1.4 Forming Redistribution

Question 1

Die cutting*

Answer 1

1. The sharp edges of the cutting die are brought down onto a thin sheet material.
2. The material can be cut, creased and perforated all on one single step.
   Used in fibre, foil, cloth, paper, corrugated fiberboard, chicken, paperboard, plastics, pressure-sensitive adhesive tapes, foam and sheet metal.

Question 2

Bending

Answer 2

Stamped out net placed onto a folding table. Some die cutting presses may be equipped with moving parts that help to bend or fold parts automatically.

Question 3

Vacuum Forming*

Answer 3

1. A sheet of plastic is heated to a temperature suitable for forming.
2. A mould is then pushed up into the plastic sheet.
3. The ‘vacuum’ is turned on and this pumps out all the air beneath the plastic sheet.
4. The sheet has the shape of the former pressed into its surface.
   Used in yoghurt pots, trays and box inserts

Question 4

Thermoforming*

Answer 4

1. Sheet plastic is held securely between the two halves of the mould.
2. The plastic is heated just above its softening point.
3. The mould halves close and a vacuum is applied through the lower/negative mould.
4. The upper/positive mould ensures the required amount of detail is achieved.
   Used to make bath tubs and food packaging such as cake boxes

Question 5

Calendering*

Answer 5

1. Pre mixed thermoplastic material is fed into rollers.
2. Rollers are heated to just above the softening point
   of the thermoplastic.
3. The plastic is forced through a gap roller to determine
   the thickness of the final product.
4. The final roller chills the material.
   Used to make polymer film

Question 6

Injection Moulding**

Answer 6

1. A performed charge (compressed plastic powder) is placed between the two halves of the mould.
2. The mould is heated to a temperature that will allow the long chain molecules of the thermosetting
   plastic to fix together (this is called cross-link).
3. The mould is closed and held together for a period of time that will allow all cross-links to be formed.
   Used to make complex thermoplastic items such as computers, tv’s, vacuum cleaners

Question 7

Blow Moulding*

Answer 7

1. The plastic is fed in granular form into a ‘hopper’
   that stores it.
2. Heated plastic granules are injection moulded into a pre-form shape which is positioned into a mould.
3. Air is forced into the mould which forces the plastic
   to the sides, giving the shape of the bottle.
4. The mould is then cooled and is removed.
   Used in hollow products such as bowls

Question 8

Rotation Moulding*

Answer 8

1. Moulds are loaded with a precise
   amount of thermoplastic
   powder.
2. The mould is clamped together.
3. The mould is then rotated in a heated chamber and the thermoplastic is melted.
4. The continuous rotation ensures the thermoplastic covers all of the inside of the mould.
5. The mould is cooled and then opened.
6. The product is extracted.
   Heavy duty hollow objects such as cones and kayaks

Question 9

Extrusion

Answer 9

1. Granules of plastic powder or granules are poured
   or fed into a hopper.
2. A motor turns a thread which pushes the granules
   along a heater section.
3. The heater softens the plastic which is then forced
   through a die.
4. As the plastic leaves the die it is cooled.
5. The extruded product is then cut to the required
   length.
   Used to make hollow tubes and solid rods

Question 10

Compression Moulding

Answer 10

1. A performed charge (compressed plastic powder) is
   placed between the two halves of the mould.
2. The mould is heated to a temperature that will allow
   the long chain molecules of the thermosetting plastic to fix together (this is called cross-link).
3. The mould is closed and held together for a period
   of time that will allow all cross-links to be formed.
   Used to make electrical plug fittings

Question 11

Press Forming

Answer 11

1. Sheet metal materials/blanks are loaded into a hydraulic press and clamped into the blank holder.
2. The punch forces the material through the die so it
   takes the shape of the punch.
   Used to make metal seats and car body panels

Question 12

Metal Spinning*

Answer 12

Used to shape stainless steel kettles or saucepans

1. A former called a ‘mandrel’ is put into the chuck. The metal sheet is held between the mandrel and tail stock.
2. The roller is moved into the blank and rotated with the mandrel
3. The roller is moved along the mandrel as pressure is applied.
4. The product is removed and trimmed.

Question 13

Drop Forging

Answer 13

Very large forces are exerted onto a pre-heated metal billet between the die halves.
Used to make spanners

Question 14

Wrought iron forging

Answer 14

Form of iron suitable for forging and bending as opposed to casting. Low carbon content so can be hammered into shape. Can be shaped using hand tools used for one-off and batch production.
one-off or batch production items

Question 15

Metal rolling

Answer 15

Hot metal is heated above recrystallisation temperature (hot rolling) or below (cold rolling) and is fed through sets of rollers to reduce its thickness. Used to create I beams and rails. Hot rolling results in uniform mechanical properties throughout the sample. But the surface is usually coated with carbon deposit with a large tolerance. Cold rolling has a righter tolerance as carbon isn’t formed. The surface is much better and is used in home appliances and filing cabinets.

Question 16

Sand Casting*

Answer 16

1. A pattern is made.
2. Each part of the pattern is placed on a base board.
   A mould box half is placed over it.
3. Sand is packed around the pattern forcing it into
   contact with the pattern.
4. The pattern is removed from the mould half.
5. The mould halves are fitted together with locating pins ensuring correct alignment.
6. Molten metal is poured into the running gate.
7. Once the metal has solidified the mould is broken
   open.
   Used to make carraige wheels, wood vices, drain covers and post boxes

Question 17

Die Casting**

Answer 17

1. Molten metal is poured into a chamber.
2. An injection piston or plunger forces the molten metal under high pressure into the casting cavity.
3. The pressure is maintained until the metal solidifies.
4. Injector pins are used to push the components out of the die.
   toy cars, collectable figures and handles

Question 18

Investment Casting

Answer 18

Used for jewellery or collectable figures
1. A wax mould is created and them dif coated with refractory clay
2. Baked in a kiln and wax is burned away
3. Metal is poured into the mould and clay is broken away
Used in jewellry

Question 19

Low-Temperature pewter casting

Answer 19

Pewter is an alloy with a low melting point, used in jewellery and keys
A mould is made from MDF
The mould is sandwiched between two pieces of MDF and clamped
The pewter is melted and ladled into the sprue
The sprue is removed with a junior hacksaw
Casting is polished

Question 20

MIG welding*

Answer 20

Used in bike frames
USes an electric arc to create heat
A wire electrode made from the same metal as the one being welded melts the arc and fills the gap between the two pieced being joined.
the welding gun is swirled
An inert gas such a co2 forms a flux shield preventing oxidization of the joint.

Question 21

TIG welding

Answer 21

1. TIG generates heat via an arc of electricity jumping from a (tungsten metal) electrode to the metal surfaces you intend to weld.
2. The heat is sufficient to melt the joint edges.
3. The electrode is coated in flux which when melted, prevents the joint from becoming oxidised.

Question 22

Oxy-acetylene welding

Answer 22

Used to weld low carbon steel useful for quick repair jobs where there is no electricity. Uses to gases to form an intense flame. Adjusted for different purposes such as flame cutting, welding or brazing.

Question 23

Brazing

Answer 23

1. The metal to be joined must first be cleaned so that grease and dirt is removed.
2. Flux is brushed along the joint to prevent oxidation taking place on the metal surfaces.
3. Pressurised gas and air is fed through a nozzle and ignited.
4. The joint is heated with the flame until eventually it becomes so hot that it becomes red in colour.
5. A brazing rod (copper-zinc alloy) is then pushed gently against the joint and if the temperature is right the end of the rod will melt and begin to run along the joint. The rod is fed into the joint until a brazed joint is complete.

Question 24

Riveting/Pop Riveting

Answer 24

Used in trowels
Rivets are metal fasteners with a head at the end and a tail at the other used to join sheet metal. Place the head in a set tool through the drilled metal and tail should be sticking out. A hammer can then be used squeeze the pieces together.

Question 25

Self-Tapping Screws

Answer 25

Used to join thin sheet metal. (standard screws) can be removed for maintenance.

Question 26

Machine Screws

Answer 26

Used to join thicker pieces of metal such as gear housing. The thread covers the entire length of the shaft. The top of the two pieces to be joined will have a clearance hole larger than the thread on the bolt.

Question 27

Milling

Answer 27

Work to be machined is clamped onto the table. The table can run the x,y,z directions. Milling is used to cut slots, shape edges or to drill thread holes.

Question 28

Turning

Answer 28

Used to shape metal on a central lathe

Cutting tools held in a tool post. Cutting tools made from high-speed steel. Liquid coolant is applied.

Question 29

Flame Cutting

Answer 29

Uses oxy-acetylene gas to create aflame over 3500C. Used to cut low carbon steel and alloy steel plates.

Question 30

Plasma Cutting

Answer 30

Used for cutting steel (e.g sculptural signs) Plasma is a super-heated ionised gas that is electrically conductive and when combined with a gas and an electric arc created by transformer forms a jet of plasma.

Question 31

Punching/Stamping

Answer 31

Wastage process used by CNC which stamp out sections of sheet material using punches. CAD is used to determine the most efficient layout of a sheet known as nesting.

Question 32

Bolts

Answer 32

Bolts used to join wood are called coach bolts and the thread runs 2/3 across the bolt. A square piece under the head prevents the bolt from rotating.

Question 33

Lamination

Answer 33

Typically uses a vacuum bag

Question 34

Steam Bending

Answer 34

1. Tools used for the steaming process include: a steam box, a steam or heat generator, a thermometer and a hose.
2. Steam boxes may be constructed from PVC pipe and must completely encase the wood so that the steam may saturate the entire length of the material.
3. The wood is steamed and softened.
4. Once the wood is becomes flexible it can become manipulated

Question 35

Polyvinyl Acetate (PVA)

Answer 35

Indoor furniture

Question 36

Contact Adhesives

Answer 36

Used for large areas such as sheet metal, used to join the same or different material. No clamping required.

Question 37

UV hardening adhesives

Answer 37

A clear liquid that cures when exposed to IV. Used to join metal, glass and polymers. Used for glass products or when transparency is important.

Question 38

Solvent Cement

Answer 38

Used to join polymers.

Question 39

Jigs and fixtures

Answer 39

Holds work in a place while a manufacturing process takes place. A jig both holds the work and guides a tool. Ensure parts or components can be repeatedly and accurately. They speed up manufacture.

Question 40

Sanding Jigs

Answer 40

Guide timer on a belt sander (Ensure 90 degrees)

Question 41

Routing Jigs

Answer 41

To shape wood accurate and consistently. Beam compass can allow cutting of different diameter.