不同类型的绘图系统总结.pptx

BRANCH:TEXTILETECHNOLOGY(sem:4th)

SUBJECT:YARNMANUFACTURING-IIGROUPNO:

1

PREPAREDBY:CHIRAGBANSAL(160420129003)CHAUDHARYVIKESH(160420129002)CHANDARANASMIT(150420129002)GUIDEDBY:PROF.SUDHIRYARDI

WHATISDRAFTING:Draftingisthecreationofadrawingorothergraphicalrepresentationofabuilding,mechanicaldeviceorotherstructureforthepurposesofdetermininghowthedeviceshouldbecreated.Draftingisusedasapartofthedesignandfabricationprocesses.Draftingcanbedonebyhandorusingspeciallydesignedcomputerprogramsandmechanicaldrawings.Draftingarrangementisthemostimportantpartofthemachine.ItinfluencesmainlyevennessandstrengthThefollowingpointsarethereforeveryimportant

ELEMENTSOFADRAFTINGSYSTEM:3/3DoubleApronDraftingSystem

DIFFERENTTYPESOFDRAFTINGSYSTEMS

1)3-OVER-3DOUBLEAPRONDRAFTINGSYSTEM:?Inproductionofaroving,a3-over-3rollerwithdoubleaprondraftingsystemiscommonlyusedtoattenuatethesliver.?Inasystemofthreepairsofrollers,therearetwodraftingzones.Thefirstorbackzoneisdesignatedthe“breakdraft,”whilethesecondorfrontzoneiscalledthe“maindraft”.?Apairofendlessapronsispositionedinthehigh-draftfrontzoneandmadetomoveatthesurfacespeedofthemiddle-rollerpair.?As?bersenterthehigh-draftfrontzone,theapronswillholdthemandassistinkeepingthemmovingatthesurfacespeedofthemiddlerollers,whilepreventingtheshort-?bersbeingdraggedforwardbythose?bersnippedandacceleratedbythefrontrollers.

Themagnitudeofbreakdraftisusuallysmall,varyingbetween1.1and1.5;thereforethe?frontdraft(i.e.maindraft)?isresponsibleforthemajorpartofthetotalattenuationdesired.?Thetotaldraftisdefinedastheratioofthesurfacespeedofthefrontrollstothesurfacespeedofthebackrollsandisaproductofthebreakdraftandthemaindraft:

2)4-OVER-4DOUBLEAPRON