Manufacturing Flashcards
What is one-off production?
Unique, handmade items
High cost, high skill
What is batch production?
Limited quantity, set number
Jigs & templates used
What is mass production?
Large-scale, identical products
Assembly lines
What is continuous production?
24/7 production
Fully automated, low cost per unit
What is CNC?
Computer numerical control
What is CNC milling?
Removes material from block with a rotary cutter
Controlled by CNC
Very precise
What is turning?
Used to manufacture things with rotational cross section by removing material
What is sheet pressing?
Sheet metal is shaped by pressing into a mould by a die
Done cold
What is stamping?
A broad term that includes pressing and punching
What is punching?
Holes are cut out of sheet metal with a punch and die
Done cold
What is casting?
Pouring molten materials into a shaped mould to be removed once solidified
Describe the process of sand casting
1) The pattern is placed inside a box
2) The box is filled with moulding sand
3) The box is opened and pattern removed
4) Runners, risers and sprues added so air pockets can escape
5) Molten metal poured through sprue and runner
6) Material left to cool
7) Casting is finished and imperfections removed.
Describe the process of die casting
1) Metal mould (core & cavity) is coated with lubricant.
2) Metal is melted.
3) Molten metal is injected into the mould under high pressure.
4) Metal cools and solidifies in the mould.
5) Finished part is ejected from the mould.
6) Post-processing (trimming, coating) may be required.
What are dies in die casting made from?
Tool steel
What is forging?
Hot metals are compressed in a mould to make 3D forms
What is extrusion (metal)?
Metal is heated elsewhere then loaded in
Pushed through die by a piston
Must be straightened after (with rolling)
What is rolling?
Rolling hot metal with wheels to give it consistent cross section
Strong force between wheels
Continuous
What is drawing?
Reducing the diameter of a wire or bar by pulling it through a die
Cold
Describe injection moulding
1) Polymer granules fed into hopper and released into injection chamber
2) Heated until melted
3) Archimedean screw turns, forcing molten plastic into injection mould
4) Mould is opened (and pins push mould out)
Describe vacuum forming
1) Plastic sheet is clamped above mould
2) Plastic sheet is heated until soft
3) Vacuum bed and mould moved up through plastic
4) Air sucked out, plastic sheet drawn onto mould
Why must vacuum form moulds have draft angles?
Easy Removal
Prevents Damage
Reduces Friction
Why are holes sometimes added to vacuum forming moulds?
To allow trapped air to escape
Prevent bubbles
Describe extrusion (polymers)
1) Polymer granules fed into hopper and released into injection chamber
2) Heated until melted
3) Archimedean screw turns, forcing molten plastic through die
Describe blow moulding
1) A parison (softened plastic tube) is inserted into mould
2) Air blown into parison
3) Parison expands to fill mould
4) Mould is opened to release the plastic (and unneeded bit cut off)
