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－page 249 for detail
Castability: the ease with a metal can be cast to obtain a part with good quality. Test method for castability：
宁波大学工学院
Manufacturing Engineering
宁波大学工学院
Manufacturing Engineering
Casting
1.5 Sand casting
Cores: For casting with internal cavities or passages, cores are used. Core are placed in the mold cavity before casting to form the interior surfaces of the casting and removal from the finished part during shakeout and further processing.
宁波大学工学院
Manufacturing Engineering
Casting
1.5 Sand casting
Patterns: are used to mold the sand mixture into the shape of the casting.
pattern materials: Table 11.3, See P.267
Allowing it to cool;
(b)
(c)
Removing the metal from the mold.
宁波大学工学院
Manufacturing Engineering
Casting
1.2 Casting process
Solidifications of metals:
Pure metals
宁波大学工学院
Manufacturing Engineering
Casting
1.5 Sand casting
宁波大学工学院
Manufacturing Engineering
Casting
1.5 Sand casting
Why sand is used for casting? reading… See P.264 Components of sand molds and their functions: (1) Flask - - cope and drag; (2) Pouring basin (3) Sprue (4) Running system (5) Riser (6) Core (7) Vent
宁波大学工学院
Manufacturing Engineering
Casting
1.4 Casting defects
See Fig.10.11
宁波大学工学院
Manufacturing Engineering
Casting
1.4 Casting defects
Porosity: may be caused by shrinkage or gases or both. Methods to reduce or eliminate porosity
宁波大学工学院
Manufacturing Engineering
Casting
1.2 Casting process
Casting process:
(a)
Pouring molten metal into a mold patterned after the part to be manufactured;
宁波大学工学院
Manufacturing Engineering
Casting
1.1 Concept of casting
Advantages:
Complex shapes with internal cavities or hollow sections Very large parts Almost all metals, suitable for workpiece materials difficult to process by other means Competitive with other processes
宁波大学工学院
Manufacturing Engineering
Casting
1.7 Foundry and automation
宁波大学工学院
Manufacturing Engineering
Casting
1.7 Foundry and automation
Safety in foundry: Dust, fumes from molten metal, fuel for furnaces
Two groups of casting activities: 1. Pattern and mold making---- CAD, CAM, RPM 2. Melting the metals, pouring molten metal into mold ----automated machinery, industry robot
宁波大学工学院
Manufacturing Engineering
Casting
1.7 Foundry and automation
Advantages of foundry automation:
Wide variety and sizes of casting at high production, at low cost, and with good quality control.
Casting
1.4 Casting defects
Main influence factors: Materials, part design, processing techniques Seven categories: （1）metallic projections （2）cavities - - porosity （3）discontinuities (4) defective surface (5) Incomplete casting (6) Incorrect dimension or shape (7) Inclusions
— avoid cavities by shrinkage
(1) Adequate liquid metal (2) Internal or external chills
宁波大学工学院
Manufacturing Engineering
Casting
1.4 Casting defects
－－－－－－－－－－－－－－－－ Reading program: P.256, example.
Please refer to chapters 10 and 11
宁波大学工学院
Manufacturing Engineering
Casting
Metal casting--key words
Casting Mold Grain Fluidity
Sand casting/ die casting
Investment casting Foundry
Pattern/core/porosity/ shrinkage
宁波大学工学院
Manufacturing Engineering
Casting
1.1 Concept of casting
Casting: process which involves pouring molten metal into a mold cavity, then obtains the shape of the cavity.
宁波大学工学院
Manufacturing Engineering
Casting
1.5 Sand casting
Sandoperation: p.271
宁波大学工学院
Manufacturing Engineering
Casting
1.6 Investment casting
Homework--questions： 1. State the sequences of investment casting operation. 2. Explain the meaning of “investment”. 3. In the operation of “pattern meltout”, mold is fired to 650-1050 C for 4 hours, why? 4. Describe the advantages and limitations of investment casting
Manufacturing Engineering
Casting
1. Metal casting
1.1 Concept of casting
1.2 Casting process
1.3 Fluid flow 1.4 Casting defects
1.5 Sand casting
1.6 Investment casting 1.7 Foundry and automation
宁波大学工学院
Manufacturing Engineering
Casting
1.5 Sand casting
Advantages and limitations:
-- See Table Βιβλιοθήκη Baidu1.1, (P.8); Table 11.2, (P.9)
Process of sand casting: (1) Place a pattern having the shape of the desired casting in sand to make an imprint; (2) Incorporating a gating system (3) Filling the resulting cavity with molten metal (4) Allowing the metal to cool until it solidifies (5) Breaking away the sand mold (6) Remove the casting
Alloys
宁波大学工学院
Manufacturing Engineering
Casting
1.2 Casting process Influence of grain size on casting properties:
Strength ductility
micro-porosity
tendency for the casting to crack.
宁波大学工学院
Manufacturing Engineering
Casting
1.1 Concept of casting
Applications: Many parts and components, for examples…
宁波大学工学院
Manufacturing Engineering
Casting
1.1 Concept of casting
Trends:
Mechanization and automation of the casting process Increasing demand for high-quality castings with close dimensional tolerances and no defects
宁波大学工学院
Manufacturing Engineering
Casting
1.3 Fluid flow
Casting system
宁波大学工学院
Manufacturing Engineering
Casting
1.3 Fluid flow
Fluidity: the capability of the molten metal to fill mold cavities. Influence factors of fluidity （1）Characteristics of the molten metal （2）Casting parameters
Castability: the ease with a metal can be cast to obtain a part with good quality. Test method for castability：
宁波大学工学院
Manufacturing Engineering
宁波大学工学院
Manufacturing Engineering
Casting
1.5 Sand casting
Cores: For casting with internal cavities or passages, cores are used. Core are placed in the mold cavity before casting to form the interior surfaces of the casting and removal from the finished part during shakeout and further processing.
宁波大学工学院
Manufacturing Engineering
Casting
1.5 Sand casting
Patterns: are used to mold the sand mixture into the shape of the casting.
pattern materials: Table 11.3, See P.267
Allowing it to cool;
(b)
(c)
Removing the metal from the mold.
宁波大学工学院
Manufacturing Engineering
Casting
1.2 Casting process
Solidifications of metals:
Pure metals
宁波大学工学院
Manufacturing Engineering
Casting
1.5 Sand casting
宁波大学工学院
Manufacturing Engineering
Casting
1.5 Sand casting
Why sand is used for casting? reading… See P.264 Components of sand molds and their functions: (1) Flask - - cope and drag; (2) Pouring basin (3) Sprue (4) Running system (5) Riser (6) Core (7) Vent
宁波大学工学院
Manufacturing Engineering
Casting
1.4 Casting defects
See Fig.10.11
宁波大学工学院
Manufacturing Engineering
Casting
1.4 Casting defects
Porosity: may be caused by shrinkage or gases or both. Methods to reduce or eliminate porosity
宁波大学工学院
Manufacturing Engineering
Casting
1.2 Casting process
Casting process:
(a)
Pouring molten metal into a mold patterned after the part to be manufactured;
宁波大学工学院
Manufacturing Engineering
Casting
1.1 Concept of casting
Advantages:
Complex shapes with internal cavities or hollow sections Very large parts Almost all metals, suitable for workpiece materials difficult to process by other means Competitive with other processes
宁波大学工学院
Manufacturing Engineering
Casting
1.7 Foundry and automation
宁波大学工学院
Manufacturing Engineering
Casting
1.7 Foundry and automation
Safety in foundry: Dust, fumes from molten metal, fuel for furnaces
Two groups of casting activities: 1. Pattern and mold making---- CAD, CAM, RPM 2. Melting the metals, pouring molten metal into mold ----automated machinery, industry robot
宁波大学工学院
Manufacturing Engineering
Casting
1.7 Foundry and automation
Advantages of foundry automation:
Wide variety and sizes of casting at high production, at low cost, and with good quality control.
Casting
1.4 Casting defects
Main influence factors: Materials, part design, processing techniques Seven categories: （1）metallic projections （2）cavities - - porosity （3）discontinuities (4) defective surface (5) Incomplete casting (6) Incorrect dimension or shape (7) Inclusions
— avoid cavities by shrinkage
(1) Adequate liquid metal (2) Internal or external chills
宁波大学工学院
Manufacturing Engineering
Casting
1.4 Casting defects
－－－－－－－－－－－－－－－－ Reading program: P.256, example.
Please refer to chapters 10 and 11
宁波大学工学院
Manufacturing Engineering
Casting
Metal casting--key words
Casting Mold Grain Fluidity
Sand casting/ die casting
Investment casting Foundry
Pattern/core/porosity/ shrinkage
宁波大学工学院
Manufacturing Engineering
Casting
1.1 Concept of casting
Casting: process which involves pouring molten metal into a mold cavity, then obtains the shape of the cavity.
宁波大学工学院
Manufacturing Engineering
Casting
1.5 Sand casting
Sandoperation: p.271
宁波大学工学院
Manufacturing Engineering
Casting
1.6 Investment casting
Homework--questions： 1. State the sequences of investment casting operation. 2. Explain the meaning of “investment”. 3. In the operation of “pattern meltout”, mold is fired to 650-1050 C for 4 hours, why? 4. Describe the advantages and limitations of investment casting
Manufacturing Engineering
Casting
1. Metal casting
1.1 Concept of casting
1.2 Casting process
1.3 Fluid flow 1.4 Casting defects
1.5 Sand casting
1.6 Investment casting 1.7 Foundry and automation
宁波大学工学院
Manufacturing Engineering
Casting
1.5 Sand casting
Advantages and limitations:
-- See Table Βιβλιοθήκη Baidu1.1, (P.8); Table 11.2, (P.9)
Process of sand casting: (1) Place a pattern having the shape of the desired casting in sand to make an imprint; (2) Incorporating a gating system (3) Filling the resulting cavity with molten metal (4) Allowing the metal to cool until it solidifies (5) Breaking away the sand mold (6) Remove the casting
Alloys
宁波大学工学院
Manufacturing Engineering
Casting
1.2 Casting process Influence of grain size on casting properties:
Strength ductility
micro-porosity
tendency for the casting to crack.
宁波大学工学院
Manufacturing Engineering
Casting
1.1 Concept of casting
Applications: Many parts and components, for examples…
宁波大学工学院
Manufacturing Engineering
Casting
1.1 Concept of casting
Trends:
Mechanization and automation of the casting process Increasing demand for high-quality castings with close dimensional tolerances and no defects
宁波大学工学院
Manufacturing Engineering
Casting
1.3 Fluid flow
Casting system
宁波大学工学院
Manufacturing Engineering
Casting
1.3 Fluid flow
Fluidity: the capability of the molten metal to fill mold cavities. Influence factors of fluidity （1）Characteristics of the molten metal （2）Casting parameters