Chapter 2 Sketching� � 1

Chapter 2Sketching2.1� W16x50 Beam

2.2� Triangular Plate

2.3� More Details

2.4� M20x2.5 Threaded Bolt

2.5� Spur Gears

2.6� Microgripper

2.7� Review

Chapter 2 Sketching� Section 2.1 W16x50 Beam� 2

Section 2.1W16x50 Beam

16.2

5"

.628 "

.380"

7.07 "

R.375"

W16x50

[1] Wide-flange I-shape section.

[2] Nominal depth 16 in.

[3] Weight 50 lb/ft.

Problem Description

Chapter 2 Sketching� Section 2.1 W16x50 Beam� 3

• Start up DesignModeler

• Sketching/Modeling modes

• Draw>Rectangle

• Draw>Polyline

• Dimensions>General

• Dimension>Horizontal

• Dimensions>Display

• Dimensions>Move

• Modify>Copy/Paste

• Modify>Trim

• Modify>Fillet

• Constraints>Symmetry

• Auto Constraints

• Constraint Status

• Extrude

Techniques/Concepts

Chapter 2 Sketching� Section 2.1 W16x50 Beam� 4

[2] Click-sweep: continuous selection. [3] Right-click: open

context menu.

[4] Right-click-drag: box zoom.

[5] Scroll-wheel: zoom in/out.

[6] Middle-click-drag: rotate.Shift-middle-click-drag: zoom.

Control-middle-click-drag: pan.

Basic Mouse Operations in Sketching Mode

[1] Click: add/remove a sketching

entity to/from the selection set.

(ESC to deselect all.)

Chapter 2 Sketching� Section 2.2 Triangular Plate� 5

Section 2.2Triangular Plate

40

mm

30 mm

300 mm

[1] The plate has three planes of

symmetry.

[2] Radii of the fillets

are 10 mm.

Problem Description

Chapter 2 Sketching� Section 2.2 Triangular Plate� 6

Techniques/Concepts

• Draw>Arc by Center

• Dimensions> Radius

• Modify>Replicate

• Modify>Offset

• Constraints>Equal Length

• Weak/Strong Dimensions

• Weak/Strong Constraints

• Selection Filter

• Single/Box Selection

Chapter 2 Sketching� Section 2.2 Triangular Plate� 7

2D Graphics Controls

[8] Undo. [9] Redo.

[2] Zoom to Fit.

[4] Box Zoom.[5] Zoom.

[1] Look At.

[6] Previous View.

[7] Next View. [3] Pan.

Chapter 2 Sketching� Section 2.3 More Details� 8

• Pull-down Menus and

Toolbars

• Mode Tabs

• Tree Outline

• Sketching Toolboxes

• Graphics area

• Details View

• Status Bar

• Separators

Section 2.3 More Details

Chapter 2 Sketching� Section 2.3 More Details� 9

[1] Currently active plane.

[2] To create a new plane, click New

Plane.

[4] There are many ways of creating new planes.

Sketching Planes

• A sketch must be created on a

sketching plane; each plane may contain

multiple sketches.

• In the beginning of a DesignModeler

session, three planes are automatically

created: XYPlane, YZPlane, and

ZXPlane.

[3] Active sketch can be switched

using the pull-down list, or by clicking

in Tree Outline.

Chapter 2 Sketching� Section 2.3 More Details� 10

Sketches

• A sketch consists of points and edges; edges may be straight lines or curves.

• Multiple sketches may be created on a plane.

[1] To create a new sketch on the active sketching plane,

click New Sketch.

[2] Currently active sketch.

[3] Active sketching plane can be

switched using the pull-down list, or by

clicking in Tree Outline.

Chapter 2 Sketching� Section 2.3 More Details� 11

Auto Constraints

• C� - The cursor is coincident with a line.

• P� - The cursor is coincident with another point.

• T� - The cursor is a tangent point.

• � � - The cursor is a perpendicular foot.

• H� - The line is horizontal.

• V� - The line is vertical.

• //� - The line is parallel to another line.

• R� - The radius is equal to another radius.You can turn on/off Auto

Constraints.

Chapter 2 Sketching� Section 2.3 More Details� 12

Sketching Toolboxes

Chapter 2 Sketching� Section 2.4 M20x2.5 Threaded Bolt� 13

Section 2.4M20x2.5 Threaded Bolt

Problem Description

M20x2.5

[1] Metric system.

[2] Nominal diameterd = 20 mm.

[3] Pitchp = 2.5 mm.

Chapter 2 Sketching� Section 2.4 M20x2.5 Threaded Bolt� 14

32

11×

p=

27.5

d

1

d

Externalthreads(bolt)

Internalthreads(nut)

H

H4

H8

p

Minor diameter of internal thread d

1

Nominal diameter d

H = ( 3 2)p = 2.165 mm

d1= d � (5 8)H × 2 =17.294 mm

p

Chapter 2 Sketching� Section 2.4 M20x2.5 Threaded Bolt� 15

• Modify>Replicate

• Constraints>Fixed

• Revolve

Techniques/Concepts

Chapter 2 Sketching� Section 2.5 Spur Gears� 16

Section 2.5Spur Gears

Problem Description

• To satisfy the fundamental law

of gearing, the gear profiles

are cut to an involute curve.

Chapter 2 Sketching� Section 2.5 Spur Gears� 17

[7] Common tangent of the pitch circles.

[6] Contact point (pitch

point).

[8] Line of action (common normal of contacting gears). The pressure angle is 20o.

[3] Pitch circlerp = 2.5 in.

[9] Addendumra = 2.75 in.

[10] Dedendumrd = 2.2 in.

[1] The driving gear rotates clockwise.

[2] The driven gear rotates

counter-clockwise.

[4] Pitch circle of the driving

[5] Line of centers.

[12] The fillet has a radius of

0.1 in.

[11] The shaft has a radius of 1.25 in.

Chapter 2 Sketching� Section 2.5 Spur Gears� 18

Techniques/Concepts

• Draw>Construction Point

• Draw>Spline

• Modify>Replicate

• Constraints>Perpendicular

Chapter 2 Sketching� Section 2.6 Microgripper� 19

Section 2.6Microgripper

Problem Description

[2] Actuation direction.

[1] Gripping direction.

[3] SMA actuator.

[4] Glass bead.

Chapter 2 Sketching� Section 2.6 Microgripper� 20

480

144

176

280

400

140

212

77

47

87

20

R25 R45

32

92

D30

Unit: µm

Thickness: 300 µm

Chapter 2 Sketching� Section 2.6 Microgripper� 21

Techniques/Concepts

• Constraints>Equal Radius

• Copy bodies (Mirror)

• Create new sketch

• Constraints>Tangent

• Multiple parts