Design Guides for Plastics

April2009DesignGuidesforPlasticsCliveMaier,EconologyLtdTANGRAMTECHNOLOGYThispublicationismadeupofaseriesofarticlespublishedinPlasticsandRubberWeeklyasapiecework.ThekindassistanceoftheauthorandPRWisacknowledgedinthepublicationofthework.ThepublicationwillbeupdatedinaregularbasisasnewsectionsoftheguidearepublishedbyPRW.Thedesignhintsinthisbookletaregiveningoodfaithandrepresentcurrentgoodpractice.Theshortnatureofthehintsmeansthatnotallinformationcanbeincluded.Noresponsibilitycanbetakenforanyerrorsorconsequentialdamagesresultingfromusingthesehints.Thispublicationmaybefreelyreproducedexceptforsaleoradvertisingpurposes.Itmaybehostedonwebsitesforfreedownloadingprovidingthatitisusedinit’sentiretyandthatreferenceismadetotheoriginalpublication.©CliveMaier2004TypesetbyTangramTechnologyLtd.ContentsPreface...........................................................................................1Introduction...................................................................................2Injectionmoulding.........................................................................4Basics1.Wallthickness..........................................................................................52.Corners......................................................................................................63.Ribs...........................................................................................................74.Bosses....................................................................................................105.Designforrecycling..............................................................................13Specialfeatures6.Livinghinge...........................................................................................187.Bearings.................................................................................................208.Gears.......................................................................................................23Assembly9.Pressfits.................................................................................................2810.Snap-fits.................................................................................................2911.Hotairstaking........................................................................................3312.Ultrasonicwelding..................................................................................3813.Hotplatewelding....................................................................................4014.Spinwelding...........................................................................................4115.Frictionwelding......................................................................................4216.Inductionwelding...................................................................................4317.Laserwelding..........................................................................................4418.Adhesiveandsolventbonding..............................................................45Specialtechniques19.Designforoutsertmoulding.................................................................5020.Designforgasassistinjectionmoulding..................................PlannedExtrusion..........................................................................................21.Designforprofileextrusion........................................................PlannedBlowmoulding.................................................................................22.Designforextrusionblowmoulding..........................................PlannedThermoforming................................................................................23.Designforthermoforming...........................................................PlannedDesigninformation24.Designinformationsources...................................................................63April2009April20091PrefaceThissetofhintsandtipsforplasticsproductdesignersisintendedasasourcebookandan'aidemémoire'forgooddesignideasandpractices.Itisasourcebookforplasticsproductdesignersatalllevelsbutitisprimarilyaimedat:•studentdesignerscarryingoutdesignworkforalllevelsofacademicstudies;•non-plasticsspecialistsinvolvedinthedesignofplasticsproducts;•plasticsspecialistswhoneedtoexplaintheirdesigndecisionsandthedesignlimitationstonon-plasticsspecialists.Thebookcoverseachtopicinasinglepagetoprovideabasicreferencetoeachtopic.Thisspaceconstraintmeansthateachtopicisonlycoveredtoabasiclevel.Detailedplasticproductdesignwillalwaysrequiredetailedknowledgeoftheapplication,theprocessingmethodandtheselectedplastic.Thisinformationcanonlybeprovidedbyrawmaterialssuppliers,specialistplasticsproductdesignersandplasticsprocessorsbutthereisaneedtogetthebasicsoftheproductdesignrightinthefirstinstance.Usingthehintsandtipsprovidedinthisguidewillenabledesignerstoreduceinitialerrorsandwillleadtobetterandmoreeconomicdesignwithplastics.Ihopethisshortworkwillimprovethebasicdesignofplasticsproductsandifitcandothisthenitwillhav