Section 2: Engineering Manufacturing processes

Question 1

Sintering

for metals

Answer 1

The use of heat to convert a powder into a solid, without becoming a liquid

• a mould is made of the product which is filled with metal powder
• high pressure is applied to the powder, suing idustrial press
• powder is heated to a temp below melting poing of metal
• individiual particles of metal powder fuse together

higher the pressure and temperature = greater strength of final product

Question 2

Pros of sintering

Answer 2

Pros:
1. doesn’t need much energy as casting process
2. can create products from different mixture of powders
3. create products with lower density than solid metal

Question 3

Rapid prototyping

for polymers

Answer 3

The use of addititive manufacture to make a complete part of component in a single operation
Eg: fused deposition modelling (3D printing) and stereolithography (use of laser to make polymer products)

Question 4

Pros and cons of rapid prototyping

Answer 4

Pros:
* complex parts can be carried out more quickly than several separate parts
* allows rapid evaluation
* unique designs can be made

Cons:
* limited range of materials

Question 5

Fused deposition modelling

type of rapid prototyping process

Answer 5

• a 3D CAD drawing is created, which has been broken down into a series of layers
• first layer is melted and deposited by printing head, so sits on the base. cools and solidifies when it is deposited
• printing head rises by the thickness of one layer, deposits next layer of polymer, sits on first layer (this step repeats until full thickness has been acheived)
• finished item can be removed from base

this process is used in 3D printing

Question 6

Sawing

material removal: cutting

Answer 6

• uses movement to progressively cut away material
• each saw tooth cuts a small groove into a material

the harder the material, the smaller the saw teeth

Question 7

Types of saws

material removal: cutting

Answer 7

Hacksaw: cut metal and polymers
Coping saw: cuts curves shapes. cuts polymers or timber
Tenon saw: timber
Jigsaw: most types of material/thickness

Question 8

Shearing

material removal: cutting

Answer 8

• applying a force from opposite sides of a metal sheet causing the sheet to separate

Question 9

Laser cutting

material removal: cutting

Answer 9

• used to cut thin sheets of polymer or metal
• the material along the cut line is vapourised

Question 10

cylindrical

material removal: turning

Answer 10

• produces a uniform shape of same diameter
• tool moves along the length of the material (reduces diameter)

Question 11

Taper

material removal: turning

Answer 11

• diameter is larger at one end, and smaller at the other

Question 12

Boring

Material removal: turning

Answer 12

• use of a single-point tool to produce an internal hole

Question 13

Face milling

Question 14

Slot milling

Question 15

Bending

shaping, forming, manipulation

Answer 15

• physically deforming a material
• forcing something straight into a curve or angle

Question 16

Folding

shaping, forming, manipulation

Answer 16

• changing the dimentions or shape of a solid maerial, without changing volume
• bending material over itself, so one part cover another

Question 17

Press forming

shaping, forming, manipulation

Answer 17

used to change the shape of a sheet material using pressure from a press
* place a sheet of material 2 moulds/ram and die.
* the ram and die/moulds fit together with a thin gap between them in the shape required
* a press applies pressure to permanently deform the metal sheet

Question 18

Punching and stamping

shaping, forming, manipulation

Answer 18

punching: a hole is made, and material pushes out is scrap
shtamping: the shape pushed out is required, and the metal around it is scrap

Question 19

Sand casting

casting and moulding

Answer 19

a shaping process where a mould, made form sand, is filled with molten metal
* molten metal is poured into the mould through the sprue, and allowed to solidify
* each sand mould is used just once as sand is knocked/shaken off the casting. Sand can be resused to make other moulds
* sprue, riser, runner can be cut off the cast part

Question 20

Pressure die casting

Answer 20

a shaping process where molten metal is forced into a resuable metal mould
* during casting process, the parts of the die is brought together.
* the pressure forces the liquid metal into the cavity
* once metal has solidified, the die is taken apart and cast part removed

Question 21

Injection moulding

Answer 21

a shaping process for polymers, where polymer is forced into a reusable metal mould
* polymer granules are loaded into feed hopper
* rotating screw pushes polymer along, melted by heaters
* liquid polymer is compressed by cone shaps. increases pressure, liquid is forced into the mould
* mould is cooled, component ejected

Question 22

Threaded fastening

Answer 22

products such as screws, nuts, bolts that can be used to make a temporary joint

Question 23

Rivets

Answer 23

used to hold sheets of material together
* hole is drilled into overlapping sheets of material
* rivet is inserted through hold, ends are hammered to mechanically hold sheets in place

Question 24

Soldering

Answer 24

a joining process where metal parts are attached together using a filler wire, which melts and runs between them, typically melted using a soldering iron.

Question 25

Welding

Answer 25

a joining process for metal parts where the edges of the parts are melted and form the joint, with additional filler metal if needed

Question 26

Brazing

Answer 26

a joining process where metal parts are attached together using a filler wire which melts and runs between them, with heat provided