Lecture 2 Flashcards

1
Q

How to get the right sketch for a revolved part

A

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

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2
Q

Chamfer vs fillet

A

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

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3
Q

What is an additive process

A

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

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4
Q

Benefits to 3D printing

A

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

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5
Q

Two types of 3D printing

A

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

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6
Q

3d printing consideration

A

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

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7
Q

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

A

shapes must be less than 2.0 inches

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8
Q

tolorance

A

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

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9
Q

tighter toranceing

A

more expension and costly because you have to be precise

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10
Q

Nominal Size
Basic size

A

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

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11
Q

Lower limit and upper limit

A

1.Lower limit:smallest allowable size for a dminesion

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

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12
Q

Tolerance math

A

tolerance is the upper limit-the lower limit

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13
Q

Minimum clearnace

A

lower lmit of the hole-Upper limit of the shape

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14
Q

Maximum clearance

A

upper limit of the holes -lower limit of the shape

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15
Q

clearance or free fit

A

The shaft is always smaller than the hole it interfaces with

positive and minimum maximum clearance

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16
Q

Interference fit

A

The shaft is bigger than the hole it interfaces with

negative mimum and maximum clearnace

(Ikea funiture need to be hammered inplace)

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17
Q

transtion fit

A

The fir between two obejcts trnation a clearance and interfence fit

negtive mimumum clearnce
postive maximum clearance.

(door stop)

18
Q

In fill are

A

It is the internal structure + density

19
Q

Infill density

A

Infil density can affect objects cast, mass and strenght

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

20
Q

3D printing wall thickmess

A

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

21
Q

Nozzle diamters

A

either 0.35mm or 0.40mm

22
Q

3D printing overhanges

A

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

23
Q

How parts get mad eint he rela world

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

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

24
Q

detailed drawing-

A

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

25
Q

Drawing include

A

isometric, top, right and front view

26
Q

Drawing/product standards

A

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

27
Q

Section view

A

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

28
Q

Detailed view

A

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

29
Q

Center mark or cneter lines

A

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

30
Q

Chamfer dimension

A

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

31
Q

Fillet dimensions

A

It has one dimension which is radius of the fillet

32
Q

Section view in a detailed drawing

A

-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
-

33
Q

steps to cretaing a scetion view

A

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

34
Q

Considation for toddler toy

A

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

35
Q

ASTM

A

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

36
Q

ASTM F980

A

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

37
Q

Broken view

A

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

38
Q

Rule for dimensioning

A

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)

39
Q

Mates

A

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

40
Q

Practive assembly 10/legos

A

-hole and cylinder is conentric

head base to neck base is coincident

41
Q

Concentric mates

A

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

42
Q

why use exploded assembly

A