Learning Objectives List and recognize by name; symbol; and ANSI number these materials: - Cast Iron - Aluminum - Brass, Bronze, - Steel - Zinc or Copper Identify a drawing as being a: - Full Section - Offset Section - Revolved Section - Half Section - Broken-Out Section - Removed Section Given an orthographic view; draw section views: - In Pencil or - In AutoCAD Use revolutions and partial views (as conventional practices) to construct sectional views of an object. List the parts of a drawing which do not get crosshatched, even if the cutting plane passes through them. Sketch a cutting plane for any of the sections listed above
R eadiness A ssessment T est 9.2.1 Individually answer the following questions. You will be given 2 minutes:
R eadiness A ssessment T est 9.2.1 Individually answer the following questions. You will be given 2 minutes: List 4 types of sectional views.
Team Discussion Item As a team, discussing the following question: What is the purpose of sectional views?
Purpose of Sections Show internal detail Replace complex orthographic views Describe materials in an assembly Depict assembly of parts
Sectioning Practices Different parts at different angles Hatch spacing of about 1/16”-1/8” Cutting plane line.020” wide (bold) Section or hatch lines -- thin.007” Visible lines -- wide.015” Not parallel or perpendicular to boundary
When sectioning an assembly of several parts, draw section lines at varying angles to distinguish separate parts. Sectioning Practices
Most common ANSI Material Patterns ANSI 31 -- Cast Iron, General ANSI 32 -- Steel ANSI 33 -- Brass, Bronze, Copper ANSI 38 -- Magnesium, Aluminum Earth ANSI No. Name Pattern
What is ANSI?.
Available Hatch Patterns in AutoCAD
Cutting Plane The sight arrows at the end of the cutting plane are always perpendicular to the cutting plane. Line thickness of the cutting plane is the same as the visible object line. The direction of the arrow indicates the line of sight. CUTTING PLANE LINE
Types of Sections……..Fig #: Broken-out section……………6.3 Conventional breaks………….6.4 Full section……………………..6.5 Half section……………………..6.8 Revolved section……………..6.10 Removed section……………..6.11 Offset section………………....6.12 (See Essentials of Engineering Design Graphics by Vinson for figure references)
Full Section Cutting plane passes through entire object Hidden lines are omitted Visible lines “behind” the cutting plane must be shown
Individual Exercise (7 min) ● Sketch a full section of the object shown below
Individual Exercise (7 min) ● Were you correct ? ● What material (hatch pattern) did you use?
A quarter of assembly removed Half of view is cross-hatched Half section: ALL hidden lines may be omitted Center line divides halves Center line remains only if associated feature is sectioned CUTTING PLANE LINE
Bend the cutting plane to show more features Offset section: CUTTING PLANE LINE
Sectional view does not denote location of offset Offset section: CUTTING PLANE LINE
Show cross- sections by rotating sections 90 o The section view stays on the object. Revolved section:
Removed section: Removed sections are offset from the object.
Broken out section: Used to section a small portion of the object Does not modify the rest of the view
Conventional Practices Conventional practices are accepted drawing techniques that violate the rules of orthographic projection They are designed to simplify orthographic drawing of complex features.
Aligned Parts: ArmsLugs
Aligned Parts: Single Arm Ribs & Holes
Parts Not Sectioned. Don’t crosshatch (even though the cutting plane may pass thru them): –Ribs, webs, spokes –Thin parts like gaskets –Ball bearings, roller bearings –Most vendor items: Bolts Washers Shafts Nuts Screws Pins
Partial Views Use partial views to conserve space Which half depends on whether you section the view or not.
Conventional breaks: …….For extremely large parts
Crosshatching in AutoCAD AutoCAD can apply a given pattern to fill an area The area must be a closed area To fill the area use the BHATCH command.
Pair Homework Assignment Drawings (in AutoCAD): –28all –29 all –32a, b, c –34all Due: Beginning of class 10.2