© Pearson & GNU Su-Jin Kim© Pearson & GNU Su-Jin Kim
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Manufacturing Processes Manufacturing Processes
Powders metallurgy(Powders metallurgy( 분말금속분말금속 ))Ceramics(Ceramics( 세라믹세라믹 ))
Glasses(Glasses( 유리유리 ))
Associate Professor Su-Jin Kim
School of Mechanical EngineeringGyeongsang National University
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Contents
Powder Metallurgy( 분말야금 )1. Powder production2. Blending or mixing3. Compaction4. Sintering
Ceramic1. Mixing particles with additives2. Shaping3. Drying & Firing
Glass1. Plate, Tubing2. Blowing, Pressing
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Powder Metallurgy Usage
http://www.hmptech.com
PM1: http://www.youtube.com/watch?v=n_FW7Q2xO5o
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Powder Metallurgy
1. Powder production2. Blending or mixing( 혼합 )3. Compaction( 압축 )4. Sintering( 소결 )5. Finishing operations( 마무리가공 )
http://www.youtube.com/watch?v=1Mjsi2F2MrY
PM2: http://www.youtube.com/watch?v=iQIsk44JUYs&feature=related
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Powder ProductionAtomization ( 입자화 )• Liquid-metal stream is broken into powder by water jet.
Reduction ( 환원 )• Metallic oxides are reduced to the metallic state.
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Particle size and shape• Particle size is measured and controlled by screening.• Particle shape is expressed by aspect ratio or shape
factor.• Size and shape of particles affect the processing
characteristics of the powder.
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Blending metal powders ( 혼합 )
• Blending (mixing) powders is the second step, and the purposes are:
1. to impart physical and mechanical properties and characteristics to the P/M part
2. obtain uniformity from part to part3. lubricants are mixed to improve flow characteristics4. binders are used for sufficient green strength
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Compaction( 압축 ) of metal powders
• Powders are pressed into shapes using dies and presses.
• Obtain the required shape, density and particle-to-particle contact.
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Compaction of metal powders
• The density after compaction depends on:
1. compaction pressure2. powder composition3. hardness of the powder
• Higher the density, higher the strength and elastic modulus of the part.
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Sintering• Sintering ( 소결 ) is where compacted metal powder is
heated to below its melting point for the bonding of the individual metal particles.
• Sintered density increases with temperature and time.
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Metal Injection Molding (MIM)
1. Mixing: metal + polymer2. Injection monding3. Debinding4. Sintering
• Ceramic Injection Molding (CIM)1. Mixing: ceramic + polymer…
MIM: http://www.youtube.com/watch?v=BxJaq-WpIIc&feature=related
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Design for Powder Metallurgy
1. Simple & uniform shape2. Easy ejection from die3. Large tolerance reduce cost4. Avoid sharp radius
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Economics of Powder Metallurgy
• The cost depends on method of powder production, its quality and quantity purchased.
• Due to high cost of punches, dies and equipment for P/M processing, production volume must be high.