MAE 1351 - Exam 1 Guide

Engineering

The art of making things works

Roles of Engineering Graphics

1. Communication

2. Record Keeping

3. Analysis

What is engineering?

The profession that applies knowledge of mathematical and natural sciences to develop and utilize materials and forces of nature.

What is the goal of engineering?

To benefit humanity through the economical use of materials and forces of nature.

Design (noun)

An original manifestation of a device or method created for performing one or more useful functions.

Design (verb)

The process of creating a design (noun).

Drawing

A collection of images and other detailed graphical specifications intended to represent physical objects or processes for accurate re-creation.

Project

In engineering, a collection of tasks that must be performed to create, operate, or retire a system or device.

System

A collection of parts, assemblies, structures, and processes that work together to perform one or more prescribed functions.

Descriptive geometry

A two-dimensional graphical construction technique used for geometric analysis of three-dimensional objects.

Instruments

In engineering drawing, mechanical devices used to aid in creating accurate and precise images.

Parts

An object expected to be delivered from a fabricator as a single unit with only its external dimensions and functional requirements specified.

Assembly

A collection of parts and/or subassemblies that have been put together to make a device or structure that performs a specific function.

Engineer (noun)

a person who engages in the art of engineering

Engineer (verb)

To plan and build a device that does not occur naturally within the environment

Fabricate

To make something from existing materials.

2-D Drawings

mathematical modeling or drawing where the appearance of parts, assemblies, or structures are represented by a collection of 2-D geometric shapes

Computer-aided design (CAD)

The process by which computers are used to model and analyze designed products.

Three-dimensional (3-D) modeling

Mathematical modeling where the appearance, volumetric, and inertial properties of parts, assemblies, or structures are created with the assistance of computers and display devices.

Solid modeling

Three-dimensional modeling of parts and assemblies originally developed for mechanical engineering use but presently used in all engineering disciplines.

Images

a collection of printed, displayed, or imagined patterns intended to represent real objects, data, or processes

Model

A mathematical representation of an object or a device from which information about its function, appearance, or physical properties can be extracted.

Visualization

The ability to create and manipulate mental images of devices or processes.

Optimization

Modification of shapes, sizes, and other variables to achieve the best performance based on predefined criteria.

Problem identification

The first stage in the design process where the need for a product or a product modification is clearly defined.

Life cycle

The amount of time a product will be used before it is no longer effective.

Green engineering

The process by which environmental and life cycle considerations are examined from the outset in design.

Weighted decision table

A matrix used to weigh design options to determine the best possible design characteristics.

Mass properties analysis

A computer-generated document that gives the mechanical properties of a 3-D solid model.

Mass Properties Analysis Machines

CNC, SLA, SLS, LOM, FDM, SGC, and inkjet printing techniques.

As-built drawings

The marked-up drawings from a civil engineering project that show any modifications implemented in the field during construction.

Graphical user interface (GUI)

The format of information on the visual display of a computer, giving its user control of the input, output, and editing of the information.

Primary modeling planes

The planes representing the XY-, XZ-, and YZ-planes in a Cartesian coordinate system.

Principal viewing planes

The planes in space on which the top, bottom, front, back, and right and left side views are projected.

Datum planes

The planes used to define the locations of features and entities in the construction of a solid model.

Sketches

Collections of 2-D entities.

Sketching editor

A software tool used to create and edit sketches.

Profile

A planar sketch that is used to create a solid.

Revolved solid

A solid formed when a profile curve is rotated about an axis.

Constraints

Geometric relationships, dimensions, or equations that control the size, shape, and/or orientation of entities in a sketch or solid model.

Geometric constraints

Definitions used to control the shape of a profile sketch through geometric relationships.

Dimensional constraints

Measurements used to control the size or position of entities in a sketch.

Algebraic or Associative constraints

Constraint that define the value of a selected variable as the result of an algebraic expression containing other variables from the solid model.

What are variational techniques?

Modeling techniques that involve algebraic expressions or equations.

What do variational techniques express?

Relationships between a number of variables and constants.

What can be calculated in variational techniques?

Any one variable when all of the others are known.

parametric techniques

Modeling techniques where all driven dimensions in algebraic expressions must be known for the value of the dependent variables to be calculated.

Driven Dimension

A variable connected to an algebraic constraint that can be modified only by user changes to the driving dimensions.

Driving Dimension

A variable used in an algebraic constraint to control the values of another (driven) dimension.

ground constraint

A constraint usually applied to a new sketch to fix the location of the sketch in space.

Regeneration

The process of updating the profile or part to show its new shape after constraints are added or changed.

Protrusion

A feature created by the addition of solid volume to a model.

Cut (noun)

A feature created by the removal of solid volume from a model.

Cut (verb)

To remove the volume of interference between two objects from one of the objects.

Blind extrusion

An extrusion made to a specified length in a selected direction.

sketching plane

A plane where 2-D sketches and profiles can be created.

Extrude to a selected surface

an extrusion where the protrusion or cut begins on the sketching plane, and stops when it intersects a selected surface

Extrude through all

An extrusion that begins on the sketching plane and protrudes or cuts through all portions of the solid model that it encounters.

Extrude to the next surface

An extrusion begins at the profile and the protrusion or cut stops when it intersects the next surface encountered

Double-sided extrusion

A solid formed by the extrusion of a profile in both directions from its sketching plane.

features

distinctive geometric shapes on solid parts; 3-D geometric entities that exist to serve some function

Base feature

The first feature created for a part, usually a protrusion

Chamfer

Angled cut transitions between two intersecting surfaces.

Fillets

Smooth transitions of the internal edge created by two intersecting surfaces and tangent to both intersecting surfaces.

rounds

Smooth radius transitions of external edges created by two intersecting surfaces and tangent to both intersecting surfaces

holes

A cut feature added to a model that will often receive a fastener for system assembly

Shelling

Removing most of the interior volume of a solid model, leaving a relatively thin wall of material that closely conforms to the outer surfaces of the original model.

Ribs

Constant thickness protrusions that extend from the surface of a part and are used to strengthen or stiffen the part.

Webs

Small, thin protrusions that connect two or more thicker regions on a part.

Boss

A slightly raised circular area, usually used to provide a small, flat, clean surface.

Draft

A slight angle in the otherwise straight walls of a part, usually used to facilitate its removal from a mold.

Groove

A long, shallow cut or annulus.

Island

An elongated or irregularly shaped raised area, usually used to provide a flat, clean surface.

Keyseat

An axially oriented slot of finite length on the outside of a shaft.

Keyway

An axially oriented slot that extends the entire length of a hole.

Slot

A straight, long cut with deep vertical walls.

Spot face

A shallow circular depression that has been cut, usually used to provide a small, flat, clean surface.

Taper

A slight angle in the otherwise cylindrical walls of a part, usually used to facilitate its insertion or removal into another part.

Cosmetic features

Features that modify the appearance of the surface but do not alter the size or shape of the object.

Datum geometries

Geometric entities such as points, axes, and planes that do not actually exist on real parts, but are used to help locate and define other features.

Feature array or pattern

A method for making additional features by placing copies of a master feature on the model at a specified equal spacing.

Master feature

A feature or collection of features that is to be copied for placement at other locations in a model.

Mirrored feature

A feature that is created as a mirror image of a master feature.

Blend

A solid formed by a smooth transition between two or more profiles.

Swept feature

A solid that is bound by the surfaces swept out in space as a profile is pulled along a path.

Path or Trajectory

The specified curve on which a profile is placed to create a swept solid.

Fixture

A mechanical device, such as clamps or brackets, used for holding a workpiece in place while it is being modified.

Tool bit

A fixed or moving replaceable cutting implement with one or more sharpened edges used to remove material from a part.

Workpiece

A common name for a part while it is still in the fabrication process, that is, before it is a finished part.

Standard commercial shape

A common shape for raw material as would be delivered from a material manufacturer.

Sawing

A cutting process that uses a multi-toothed blade that moves rapidly across and then through the part.

Turning

A process for making axially symmetric parts or features by rotating the part on a spindle and applying a cutting to the part.

Lathe

A machine used to make axially symmetric parts or features using a material removal process known as turning.

Boring

The general process of making a hole in a part by plunging a rotating tool bit into a part, moving a rotating part into a stationary tool bit, or moving a part into a rotating tool bit.

Drilling

A process of making a hole by plunging a rotating tool bit into a part.

Drill bit

A long, rotating cutting tool with a sharpened tip used to make holes.

Drill press

A machine that holds, spins, and plunges a rotating tool bit into a part to make holes.

Blind hole

A hole that does not pass completely through a part.

Tapped hole

A hole that has screw threads inside it.

Tap

The machine tool used to form an interior thread.