Cutting Technology –chip removing –the largest class of manufacturing activities in engineering production –~1.87 million machine tools –~$168 billion.

Cutting Technology

– chip removing

– the largest class of manufacturing activities in engineering production

– ~1.87 million machine tools

– ~$168 billion - the total value of the machining operation

– numerical control of machine tools

– flexible manufacturing

• Single point tool operations– turning, boring, planing, and shaping

– the peripheral speed of the workpiece - the cutting speed

– the mean value

– the depth of cut is

– the metal removal rate is

• b- chip width

• h- chip thickness

• fr - feed per revolution

ndndv 2211 π v π

2

π 21 ddnvm

2

21 ddd

vfravhbvAQ

• Tool geometry - the side cutting edge angle

– the tool consists of a cutting insert and a tool holder

• The tools

• boring tools

• classical system

•7 - turn a taper•8 - rough turn a tapered thread•9 - finish the thread•10 - drill a short hole•11 - bore the hole to a larger and more accurate diameter•12 - cut an internal groove•13 - cut a short thread in the end of the hole

• Automated machine tools– lead, set, clamp, and change tools

– control the path of the tool relative to the workpiece

– carry out measurements

• Drilling operations

– the metal removal rate:

• d - hole diameter

• fr - feed rate (feed per revolution)

• n - rotational speed

– the chip area for each edge:

• ft = fr/2 = feed per tooth

– the tangential force in the direction of the cutting speed v is:

– the torque is:

– the power is:

• Ks - specific force

frnA

dQ

2

2

dftA

A

frdKs

ftdKsFt

2

)Nm(100082

2

frdKsd

FtT

QKsnfrdKs

nTTwP

4000

22

Drilling Machines

– the positioning of the spindle relative to the workpiece for the proper location of the hole

– if the location is specified to a close tolerance, this cannot be accomplished manually without additional aids

– jig boring machines

• accurately positioned x, y coordinate motions to drill and bore holes in jigs with precise positions

• economical for medium size series of workpieces

• small-lot production on NC drilling machines

• mass production - use multispindle drilling machines as a part of a transfer line

• Multipoint tool operations

– the tooth period:

– the mean metal removal rate is:

– ar - the radial depth of cut

– aa - the axial depth of cut

– f - feed rate

– the mean power is:

nmTt

1

faaQMRR arm

QKsP

• Ways of clamping milling cutters

• Broaching– motion: rectilinear

– no feed motion

– the teeth on the tool are so arranged that they increase in height

– the operation is carried out in one pass

– suited to mass production of surfaces that are straight in at lease one direction

– for machining internal and external surfaces

– gears

– the geometry of the broach completely determines the whole operation

– the machine supplies one linear cutting motion

– pull

– push type machine

– specialized (workpiece moves while the tool is stationary)