CUTTING PLANECutting plane is a plane that imaginarily cutsthe object to reveal the internal features.Cuttingplane Cutting plane line Section lines
CUTTING PLANE LINECutting plane line is an edge view of the cutting plane. Indicate the path of cutting plane.
CUTTING PLANE LINESTYLES Thick lineANSI Viewingstandard direction Thick line Viewing directionJIS & ISO Thin linestandard Viewing direction
SECTION LININGSection lines or cross-hatch lines are used toindicate the surfaces that are cut by the cuttingplane. Section lines Drawn with 4H pencil.
SECTION LINES SYMBOLS The section lines are different for each of material’s type. For practical purpose, the cast iron symbol is used most often for any materials.Cast iron, Steel Concrete Sand WoodMalleable iron
SECTION LINING PRACTICE The spaces between lines may vary from 1.5 mm for small sections to 3 mm for large sections. COMMON MISTAKE
SECTION LINING PRACTICE It should not be drawn parallel or perpendicular to contour of the view. COMMON MISTAKE
KIND OF SECTIONS1. Full section2. Offset section3. Half section4. Broken-out section5. Revolved section (aligned section)6. Removed section (detailed section)
FULL SECTION VIEWThe view is made by passing the straight cutting planecompletely through the part.
OFFSET SECTION VIEWThe view is made by passing the bended cutting planecompletely through the part. Do not show the edge views of the cutting plane.
TREATMENT OF HIDDEN LINES Hidden lines are normally omitted from section views.
HALF SECTION VIEWThe view is made by passing the cutting plane halfwaythrough an object and remove a quarter of it.
HALF SECTION VIEW A center line is used to separate the sectioned half from the unsectioned half of the view. Hidden line is omitted in unsection half of the view.
BROKEN-OUT SECTION VIEWThe view is made by passing the cutting plane normal to theviewing direction and removing the portion of an object infront of it.
BROKEN-OUT SECTION VIEWA break line is used to separate thesectioned portion from theunsectioned portion of the view.Break line is a thin continuous line(4H) and is drawn freehand. There is no cutting plane line.
EXAMPLE : Comparison among several section techniques
REVOLVED SECTION VIEW Revolved sections show cross-sectional features of a part. No need for additional orthographic views. This section is especially helpful when a cross-section varies.
REVOLVED SECTION VIEWSteps in constructionGiven Edge view of cross-sectionStep 1a. Assign position of cutting plane.b. Draw axis of rotation in front view.
REVOLVED SECTION VIEWSteps in constructionGivenStep 2a. Transfer the depth dimension to the front view.
REVOLVED SECTION VIEWSteps in constructionGivenStep 3a. Draw the revolved section.b. Add section lines.
REVOLVED SECTION VIEWSteps in constructionGiven FINAL PICTURE
REVOLVED SECTION VIEWPlacement of revolved section 1. Superimposed to orthographic view. 2. Break from orthographic view. Break Superimposed
REMOVED SECTION VIEW 6. Removed section Removed section is revolved section. Section view is shown outside the view. Used where space does not enough for revolved section Can be located elsewhere on a drawing with properly labeled
CONVENTIONAL PRACTICEFor long objects that have to draw in a small scale tofit them on the paper, it is recommended to removeits long portion (which contains no importantinformation) and draw the break lines at the brokenends.
ENGINEERING DESIGNPROCESS RESULT Design a part Sketches of ideas Multiview Create Shape drawings Drawing 1. Size, Location Dimensioning 2. Non-graphic informationManufacture
DEFINITIONDimensioning is the process of specifying part’ s information by using offigures, symbols and notes. This information are such as: 1. Sizes and locations of features 2. Material’s type This course 3. Number required 4. Kind of surface finish 5. Manufacturing process 6. Size and geometric tolerances
DIMENSIONING SYSTEM1. Metric system : ISO and JIS standards This course Examples 32, 32.5, 32.55, 0.5 (not .5) etc.2. Decimal-inch system Examples 0.25 (not .25), 5.375 etc.3. Fractional-inch system 1 , 3 Examples 5 etc. 4 8
EXTENSION LINESLeave a visible gap (≈ 1 mm) from a view and start drawing an extension line.Extend the lines beyond the (last) dimension line 1-2 mm. COMMON MISTAKE Visible gap
EXTENSION LINESDo not break the lines as they cross object lines. COMMON MISTAKE Continuous
DIMENSION LINESDimension lines should not be spaced too closeto each other and to the view. Leave a space at least 2 times of a letter height. 16 34 11 35 Leave a space at least 1 time of a letter height.
DIMENSION FIGURESThe height of figures is suggested to be 2.5~3 mm.Place the numbers at about 1 mm above dimensionline and between extension lines. COMMON MISTAKE 34 11 34 11
DIMENSION FIGURES When there is not enough space for figure or arrows, put it outside either of the extension lines. Not enough space Not enough space for figures for arrows16.25 1 16.25 1 1 or
DIMENSION FIGURES : UNITSThe JIS and ISO standards adopt the unit of Length dimension in millimeters without specifying a unit symbol “mm”. Angular dimension in degree with a symbol “o” place behind the figures (and if necessary minutes and seconds may be used together).
DIMENSION FIGURES : ORIENTATION1. Aligned method The dimension figures are placed so that they are readable from the bottom and right side of the drawing.2. Unidirectional method The dimension figures are placed so that they can be read from the bottom of the drawing. Do not use both system on the same drawing or on the same series of drawing (JIS Z8317)
EXAMPLE : Dimension of length using aligned method. 30 30 30 30
EXAMPLE : Dimension of length using unidirectional method. 30 30 30 30 30 30 30 30
EXAMPLE : Dimension of angle using aligned method. 45o 45o 45o 45o
EXAMPLE : Dimension of angle using unidirectional method. 45o 45o 45o 45o 45o 45o 45o 45o
LOCAL NOTESPlace the notes near to the feature which theyapply, and should be placed outside the view.Always read horizontally. COMMON MISTAKE 10 Drill 10 Drill 10 Drill ≈ 10mm Too far
THE BASIC CONCEPTDimensioning is accomplished by adding size and location informationnecessary to manufacturethe object.This information have to be Clear Complete Facilitate the - manufacturing method - measurement method
EXAMPLE L LDesignedpart L S L STo manufacture this part Swe need to know… 1. Width, depth and S thickness of the part. 2. Diameter and depth of the hole. “S” denotes size dimension. 3. Location of the holes. “L” denotes location dimension.
ANGLETo dimension an angle use circular dimensionline having the center at the vertex of the angle. COMMON MISTAKE
ARCArcs are dimensioned by giving the radius, in theviews in which their true shapes appear.The letter “R” is always lettered before the figuresto emphasize that this dimension is radius of anarc. or
ARC The dimension figure and the arrowhead should be inside the arc, where there is sufficient space.Sufficient space Sufficient space Insufficient space for both. for arrowhead only. for both. Move figure outside Move both figure and arrow outside R 62.5 R 6.5 R 58.5
ARCLeader line must be radial and inclined withan angle between 30 ~ 60 degs to the horizontal. COMMON MISTAKE R62.5 R62.5 R62.5 R62.5 R62.5 R62.5
ARCUse the foreshortened radial dimension line,when arc’ s center locates outside the sheet orinterfere with other views. Method 1 2 Drawing sheet
FILLETS AND ROUNDS Give the radius of a typical fillet only by using a local note. If all fillets and rounds are uniform in size, dimension may be omitted, but it is necessary to add the note “ All fillets and round are Rxx. ” R6.5 R12 NOTE:NOTE: All fillets and round are R6.5All fillets and round are R6.5 unless otherwise specified. Drawing sheet
CURVEThe curve constructed from two or more arcs,requires the dimensions of radii and center’slocation. COMMON MISTAKE Tangent point
CYLINDERSize dimensions are diameter and length. Location dimension must be located from its center lines and should be given in circular view.Measurement method
CYLINDERDiameter should be given in a longitudinal view with the symbol “f ” placedbefore the figures. f 100 f 70
HOLES Size dimensions are diameter and depth. Location dimension must be located from its center lines and should be given in circular view.Measurement method
HOLES : SMALL SIZE Use leader line and local note to specify diameter and hole’s depth in the circular view.1) Through thickness hole f xx f xx Thru. xx Drill. xx Drill, Thru. or or or
HOLES : SMALL SIZE Use leader line and local note to specify diameter and hole’s depth in the circular view.2) Blind hole f xx, yy Deep xx Drill, yy Deep or Hole’s depth
HOLES : LARGE SIZEUse extension and Use diametral Use leader line dimension lines dimension line and note f xx
HOLES COMMON MISTAKE f xx f xxf xx Rxx f xx f xx
CHAMFER Use leader line and note to indicate linear distance and angle of the chamfer. S q SFor a 45o chamfer or CS S S
ROUNDED-END SHAPES Dimensioned according to the manufacturing method used.f 12 Center to Center Distance R12 21 5
ROUNDED-END SHAPESDimensioned according to the manufacturingmethod used. R12 12 21 Center to Center Distance 5
ROUNDED-END SHAPESDimensioned according to the manufacturingmethod used. R12 12 16 21
ROUNDED-END SHAPES Dimensioned according to the manufacturing method used. R1212 27 Tool cutting distance
ROUNDED-END SHAPESDimensioned according to the standard sizes ofanother part to be assembled or manufacturingmethod used. Key (standard part) 25
ROUNDED-END SHAPESDimensioned according to the standard sizes ofanother part to be assembled or manufacturingmethod used. 20