Warsaw, IN


Product DescriptionProduct DescriptionZimmer to redesign a Zimmer to redesign a flexible drill shaftflexible drill shaftCurrent shaft does not Current shaft does not meet customer meet customer requirementsrequirementsSurgeons use drill shaft in Surgeons use drill shaft in MIS to drill pilot holes for MIS to drill pilot holes for replacement hip socketsreplacement hip socketsIncisions is small, so drill Incisions is small, so drill shaft flexes to reach pilot shaft flexes to reach pilot holesholes


Surgical UseSurgical Use


Zimmer RequirementsZimmer RequirementsSurgical approved materialSurgical approved materialCleanable or Single Use (Preferred)Cleanable or Single Use (Preferred)Wide angle of orientation Wide angle of orientation -- 9090°° minimumminimumNonNon--locking angle orientationlocking angle orientationDurable Durable –– Higher torsional strengthHigher torsional strengthOperates in forward and reverseOperates in forward and reverseZimmer connectionsZimmer connectionsInstrument dimensionsInstrument dimensionsPrints Prints


Engineering SpecificationsEngineering SpecificationsNonNon--negotiablesnegotiables

Surgically approved Surgically approved materialmaterialCleanable Cleanable –– for multiple for multiple use deviceuse deviceOperate in forward and Operate in forward and reversereverseZimmer ConnectionsZimmer Connections

Angle Orientation Angle Orientation 9090°° minimumminimum

Stiffness Stiffness Deflection Deflection -- 0.150 inches0.150 inches

DurabilityDurability3 N*m or 26.6 in*lbs3 N*m or 26.6 in*lbs

Product LifeProduct LifeOne time useOne time useCost less than $50Cost less than $50


Concept GenerationConcept Generation

Braided SS Shaft Braided SS Shaft with a Teflon Corewith a Teflon Core

Polymer ShaftPolymer Shaft

NitinolNitinol ShaftShaft


Design Validation Design Validation -- TorqueTorqueExperimental AnalysisExperimental Analysis

Torque Results Torque Results Reached 26.6 Reached 26.6 inin··lbflbf of torqueof torqueMet the target value for torqueMet the target value for torqueExceeded current Zimmer requirement of 25 Exceeded current Zimmer requirement of 25 inin··lbflbf


Zimmer Flexibility Testing SetupZimmer Flexibility Testing Setup

Vertical supports Vertical supports must be 1.5 inches must be 1.5 inches apartapart

A load of 47 A load of 47 lbflbf is is applied to the shaftapplied to the shaft

Shaft must deflect at Shaft must deflect at least 0.15 inchesleast 0.15 inches


Design Validation Design Validation -- FlexibilityFlexibility

Flexibility ResultsFlexibility ResultsA load of 11 A load of 11 lbflbf was was applied.applied.The shaft deflected The shaft deflected 0.40 inches.0.40 inches.Exceeded flexibility Exceeded flexibility requirement of 0.15 requirement of 0.15 inches considerably.inches considerably.


Cost of braided stainless steel shaft: ~$4Cost of braided stainless steel shaft: ~$4Cost of Zimmer end pieces, currently: Cost of Zimmer end pieces, currently: $50/end piece.$50/end piece.

Recommendation: reduce cost by utilizing 304 Recommendation: reduce cost by utilizing 304 stainless steel materialstainless steel material

Cost AnalysisCost Analysis


Cost AnalysisCost Analysis

One time use deviceOne time use deviceBelow $50Below $50


Final Design SpecsFinal Design Specs

Length Length –– 2.75 inches2.75 inchesDiameter Diameter -- 0.250 inches0.250 inchesAssembly Assembly –– ØØ 0.096 0.096 SS Roll PinsSS Roll PinsOne time useOne time useCost Cost -- ~$37~$37


Final Design PerformanceFinal Design PerformanceAll the critical design parameters were met by

the newly designed drill shaft

Significant achievements of the braided wire shaftFlexibility requirement Torque requirementForward and reverse operationDisposable device


Impact of DesignImpact of Design

SafetySafetySurgically approved materialsSurgically approved materialsContamination risks reducedContamination risks reduced

EnvironmentalEnvironmentalNo hazardous materialsNo hazardous materialsRecycle componentsRecycle components

SocietySocietyImproves surgical operationsImproves surgical operations


Zimmer InvolvementZimmer Involvement

Platform for successPlatform for successProvided tools and resourcesProvided tools and resourcesProvided industry contactsProvided industry contacts

Contacts provided customer requirementsContacts provided customer requirementsProduct meets customer requirements where Product meets customer requirements where others do notothers do not


Purdue InvolvementPurdue Involvement

Provided understanding of engineering Provided understanding of engineering principlesprinciplesProcess of design provided clear goal: Process of design provided clear goal: meet customer requirementsmeet customer requirementsProcess of design provided steps to meet Process of design provided steps to meet customer requirementscustomer requirementsSuccess proves our educationSuccess proves our education

Technology

Senior Design - Surgical Drill Shaft