processes Flashcards
lamination (clamp)
bonding materials together which are typically wood veneers like 3mm plywood
glued together and bent over a former
held in place while drying
lamination (vacuum bagging)
vacuum bagging the former and veneers are placed under a polythene sheet
the edges of the sheet are taped down to the table a valve is fitted to the polymer and a vacuum pump sucks out the air = pressure
steam bending
combined heat and steam enables strips of timber to be made pliable so they can be shaped over a former held in
putting timber into a steam box where the timber will absorb the steam then bent over.
quicker
sandcasting
form high melting point metals into components and products
normally carried out in foundries
one off or batch production
not a high quality finish
sandcasting process
- pattern is made from wood
- drag is turned over and a second box called the cops is clamped into position over the top of the drag sprue and runner is added
- sand is packed into the cops around the runner riser and pattern a small depression is made on the surface around the sprue to make a pouring basin
- cope and drag are separated, stakes and patterns are carefully removed, connecting channels are cut to join
cope and drag reassembled
5 vent holes
6 metal poured into pouring basin down the runner
once cooled removed
die casting
lower melting point metals like aluminium uses tool steel moulds which are reusable only used in large and mass production
high quality surface finish
gravity die casting
melting the metal and then pouring into the mould which relies of gravity with a runner and a riser
thicker or heavier sections
pressure die casting
produce cast items quickly and in high volumes
hot chamber pressure die casting
morels metal is stored in a chamber which is part of the machine a pneumatic and hydraulic pinger forces a shot of molten metal through the neck into the die all filled allowing fine detail
aluminium not used
cold chamber pressure die casting
molten metal is kept separetly in a melting crucible and then ladled into the shot chamber a ram forces the metal into the mould
investment casting
lost wax casting
cast items that are intricate or awkward shapes
difficult to mould in other places
cast jewellery
stainless steel brass aluminium
investement casting process
1 excellent replica of cast is made in wax
2 wax pattern is dip coated with a refractory clay then fired in a kiln to bake the clay wax is burned leaving hollow
3 molten is poured in
4 cooled and broken away
pewter casting process
1 mould is made from mdfwith the laser cutter with sprue and runner
2 mould is sandwiched and clamped
3 pewter is ladled in
4 removed
5 hacksaw off runner and riser
6 casting filed
7 polished
vacuum forming
1 mould is placed on the bed of the machine (platen)
2 polymer sheet is clamped and heater is pulled over
3 when polymer sheet is soft platen rises and heater is removed
4 pump switches on and sucks polymer to mould
5 removed and cut
thermoforming
industrial
baths
extra detail
slow - detailed and embossed
same as vacuum just additional mould presented into the surface
traps the polymer
calendering
smoothing and rolling process
thin polymer sheets
heating pellets of thermoplastics so that it melts and then extruded through heated rollers
industrial
continuous
line bending
produce bends in sheet thermoplastic like acrylic
one off of limited
slow and labour intensive
melted and bent
lamination
3d products from fibre based composites like GRP
boats yachts kayaks
1 mould or former in shape
2 coated with release agent like wax
3 top layer of gel coat is applied - polyester resin
4 fibreglass is laid over resin is rolled over (stippling)
5 repeated until desired thickness
6 sets
injection moulding
1 thermoplastics granules poured into hopper
2 screw thread is rotated by a motor
3 heaters melt
4 hydraulic ram forces screw thread forward
5 mould is water cooled
6 removed
7 trimmed
blowmoulding
1 polymer fed into hopper
2 archimedean screw pulls the polymer through the heated section
3 melted polymer extruded as a tube
4 air is injected forming to sides
5 ejected
rotational moulding
heavy duty seamless hollow objects that need a large wall thickness like traffic cones
1 granules into mould
2 transferred to oven at about 270degrees
3 rotated slowly less than 20 times per min
4 when at thickness it’s cooled
5 removed
extrusion
solid rod or hollow tube or I and T sections
1 granules in hopper
2 moved the polymer granules past the heaters
3 heaters soften polymer
4 ram pushes the screw through the steel die making shape
5 may be supported by rollers
6 cooled and cut
compression moulding
urea or melamine formaldehyde
electrical light fittings
1 slug of thermoset is inserted into moulds
2 closed with hydraulic pressure making it take shape of mould
3 cross linking to allow it to cure
4 opens and removed
5 flash removed
mig welding
weld thin gauge metal or aluminium
heat generated is localised will not burn or distort
joining tubular steel in products like climbing frames
one off fabrication
electric arc to produce heat melting the joint area
uses inert gas likr co2 to form flux shield
helps prevent oxidisation
tig welding
used to weld metals like stainless steel aswell as aluminium and copper
electric arc welding process
electrode doesn’t melt in the process
separate filled rod used gas shield of argon to protect from oxidisation
allows for greater control by the operator
so high levels of skill needed and slow
swimming pool ladders
oxyacetylene welding
low carbon steel sheet, tube or plate where arc welding processes aren’t available
useful for quick repair jobs
mixture of oxygen and acytylene to form an intense flame that can burn at temps of 3500 degrees stored in separate bottles and moxed in a blow torch
1 metal prepared by grinding an angle on the edges of the two edges forming a V shape
2 joint area heating to form a melt pool steel filler rod is introduced
form a continuous bead along joint
riveting
join sheet metal or plate
head at one end and shaft at other
overlapped and drilled
rivet shaft is inserted into hole
the end is hammered in squeezing the two pieces together
pop riveting
thin sheet of metal
rivet and pin
rivet head pushed through hole drilled through the two pieces of metal being joined
head squashes pulling together
when underside of joint is inaccessible
self tapping screws
joining thin sheet metal
pilot hole is drilled through the metal parts to be joined
has a course thread
when screwed in cuts it’s own hole
when panels needs to be removed for maintenance
children’s toys
machine screws
thicker pieces of metal together
inspection covers on motor or gear housings or parts that need to be removed for maintenance
they have a thread the entire length of the shaft
nut and bolt
put all the way through both pieces of metal and then a nut is tightened on to the end of the bolt to keep pieces together
nyloc nuts= nylon to deform to the bolts shape
press forming
sheet metal into 3D
medium carbon steel
aluminium
mass production
dies are made from hardened steel
spinning
body of stainless steel kettles
radial symmetry
spinning sheet metal at high speed
mass production
set up by computer controlled machines
- mandrel put under chuck sheet metal held in place
- roller tool is moved into the blank and is rotated with the mandrel stretching
- roller tool is moved along mandrel as pressure is maintained against the rotating blank
- roller tool is moved to end while still in contact with blank
- removed and trimmed
cupping and deep drawing
tube like shapes
depth of pressing exceeds the diameter
multi operation process
mass continuous production
- pressing blank is clamped over a deep drawing die using a retainer
- hydraulic press moved the deep drawing punch to be in contact with the blank, makes cup shape
- pressed further down
drop forging
hot metal into finished products
needs to be tough and hard
spanner’s pliers
- cast tool steel die, secured to top of anvil
- ram equipped
- billet to be forged is heated to above recrystallisation temp
- heated billet placed by an operator into the anvil die hydraulic ram brought down with force
- lifted and cooled
wrought iron forging
wrought iron is a form of iron that is suitable for forging rolling and bending rather than casting
very low carbon content
shaped using hand tools
milling
machine that looks like a drill
clamped
can run in X and Y and Z
cut slots
shape the the edge
manually or computer controlled
turning
centre lathe
bar can be held in rotating chuck and machined to reduce the diameter and to square or face off the end thread and drill
manual or CNC
cutting tools in tool post
plasma cutting
super heated ionised gas electrically conductive
plasma cutter uses conductive gas to transfer energy from the power supply to the conductive material
cut is faster and cleaner
directed out of torch
gas forced through nozzle
one off production
punching/stamping
wastage process
computer controlled machines
stamp out sections of sheet metal
X and Y
graphic user interface specialist programming not needed
punch pushes through sheet
butt joint
adhesive such as PVA
light weight applications
clamp until dry
mitre joint
simple gluing
at a 90 degree corner using 45 degree ends
comb joint
make boxes
two pieces being interlocked
increased glue surface area
dovetail joint
drawers
directional strength
once glued impossible to pull apart
router and jig or dovetail saw
housing joint
framework construction
cabinets
shelving
groove in one piece
second piece inserted
half lap joint
simple frames or boxes
step in end of each piece
large gluing surface
easy to mark out
knock down fittings
flat pack furniture
supply products that are not assembled
reducing costs
modesty blocks
polymer cloak that have moulded holes to take screws block to panel
cupboards of storage units
barrel nut and bolt
cross dowel
bolt is inserted through the other piece of timber and tightened into the cross dowel
flat pack furniture
cam lock connector
metal dowel that is scrweed into one of the pieces by inserting a screwdriver into the slot on the side
that cam is a disk that fit into a pre drilled hole
locks into cam
wood screws
coarser pitch
thread
conical head to flush
slot head - slot head screw driver wall products
phillips contact with screw driver 57 degree angle
pozidriv allow greater torque power screwdrivers
bolts
join wood pieces
coach bolts
thread runs 2 thirds
square piece that digs into wood
when tightened can’t be undone
turning
machining wood on a wood lathe
turning between centres- machine a spindle such as chair legs and table legs turning between centres enables the spindle to be machined to a reduced diameter
turning on a faceplate- domes or bowls
turning on a lathe
routing timber
slots and holes
decorative mouldings
table top
electric plunge router
CNC routers for natural timbers manufactured boards
CAD drawings downloaded
milling timber
timbers can be machined
small sized basic jobs
rough prototypes
