先进制造工艺英文
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Principles of Machini
Types of Advanced Machining Processes
Chemical Machining Electrochemical Machining Electrical Discharge Machining Wire EDM Laser Beam Machining Electron Beam Machining Plasma Arc Cutting Ultrasonic Machining Water Jet Machining Abrasive Jet Machining
8
Electrical Discharge Machining (EDM)
9
Electrical Discharge Machining
Successive electric arcs melt tiny droplets from surface of workpiece
Frozen droplets must be flushed away Electrodes are made from graphite,
3
Typical Parts
Skin panel for missiles and aircraft Turbine blades, nozzles, sheet metal,
small-diameter deep holes, dies, thick metallic and nonmetallic parts
shapes Normally followed by abrasive finishing or laser
peening to remove partially adhering particles Works with a wide variety of metals
7
Electrochemical Machining
2
The Need for Advanced Machining Processes
Traditional machining processes
• Material removal by mechanical means, such as chip
forming, abrasion, or micro-chipping
4
Chemical Machining (Chem Milling)
Chemicals are used to dissolve material
Masks are used to control attack Most common use is circuit boards
and plates for printing (Sunday comics and rotogravure) Cutting speed of 0.0025-0.1 mm/minute – very slow
12
Laser Beam Machining
13
Laser Beam Machining
Direct laser beam against surface of workpiece, as in laser welding
Successive pulses from laser gun vaporize tiny bits of workpiece
alloys
• Workpiece too slender and flexible, hard to clamp • Part shape complex, long and small hole • Special surface and dimensional tolerance requirements
5
Chemical Machining
6
Electrochemical Machining (ECM)
Combines chemical attack and electrical attack High material removal rate Masking is used to control attack Conforming electrodes are to control shape Commonly used for aircraft parts such as airfoil
copper or copper-tungsten alloy Material removed from electrode by arc Recast layer of approximately 0.001” in
depth left on surface Secondary process such as chemical
Advanced machining processes
• Utilize chemical, electrical, and high-energy beams
The following cannot be done by traditional processes:
• Workpiece strength and hardness very high, >400HB • Workpiece material too brittle, glass, ceramics, heat-treated
machining used to remove recast layer
10
Wire EDM
11
Wire EDM
Uses fine brass wire Wire is used once Easily computer controlled Cutting path must contain straight lines Slow cutting speed Wire breakage is a problem Shallower recast layer than conventional EDM
Types of Advanced Machining Processes
Chemical Machining Electrochemical Machining Electrical Discharge Machining Wire EDM Laser Beam Machining Electron Beam Machining Plasma Arc Cutting Ultrasonic Machining Water Jet Machining Abrasive Jet Machining
8
Electrical Discharge Machining (EDM)
9
Electrical Discharge Machining
Successive electric arcs melt tiny droplets from surface of workpiece
Frozen droplets must be flushed away Electrodes are made from graphite,
3
Typical Parts
Skin panel for missiles and aircraft Turbine blades, nozzles, sheet metal,
small-diameter deep holes, dies, thick metallic and nonmetallic parts
shapes Normally followed by abrasive finishing or laser
peening to remove partially adhering particles Works with a wide variety of metals
7
Electrochemical Machining
2
The Need for Advanced Machining Processes
Traditional machining processes
• Material removal by mechanical means, such as chip
forming, abrasion, or micro-chipping
4
Chemical Machining (Chem Milling)
Chemicals are used to dissolve material
Masks are used to control attack Most common use is circuit boards
and plates for printing (Sunday comics and rotogravure) Cutting speed of 0.0025-0.1 mm/minute – very slow
12
Laser Beam Machining
13
Laser Beam Machining
Direct laser beam against surface of workpiece, as in laser welding
Successive pulses from laser gun vaporize tiny bits of workpiece
alloys
• Workpiece too slender and flexible, hard to clamp • Part shape complex, long and small hole • Special surface and dimensional tolerance requirements
5
Chemical Machining
6
Electrochemical Machining (ECM)
Combines chemical attack and electrical attack High material removal rate Masking is used to control attack Conforming electrodes are to control shape Commonly used for aircraft parts such as airfoil
copper or copper-tungsten alloy Material removed from electrode by arc Recast layer of approximately 0.001” in
depth left on surface Secondary process such as chemical
Advanced machining processes
• Utilize chemical, electrical, and high-energy beams
The following cannot be done by traditional processes:
• Workpiece strength and hardness very high, >400HB • Workpiece material too brittle, glass, ceramics, heat-treated
machining used to remove recast layer
10
Wire EDM
11
Wire EDM
Uses fine brass wire Wire is used once Easily computer controlled Cutting path must contain straight lines Slow cutting speed Wire breakage is a problem Shallower recast layer than conventional EDM