SMAmaterialthatsuccessfully operatesthemechanism, butpulloutforcefluctuatesdependingonhow welltheSMAshapingisperformed. Tolerances needtobeheldtighterwithintheassembly. Ahigherlevelofredundancy canbeachieved withheaterelements directly attached oneachstrip.Also, therewillbefasterresponse timesforinitiation oftherelease ifheaters drivetheSMAratherthanthe entirehousing andassembly. APLhasapplied heaters tosimilartypesofmaterial. Leafsprings maybeincorporated intothedesigntoprovide aresetcapability andalsotoprovide a meansforhavingconsistent reset.Arangeofstripsizesandvarious waysofrestraint ontheplunger will beinvestigated. Thiscouldleadtoamoreoptimum approach, higherrestraint capability, andgreater miniaturization. Lessons Learned Designing anddeveloping mechanisms atthisscalerequires adifferent approach thanwhatmost mechanism designers areaccustomed to.Thereareanumber ofconsiderations thatmustbeaddressed inordertoensure correct, optimal performance ofthesemechanisms. Theseissuesalsoencompass not onlyoperational considerations, butalsoissuesthatindirectly affectamechanism's performance ifnot adequately addressed, suchasfabrication andassembly. Tolerances andWorkin.q withSmallParts Working withpartsthisscaleintrinsically leadstotolerance issues. Asmalldimensional discrepancy ona partcanleadtoasignificant change inmechanism performance. OntheMiniSep-Nut, theinitialparts weremachined withtoogreatoftolerance, preventing thenutsegments fromforming atightnuttothread thescrewinto.Inasecond iteration, thecollarwasmachined-to-fit toachieve aclosefitwiththehousing andnutsegments, providing atightinterface forthescrewthreads. Itisimportant toremember when designing smallcomponents thatsomeofthepartsmayneedsecondary machining toachieve the desired assembled fit.Themechanisms inthistoolkitweredesigned sothatthedimensional variations leadtoaminimal impactonthemechanism's overallperformance. Thesizeofthecomponents created somedifficulties infabrication. Asdiscussed, tighttolerances required onsmalldimensions madethepartsmoreexpensive. Themostdifficult partstomachine were thescrewandnutfortheMicroSep-Nut. Thescrewhada0.80-127 threadwitha0.76-mm shaft.The screwsizeandthreadmadethecomponent veryfragile. Duringthecutting ofthethreads, theshaft deformed. Itwouldhavebeenbeneficial toutilizeaspecialized vendorwithaSwissmillingmachine and experience infabricating miniature components. Miniaturized components areverydifficult tohandle withmanual machining andhandassembly processes. Automated ortooledprocesses areneeded toholdtightertolerances, improve consistency, andsimplify theassembly oftheactualmechanism. Additional attention couldberequired duetopossible changes inmaterial selection, which mightalsointroduce newchallenges inthefabrication of components andassembly ofthemechanism. ShapeMemory Alloy TheuseofShapeMemory Alloy(SMA)creates anumber ofconsiderations thatmustbeexamined as partofthedesignprocess. Additional workwithSMAwillallowforadditional understanding ofthisunique material andconfigurations thatoptimize itsperformance. Itiscriticaltocarefully characterize theperformance oftheSMAelement priortoincorporating itintothe design. Bydoingso,thiswillhelpthedesigner understand thebehavior oftheSMA.Manyofthecustom shapes orformsaresomewhat inconsistent intheirbehavior, anditisimportant tounderstand these effectsandhowtheywillimpacttheoverallmechanism design. Thecontrolstrategies forapplying powerdirectly totheSMAmustbecarefully considered andapplied. It iseasytodamage theSMAelement ifpowerisapplied fortoolong.IftheSMAelement isheatedfortoo long,itcantakeanewset. 299