Lecture 2

Question 1

How to get the right sketch for a revolved part

Answer 1

1.Which axix would be serve as the axxis of roration
2.What shape is your starting point from the revolved boss/base feature

Question 2

Chamfer vs fillet

Answer 2

Chamfer refer to angled or beveled edeges
fillets refer to rounded edges

Question 3

What is an additive process

Answer 3

It is an example od additve manufacturing, where material is added in sequential layers to create the final object

Question 4

Benefits to 3D printing

Answer 4

1.Rapid prototyping-make a mock up of design really quickly

2.Minimal waste-using what you need because you go layer by layer
3.reducecost-reduce cost by mock up to see if design works better ebfore you buy

4.energy saving-technology, precise, material cheaper before you buy

Question 5

Two types of 3D printing

Answer 5

1.Fillamend 3d printers
-more accessiable and common
-It heats and cools the polymer fillament as it is dispense in layers

2.Resin 3d Printing
-most precise and expensive
-utilizes beams of uv light to cure resinous polymer into the desired shape

Question 6

3d printing consideration

Answer 6

1.tolorancing between parts/features
2.shrinkage and expansion
3.In fills
4.wall thickness
5.overhngs and supports

Question 7

The diamter of the circular hole is 2.0 inches.WHat does it need to be to fit

Answer 7

shapes must be less than 2.0 inches

Question 8

tolorance

Answer 8

The allowable variation of a given dimension to achieve proper function-depend on function of th epart

Question 9

tighter toranceing

Answer 9

more expension and costly because you have to be precise

Question 10

Nominal Size
Basic size

Answer 10

Nominal size-used for general description not exact like 2x4 \lumber or 1.5x3.5

Basic size-nominal size that get converted to a decimal like 5/8in screw is 0.6250 major diameters

Question 11

Lower limit and upper limit

Answer 11

1.Lower limit:smallest allowable size for a dminesion

2.Upper limit is the largest allowable size for a dimesnsion

Question 12

Tolerance math

Answer 12

tolerance is the upper limit-the lower limit

Question 13

Minimum clearnace

Answer 13

lower lmit of the hole-Upper limit of the shape

Question 14

Maximum clearance

Answer 14

upper limit of the holes -lower limit of the shape

Question 15

clearance or free fit

Answer 15

The shaft is always smaller than the hole it interfaces with

positive and minimum maximum clearance

Question 16

Interference fit

Answer 16

The shaft is bigger than the hole it interfaces with

negative mimum and maximum clearnace

(Ikea funiture need to be hammered inplace)

Question 17

transtion fit

Answer 17

The fir between two obejcts trnation a clearance and interfence fit

negtive mimumum clearnce
postive maximum clearance.

(door stop)

Question 18

In fill are

Answer 18

It is the internal structure + density

Question 19

Infill density

Answer 19

Infil density can affect objects cast, mass and strenght

20-30 is suffiencient
higher infill-takelonger, cost more money for materials.

Question 20

3D printing wall thickmess

Answer 20

The thinnest usable featuures can be when pritned 2x3 times larger than the nozzle diamter.

Question 21

Nozzle diamters

Answer 21

either 0.35mm or 0.40mm

Question 22

3D printing overhanges

Answer 22

The additve process of 3d printing means that certain features of structures cannot be printed without building in a support structures

Question 23

How parts get mad eint he rela world

Answer 23

1. raw materials-3d printing/maching/milling/sculping

2.Technician make deatiled drawing which are for of tehcnical communciation

Question 24

detailed drawing-

Answer 24

Detailed drawing are a form of tehcnical communication and common lanaguage to communicate with others about parts

give information about dimension, cetrian fetaures, threads, callouts from hole wizard,chamfers, fillets, symmetry,material,massm volume, density

Question 25

Drawing include

Answer 25

isometric, top, right and front view

Question 26

Drawing/product standards

Answer 26

American national standards instituteor ANSI(USA)
Internationl orgainzation for standeridizdatio:ISO(WORLD)

Question 27

Section view

Answer 27

Scetion veiw allows us to see a parts interior, it important to communicate info about internal features of a part

Question 28

Detailed view

Answer 28

It is a zoomed up/in view of a area on parts
-you add it when their are small defined featues that are difficult to see int he normal view

Question 29

Center mark or cneter lines

Answer 29

Circular features require center marks or center line

Centermakers-use view where it appear as a circle

center lines-use in view where it appears as a rectangle

Question 30

Chamfer dimension

Answer 30

Chamfer has 2 dimension(size of the chamfer and angle of the chamfer

Question 31

Fillet dimensions

Answer 31

It has one dimension which is radius of the fillet

Question 32

Section view in a detailed drawing

Answer 32

-Have to show internal features of a part assmebly

-include if have rotational symmetry
-create from existing top, right, front views
-a cut plane can be a straight line line or follow another path cutting line
-

Question 33

steps to cretaing a scetion view

Answer 33

1.Indeitify the view
2.use the section view tool and choose your cutting line or place
3.apply cutting line by selecting appriate boundaries and endpoints
4.Drag your scetion view to an empty space in your sheet

Question 34

Considation for toddler toy

Answer 34

not just aesthtic but education
-spatail reasoning
hand-eye condiation
regcondtion of shapes
congnitve stimulation
safety is a piroirty

Question 35

ASTM

Answer 35

Material standards(American scoeuty for Testing material)(formed 1898 because of railroad)(ASTM F980 safety standard for toy)

Question 36

ASTM F980

Answer 36

standard consumer safety sepcification for toy safety

cover hazards thare are forseeable

does not cover product perfoamce or qualily just t safety

test method:material, use sterility, and types

Question 37

Broken view

Answer 37

for long slender parts, shaft/beam, you commonly would us broken view to save space on the detailed drawing

Question 38

Rule for dimensioning

Answer 38

1.No deuplicate/unessarty dimensions(most dimension in front view)
2.Dimensions should be placed int he view that best describes the shape of the feature(Cylinder are postive dimensions-cross section view as rectangle)(Holes are consider negative-dimension appear in circle)
3.Circles are dimensioned by their diameter, arcs are dimensioned by a radius(les than 360,fillets, half circles)
4.Avoid crossing dimension lines/extensions
5.Avoid dimensioning to hidden lines(but centerlines are ok)

Question 39

Mates

Answer 39

Mate are like constriants in 2d sketch, you force linnes to be parallel, perpendicular ot intersect at the midepoint, to run tangent to an arc etc

We have mate to force 3d parts/features of a part to have specific relationships between them,

more mates =more resirtction-consider functions

Question 40

Practive assembly 10/legos

Answer 40

-hole and cylinder is conentric

head base to neck base is coincident

Question 41

Concentric mates

Answer 41

side cover to hosuing
-circular feature usually indicates a concentric mate

side cover back flush with front surface of housing
-must be coincident

home of side over and holes in housing
-concentric

fasterner to side cover and hosuing
-concentric for the festerners with both compoenets

Question 42

why use exploded assembly