© Pearson & GNU Su-Jin Kim Powders, Glasses Manufacturing Processes Powders metallurgy( 분말금속 ) Ceramics( 세라믹 ) Glasses( 유리 ) Associate Professor Su-Jin KimSu-Jin Kim School of Mechanical Engineering Gyeongsang National University

© Pearson & GNU Su-Jin Kim Powders, Glasses Manufacturing Processes Contents Powder Metallurgy( 분말야금 ) 1.Powder production 2.Blending or mixing 3.Compaction 4.Sintering Ceramic 1.Mixing particles with additives 2.Shaping 3.Drying & Firing Glass 1.Plate, Tubing 2.Blowing, Pressing

© Pearson & GNU Su-Jin Kim Powders, Glasses Manufacturing Processes Powder Metallurgy Usage PM1:

© Pearson & GNU Su-Jin Kim Powders, Glasses Manufacturing Processes Powder Metallurgy 1.Powder production 2.Blending or mixing( 혼합 ) 3.Compaction( 압축 ) 4.Sintering( 소결 ) 5.Finishing operations( 마무리가공 ) PM2:

© Pearson & GNU Su-Jin Kim Powders, Glasses Manufacturing Processes Powder Production Atomization ( 입자화 ) Liquid-metal stream is broken into powder by water jet. Reduction ( 환원 ) Metallic oxides are reduced to the metallic state.

© Pearson & GNU Su-Jin Kim Powders, Glasses Manufacturing Processes 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.

© Pearson & GNU Su-Jin Kim Powders, Glasses Manufacturing Processes 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 part 3.lubricants are mixed to improve flow characteristics 4.binders are used for sufficient green strength

© Pearson & GNU Su-Jin Kim Powders, Glasses Manufacturing Processes Compaction( 압축 ) of metal powders Powders are pressed into shapes using dies and presses. Obtain the required shape, density and particle-to- particle contact.

© Pearson & GNU Su-Jin Kim Powders, Glasses Manufacturing Processes Compaction of metal powders The density after compaction depends on: 1.compaction pressure 2.powder composition 3.hardness of the powder Higher the density, higher the strength and elastic modulus of the part.

© Pearson & GNU Su-Jin Kim Powders, Glasses Manufacturing Processes 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.

© Pearson & GNU Su-Jin Kim Powders, Glasses Manufacturing Processes Metal Injection Molding (MIM) 1.Mixing: metal + polymer 2.Injection monding 3.Debinding 4.Sintering Ceramic Injection Molding (CIM) 1.Mixing: ceramic + polymer … MIM:

© Pearson & GNU Su-Jin Kim Powders, Glasses Manufacturing Processes Design for Powder Metallurgy 1.Simple & uniform shape 2.Easy ejection from die 3.Large tolerance reduce cost 4.Avoid sharp radius

© Pearson & GNU Su-Jin Kim Powders, Glasses Manufacturing Processes 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.