Vitreous Enameling
Enameling has been used for thousands of years for its decorative and protective properties. It is essentially a sophisticated process that uses heat to fuse a thin layer of glass powder onto a metal surface. Various colors can be produced using different types of mineral.
The metallic surface of the object to be enameled is first engraved with the desired pattern or shape. Powdered glass is then carefully poured into the grooves of the engraved shape and the object is fired in a kiln. The heat melts the powdered glass and the resulting liquid spreads evenly within the shape. When the object cools down the enamel hardens to form a hard, smooth, glass surface.
Typical application
Enamel is resistant to heat and wear, and is therefore often used in everyday products such as kitchen cooktops, saucepans, and washing-machine drums.
Because the coating is completely fireproof and the colors remain vibrant for hundreds of years, vitreous enameling is useful for signs and other graphics—for example, the famous station signs and maps for the London Underground in the UK.
Sustainability
Enameled products are extremely durable, and the brilliance of the original colors is still visible after hundreds of years. The main issue is the amount of heat required to fire them in the kiln.
Further information
www.kingfisherenamelling.com
Glossary
annealing The process of reducing the stresses in a material by the application of heat in a controlled manner. It involves glass or metal being heated and/or cooled slowly in a lehr (an oven or kiln), thus bringing about a relaxing of the internal stresses in the material.
axisymmetric A three-dimensional form that is symmetric around a single axis; a typical example might be a cone.
bar A term used in industry to describe pressure in a vessel. 1 bar is equal to 14.504 pounds per square inch (psi), 0.98692 atmospheric pressure or 100,000 pascals (Pa).
billet In engineering terms a billet is a solid lump of steel from which are made rods, bars, and sections.
biscuit/bisque Refers to a ceramic that has been fired but not glazed. The firing takes place at around 1830°F. A ceramic piece that is biscuit-fired is porous.
burring A rough, often sharp, edge left on a piece of metal after it has been cut, cast, or drilled. Although only a minor by-product of various forms of production, it is sufficiently noticeable that companies have been set up expressly to deal with deburring in its many forms.
CAD Computer-Aided Design.
chip-forming cutting Methods of making components that create chips of material as a result of the cutting process. A typical example would be milling. See also non-chip-forming.
CNC Computer Numerical Control.
CNC folding A process used to create three-dimensional hollow forms by the action of computer-controlled creasing and folding of a flat sheet material. Think of a child’s metal pencil-case.
cold working Working and forming metal or glass at a temperature below that at which it recrystallizes, or, in simple terms, without the use of heat. See also work hardening.
commodity polymers These have a lower mechanical performance than engineering polymers (see below) and include polypropylene and polyethylene.
composites Materials that are made of two or more ingredients. The term is generally used to refer to materials with advanced properties that are made from a combination of polymer resins and fibers.
crazing An imperfection in a ceramic glaze that appears as a fine cracking.
deep draw Refers to a component that has been produced by a long punch that draws the metal into a deep shaft. Impact extrusion is an example of a process that produces a deep draw.
die The terms “die” and “mold” are virtually the same and refer to a form, generally made of steel, that is used as a cavity into which material is added, and which imparts its shape onto the component. See also tools.
draft angle See draw.
draw This is the taper that you will need to consider when designing parts using many molding processes. It is generally a slight angle that allows parts to be easily ejected from a mold.
engineering polymers Plastic materials with performance characteristics, for example: nylon, acetyls, and thermoplastic elastomers (TPEs). Compare commodity polymers.
fabrication A metalworking term used to describe the construction of components by assembling and fixing together various parts, rather than the manufacture by, for example, molding or casting in a single operation.
fettling A final cleaning-up of a ceramic piece before it is fired.
flange A lipped detail or rim that is usually straight and located on the edge of a metal part. Its function is to add stiffness and to facilitate joining to another part.
flash In production, the flash (or flashing) is the excess metal left on a part after a forming operation. It is unwanted and generally needs to be removed.
gate This is a term that is mentioned quite often in connection with plastic molding. It refers to the orifice through which the hot, molten plastic enters the mold cavity.
gel coats A term specific to composites, it refers to a quick-setting coating applied to the internal surface of a mold to provide an improved, highly glossy, protective surface finish.
gob A term used in glass blow molding that refers to the sausage-shaped, measured quantity of molten glass before it enters the mold and is blown.
“green” state The wet, semihard physical state of a ceramic component before it has been fired.
jig In production, a jig is a structure used to control or restrict the movement of a component or material while it is being worked on, assembled, or glued.
lathing Otherwise known as turning but generally used in the context of working in metal.
mandrel Often used in metal spinning to describe the solid form against which the sheet of metal is spun to achieve the desired shape.
matrix When using composites, the matrix is the material to which the fibers are added—often a liquid polymer.
micron One thousandth of a millimeter.
mold See die.
non-chip-forming cutting A term used to describe cutting methods that do not result in chips of material being formed. These methods are very clean and include, for example, laser or water-jet cutting, where the material is blasted or vaporized leaving no “chips.”
outgasing A term used to describe the emission of a volatile gas during the processing of plastics, for example in injection molding. There are many established ways of removing these gases.
parting lines The fine line that stands proud on the surface of a component that is often left after molding. Essentially it is where the two or more parts of a mold have separated. Also known as witness lines.
postprocess operations Any process that takes place after the main production is referred to as “post.” Examples include: post finishing, where surfaces might need to be cleaned up; and post forming, post working, or post-machining where a secondary process is used to complete the component. These might include drilling a hole or deburring.
pre-form Used predominantly in blow molding to describe an injection molded, semiformed component before it has been fully molded. A kind of product in its embryonic stage.
psi A unit of pressure that stands for pounds per square inch. See also bar.
re-entrant angles See undercuts.
refractory materials Materials with very high temperature-resistance that are used in furnaces or kilns. Many ceramics are “refractories,” which is another way of describing these materials.
risers A term used in metal casting to describe a shaft in the mold that acts as a reservoir from which molten metal can be drawn to offset the shrinkage that takes place in metal casting once the metal cools and solidifies. See also runners.
runners The shaft into which metal is poured during casting. See also risers.
sink marking This is a common, often easily solved, problem that occurs in injection molding. It is when plastic that needs to be formed into a flat surface exhibits a slight indent or depression, the “sinking.” This is often because of local shrinkage of the material within the component.
solid-state forming An umbrella term used to describe the processing of materials usually at room temperature. Examples include impact extrusion and rotary swaging.
sprue This is the tapered piece of plastic that is left attached to a component as the result of injection or compression molding. It occurs where the plastic flowed into the mold from the nozzle. Evidence of where this has been cut off can often be seen in cheap moldings.
substrate A term generally used to describe the surface material onto which a secondary layer of material is applied. It can be considered as something like the base material.
tempering The purpose of tempering is to reduce the hardness of steel by relieving the stresses in the material. The process involves heating the steel to a temperature below the transformation range and then cooling it slowly in air.
tensile strength When a material is stretched so that the length increases and the cross-section decreases, tensile strength is the amount of stress that the material is able to withstand.
thermal expansion Most materials expand when heated and contract when cooled. Thermal expansion is defined as the ratio between increase in temperature and increase in dimension of the material.
thermoplastics Together with thermosets (see below) the term is one of the main classifications for grouping plastics. Unlike thermosets, thermoform plastics can be reheated and subsequently remolded.
thermosets Plastics that once formed cannot be reheated or remolded. Also known as thermosetting plastics. Compare thermoplastics.
tools A general term (also “tooling”) that refers to the part of the production setup that could loosely be described as a mold (see above). However, tooling is not necessarily the male or female mold itself, but the complete mechanism that is in direct contact with the material. It may refer to either a mold, cutters, or formers.
undercuts This is a very common term used in many forms of molding to describe details in a component that would restrict that component’s removal from a mold. Also often referred to as re-entrant angles.
witness lines See parting lines.
work hardening The best way of explaining this phenomenon is that when a piece of metal is bent (“worked”) continuously it becomes increasingly hard and difficult to bend, and eventually it breaks. Annealing (see above) at regular intervals prevents this and allows for further working. See also cold working.
Index
acid etching 163
Acme Metal Spinning (USA) 57
Acme Thunderer whistle 50, 51
Acme Whistles (UK) 50
advanced technologies 239-59
Air Switch flask lamp 116-7
Air-Chair 201
Alias (Italy) 181, 182
alloys 44, 72
backward impact extrusion 146-8
ceramic coating 270
explosive forming 67-9
forging 187-9
high-pressure die-casting 219-21
investment casting 224-7
laser cutting 47
metal injection molding (MIM) 216-8
sand casting 228-30
superforming 70, 72
wire EDM (electrical discharge machining) 44
Allwood, Julian 257
ALPI (Italy) 84
aluminum, superforming 10-11, 70-2
anodizing 279
Apple design studio 104, 279
Apple iMac aluminum stand 104
Apple iPod Shuffle 279
Apple Mini iPod 279
Arad, Ron 72, 279
architectural mesh 108-9
Aridion™ 269
Arola, Antoni 112
Around the Roses table 262
autoclave molding 12-13, 156-7
automated CAD-driven machines 17
back pressure forming 71-2
backward impact extrusion 12-13, 146-8
Bakelite 174
balloon 134
balloon former 134
ballpoint pen, BIC® Cristal® 196
Barthes, Roland 196
bath, “Loo” range 234
bearings 169, 171
bench, Berta Vilagrassa 265
bending 59
plywood 10-11, 80-2, 113, 184
Bengtsson, Mathias 158
Berta Vilagrassa bench 265
beverage can, pull tab 59
BIC® (France) 196
BIC® Cristal® ballpoint pen 196
Bich, Marcel 196
bike, MN01 70
binders 216-17
Black Honey bowl 246
blanking 59
blow and blow molding, glass 9, 12-13, 115, 120-3
blow forming 76, 77
blow molding 12-13, 115, 127-8, 129-31
blown film 12-13, 92-3
blown glass 120
Blumer, Riccardo 181, 182
body panels, bus 176
Boontje, Tord 263
boring 18
Bosch 172
bottles
glass 120-3
Kikkoman 120
plastic 6, 76, 115, 128, 130, 133
Sigg 146
bowls 29, 46
Black Honey 246
mortar 27, 28
paper 46
Brighton University (UK) 184
broaching 20
bronze 168-9
bubble forming 70-1, 72
Bruni, Vetrerie (Italy) 124
bubble forming 70, 71, 72
Bunte, Amelie 143
business card, Mikroman 38
Buxton, Sam 38
C1 chair 248
CAD files 8, 19, 46, 192-3, 239, 244, 246-7, 252
calendering 12-13, 90-1
Cambridge University 257
Campbell, Louise 42
Cantu, Homaro 240
car hood ornament, “Spirit of Ecstasy” 224, 225
carbides 44
carbon, reinforcement fibers 152, 153
carbon nanotubes 25
case hardening 272
cavity forming 70-1
cell phone cover 242
centrifugal casting 12-13, 161-3
centrifuging 161, 162
Ceram Research (UK) 234
ceramics
coating 270
cold isostatic pressing (CIP) 172-3
compression molding 174
formers 134-5
glazing 281
hot isostatic pressing (HIP) 170-1
injection molding (CIM) 222-3
jiggering and jollying 29-32
laser cutting 47
pressure-assisted slip casting 141, 234-5
sintering 168
slip casting 137, 140-2, 235
thick film metalizing 273
turning 26-8
viscous plastic processing (VPP) 234-5
chairs 53
Air-Chair 201
AP Stool 80
CI 248
Extrusions 96-7
Gubi 83, 85
Laleggera range 181
Parupu 78
Pollock 138
Prince 42
Seggiolina POP 178, 179
Sparkling 6, 130
spun carbon 158
chemical milling 10-11, 38-9
chemical polishing 276
chemical vapor deposition 273
chip-forming processes 18, 59
chocolate Easter eggs 137, 139
chocolate-box tray 64
Chorchoj, Olgoj 118
chrome plating 262, 279
Cinderella table 21-2
circumferencial winding 158
closed-die forging 187-8, 190, 191
CNC Auto Motion (USA) 23
co-extrusion blow molding 127, 132-3
CO2 silicate casting 228
cold isostatic pressing (CIP) 14-15, 27, 30, 172-3
complex parts 194-237
composite materials
autoclave molding 156-7
contact molding 154
fiber-reinforcement 99, 100, 101, 102, 152, 154, 156, 158, 175
filament winding 158
MuCell® injection molding 203-5
Pulshaping™ 12-13, 102-3
pultrusion 99-101
reaction injection molding (RIM) 199-200, 211
transfer molding 176
vacuum infusion process (VIP) 154-5, 176
compression molding 14-15, 102, 172, 174-5, 207
computer numerical control (CNC) cutting 10-11, 19, 21-3, 43, 81
concrete 244
“contact forming” 69
contact molding 12-13, 152-3, 207
continuous lengths of material 89-113
contour crafting 14-15, 244-5
Cornerstone Research Group (USA) 255
cross-laminating veneers 80-1
Curvy Composites (UK) 7, 87, 184
cutting, metal 59
cutting tools 17
David Design (Sweden) 228
Davy, Sir Humphrey 164
deburring 275
decalization 277
decoration 212-5
decorative finishing techniques 262-7, 279-81
decorative metal screens 108
deep three-dimensional forming, plywood 10-11, 83-5
Demakersvan (Holland) 21-2
dental bracket, used in braces 222, 223
Desert Storm architectural panels 67
desktop printers 240-3
Diamonex 272
Diamon-Fusion® 273
diaphragm forming 72
die cutting 10-11, 37, 40-1
die-pressing and sintering 168
dinner tray 86
dip coating 280
dip molding 12-13, 134-6, 280
direct extrusion see forward impact extrusion
Dixon, Tom 262
drape forming 65
draping 53
drilling 20
drop forging
see closed-die forging
dry-bag pressing 172, 173
DuPont™ 278
DuraPulp 78, 79
dynamic lathing 19, 26-8
E-Go laptop 214
edible menu 240
Ekuan, Kenji 120
electrical plug 174-5
electroforming 12-13, 164-5
micro-moulds 14-15, 250-1
electromagnetic forming 6, 10-11, 54-5
electron-beam machining (EBM) 10-11, 24-5, 35
electroplating 164, 169, 262, 265
electropolishing 265
enameling 281
engineering components 216
European Space Agency 270
Exjection® (Germany) 6, 12-13, 94-5
expanded plastic foam
foam molding 14-15, 178-80
foam molding into plywood shell 14-15, 180-3
reaction injection molding (RIM) 14-15, 153, 199-200, 211
expanded polypropylene 178, 179, 180
explosive forming 10-11, 67-9
extrusion 6, 94, 96-8, 146, 203, 205, 244
extrusion blow molding 12-13, 127, 132-3
Extrusions chair/bench 96-7
facing 18
Faraday, Michael 134
Fiam Italia (Italy) 52
fibers, reinforcement 99-101, 154, 156, 158, 175, 176, 199
fiber-reinforced plastics 99-101, 102, 152
filament winding 12-13, 158-60, 255-6
film insert molding
see in-mold decoration
finishing techniques 6, 18, 260-80
decorative 262-7, 279-81
functional 268-81
see also under
individual entries
Fiskars (Finland) 209
flat swaging 107
Flexiform 234
flocking 163
fluid forming
see hydroforming, metal
foam molding 14-15, 178-80
into plywood shell 14-15, 180-3
see also reaction injection molding (RIM)
Ford Motor Company 177
forging 14-15, 146, 167, 187-9
forward impact extrusion 146, 147
Foster, Norman 72
Franzheld, Robert 143
Fraunhofer Institute (Germany) 26, 192
free internal pressure-formed steel (“FIDU”) 10-11, 73-5
Full Blown Metals (UK) 76
functional finishing techniques 268-81
furniture 6, 7
plywood 21-2, 80-5, 113, 181-3
sheet material 37
veneers 83, 85, 113, 181
see also tables; chairs
Galen, Marcel van 214
galvanizing 275
garden secateurs 209
Gardone, Massimo 262
gas-assisted injection molding 14-15, 153, 196, 197, 200, 201-2, 211
gas cutting
see oxyacetylene cutting
gas welding
see oxyacetylene cutting
glass
blow and blow molding 12-13, 120-3
blowing by hand 12-13, 115-19, 121
lampworking 12-13, 118-19
press and blow molding 124-6
pressing 12-13, 231-3
protective coatings 273
roll forming 104
sandblasting 267
sintering 168
slumping 10-11, 52-3
vitreous enameling 281
GoreTex® 278
granite 23
graphics, application of 262, 265, 266, 268, 277, 280
gravity die-casting 220
Gubi (Denmark) 83
Gubi chair 83, 85
hand lay-up molding 152, 154
hand-blown glass 12-13, 115, 116-7, 121
handrail system, T-section 143
hard steels 44
metal injection molding (MIM) 14-15, 216-8
Haunch of Venison (UK) 56, 97
Hay (Denmark) 42
Heatherwick, Thomas 56, 96-7
helical winding 158, 159
“High Funk” table legs 228
high-energy-rate forming
see explosive forming
high performance alloys 44
high temperature coatings 272
high-density polyethylene (HDPE) 128
high-pressure die-casting 14-15, 169, 219-21
hip-bone plate 24
Holdcroft, Harold 236
hollow components, with thin wall section 115-65
hot foil blocking 266
hot isostatic pressing (HIP) 14-15, 27, 30, 169, 170-1, 222
Hudson, Joseph 50
HVAC valve component 203
hydrodynamic machining
see water-jet cutting
hydroforming, metal 12-13, 143-5
Ideal Standard (UK) 234
IDT Systems (UK) 212
iMac aluminum stand, Apple 104
impact extrusion 146-7
in-mold decoration 14-15, 212-3, 268
Inclosia Solutions 214
incremental sheet-metal forming 14-15, 57, 257-9
indirect extrusion see backward impact extrusion
industrial craft 257
industrial weaving 108
Industrial Origami® (US) 6, 10-11, 61-3
inflated stainless steel pillows 76