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Objectives

• The development of tools throughout history

• The standard types of machine tools used in shops

• The newly developed space-age machines and processes

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History of Machine Tools

• Began during stone age (<50,000 years ago)– Hand tools of wood, animal bones, or stone

• Bronze age (4500 to 4000 b.c.)– Copper and bronze implements

– Power-operated (animal power)

• Iron age (1000 b.c.)– Iron replaced bronze

– Domesticated animals provided power

– Commodities handmade by skilled craftspeople

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History of Machine Tools

• Machine age (~300 years ago)– Explored new sources of energy (water)

• Industrial age began when James Watt produced first steam engine (1776)– Steam engine provided power to other areas– Machines improved

• Steam/steel in ships, railroads, steam tractors• New power – electricity produced by generators• Diesel and gasoline engines

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History of Machine Tools

• Progress continued slowly during first part of 20th century– Spurts during the two world wars

• Since 1950s, progress rapid• Now in space age

– Atom harnessed: nuclear power– Journey to moon and outer space– Calculators, computers, robots commonplace– Can mass produce parts to millionths of an inch

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Improved Production

• Constant improvement made modern machine tools more accurate and efficient

• Improved production and accuracy

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Common Machine Tools

• Generally power-driven metal-cutting or -forming machines used to shape metals– The removal of chips– Pressing, drawing, or shearing– Controlled electrical machining processes

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Machine Tool Capabilities

• Holding and supporting the workpiece

• Holding and supporting a cutting tool

• Imparting a suitable movement (rotating or reciprocating) to the cutting tool or the work

• Feeding the cutting tool or the work so that the desired cutting action and accuracy will be achieved

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Machine Tool Categories

• Four broad categories– Chip-producing machines– Non-chip-producing machines– New-generation machines– Multi-tasking machines

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Chip-producing Machine

• Form metal to size and shape by cutting away unwanted sections

• Generally alter shape of steel-produced products– Casting– Forging http://youtu.be/Ylnzn_rojp4 forging wheels

– Rolling

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Non-chip-producing Machines

• Form metal to size and shape by pressing, drawing, punching, or shearing

• Produce parts by compressing granular or powdered metallic materials

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New-Generation Machines

• Perform operations that cannot be done on

chip- or non-chip-producing machines

• Use either electrical or chemical energy

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Multi-tasking Machines

• Combined machining and turning center

• Can produce virtually any shape part from rough to finish

• Consists of turning center with two independent spindles and vertical machining center with rotary tool spindle

• Combine Information Technology (IT) and Manufacturing Technology (MT)

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Machine Tool Performance

• Metal-removal rate– Depends upon cutting speed, feed rate, and depth

of cut

• Accuracy– How precisely machine can position cutting tool

to given location once

• Repeatability– Ability of machine to position cutting tool

consistently to any given position

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General Machine Shop Tools

• Tools basic to production of metal components

• Operations most commonly performed: turning, boring, threading, drilling, reaming, sawing, milling, filing, and grinding

• Basic Machine tools– Drill press, engine lathe, power saw, milling

machine and grinder

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Drill Press

• First mechanical device developed

• Used primarily to produce round holes

• Function to grip and revolve cutting tool

• Common operations– Drilling, reaming, spot facing, countersinking,

counterboring, and tapping

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Engine Lathe

• Used to produce round work

• Workpiece held and mounted on lathe spindle which is revolved against cutting tool

• Common operations– Straight turning, tapering, facing, drilling, boring,

reaming, and thread cutting

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Two Types of Metal Saw

• Reciprocating cutoff saw– Used to cut work to length only

• Bandsaw– Horizontal

• Used to cut work to length

– Vertical• Used to cut work to length and shape

Material in vise and saw bladebrought into contact with work

Material on table and brought into contactwith continuous-cutting saw blade

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Milling Machine

• Two types: horizontal and vertical milling

• Use one or more rotating milling cutters with single or multiple cutting edges

• Workpiece fed into revolving cutter

• Accessories allow wide variety of operations– Drilling, reaming, boring, counterboring and spot

facing

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Grinder

• Use abrasive cutting tool on workpiece– Bring to accurate size

– Produce high surface finish

• Surface of work brought into contact with revolving grinding wheel

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Common Types of Grinders

• Surface– Used to produce flat, angular, or contoured surfaces

• Cylindrical– Used to produce internal and external diameters

• Cutter and Tool– Used to sharpen milling machine cutters

• Bench or Pedestal– Used for offhand grinding and sharpening

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Special Machine Tools

• Designed to perform all operations necessary to produce single component

• Include– Gear-generating machines– Centerless, cam and thread grinders– Turret lathes– Automatic screw machines

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CNC Equivalent of Engine Lathe

• Capable of machining round parts in one sixth time of skilled machinist

• Two centers– Chucking

• Designed to machine parts in a chuck (holding and driving device)

– Turning • Designed mainly for shaft-type workpieces supported

by some type of tailstock center

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Robotics

• One of fastest-growing areas of manufacturing industry

• Numerical control applied to robots

• Capable of handling materials and changing machine tool accessories easily and efficiently

• http://youtu.be/kpi1LSvX1wA wheels being designed and produced.

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Lasers

• Used increasingly for cutting and welding

• Used in sensing devices for extremely accurate measuring and surveying

• Used for many materials beyond metals

• http://www.youtube.com/watch?v=M_ayRAHezjM&feature=related