DT essentials (cramming) Flashcards
(59 cards)
1
Q
What are physical properties?
A
- properties of any material that can be measured in their natural state
2
Q
What physical properties are there?
A
- absorbency
- denisty
- electrical conductivity
- fusibility
- thermal conductivity
3
Q
What is absorbency?
A
- ability of a material to soak up or draw in heat, light or moisture
4
Q
What is density?
A
- the mass per unit volume of any material
- how solid a material is
5
Q
What is electrical conductivity?
A
- measure at which a material can transport electricity
6
Q
What is fusibility?
A
- the ability of a material to be converted to a solid to fluid state by heat and combined with another material
7
Q
What is thermal conductivity?
A
- measure of a material’s ability to transfer heat
8
Q
What are working properties?
A
- how a material responds when it is manipulated or worked
9
Q
What working properties are there?
A
- ductility
- elasticity
- hardness
- malleability
- strength
- toughness
10
Q
What is ductility?
A
- ability of a material to be stretched or drawn or pulled without breaking
11
Q
What is elasticity?
A
- ability to return to original shape after stretching or compression
Lycra used for sportswear - freedom of movement
12
Q
What is hardness?
A
- ability to withstand impact, wear, abrasion and identation
tungsten = hard, used for saws, knives, drills
13
Q
What is malleability?
A
- ability to be bent or shpaed without cracking or splitting
14
Q
What is strength?
A
- ability to withstand a force
- eg pressure, compression, tension or shear
15
Q
What is toughness?
A
- ability to absorb shock without fracturing
16
Q
What is compression?
give an example
A
- pushing force applied to either end of material
concrete pillar holding up building
17
Q
What is bending?
give an example
A
- tension on bottom
- compression on top
eg aluminum diving board
18
Q
What is torsion?
give an example
A
- when a material is twisted
eg brass key
19
Q
What is tension?
give an example
A
- pulling force on either end of material
nylon climbing rope
20
Q
What is shear?
A
- acts on object parallel to its length
low carbon steel screw used to hang something on a wall
21
Q
What are the differences between hardwood and softwood?
A
- hardwood = grows slower, more expensive
- softwood = grows faster, cheaper
22
Q
How are timber converted into a workable form?
A
- felled
- debarked - removes bark + branches
- conversion and sawing = converts logs into more managable planks
- seasoned - reduces moisture content = less prone to shrinkage, warping (air dried or kiln dried)
- planer thicknesser used to make timber smooth all round, precise dimensions
23
Q
Describe air dried seasoning
A
- timber separated and stacked under protective, roofed structure
- open sides = air circulates
- 3 months - 1 year
- cheap
24
Q
Describe kiln-dried seasoning
and draw a diagram
A
- kiln filled with steam
- moisture content gradually reduced
- more expensive
- 3-5 days
25
What is linear movement?
- movement in **one direction** along a **straight line**
26
What is reciprocating motion?
- **repetitive** **up and down** or **back and forth** linear motion
27
What is rotary motion?
- movement on or around an axis
28
What is oscillating movement?
- movement **backwards and forwards** along a **curved** path
29
What is a first order lever?
| example
fulcum in middle
pliers
30
What is a second order lever?
| example
- load in middle
- wheelbarrow
31
What is a third order lever?
| example
- effort in middle
- tweezers
32
How do you calculate mechanical effort?
load/effort
33
What are the six Rs?
1) Rethink
2) Refuse
3) Reduce
4) Reuse
5) Repair
6) Recycle
34
What is rethink?
- is there **better way of designing** product?
- impact of design
| responsibility of desinger, manufacturer
35
What is refuse?
- avoid using materials that are not socially/ environmentally unacceptable
- don't buy a product if you don't need it
| responsibility of the consumer
36
What is reduce?
- make **durable and long-lasting** products
- reduce **consumption** and **waste**
- reduce **energy** and **transport**
| responsibility of designer, manufacturer, distributor
37
What is reuse?
- produce used again for **another purpose**
| responsibility of consumer
38
What is repair?
- **repair** where possible **instead of replace**
| responsibility of designer, manufacturer, consumer
39
What is recycle?
- take product apart
- convert parts into usable materials
| responsibility of designer, manufacturer, consumer
40
What is turning?
| draw a diagram
- **wastage process**, typically **wood + metal**
- **lathes** used to **turn** timber/metal at **speed**
- wood **turned** on **rotating chuck**
- **tool = stationary**, moved into **path of work piece** (or done by **CNC machines**)
- **speed of rotation** of work piece **altered** (reflect **diameter**, **material** being turned)
- **long** pieces of work = **support from both ends**
- produces **bowls**, **spindles** in **wood**
- *bore holes*, *turn threads*, allow *drilling operations* in all materials
41
What is batch production?
- make **consistent products**
- produced in **large batches**, **reduce overall cost** of item
- **templates, jigs, moulds** ensure consistency of production
- each batch **tested** for **quality** and **uniformity**
- machinery may need **recalibration between batches** = down time
| seasonal items, newpapers, baked goods
2-thousands
42
What is mass production?
- **standardised** products in **large quantities**
- **automation** of processes, **assembly lines** = **efficient** for high volume
- **fewer workers**
- **set-up costs** for machinery/ robots = **high**
- costs **spread over large no. of goods** (reduces cost per unit)
| vehicles, mobile phones
1000s to millions
43
What is a prototype?
- **representation** of product
- **evaluate + test** design
- confirm **design methods + costs**
- eg **physical/ CAD models**
| 1
44
What is one-off production?
- manufacture of **single item**
- **high quality**, bespoke
- **high cost**
| bespoke furniture, hand made wedding dress
45
What is continuous production?
- **24 hrs** a day, **7 days** a week
- **expensive** to run
- **highly automated, small work force**
- machinery = **large volumes** of 1 item
| millions to billions
components
46
How is MDF made?
1) wood processed into **chips/particles**
2) mixed with **adhesive**
3) **compressed** into shape with **rollers,** **heated** to **cure adhesive**
4) boards **trimmed** to standard sizes
47
What is 3D printing?
| Draw a diagram of 3D printing
- builds **3D object** using reels of **thermoplastic**
- use **CAD files** that are converted to **series of co-ordinates** (G-code)
- printer follows to build up object in **layers**
- **monitor** printing process - nothing goes wrong
- **remove** from **printing bed**
- **additive** manufacturing
48
What is laser cutting?
| Diagram
- directs laser beam at **precise focal length** to **cut, etch** or **engrave** on material
- material placed on **bed**, **CAD file** loaded
- **speed, power** and **dimension settings** according to **material**
- accurate- laser beam does not **blunt or wear out**
- consumes lots of **power**
49
How is plywood made?
- thin **veneers** of wood at **90 degrees** to each other
- **glued** to create **composite**
- **pressed** and **heated** until **adhesive sets**
- **decorative laminate surface** added (flooring, furniture)
50
Process of tanalisation
1) **vaccum** empties air from cells of timber
2) **flooded with preservative** under vaccum
3) preservative **forced deep**, **high pressure**
4) vaccum **extracts excess**
5) draws in **surface excess** under **low pressure** = left to **dry**
51
What is tolerance?
- **amount of error allowed** for task
- used in **quality checking**
- products + systems = **perform correctly** given criteria
52
What is ergonomics?
- designing workspaces + **environments to fit ppl** who use them
- **minimises risk of injury**
53
What is anthropometrics?
- study of **human body**, its **measurements and proportions**
54
What is a design specification and what is it used for?
- **measurable** criteria (more specfic than design brief)
- used to **test** and **evaluate** design concepts/ at end of project
- **summarises research**
- **modify** design as **iterative design** process
55
Describe primary data
- data collected **first hand**
- created by those **needing data**
tailored to specific needs
| up to date, relevant
## Footnote
time consuming, large number of ppl needed
56
What are sources of primary data?
- interviews
- surveys
- focus groups
- product analysis
57
Describe secondary data
- information created by **others**
| already collected, free, large amount available
58
Give examples of secondary data
- books
- government data
- exemplar work from others
| out of date, not specific enough
59
