16 Metal Processes Flashcards
3 types
Forming
Redistribution
Wastage
Forming - process where no material removed, but materials deformed to make required shapes
Redistribution - material is changed from 1 form to another without loss of material.
Wastage - proceed that cuts away material to leave desired shape
Forming
Press forming
What is it used in conjunction with
Make what type of objects
Spinning
What’s special about the lines shown on it when formed, which shows that it used spinning
Press forming:
Make metal seats, car body panels, boxes
Make 3D
Used with robots to lift sheet in place
Good for mass production or large scale batch
Uses sheets form
Diagram - holding force, drawing force, punch, blank holders blank, female die
Spinning:
Make body of stainless steel kettles, pans, light shades
Product may show parallel lines where sheet is forced into MANDREL
Uses sheet
Diagram - head stock, spindle, mandrel, sheet, clamp, tail stock
Forming
Cupping & deep drawing
What does it start with
What happens to metal as deep drawing punch is lowered
Dis
Make tube like shapes, eg fire extinguisher, aerosols cans, drink cans
Starts with metal blank (round sheet)
Metal stretched into shape
High tooling cost
Used for large scale mass or continuous
Diagram - deep drawing punch, retainer, press blank, deep drawing die
Forming, easy
Drop forging
Used for products that need to be …..?
What does it maintain in the product
What happens to metal bullet before pressed and after
Wrought iron forging
Drop forging:
Makes spanners, pliers and screw driver shafts etc
Uses for p. thatt need to be tough + hard
Maintains internal grain and therefore strength
Hot metal billet shaped on anvil, then pressed into shape, then cooled
Suitable for mass production
Diagram - ram, upper & lower die, anvil
Wrought iron forging:
Make decorative metal work such as gate scrolls, decorative fencing
Uses wrought iron of bar stock form
Can be hand OR hydraulic press
Suitable for one off or small batch
Forming easy
Bending
What does it not do
Where can it be done
Rolling - Hot and Cold
Bending Make seams in edges or bends metal to make casing Does not include punching or trimming Can be done in schools Large scale batch in industry Uses sheets or plate His punch and die
Rolling -
Hot rolling makes - I beams, bars, plates X railway tracks
Cold rolling - filing cabinets, chairs, containers
Hot rolling = uniform mechanical properties, no deformation or stresses
Usually Coated with C deposits which must be removed using acid pickling
Cold rolling = has tighter tolerances, better surface finish
Both uses billet
Redistribution
Sand casting
How labour intensive
Dis of finish
Makes train wheels, clamps and vices, motor housing
Is a labour intensive
Not high quality surface finish
Suitable for 1 OFF or SMALL BATCH
Uses molten metal from billet
Diagram - cope drag, sprue pin make runner and riser, vents
Redistribution
Sand casting
How labour intensive
Dis of finish
Makes train wheels, clamps and vices, motor housing
Is a labour intensive
Not high quality surface finish
Suitable for 1 OFF or SMALL BATCH
Uses molten metal from billet
Diagram - cope drag, sprue pin make runner and riser, vents
Redistribution
Gravity die casting
What type of metals can it do
Why is it called gravity die cast
How thick
Makes alloy wheels, engine components, door knobs & handles
Only lower melting point metals eg Al, Al alloys, Zn alloys
Relies on gravity to help flow
Used for thicker mould section
Used for VERY LARGE batch and mass
Redistribution
Pressure die casting:
Whats similar about both
Hot chamber
Where is the molten metal stored
How quick is it
Cold chamber
How is molten metal put in
Hot chamber and cold chamber both make
Toy cars, collectible figures, decorative door knobs handles
- same as gravity die cast in that it’s for low melting point metals Al, Zn alloys
Hot chamber :
Molten metal stored in chamber then a shot of this forced into die.
FAST process
Used for very large batch and mass (same)
Cold chamber:
Molten metal ladled into shot chamber and hydraulically pushed into chamber
Very large batch and mas
Redistribution
Investment casting (lost wax casting)
What special shiz is it used for and
Why is it used for it
Low temperature pewter casting
Investment
Used for jewellery, hip joint replacements
So basically intricate or awkward shapes that would be difficult to do with other processes
HIGH QUALITY finish
Wax patterns cast from a MASTER mould, so repeatable process
Pewter casting:
Used for jewellery key fobs and decorative components
Used in schools
Can be done with simple MDF moulds
One off or small batch (if use Al moulds)
Addition
MIG welding
What does it use - 2 things
What is it suitable for
TIG
What 2 things does it use
Adv and 2 dis
MIG- Metal Inert Gas
Make TUBULAR PRODUCTS like climbing frames, bike framea, car exhausts
Uses an electrode wire + inert gas eg argon or co2
Suitable for 1 off or on assembly line
TIG
Make STAINLESS STEEL ladders or car exhausts
Uses a filler rod and inert gas (argon or He)
Makes acurate strong welds, but requires high skill and takes long
Addition
Oxy-acetylene welding
What metal and stock forms
When is it used
What does it use
Spot welding
What metal
Used to weld MILD STEEL sheet tube or plate where arc welding isn’t available
Useful for quick repair jobs or in remote locations where there is no electricity
Uses steel filler rod
Spot welding:
Used to weld MILD STEEL SHEET metal at points along a length
sheet held between 2 electrode that form a weld when charged electrode touches metal
Fabrication
Soldering
Which metals and what applications
Brazing (hard soldering)
What is it suitable for and why
What does it use
What is its speciality that it can join together
Soldering:
Lightweight applications, thin gauge metals only
Joining precious metals for jewellery or copper pipe in plumbing
Uses filler metal of lower melting than metal being joined. Usually alloy of tin&copper
Brazing
Lower temp than welding so suitable for thinner gauge mild tube or bar
Uses brass filler rod. Uses Oxy-acetylene or gas + compressed air brazing hearth
1 off or small batch
Join dissimilar metals such as mild steel to Al or Cu or nickel
Addition
Riveting and pop riveting
What does it use
When is pop riveting a better choice
Joins sheet metal or plate
Riveting uses 2 pieces that are overlapped and drilled. The end of the shaft is then hammered over to join. Look at diagram to get it
Pop riveting uses rivet gun and rivet pins. Good for where underside of joint is inaccessible
Temporary fasteners and joining methods When are there used - 2 main 3 types: Self tapping screws Machine screws Nut and bolt
Used when p. may need to be disassembled or accessed for repair
Self tapping screws:
Joins thin metal sheet
Pilot hole drilled through. Screw is screwed in and cuts its own thread.
Machine screws :
Joins thicker pieces of metal eg inspection covers in motor or gear housing
A type of bolt where the thread us the whole length of shaft
Top part to be joined has larger home than thread of bolt. Bolt goes through this and is screwed into threaded hole in second piece.
Often tightened with spanner or Allen key
Nuts and bolts:
Similar to machine screws, but instead of being inserted into thread hole, it goes all the way through both pieces and nut is tightened in end to keep pieces together
