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Casting - Coggle Diagram

- - - - Casting = tapered/undercut
  - - - Mold: Metal
      - Application:
        
        Relatively simple products
        
        No pressure is used
        
        Smooth castings
        
        Accurate
        
        Due to metal mold
      - Materials:
        
        Non-ferrous
        
        low melt temp
        
        Sometimes cast iron
        
        Cores: Sand or metal
      - Expensive (Metal mold)
      - High production speeds
      - Metal poured only with gravity
      - Process:
        
        2 Halves
        
        Pour in metal (top)
        
        Let solidify
        
        Remove product
    - - Mold: mostly metal
      - Implementation:
        
        Pore free: (no bubbles/ gas inclusion)
        
        smooth castings
      - Material:
        
        Al- and Mg- alloys
      - Process:
        
        Fill shape with slight over
        
        Pressure through a refractory
        
        tube on top of the oven
      - Vacuum casting is a variant of low pressure casting
    - - Cold chamber method
        
        Oven = seperate
        
        Material: Mostly Al- and Mg- Alloys
        
        Pressure: 15-150 Mpa
        
        Example: Camera housing
      - Hot chamber method
        
        Oven = part of the machine
        
        Material: Low melting alloys
        
        Pressure: 3-30 Mpa
        
        Material = molten in machine --> can cause problems with Oxidation
        
        Example : pin box metal zipper
    - - Lengths up to 15m
      - Diameter: 15mm - 3m
      - Process:
        
        Molten metal poured in mold
        
        Mold starts rotating
        
        Metal moves to outsides
        
        Makes hollow product
    - - Advantages over perm mold casting
        
        Stronger products
        
        Larger production speed
        
        Lower weight (small wall thickness)
      - Process:
        
        Molten metal = poured in mold
        
        Flows into cavities of mold
        
        Starts rotating
        
        Material = forced into cavities
      - Products are axial symmetric
        
        Example: Wheel with rims
  - - - Uses: Slight overpressure
    - - Uses: Vacuum
    - - Uses: Gravity
    - - Uses: High pressure
- - - - Starts: Coal mining
        
        Coal = Baked in oven (Coked)
    - - Fine ore = prebaked
        
        Pallets
        
        Sinter (chunk)
    - - Cokes + sinter + pellets = Liquid Pig iron (1500*C)
        
        In Blast furnaces
        
        Height = 40m
        
        Temperature = 1650*C
        
        Molten metal = at the bottom
        
        Put into carts for refinery
        
        Impurities = at the top
        
        Diameter 10
    - - Ingots or Coils
    - - Pig iron --> metal
        
        By Lowering carbon content by blowing oxygen
  - - - Material Type
        
        Viscous --> Polymer-processing (Plastics)
        
        Powder --> Powder metallurgy
        
        Liquid --> Casting (ingots)
  - - - Casting Structure + segregation
        
        Metal Alloy
        
        Same as Pure, but center has small grains
        
        Mechanical properties: not equally divided
        
        Added nucleating agents
        
        Inorganic materials added to increase the crystallinity and Speed up cooling.
        
        Mechanical properties: equally divided
        
        Medium-small Grain throughout the structure
        
        Pure metal
        
        At wall of mold: Grains are very small
        
        This place solidifies first
        
        Inside of mold: Grains get bigger
      - Structure looks different depending on cooling rate
    - - Can have Complex / curved shapes
      - Wall thickness restrictions
        
        Thicker wall = longer solidification time
    - - Single piece
      - Huge batch size
  - - - Size accuracy
      - Material
        
        If product = metal, You can't use material with same melting point
      - Detailing / Surface quality
        
        Sand casting = rough surface finish Bad choice for alot of details
      - Geometry / complexity
        
        Difficult to remove: choose expendable mold
      - Product size
    - - Startup time
      - Finishing
      - Batch size
        
        Injection molding = many products
        
        Forging = little amount of products
  - - - Parting line (in a permanent mold) = Always visible + should be removed
      - Mold release: Must be possible to remove product from mold
        
        Undercut: when product can't be removed
      - Can have a Complex geometry
    - - Shrinkage in solid state: Volume reduction during cooling, after solidification
        
        Model need shrinkage allowance
        
        Design the model bigger
      - Solidification Shrinkage: Volume reduction during solidification
        
        Solution, Riser: A Stock of liquid material to fill cavities.
        
        This part stays liquid the longest
        
        Solidification goes in direction of Riser
        
        Atoms rearrange into crystal structure
    - - Cores: Used to make hollow spaces
        
        Should be removable
        
        External mold used for Big/complex models
      - Mechanization
        
        Molding / Casting Machines
  - - - Avoid wall thickness diffferences
- - - - Apply High Pressure: 300 - 1000MPa
      - Into a chape
    - - At high temperatures
      - Sometimes finishing necessary
        
        Shape Calibration, heat treatment
      - Final porosity (amount of empty space) depends on:
        
        Geometry, size powder parts
        
        Compression pressure
        
        Sintering temperature
        
        Sintering time
        
        Product geometry
  - - - Hard to make
    - - Product becomes hard to remove
    - - Details are hard to make
    - - Expensive molds
  - - - Which heats the material
- - - - Green molding sand
        
        Manual molding
        
        Usually contains clay
      - Synthetic sand
        
        Furan resin
        
        Cure time is different
        
        Cement bonded
        
        CO2 Cured
      - Core sand
    - - Disadvantages
        
        Bad surface quality
        
        Large Tolerances
        
        Finishing = (almost) always necessary
      - Advantages
        
        No size, shape or weight limit
        
        Low tooling cost
        
        Good for (almost all) metal alloys
        
        Can withstand high temperatures
  - - - Mold material = Coated sand (with thermoset)
      - Product geometry
        
        Sharp corners
        
        Thin walls
        
        Smooth surface
      - Pattern = made of Metal
        
        Heated +-300*C
      - Larger Batches
    - - Disadvantages
        
        Limited product size
        
        Bigger mold = Fragile mold
        
        Expensive molds and machines
      - Advantages
        
        Accurate tolerances possible (Mold is made from metal)
        
        Good surface quality
        
        High manufacturing speed
  - - - Accurate
      - Smooth casting
      - Works for non-releasing shapes
      - Mostly small
    - - Cast steel
      - Titanium alloys
      - Non-Ferrous
      - Cast iron
    - - Disadvantages
        
        Limited size possible
        
        Expensive patterns and molds
        
        Labor-intensive
        
        Takes a long time
      - Advantages
        
        Complex shapes possible
        
        High accuracy
        
        Good surface quality
        
        Suited for almost all metal alloys