C-Enhancements, Processes and Finishes

Question 1

Polymer additives-Lubricants?

Answer 1

-The addition of wax reduces the viscosity of the molten polymer.
-It allows more intricate shapes to be formed or allows the moulding temperature to be lowered, which saves energy.

Question 2

Polymer additives-Thermal antioxidants?

Answer 2

-They prevent the polymer oxidising or discolouring due to excessive heat during processing.

Question 3

Polymer additives-Pigments?

Answer 3

-Tiny particles mixed into the polymer in its molten state to give colour to the final product.

Question 4

Polymer additives-Antistatics?

Answer 4

-Plastics are used to insulate products but it can lead to a build-up of static electricity, which attracts dirt and dust.
-Antistatics improve surface conductivity by attracting moisture, therefore reducing the static charge.

Question 5

Polymer additives-Flame retardants?

Answer 5

-When added to polymers it reduces the likelihood of combustion or the spread of fire.

Question 6

Polymer additives-Plasticisers?

Answer 6

-They are added to allow plastics to become less hard and brittle.
-Added to food wrap to allow it to be stretched over food.

Question 7

Polymer additives-Fillers?

Answer 7

-They provide bulk to the product meaning that less polymer is required and improve the polymer’s properties.

Question 8

Polymer additives-Antioxidants?

Answer 8

-Helps to reduce the deterioration of a polymer from exposure to oxygen in the air.

Question 9

Polymer additives-UV light stabilisers?

Answer 9

-Prevent polymer chains from being broken down by sunlight.

Question 10

Polymer additives-Biodegradable plasticisers?

Answer 10

-They make the polymer more flexible, softer, and easier to break down, which can lead to a faster degradation time.

Question 11

Polymer additives-Bio-Batch additives?

Answer 11

-Oxy/Photo/Hydro-degradable additives can be added to polymers to help reduce degradation times.

Question 12

Metal enhancements-Work hardening?

Answer 12

-Bending, rolling, or hammering the crystals within a metal are distorted, leading to improved tensile strength and hardness.
-The crystals are prevented from moving freely, which can result in less ductility.

Question 13

Metal enhancements-Annealing?

Answer 13

-Used to make a work-hardened metal easier to work with by making it less brittle and more ductile.
-The metal is heated and then very slowly cooled allowing the metal crystals to grow and then move back into place.

Question 14

Metal enhancements-Case hardening?

Answer 14

-Creates a surface with a greater hardness and more resistance, while the inner core retains its softer properties.
-Stage 1:Carburising, it changes the chemical composition of the surface by increasing the surfaces carbon contant.
-Stage 2:Quenching, the hot metal is quenched in water, which seals the hard surface case.

Question 15

Metal enhancements-Hardening?

Answer 15

-Medium/High carbon steel are heated and then held at this temperature for a given time then quenching it.
-It will alter the crystalline structure, which greatly increases the hardness but also the brittleness.

Question 16

Metal enhancements-Tempering?

Answer 16

-It is carried out after hardening to reduce the excessive hardness and increase the toughness.
-It is heated below the critical point and then cooled, the rise in temperature causes a reduction in hardness.

Question 17

Wood enhancements-Resins?

Answer 17

Manufactured boards use resins to produce boards that are not affected by temperature and humidity as much as solid woods. Also, have uniform strength with none of the grain problems seen with solid woods.

Question 18

Wood enhancements-Laminations?

Answer 18

Veneers are laminated onto the surface of cheaper woods to enhance the properties.

Question 19

Wood enhancements-Preservatives?

Answer 19

Used to protect the wood from insect and fungal attacks, they penetrate the timber to give it enhanced properties.

Question 20

Wood enhancements-Pigments?

Answer 20

Give different coloured shades to enhance the aesthetics of the wood products.

Question 21

Wood enhancements-Modified natural polysaccharides?

Answer 21

They effectively cure within the wood to give it increased toughness and hardness.

Question 22

Wood enhancements-Structural composite lumber and Laminated veneer lumber?

Answer 22

Engineered woods made by layering veneers or strands of woods with resins and then heat is used to cure them. They are less prone to defects like warping, splitting or shrinking.

Question 23

Polymer processes-Vacuum forming?

Answer 23

-The mould, with a draft angle. is placed on the bed of the machine, which is called the platen. The platen is lowered to the bottom of the machine.
-Polymer sheet is clamped over the mould and heated.
When the polymer has softened, the platen is raised into the polymer and the heat is removed.
-The vacuum is switched on, which sucks the polymer onto the mould.
-Once the polymer has cooled and returned to a solidified state, the platen is lowered and the vacuum is switched off.
-The mould is removed and any excess polymer is trimmed off.

Question 24

Polymer processes-Thermoforming?

Answer 24

-It is similar to vacuum forming except there is an additional mould applied at the same time as the vacuum.
-The two moulds trap the softened polymer in between them, giving extra detail to the moulding.
-Used for fine details such as embossed logos and lettering.

Question 25

Polymer processes-Calendering?

Answer 25

-Used to make thin polymer sheets and films. -Works by heating pellets of thermoplastics, which are then extruded being a series of heated rolllers to make it thinner. -It is then finished on cooling rollers before being cut into into standard stock sheet sizes.

Question 26

Polymer processes-Line bending?

Answer 26

-Uses an electrical heated element that provides heat along a line, in order to produce bends in sheets of thermoplastics. -Typically used to make products such as boxes. -It is labour intensive and quite slow.

Question 27

Polymer processes-Lamination (lay-up)?

Answer 27

-The mould is coated with a release agent or covered with parcel tape. -A top layer of gel coat is applied. -Fibreglass matting is laid over the former, then a polyester resin is brushed onto the matting and a small roller is used to push out any air bubbles and smooth out the matting. -This is repeated until the desired thickness is achieved. -The GRP is then allowed to set before being removed from the mould.

Question 28

Polymer processes-Injection moulding?

Answer 28

-Thermoplastic granules are poured into a hopper. -A screw thread is rotated, which pulls the granules through the chamber and past heaters. -When the polymer has melted, a hydraulic ram forces the screw thread forward, which injects the polymer into the mould. -The mould is water-cooled, which enables the polymer to harden quicker. -The mould opens and ejector pins push the moulding out. -Any excess polymer is trimmed.

Question 29

Polymer processes-Blow moulding?

Answer 29

-The polymer is fed into a hopper. -A screw pulls the polymer through a heated section, melting the polymer. -The melted polymer is extruded as a tube, which is called a parison. -The mould sides close around the parison and air is injected into the mould, forcing the polymer to the sides. -The polymer is allowed to cool, then the mould opens and the finished bottle is ejected.

Question 30

Polymer processes-Rotational moulding?

Answer 30

-Polymer powder or granules are loaded into a mould, which is clamped and sealed. -The mould is transferred to an oven and heated. -The mould is rotated around two axes and the polymer is coated around the inside of the mould. -Once the polymer is at the correct thickness, the mould is cooled. -When the polymer has solidified the part will shrink slightly allowing it to be removed from the mould.

Question 31

Polymer processes-Extrusion?

Answer 31

-Polymer granules are poured into a hopper. -The screw moves the polymer granules past heaters, which softens the polymers. -When sufficient polymer has melted a hydraulic ram pushes the screw, forcing the polymer through a steel die. -The extrusion may be supported by rollers as it leaves the die and is cooled by water or air. -The extrusion is then cut to the desired length.

Question 32

Polymer processes-Compression moulding?

Answer 32

-A thermoset polymer is inserted between the two halves of a preheated mould. -The moulds are closed and a hydraulic press is applied. The pressure ensures that the polymer takes the shape of the mould. -When the moulding has cured, the machine opens and the polymer is removed. -Excess polymer known as flash is removed.

Question 33

Metal processes-Press forming?

Answer 33

-Sheet metal is clamped over a die of the product. -A hydraulic press pushes the die into the sheet metal, cutting blades may be used to punch holes or trim excess material. -The die is lowered and the pressed sheet component is removed. -The sheet may be placed into further press forming machines for more complex shapes.

Question 34

Metal processes-Spinning?

Answer 34

-A former called a mandrel is put into a chuck and the sheet metal is held in place between the mandrel and the tail stock. -The roller tool is moved into the sheet and is rotated with the mandrel. -The metal will start to stretch the metal over the mandrel. -The roller is moved along the mandrel maintaining constant pressure. -The roller is moved to the end of the mandrel in order to finish the shape of the product. -The finished product is removed from the mandrel and any excess material is removed.

Question 35

Metal processes-Cupping and deep drawing?

Answer 35

-The pressing blank is clamped over a deep drawing die. -A hydraulic press moves the deep drawing punch to be in contact with the blank, it then pushes the blank into the die cavity making a cup shape. -The cup is then forced further down to make the desired tube shape.

Question 36

Metal processes-Drop forging?

Answer 36

-A die is secured to the top of an anvil. -A ram is also equipped with a die that resembles a mould. -The billet is heated above its recrystallisation state, which prevents the product from work hardening. -The heated billet is placed into the anvil die and the hydraulic ram is brought down with a force. -The ram is lifted and the final product removed.

Question 37

Metal processes-Wrought iron forging?

Answer 37

-Wrought iron is heated in a forge. -It is then held with tongs and hammered over an anvil until the desired shape is reached.

Question 38

Metal processes-Bending?

Answer 38

-Clamping the stock metal between a complementary punch and die. -The punch is forced into the metal in order to bend it.

Question 39

Metal processes-Rolling?

Answer 39

-A stock metal is passed through a set of rollers to reduce the thickness. -Can be hot rolled, will have uniform properties throughout and no faults but the surface can be coated with carbon deposits. -Can be cold rolled, no carbon deposits will form and therefore a tighter tolerance.

Question 40

Metal processes-Sand casting?

Answer 40

1) A pattern is made of the item being cast and then sand is packed around it. 2) A second box is clamped on top with the top half of the pattern and wooden stakes are added to create the sprues. 3) Sand is again packed into the second box. 4) The boxes are separated and the pattern and stakes are removed and then the boxes are clamped back together. 5) Molten metal is poured into the sprue and when the cavity is full it flows up the riser to indicate it is full. 6) Once it is cooled the sand is removed and the runners and risers are cut off with a hack saw. -It is slow and labour intensive as the moulds are single use so is only used for one-off batch production. -It does not give a very high quality finish.

Question 41

Metal processes-Die casting?

Answer 41

-Uses complex and costly moulds making it only suitable for large batch and mass production. -It provides a high quality surface finish. -Gravity die casting, as in sand casting the metal flows down the runner and up the riser filling the mould and once it has cooled the mould is opened. -Pressure die casting casts items quickly and in high volumes: *Hot chamber, the molten metal is force into the mould under high pressure to fill the mould, which allows fine details to be moulded. *Cold chamber, the molten metal is heated sperately and then ladled into the chamber where the ram forces it into the mould.

Question 42

Metal processes-Investment casting?

Answer 42

-Used to cast intricate or awkward shapes. 1) A pattern of the product is made using wax. 2) The pattern is dip coated with clay and then fired to make it hard, the wax is then burned away leaving a hollow mould. 3) Molten metal is poured into the clay mould. 4) Once it has cooled the clay is then broken away.

Question 43

Addition and Fabrication processes-MIG welding?

Answer 43

-An electrical arc creates heat which melts the joint area. -A wire electrode of the same material being joined also melts into the arc and fills the gap between the two pieces. -The operator swirls the welding gun as they move over the joint to form a continuous bead of weld. -The electrode wire is stored on a reel and advances through the welding gun as the trigger is pressed (One handed). -An inert gas forms a flux sheild, the gas replaces the oxygen to prevent oxidation at the joint.

Question 44

Addition and Fabrication processes-TIG welding?

Answer 44

-Similar to MIG welding but the tungsten electrode does not melt and instead a separate filler rod is used (Two-handed). -The processor allows for greater control and a more accurate and stronger weld but it requires a high skill level and is quite slow.

Question 45

Addition and Fabrication processes-Oxy-acetylene welding?

Answer 45

-Uses a mixture of high pressure gases to form an intense flame. 1) The metal is prepared by grinding an angle on the edge to create a V shape when the pieces are joined. 2) The joint is heated and a steel filler rod is introduced into the area to form the seam.

Question 46

Addition and Fabrication processes-Brazing?

Answer 46

-Uses lower temperature and the resulting joint is not as strong as welding. 1) The material to be joined is cleaned and degreased. 2) The two pieces are clamped together. 3) A flux is applied to prevent oxidising. 4) The joint is heated and a brazing rod is applied to the area. 5) It will flow along the joint to the hottest area, so can be made to follow the joint by manipulating the torch.

Question 47

Addition and Fabrication processes-Soldering?

Answer 47

-Can only be used for lightweight applications. -The metals should be clean and no gaps between the areas being joined. -It uses a filler material with a lower melting point. 1) The metal is cleaned and degreased. 2) The joint area is wired up or clamped. 3) The metal is heated up to the melting point of the solder. 4) The solder is added to the metal causing it to flow along the joint by capillary action. 5) The metal is cleaned to remove any flux residue.

Question 48

Addition and Fabrication processes-Riveting?

Answer 48

-A permanent joining method used to join sheet metal or plates. -The head of the rivet is domed shaped and the shaft is hammered over to squeeze the two pieces together.

Question 49

Addition and Fabrication processes-Pop riveting?

Answer 49

-The rivet head is pushed through a hole drilled through the two pieces being joined. -Riveting pliers grip and pull the pin, this causes the head of the rivet to be squashed and pulls the two pieces together. -The pin breaks and is disposed of. -It is ideal when the underside of the joint is not exposed.

Question 50

Temporary Fasteners and Joining methods-Self-tapping screws?

Answer 50

-A pilot hole is drilled through the pieces being drilled. -When it is screwed into the pilot hole it cuts its own thread. -Can be used where forming a screw head good increase the cost of the product. (Injection moulding)

Question 51

Wasting processes-Milling?

Answer 51

-Similar to a drill but can move left and right and forwards and backwards as well as up and down, so the workpiece can be machined in a range of directions. -Can be done manually or using a computer controlled machine.

Question 52

Wasting processes-Turning?

Answer 52

-A process carried out on a lathe. -The workpiece is held in a rotating chuck and machined to reduce the diameter to the desired dimensions.

Question 53

Wasting processes-Flame cutting?

Question 54

Wasting processes-Plasma cutting?

Question 55

Wasting processes-Laser cutting?

Question 56

Wasting processes-Punching and Stamping?

Question 57

Wood processes-Butt Joint?

Answer 57

-The simplest method of joining two pieces of timber. -It relies upon adhesives to make the bond, it is clamped and allowed to dry. -It is only suitable for lightweight applications such as modelling.

Question 58

Wood processes-Dowel joint?

Answer 58

-Glue is put into the holes and the dowels are hammered into position and the two halves are clamped together. -Is a simple joining method but stronger than a butt joint. -Typically used in flat pack furniture along with another knock down fitting.

Question 59

Wood processes-Mitre joint?

Answer 59

-Similar to a butt joint but the ends are cut to 45 degrees each and are then glued and clamped together.

Question 60

Wood processes-Comb joint?

Answer 60

-Two pieces are joined by interlocking, the comb also creates an increased gluing surface area. -The increased surface area creates a strong joint great for creating boxes

Question 61

Wood processes-Dovetail joint?

Answer 61

-Perfect for making drawers as this joint creates directional strength. -Once they are glued together they are impossible to pull apart.

Question 62

Wood processes-Mortise and Tenon joint?

Answer 62

-A square/rectangular hole (Mortise) is cut and then glue is spread inside. -A complementary-shaped tenon is cut and the two pieces are clamped together.

Question 63

Wood processes-Housing joint?

Answer 63

-Is useful for making cabinets and shelving. -A groove is cut across one piece and the end of the second piece is slotted into it. -It can be glued or not to allow it to be adjusted but it is structurally strong either way.

Question 64

Wood processes-Half lap joint?

Answer 64

-Made by cutting a step into the end of each piece. -It is simple but is stronger than a but joint because there is an increased surface area.

Question 65

Wood processes-Modesty blocks?

Question 66

Wood processes-Cam-lock connector?

Question 67

Wasting processes-Turning?

Answer 67

-Machining wood on a lathe. -Turning between two centres (Table legs), used to reduce the diameter. -Turning on a face plate, is used to machine domes and bowls, a thick piece of timber is screwed at its base to the face plate. -Turning using a chuck, used to grip the item when it is machined, used when the end of the spindle needs to be drilled but can also be used for bowls and vases.

Question 68

Wasting processes-Routing timber?

Answer 68

-Used to make slots, holes, or decorative mouldings on timber. -Can be handheld and used with guides/jigs in order to produce continuous grooves along the length of the timber. -Can be CNC, where CAD drawings are downloaded to the routers and converted into a path for the router to follow.

Question 69

Forming processes-Milling timber?

Question 70

Wasting processes-Lamination?

Answer 70

-The process of bonding to materials together, typically wood with veneers. -The materials can be glued together and bent over a former, so that when they dry they will form the shape of the former. -While drying they can just be clamped together or put in a vacuum bag where the pressure will pull the laminates together to ensure that there are no gaps in the laminating.

Question 71

Forming processes-Steam bending?

Answer 71

-Heat and steam will make timber strips pliable enough to be shaped over a former. -It is then clamped to the former until it dries. -It has advantages over laminating because it is quicker than waiting for layers of glue to dry, and it is less wasteful as laminated parts often require trimming.

Question 72

Adhesive and fixings-Polyvinyl acetate?

Question 73

Adhesive and fixings-Contact adhesives?

Question 74

Adhesive and fixings-UV hardening adhesives?

Question 75

Adhesive and fixings-Solvent cement?

Question 76

Adhesive and fixings-Jigs and Fixtures?

Question 77

Adhesive and fixings-Router jigs?

Question 78

Adhesive and fixings-Sanding jigs?

Question 79

Paper and Board Finishing-Laminating?

Answer 79

Lamination via encapsulation-The paper is fed through the laminator and heat sealed leaving a polymer sheet cover on both sides. -Lamination via surface coating-

Question 80

Paper and Board Finishing-Embossing?

Answer 80

-Creates a raised design on the surface to give a visual and tactile effect without the need of additional printing. -It uses two dies, the substrate sheet is placed between them and held under pressure until the embossed area is formed.

Question 81

Paper and Board Finishing-Debossing?

Answer 81

-The opposite of embossing, the image sits below the surface of the paper or card. -The products using this are also produced in the same way between two dies.

Question 82

Paper and Board Finishing-Foil blocking?

Answer 82

-Heat and pressure are used to create depth and texture in areas to improve the aesthetics. -The metallic foil adds contrast to the card. -Used to enhance business cards. -Similar to embossing but the design is stamped onto the material through the foil, which is then transferred to the card.

Question 83

Paper and Board Finishing-Varnishing, UV varnishing, and spot varnishing?

Answer 83

-Varnishing is used to enhance the colour as well as some protection against dirt and water. It is only suitable on precoated paper as these will not soak up the varnish. -UV varnishing, provides a very smooth finish, the varnish is applied and then cured using a UV light, it provides a high-quality finish that is abrasion and chemical resistance. -Spot varnishing, is similar to the other types of varnishing but is only applied to specific areas

Question 84

Paper and Board Printing Processes-Screen printing?

Question 85

Paper and Board Printing Processes-Flexographic printing?

Question 86

Paper and Board Printing Processes-Offset lithographic printing?

Question 87

Paper and Board Printing Processes-Digital printing?

Question 88

Polymer finishing-Adding colour?

Question 89

Polymer finishing-Acrylic spray paints?

Question 90

Polymer finishing-Overmouldings?

Question 91

Metal finishing-Cellulose and acrylic paints?

Question 92

Metal finishing-Electroplating?

Question 93

Metal finishing-Polymer dip coating?

Question 94

Metal finishing-Metal dip coating?

Question 95

Metal finishing-Powder coating?

Answer 95

-The product is statically charged and a thermoset polymer resin is sprayed on. -It causes a strong attraction between the powder and the product, the product is then baked in an oven where the heat melts the powder to give an even coating. -It is more hardwearing than paint.

Question 96

Metal finishing-Varnishing?

Question 97

Metal finishing-Sealants?

Question 98

Metal finishing-Preservatives?

Question 99

Metal finishing-Anodising?

Answer 99

-Commonly used on aluminum as it enhances the natural oxide layer, giving it increased hardness and toughness. -Can also provide a colour to the product. -An electrical current flows from the part to be treated to the negative cathode causing the oxide layer to build up evenly on the treated parts surface. -Can also be finished with a clear varnish to provide further protection.

Question 100

Metal finishing-Cathodic protection?