MAE 52 Final
What are the classes of fit?
1 loose 2 regular 3 tight
How do we dimension circles compared to arcs?
Circles are dimensioned by diameter, while arcs are dimensioned by radius
What is SIGGRAPH?
Conference organized by ACM, dedicated to graphics and interactive technique
When sketching, what is the most important first step?
Create a boundary box, and use light lines
What is the form of a threaded fastener?
Cross-sectional shape of a fastener's profile
How do we describe threads that are English?
Diameter - Threads per inch&Form - Class of fit&External or Internal ex. .25-28UNF-2A
What is chain dimensioning?
Dimensioning from a previous dimension -> suffers from tolerance stacking
What is baseline dimensioning?
Dimensioning from the end -> more reliable because each dimension is independent
What has authority in the PLM cycle?
Drawings
Types of Machining
Drilling, End Milling, Turning/Lathe, Water Jet, Laser Cutting, and Die Cutting
What are the two types of fasteners?
External thread (A), internal thread (B)
Left side of Solidworks window
FeatureManager design tree, Property Manager, Configuration Manager
Command Manager
Features, Sketch, Surfaces, etc.
Who was Jon Hirschtick/John Hirstich?
Founded SolidWorks in 1993, raised money as member of MIT blackjack team
What are the 3 views used in 3rd angle projection?
Front Top Right
Full vs. half-section
Full = shows 1/2 of an object Half-section = shows 1/4 of an object (shows 1/2 of a full section)
What is bilateral tolerance?
Tolerance in which variation is allowed on both sides (both + and -)
What is unilateral tolerance?
Tolerance in which variation is allowed only on one side (+ number, - 0.00 or vice versa)
How do lathes work?
Translates tool, rotates workpiece
What is limit tolerance?
Two numbers are stacked on top of each other: top is max, bottom is min
Who were Romney and Perot
Two presidential candidates involved in the CAD industry
What are geometric tolerances?
Used to define allowable error of features in terms of shape, form, location, orientation (symbol, then tolerance)
What is a broken view?
Used to illustrate objects that are longer and can be drawn in larger scale if we squish one part
What is a section view?
Used when interior details cannot be seen from the outside; hidden lines are removed and hatch pattern is included inside
What is an auxiliary view?
View showing true shape of inclined shape or side that is warped or cannot be dimensioned in another view
Why do we use different line widths?
We need to designate difference between visible, extension, dimension, and hatch lines
Where do we place dimensions?
We put them outside views, and in between views, and make sure dimension lines do not cross
When do we define depth?
When a hole does not go all the way through
When do we need to draw auxiliary views?
When there is no other view that has the correct dimensions of the view we want (usually holes on top of object, as they appear warped)
What is a removed/revolved section?
When we take a thin slice of an object and rotate it around a center axis
What is a broken out section?
Where we take a small portion away from an object to reveal part of its internal detail
How do we distinguish a reference dimension?
Write in parentheses ex. (4.900)
Can extension lines cross each other?
Yes! Avoid crossing dimension and extension lines though.
Can we extend center lines?
Yes, center lines can be extended and used as extension lines
Can extension lines cross?
Yes, if necessary. Dimension lines should never cross though
When adding Notes, Hole Callouts, Center Marks, and Centerlines for a Solidworks Drawing which tab do you use?
Annotation
What are some smaller CAD systems?
Autodesk - AutoCAD PTC - Creo Siemens - Solid Edge
What is the name of a section designated by a break line?
Break Section ?????
What are wo characteristics of lettering in sketches and drawing?
Capital letters, and all letters are the same height
How do end mills work?
Removes material by rotating tool and translating workpiece
How does grinding/lapping/polishing work?
Removes small amount of material by abrasion
What are the steps of PDP?
Requirements, Design, Analysis/Test, Manufacturing
What is allowance?
SH - LS smallest possible hole - largest possible shaft maximum amount of interference (tightest fit)
What are the factors that help you decide which view is the front view?
The front view has the most details, views are chosen to minimize the number of hidden lines
what is UNC, UNF, and UNEF?
unified national... coarse, fine, and extra fine
How are inches shown in decimals?
2 digits, no zero to left before decimal ex. 12.00; .44 inch
What does the document window have?
2 panels: Feature manager design tree and graphics area
Cubic curve
2 points with zero slope Only one point of inflection
Who were Ross Perot and Mitt Romney?
2 presidential candidates who had history with CAD & FEA software
What angle does isometric projection have about the horizontal?
30 degrees tilt.
What are the two commonly used angles for receding lines in oblique sketches?
45 and 30 degrees
What two organizations publish standard layouts for use with technical drawings?
ANSI and ISO
What are pictorials?
General umbrella term for 3D PHOTOGRAPH representation of object in ONE view: there are different types of pictorials
What is an inclined surface?
Has characteristic shape in 2 views, but not real size in any of the views
What is an oblique surface?
Has characteristic shape in 3 views, but not real size in any of them
What is a principal surface?
Has characteristic shape in one view, seen as line in other 2 views, real size in the one view
How do we dimension cylinders?
If visible, we dimension to the rectangle in the front view instead of the circular on the top
What is maximum clearance?
LH - SS largest hole - smallest shaft maximum amount of space (loosest fit)
What is CATIA?
Large CAD Tool, developed by Dassault Systems CAD, CAM, CAE
What is a Miter line?
Line used to build 3rd view when given 2
How do we describe threads that are metric?
M&thread diameter x pitch
What is an offset section?
Modified version of full section, offsets or bends are 90 degrees from each other
Do we dimension to hidden lines?
NEVERRRRR avoid when possible
What are orthographic projections?
NOT pictorial. We project faces of objects into different views. Each orthographic view only shows two dimensions of the object, so you must combine the views altogether (3 views make one object)
What is 1st angle projection?
used in Europe and Asia: inside the box, looking out at the walls
How are millimeters shown in decimals?
No zeroes to the right of the decimal for integers, and has zero to left before decimal ex. 12; 0.44 metric
What was UG/NX CAD?
OG name was UG; owned by McDonnell Douglas (now Boeing) CAD Software made for internal use, but people wanted to buy --> sold to Electronic Design Services i 1991, then taken private by Bain Capital in 2004 and renamed to NX CAD, finally sold to Siemens in 2007
What are examples of pictorials?
Oblique projection, isometric projection, perspective projection,
What is the difference between PDP and PLM?
PLM includes marketing, customer feedback, maintenance (stuff not included in PDP)
What is a transition fit?
Parts can either clear or interfere -- least expensive to manufacture
What is interference fit?
Parts will always interfere with each other, need force to press into each other
What is clearance fit?
Parts will never interfere
Oblique and perspective sketches are example of what kind of more general representation of an object?
Pictorials
Drawing sectional views
Places where the section cutting line touches solid, results in solid, otherwise draw what is inside
What is a leader line?
Points to an item, usually circle's radius (elbow)
What is PDP?
Product Development Process
What is PLM?
Product Lifestyle Management
Who was Edwin Thorpe?
Professor who wrote book on financial gain and beat the market (stock market)
What is an axonometric projection?
Projection lines are parallel but views of the object are not parallel to the plane of projection (view is rotated and tilted)
What happens if a fastener is left handed?
add LH to the end of the note
What is perspective pictorial?
has vanishing point, see far into distance because rays come from one point. Can have one-point, two-point, or three-point perspective
Why do we avoid oblique projections?
have lots of distortion
Heads and drives
head is top portion of fastener, shaped so that tool can be used to seat it drive is recessed profile, cut into head
What is mathematically continuous geometry?
how data is stored on computer, uses parametric functions
What does tessellated mean?
image broken into small pieces
How do we letter?
in CAPS
Who were Evans and Sutherland?
innovated computer graphics by founding companies and teaching students who went on to change technology
What is tolerance?
limit of random (unintentional) deviation of a dimension from its nominal value
What are the two benefits of using a PLM system?
minimize time, maximize money
What does 5/16-18 hole call out mean?
nominal diameter is 5/16 inches, 18 threads per inch
What is 3rd angle projection?
used in US: outside the box, looking in
How is CAD geometry stored in a Solidworks database?
with math: using cubic curves
What is needed for an auxiliary view?
project right off the surface, use T.S. to show that it is true scale
What is hatching?
shows where cutting plane passed through solid material and also the material of the part itself if we slice through multiple components, we must hatch differently avoid hatching webs or ribs or lugs if longitudinal HATCHED SECTION = THE PARTS THAT TOUCH THE CUTTING PLANE
What is the cutting plane line?
shows where to cut: removes section in front (Keep part that the arrows are pointing towards)
What is the Utah Teapot?
teapot modeled on computer with 9 patches and many vertices, became baseline for many graphic softwares
How to dimension counterbore?
⌀ .375 depth 1.000 ⌴ ⌀ .875 x depth symbol .500
How to dimension countersink?
⌀ .375 depth 1.000 ⌵ ⌀ .875 x 85° (countersink angle)
What is ⌴?
⌴ is counterbore
What is ⌵?
⌵ is countersink
