ESC 100 – Exploring Engineering

Lab 6 – Project Development and Technical Drawing

Thursday, October 17, 2013

Class re-group

• Please hand in: – HW 1 Part 1 (seminar summary) – Milestone 1 writeup

• Agenda for today: – Hand back lab reports and go over a few things – Milestone 1 group presentations

• All groups must upload their talks to the computer before we start!

– Topics for group discussion • Expectations for next week’s lab (detailed handout will be

distributed electronically Friday PM) • Websites for ordering motors and other parts • Isometric drawing/projection

– Group work on projects

Types of Axonometric Projections

Trimetric There are no equal angles between the coordinate axes

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Comparing Axonometric Views

http://www.untoldentertainment.com/blog/img/2009_09_22/axonometric_projections.jpg 4

Isometric Projection – A Closer Look

What is the true angle between the axes? 5

Circles in Isometric Drawings

• Circles cannot be transferred directly to the isometric drawing. As the object is rotated in order to view it as an isometric, holes and cylindrical features also rotate and do not appear as true circles, but as ellipses.

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Isometric Limitations

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Orthographic Projections

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View of Objects: In engineering graphics a view of an object is created by an orthographic projection. In the orthographic projection, rays (or projectors) from all points on the edges or contours of the object extend parallel to each other and perpendicular to the plane of projection.

Normal View

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• Normal Planes will appear as an edge in two views and a true sized plan in the remaining view when using three views such as a top, front and right side.

Inclined Plane Layout

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• Inclined Planes will appear as an edge view in only one of the three views. The inclined plane will appear as a rectangular surface in the other two views.

Oblique Plane

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• Oblique Planes will not appear as an edge view in any of the six views since they are not parallel or perpendicular to the projection planes.

• They always appear as a “plane” and have the same number of corners in each of the six views.

Curved Surfaces

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• A cylinder will appear as a circle in one view and a rectangular shape the other two views.

Isometric Drawing of Object with an Inclined Surface

• The orthographic drawing shown will be drawn as an isometric drawing in the following steps. Note the orientation of the inclined surface and the measurements.

O

O O

A

B

C

D

E

F

G

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Isometric Drawing – Step 1

• Step 1 - Sketching the object as if it were a complete cube without any cuts. The measurements of overall Width (A), Height (B) and Depth (C) are transferred from the orthographic to the isometric by counting grid spaces.

O

Step 1

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Isometric Drawing – Step 2

• Step 2 - The angle of the inclined surface cannot be transferred directly. Locate the corners of the inclined surface and then draw lines to connect the corners.

• Notice that edges that are parallel in the orthographic views will also be parallel in the isometric drawing.

Step 2

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Isometric Drawing – Step 3

• Step 3 - Add the rectangular cut across the left top edge. Notice that the rear edge of the cut disappears behind the raised portion of the block.

Step 3

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Isometric Drawing – Step 4

• Step 4 – Add the slot that is cut into the bottom of the block on the right side. Only one receding axis of the slot will be visible.

Step 4

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Section Views

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Section Views

Section Views