MET 101 - FINAL EXAM MULTIPLE CHOICE

What is Technical Drawing?

Accurate Representation

What is Engineering Drawing?

• Technical w/ specific tools

• Language to communicate w/ other engineers (there r standards)

CAD stands for?

• Computer Aided Design

• How can I use a computer w/ design?

CAE stands for?

• Computer Aided Engineering

• How can I use computers to help me w/ Engineering?

CAE is ________ field that CAD

BIGGER

Benefits of CAD?

• Reduce Design Time

• Produce Prototype Faster

• Better Design

What are the Design Stages?

• 1. Conceptual Design Stage

• 2. Design Development Stage

• 3. Refine & Finalize Design Stage

2 Types of Drawings (Final)?

• Freehand Sketches

• Detailed Engineering Drawings

What are Freehand Sketches?

• ability to think visually, specifically 3D visualizations (used during beginning stages of design process)

• One of most essential skills for engineer/designer

• Most powerful method to help develop visualization skills

What does CSG stand for?

Constructive Solid Geometry

What does CSG use?

• Primitive Solids (sphere/triangle/etc.)

• Boolean Operations

What are the Boolean Operations?

• Join/Union (Adding)

• Cut (Subtracting

• Intersection (Volume): Keep volume from 2 primitive solids / something that overlaps

What is Feature-Base Modeling?

• Every feature used starts w/ a parameter

• Parameter → made out of dimensions

• Ex. of features: Extrude

What is Feature Suppression?

• method that enables us to disable a feature while retaining complete feature info

•  feature can be reactivated any time (NOT DELETE)

What is Associative functionality?

allows us to change the design at any lvl. & system reflects it at all lvls automatically

What is Browser Tree/Window (History Tree/Model Tree)?

sequential record of construction steps (Start w/ biggest feature (shape))

Any flat surfaces can be a…?

Sketching Plane

Rules to fully def. a sketch:

• Fully Constraints & Dimensions

• All lines MUST have dimensions (must be added/constraints)

• Closed profiles/No open loops

• No Self-intersecting lines / Nothing overlapping

When editing use…?

 Constraints > (over) Dimensions

Driven Dimensions are?

• Reference

• Additional Dimensions

• DO NOT constrain sketch → only reflect values of dimensioned geometry

• Dimensions just there to show values

• Grayed out in ()

How many degrees of Freedom In TOTAL?

6

What are the degrees of Freedom (In the Space)

• 3 Transitional (X,Y,Z)

• 3 Rotational (X,Y,Z)

What is Pictorial?

• Show 2D image of object

• If I can’t physically move object

What are Orthographic Projections also considered to be?

Pictorial b/c 2D image

Orthographic Projections are…?

• Lines are II to each other & perp. to plane

Multi-view Orthographic Projection?

• Projection lines r II to each other & perp. to image (projection screen)

Orthographic is?

• upright which is perp. to projection screen

Plane (angle) uses which angle technique?

3rd-Angle Technique Projection (USED MORE-NATIONWIDE)

What are the different Plan (angle) views:

• Top (Top right quadrant)

• Front (Bottom left quadrant)

• Right (Bottom right quadrant)

What are the 3 Diff. Types of Pictorials?

• 1. Axonometric (measure along axes) 

• 2. Oblique 

• 3. Perspective (Still Pictorial)

What is the Axonometric (Pictorial)?

• FACE of image NOT II to plane

• Isometric

• 3 = angles

• Angles MUST add up to 360 deg.

• Each angle. = 120 deg.

• measure along axes

What is the Oblique (Pictorial)?

• Lines of sight NOT perp. to plane

• Lines of SIDE II to each other & II to plane

What is the Perspective (Pictorial)?

• Lines of Sight perp. to plane

• Lines of Sight NOT II to each other

• Adds realism to 3D pictorial

• Lines of side NOT II to each other

What are Vanishing Pts?

•  II edges/Lines of Sight converge to single pt.

1-pt observer has how many vanishing pts?

1 vanishing pt

2-pt observer has how many vanishing pts?

2 vanishing pts

3-pt observer has how many vanishing pts?

3 vanishing pts

Precedence of Lines (ORDER OF IMPORTANCE)?

• 1. Visible Object Lines (Objective Line)

• 2. Hidden Lines (Hidden Features)

• 3. Center Line/Cutting Plane Lines (Symmetrical)

• 4. Break Line

• 5. Dimension & Extension Lines

• 6. Gross Hatch / Section Lines

Every line represents intersection of…?

2 planes

What do Center Lines show?

• Symmetry of shape & freq. Eliminate need for positioning dimensions

What is included in the Title Block?

• Name of Company

• Location

• Name of Part represented

• Signature of person who make drawing & date

• Signature of checker & date of completion

• Signature of person who approved & date of approval

• Scale of drawing

• Drawing #

Drawing Size (American National Standard), Give me from smallest to largest?

A → E

What is Paper Space?

•  2D sheet of paper (create orthographic projection)

What is Model Space?

• Creating 3D Model

What are the 2 methods of positioning dimensions texts on dimension lines?

• Aligned system

• Unidirectional system

What is the Aligned System?

• Read from Bottom/Right

• A method of positioning dimension texts on dimension lines

What is Unidirectional System?

• Read from Bottom

• EASIER

• A method of positioning dimension texts on dimension lines

How should General Notes be Placed?

Horizontally

What are the General Dimensioning Rules?

• 1. Always Dimension features, NOT individual geometric entity

• 2. Choose view that best describes

• 3. Proximity Rule: Place Dimensions next to features being described

• 4. If possible place dimensions OUTSIDE view

• 5. Common Dimensions to 2

• 6. Center lines may be used as extension lines, there should be NO GAP between extension line & center line

• 7. Dimensions should be applied to 1 view ONLY. When dimensions are placed between views, ext. Lines should be drawn from 1 view NOT Both

• 8. Dimensions placed on view that shows measurement in its TRUE LENGTH

• 9. Always place shorter dimension lines inside longer ones, avoid crossing dimension lines w/ ext. Lines (no intersecting lines)

When is Baseline Dimensioning used?

• when location of feature must be controlled from common ref. point/plane

Tolerance Accumulation is _____________ w/ baseline dimensioning

NOT GOOD

When is Chain Dimensioning Used?

• when toleranced btwn adj. feature overall important than tolerance

What is Tolerance related to …?

Measurements → Limits

What is Tolerance?

• Allowable variation for any given size & provide practical means to achieve precision

• Impossible to produce any dimension to abs/accurate measurements

What happens to Tolerance when Precision is SMALL?

Decreases

What happens to Tolerance when Precision DOESN’T MATTER?

Increase

W/ Tolerance, each dimension allowed to…?

vary w/ specific zone

What is the standard tolerance?

± 0.01 (per measurement)

What is General Tolerance?

• Everywhere has the same tolerance

• Covered in Title Block

What is Bilateral?

• Variation of size is in BOTH direct.

• can be = variations / NOT = variations

• (+/-) expression

What is Unilateral?

• Variation of size ONLY 1 direction 

• Use basic size

• +/- expressions (allows variation in both +/-)

• If every dimension has diff. Tolerance added it to specific

What does ANSI stand for?

• American National Standard Institute

What does ASME stand for?

 American Society of Mechanical Engineers

What is Nominal size?

• Designed used for the purpose of gen. identification  (ex. 4in pipe)

What is Basic size/dimensions:

• Theoretical Size from which limits of size r derived

• Size from which limits r for size/location of a feature in a design

• Ex. 3.5 +/- .12 (Basic)

What is Actual Size?

• Measured size of manufactured part

• Including tolerance

• Ex. 3.44 (Actual = End Result)

What is Allowance?

• Min clearance space / Max interference

What is Maximum Material Condition (MMC)?

• Size of part when it consists of MOST material

• MORE material → Makes part HEAVIER

• Ex. Hole smaller (MMC) = MORE MATERIAL

What is the Least Material Condition (LMC)?

• Size of part when it consists of LEAST material

• LESS material → Makes part LIGHTER

• Ex. Hole bigger (LMC) = LESS MATERIAL

What are the different Fit Types?

• Clearance Fit

• Interference Fit

What is Clearance Fit?

• Internal Part < External Part

• Leaves Space

What is Interference Fit?

• Shaft Diameter > than hole

• Internal Part > External Part

• Interference/Overlapping Btwn Parts

What is Basic Hole System (BHS)?

• Start w/ MIN size of hole (basic size) 

• All size lim (hole & shaft) r derived from basic size

What is Basic Shaft System (BSS)?

• Start w/ MAX size of hole (basic size)

• All size lim (hole & shaft) r derived from basic size

What are the ANSI-5 Standard Fits (American National Standard lim & Fits/Inches)?

• RC (Running/Sliding Clearance Fits) (RC1 - RC9)

• LC (Locational Clearance Fits) (LC1 - LC11)

• LT (Transition Clearance Interference Fits) (LT1 - LT6)

• LN (Locational Interference Fits) (LN1 - LN3)

• LN (Locational Interference Fits) (LN1 - LN3)

• FN (Force/Shrink Fits) (FN1 - FN5)

What is RC (Running/Sliding Clearance Fits) (RC1 - RC9) ?

• Complete Clearance

• Continues movement

What is LC (Locational Clearance Fits) (LC1 - LC11)?

• Complete Clearance

• Specific location = stationary

• Can allow SOME movement

What is LT (Transition Clearance Interference Fits) (LT1 - LT6)?

Both above → either or of (RC or LC)

What is LN (Locational Interference Fits) (LN1 - LN3)?

• Interference

What is FN (Force/Shrink Fits)(FN1 - FN5)?

• Interference 

• Shaft = Interference

• Can NOT move it

How to calculate Shaft Tolerance?

(Maximum Material Condition) MMC_Shaft - (Least Material Condition) LMC_Shaft

How to calculate Hole Tolerance?

(Least Material Condition) LMC_Hole - (Maximum Material Condition) MMC_Hole

How to calculate Allowance?

(Maximum Material Condition) MMC_Hole - (Least Material Condition) LMC_Shaft (Min clearance / Max interference)

How to calculate Max Clearance?

(Least Material Condition) LMC_Hole - (Least Material Condition) LMC_Shaft

How to calculate Max Interference?

• (Least Material Condition) LMC_Hole - (Most Material Condition) MMC _Shaft

• (Most Material Condition) MMC_Shaft - (Least Material Condition) LMC_Hole

What are the 3 Approaches of the Assembly Modeling Methodology?

• 1. Bottom Up Approach

• 2. Top Down Approach

• 3. Middle Out Approach

What is the Bottom Up Approach?

• Create individual parts / parts pulled together

• MORE IMPORTANT: Size of individual parts / the parts are then PULLED together into an assembly (size)

What is Top Down Approach?

• Create assembly model of project → details of individual parts r added along project

• MORE IMPORTANT: Fully assembly / envelope

• Note: Creating assembly model of the project as 1st step is FALSE for Top-Bottom approach

What is Middle Out Approach?

• Mix of both bottom up and top down methods

• Constructed w/ most of the parts already created & additional parts r designed & created used assembly for construction info.

What do Assembly drawings do?

• create the part (bring the parts together)

What is the main goal of Assembly Drawings?

to reveal how parts ARE put together

Hidden Lines _____________ be used on assembly drawing

SHOULD NOT

What step should Balloons be in?

Last Step of project

What are Balloons used for?

• Identify parts by giving each part a # (can only use #’s)

What is the BOM (Bill of Materials) & Part List?

• Table where ALL parts are added together

• Need to have AT LEAST 4 columns

What should the BOM (Bill of Materials) AT MIN (MUST BE INCLUDED)?

• Part name/description

• Qty’s./ requirements

• Part #

• Material

(Can also include costs, vendor)