TECHNICAL-DRAWING

JFM210TECHNICALDRAWINGANDCOMPUTERAPPLICATIONLECTURENOTES(FIRSTPART)Assist.Prof.Dr.G.GülsevUyarAldaş1.INTRODUCTIONWhatistechnicaldrawing?|Itisaformalandprecisewayofcommunicatinginformationabouttheshape,size,featuresandprecisionofphysicalobjects.|Auniversallanguageofengineeringusedinthedesignprocessforsolvingproblems,quicklyandaccuratelyvisualizingobjects,andconductinganalysis.|Agraphicalrepresentationofobjectsandstructures.|Itcanbedonebyusingfreehand,mechanical,orcomputermethodsWhousetechnicaldrawing?SketchingorDrawing|Wewilltreatsketchinganddrawingasone.zSketchinggenerallymeansfreehanddrawing.zDrawingusuallymeansusingdrawinginstruments,fromcompassestocomputerstobringprecisiontothedrawings.ManualdraftingtoolsfortechnicaldrawingMechanicalpencils:0.7and0.5mm,or0.5and0.3mmcombinations;Pencilgrades–HBandH,orFand2Hcombinations)CompassandonedividerOnesetof45-and30/60-degreetrianglesScales(oneEnglishunitandoneMetricunit)Irregularcurve(Frenchcurve)ProtractorOnegooderaserUseofdraftingtools–afewexamplesPencilgrades2.LINES2.1.Generalinformation|Generally,technicaldrawingistheexpressionofbodies(ormatters)bylines.|Piecesarecomposedofvariablegeometriccomponent.Sidesandsurfacesofthesecomponentsarevisiblebutsomeofthemcannotbeseenbecausetheyarebehindthebacksides.|Toobtainfullandpreciseinfoaboutthepiece,drawingshouldbedonebyusingvariablelines(insteadofusingsamelines).Moreover,theselinesshouldbedrawnatsamethicknessandshapebyeveryone.TheshapesandthicknessesoflinesaregiveninTS88.•Samelineshapesandthicknessesareusedinthisdrawing.Thereforeitisverydifficulttohaveanideaoftheshapesanddimensionsofthepiece.AAA-AAA•Thisfigureshowsthesamepiece,whichisdrawnbyusingvariablelinesdifferinshapesandthicknesstoshowvisibleandinvisiblelines,axisanddimensions.Inthisway,onehaveanfullideaofthepiece.2.2-TypeoflinesAccordingtothe“TS88technicaldrawingstandard”publishedat1978,linesareclassifiedas9types:A1-Surroundingsandsidesofthematters.A2-EndofthescrewContinuousline(thick)AApplicationplacesTypeoflinesC1-Tostatetheplacethatlimitsectionandappearanceofmatterortostatetheplacetearedoff.C2-Itisusedwhenfreehandlinesaredrawnbytool.FreehandlinesZigzagline(thin)C1C2B1-BacksidesectionlineB2-Measurelines,guidelinesB3-SimplifiedaxislinesB4-AtdiagonallineswhichareusedtostateplanesurfaceB5-TostatethecodeoftheplacesContinuousline(thin)BApplicationplacesTypeoflinesG-Tostatetheplacewhichwillprocessedadditionally.(tocoat,toharden,etc.)Dashlinewithpoint(thick)GH1-ToshowthesurroundingsofneighborpiecesH2-Tostatethesecondarysituationofmovingpieces.TostatethecenterofgravityDashlinewithtwopoints(thin)HF1-TodrawthetracesatsectionplaneSectionplanewiththickendsandthinmidpoints.FE1-AxislinesofsymmetricaldrawingE2-InfrontofsectionplanesDashlinewithpoint(thin)ED1-Invisiblesurroundingandsidesofthematter.Dashline(thin)*D2.3-Drawingoflinesa-Thicknessoflinesshouldbedrawnaccordingtothestandards.b-Atfreehanddrawing:ContinuousandthicklinesshouldbedrawnbyBor2Bpencil.ContinuousandthinlinesshouldbedrawnbyHor2Hpencil.c-Dashlinesshouldbedrawnatequalspacesandthickness.Theyshouldbe3∼6mm,or0,8~1,5mmaccordingtothesizeofthepicture.3....60,8....1,5D1d-Dashlineswithpointshouldbedrawnaccordingtothesizeofthepicturewithbelowmentionedsizes.E11117....15G111110H11111011f-Intersectedcontinuouslinesshouldnotbeoverflowedoruncompletedattheinterceptpoints.Thicknessesshouldbesameandcornersshouldbesharp.g-Junctionsofcirclearcsandlinesshouldbetangent.h-Minimumspaceoftwoparallellinesshouldnotbelessthantwotimesofthethicklines.2.d2.dd:Thicknessoflines.3-GEOMETRICALDRAWINGSAnymatterisoccurredbygeometricalelementslikepoints,linesandplanes.Belowpictureshowsthistypeofmatter:PlanesurfaceLineArcPointCurvedlineEllipsesurfaceHyperbolesurfaceTangentsHelixSpherecoverCylinderWideangleConeInclinedlineNarrowangleParallellinesInterceptlinesSquareprisma.Point:Itisanon-dimensionalgeometricalelement.Itisoccurredbyinterceptionofvariouslines.Variouslinesb.Line:Itisa1Dgeometricalelementoccurredbymovingofapointinvariousdirection.Thepicturebelowillustrateslines,drawninvariousdirections,andothergeometricalelementsoccurredbytheselines.ParallellinesHorizontallineVerticallineVerticallinesZigzaglineCurvedlineCurvedlineInterceptlinesVerticalangleWideangleNarrowangleTheconnectionofthreepointsatcertainconditionsformtriangle.Theconnectionoffourpointsatcertainconditionsformsquare.Theconnectionofinfinitepointsatcertainconditionsformcircle.c.Plane:Aplaneisoccurredbyatleastthreepointsorconnectionofonepointandoneline.Aplaneisalways2D.Whenthenumberofelementformingaplaneincreases,shapeandnameoftheplanewillchange.TriangleSquareCircleAInfinitepoint4PointBACD3PointBAC3.1.1-Drawingofparallellines3.1-Geometricaldrawingsrelatedwithlinesa.DrawingparallellinetoalinefromanyPpoint(outsidefromtheline):2.AcceptpointCascenter,don’tmovethecompass.DrawanotherarcthatcrosspointPandinterceptABline,obtainpointD.3.OpenthecompassasPDarc.PutthecompasstopointCandinterceptarcb,findpointE.4.ConnectthepointPwithpointE.PABABDCRRrEPrab3.1.1.1-DrawingparallellinewithcompassesI.Way:1.