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Manufacturing Processes. Powders metallurgy( 분말금속 ) Ceramics( 세라믹 ) Glasses( 유리 ). Associate Professor Su-Jin Kim School of Mechanical Engineering Gyeongsang National University. Contents. Powder Metallurgy( 분말야금 ) Powder production Blending or mixing Compaction Sintering Ceramic
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Manufacturing Processes Powders metallurgy(분말금속) Ceramics(세라믹) Glasses(유리) Associate Professor Su-Jin Kim School of Mechanical Engineering Gyeongsang National University
Contents Powder Metallurgy(분말야금) • Powder production • Blending or mixing • Compaction • Sintering Ceramic • Mixing particles with additives • Shaping • Drying & Firing Glass • Plate, Tubing • Blowing, Pressing
Powder Metallurgy Usage PM1: http://www.youtube.com/watch?v=n_FW7Q2xO5o http://www.hmptech.com
Powder Metallurgy • Powder production • Blending or mixing(혼합) • Compaction(압축) • Sintering(소결) • Finishing operations(마무리가공) PM2: http://www.youtube.com/watch?v=iQIsk44JUYs&feature=related http://www.youtube.com/watch?v=1Mjsi2F2MrY
Powder Production Atomization (입자화) • Liquid-metal stream is broken into powder by water jet. Reduction (환원) • Metallic oxides are reduced to the metallic state.
Particle size and shape • Particle sizeis 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.
Blending metal powders (혼합) • Blending (mixing) powders is the second step, and the purposes are: • to impart physical and mechanical properties and characteristics to the P/M part • obtain uniformity from part to part • lubricants aremixed to improve flow characteristics • binders are used for sufficient green strength
Compaction(압축)of metal powders • Powders are pressed into shapes using dies and presses. • Obtain the required shape, density and particle-to-particle contact.
Compaction of metal powders • The density after compaction depends on: • compaction pressure • powder composition • hardness of the powder • Higher the density, higher the strength and elastic modulus of the part.
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.
Metal Injection Molding (MIM) • Mixing: metal + polymer • Injection monding • Debinding • Sintering • Ceramic Injection Molding (CIM) • Mixing: ceramic + polymer … MIM: http://www.youtube.com/watch?v=BxJaq-WpIIc&feature=related
Design for Powder Metallurgy • Simple & uniform shape • Easy ejection from die • Large tolerance reduce cost • Avoid sharp radius
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.