Machine Design Databook Episode 3 part 9 pptx

All cutters are high-speed steel and are form relieved.Right-hand corner rounding cutters are standard, but left-hand cutter for1inch size is also standard.. The chip thickness The power

Rounding Concave quarter

circle and flat

TABLE 25-34

Types and definitions of milling cutters (Cont.)

Arrangement

End mill Helical teeth at one

end and

circumferential

Light work,slots,profiling,facingnarrowsurfaces

50 mm

TANGED END

TAPPED END

Parallel Shank

Tee slot Circumferential

and both sides

Tee slots inmachinetable

For bolts up to

24 mmdiameter

Dovetail On conical surface

and one end face

Dovetailmachineslides

38 mm diameter,

458 and 608

40–160 mmdiameter

Screwslotting

60–400 mmdiameter

Thick Thin Clearance

Slotting and Form relievedFace mills Helical mills side mills End mills cutters Circular sawsMaterials to be milled HSS Carbide HSS Carbide HSS Carbide HSS Carbide HSS Carbide HSS CarbideCast iron

Soft (up to 160HB) 0.40 0.50 0.32 0.40 0.22 0.30 0.20 0.25 0.12 0.15 0.10 0.12Medium (160 to 220HB) 0.32 0.40 0.25 0.32 0.18 0.25 0.18 0.20 0.10 0.12 0.08 0.10Hard (220 to 320HB) 0.28 0.30 0.20 0.25 0.15 0.18 0.15 0.15 0.08 0.10 0.08 0.08Malleable irona 0.30 0.35 0.25 0.28 0.18 0.20 0.15 0.18 0.10 0.10 0.08 0.10Steel

Softa(up to 160HB) 0.20 0.35 0.18 0.28 0.12 0.20 0.10 0.18 0.08 0.10 0.05 0.10Medium (160 to 220HB) 0.15 0.30 0.12 0.25 0.10 0.18 0.08 0.15 0.05 0.10 0.05 0.08Harda(220 to 360HB) 0.10 0.25 0.08 0.20 0.08 0.15 0.05 0.12 0.05 0.08 0.03 0.08Stainlessa 0.20 0.30 0.15 0.25 0.12 0.18 0.10 0.15 0.05 0.08 0.05 0.08Brass and Bronze

Feed, mm/rev of blank

HobModule Roughing (single Roughing speeds,Type of gear Material mm thread hob) (multithread hob) Finishing m/minHigh speed reduction and step up Steel 1.5–8 1–1.5 1–1.5 0.8–1.25 9–25

One-piece construction High-speed steel Cutting portion 760 HV (62 HRC) Min

Body Carbon steel with tensile strength

not less than 700 MPa (190 HN)

Tang of Morse taper shank 320 HV (32 HRC) Min

Note: The equivalent values within parentheses are approximate

Recommendations for selection of milling cutters:

Tool Type N—For mild steel, soft cast iron and medium hard non-ferrous metals

Tool Type H—For specially hard and tough materials

Tool Type S—For soft and ductile materials

Material to be cut Tensile strength, MPa Brinell hardness,HB Tool typea

Aluminum alloy, age hardened

aTool types within parentheses are non-preferred Courtesy: IS 1830, 1971

Tolerance on thickness b of key: square, h9; rectangular, h11

cTolerance on keyway width a: light drive fit, N9

For keyway in arbor: running fit, H9; light drive fit, N9

For keyway in cutter: C11

All dimensions in inches All cutters are high-speed steel and are form relieved.

Right-hand corner rounding cutters are standard, but left-hand cutter for1inch size is also standard

a

For key and keyway dimensions for these cutters, see standard handbook

bTolerances on cutter diameters areþ1

16,
1

16inch for all sizes

cTolerance does not apply to convex cutters

dSize of cutter is designated by specifying diameter C of circular form

e

Size of cutter is designated by specifying radius R of circular form

Source: Courtesy: ANSI/ASME B94, 19, 1985, Erik Oberg Editor Etd., Extracted from Machinery’s Handbook, 25th edition, Industrial Press,N.Y., 1996

All dimensions are in inches.

All gear milling cutters are high-speed steel and are form relieved

For keyway dimensions refer to standard handbook

Tolerances: On outside diameter,þ1

16,
1

16inch; on hole diameter, through 1 inch hole diameter,þ0.00075 inch; over 1 inch and through 2 inch holediameter,þ0.0010 inch

For cutter number relative to number of gear teeth, see standard handbook

Roughing cutters are made with No 1 cutter form only

Source: Courtesy: ANSI/ASME B94, 19, 1985, Erik Oberg Editor Etd., Extracted from Machinery’s Handbook, 25th edition, Industrial Press,N.Y., 1996

In case of regular mill a left-hand cutter with left-hand helix is also standard.

Source: ANSI/ASME B94, 19, 1985, Erik Oberg Editor Etd., Extracted from Machinery’s Handbook, 25th edition, Industrial Press, N.Y., 1996

D C

D L

S

w C D

16inch.aB is the length below the shank

Source: Courtesy: ANSI/ASME B94, 19, 1985, Erik Oberg Editor Etd., Extracted from Machinery’s Handbook, 25th edition, Industrial Press,N.Y., 1996

Cutter diam of Width of Length Cutter diam of Width of Length Cutter diam of Width of Length

No cutter,D face, W overall,L No cutter,D face, W overall,L No cutter,D face, W overall,L

Cutter diam of Width of Diam of Cutter diam of Width of Diam of Cutter diam of Width of Diam of

No cutter,D face, W a hole,H No cutter,D face, W a hole,H No cutter,D face, W hole,H

All dimensions are given in inches All cutters are high-speed steel

Shank type cutters are standard with right-hand cut and straight teeth All sizes have1inch diameter straight shank Arbor type cutters havestaggered teeth

For Woodruff key and key-slot dimensions, see standard handbook

Tolerances: Face width W for shank type cutters:1

16,
0.0004,
0.0009,1and over,
0.0005,
0.000 inch

Hole size H,þ0.00075,
1:000 inch Diameter D for shank type cutters;1, through1inch diameter,þ0 016, þ0.015,7through 11,þ0.012, þ0.017;

11through 11,þ0.015, þ0.02 inch These tolerances includes an allowance for sharpening For arbor type cutters diameter D is furnished1

larger than bore and tolerance ofþ0.002 inch applies to the over size diameter

Source: Courtesy: ANSI/ASME B94, 19, 1985, Erik Oberg Editor Etd., Extracted from Machinery’s Handbook, 25th edition, Industrial Press,N.Y., 1996

The tangential component of grinding force Fz,

which constitutes the major value of grinding force

Fy = Fr

F z = F t

v g

FIGURE 25-26 Forces acting on a grinding wheel

The chip thickness

The power required by the grinding wheel

Metal removal rate in case of transverse grinding

The power at the spindle

Ft¼ Kmst vw

where

s ¼ feed rate, mm/rev

t ¼ thickness of material removed from job or depth of cut, mm

vw¼ peripheral velocity of workpiece/job, m/min

vg¼ peripheral velocity of the grinding wheel, m/min

Km¼ specific resistance to grinding of the work material, N/m2(Table 25-51)

Fy¼ Fr¼ radial component of the force in cal grinding operation, kN

cylindri-Fx¼ horizontal component of the force against the feed, kN

Fz¼ Ft¼ vertical component of the force in the cylindrical grinding operation, kN

p ¼ pitch of grains, mm

dw¼ diameter of workpiece, mm

dg¼ diameter of grinding wheel, mm þve sign for external grinding wheel,
ve for internal grinding wheel

Energy per unit volume of material removed

Vertical boring:

The power required for boring

Centerless grinding:

The peripheral grinding wheel speed

Through feed rate

Metal removal rate from through feed grinding

Metal removal rate from plunge grinding

E ¼ P bsvg

ð25-128Þ where

dr¼ diameter of regulating wheel, mm

nr¼ speed of regulating wheel, rpm

 ¼ regulating wheel inclination angle, deg

b ¼ width of cut plunge grinding, mm

sp¼ plunge in feed rate per minute ¼ ðsnwÞ, mm/min

s ¼ plunge in feed rate per work revolution, mm/rev

nw¼ workpiece revolution per minute

SHAPING (Fig 25-27)

The force of cutting can be found by empirical

formula Fz

The approximate equation 1 expression for cutting

force Fzfor cast iron

The power consumption of shaping machine

The velocity of crank pin of r radius

The peripheral velocity of the sliding block

The peripheral velocity of the driving pin of the

rocker arm at point A.

The average velocity of ram at its middle position

during its stroke Fig 25-28

Fz¼ Ft¼ 9:807Cpkdxsy SI ð25-135aÞ where Fzin N

Fz¼ Ft¼ Cpkdxsy

Customary Metric Units ð25-135bÞ where x, y, k and Cphave the same values as in lathe tools; Fzin kgf

Equation (25-135) can be also used for the case of planing machine.

(b)

(a) c

d

v 1 v2

AB

C

K

p R a

FIGURE 25-28 Ram velocity diagram of a crank shaper

The approximate/average velocity of ram

The maximum speed of ram for the average value of

Punching (Figs 25-29, 25-31 and 25-32):

Maximum shearing force or pressure to cut the

Fmax¼ pDut for round hole ð25-140Þ

¼ utP for any other contour

PunchWorkpieceDie

Work done,N-m (lbf in)

Shear punch

F

t

hτ

Penetration ratio

Punch Dimensioning:

When the diameter of a pierced round hole equals

stock thickness, the unit compressive stress on the

punch is four times the unit shear stress on the cut

area of the stock, from the formula.

The maximum allowable length of a punch can be

calculated from the formula

For clearance between punch and die

c ¼ x

where

Fmax¼ maximum shear force, kN (lbf)

u¼ ultimate shear stress, taken from Table 25-54

t ¼ material thickness, mm (in)

c¼ unit compressive stress on the punch, MPa (psi)

 ¼ unit shear stress on the stock, MPa (psi)

t ¼ thickness of stock, mm (in)

d ¼ diameter of the punched hole, mm (in)

A value for the ratio d=t of 1.1 is recommended.

L ¼ d 8

 E



d t

1=2

ð25-144Þ where d=t ¼ 1:1 or higher value

E ¼ modulus of elasticity, GPa (psi) Refer to Tables 25-52 and Fig 25-36.

Punch holderPunchStripperDie blockDie holderGuide pins

Guide pin busing

Bolster plote

FIGURE 25-31 Common components of a simple die

Courtesy: F W Wilson, Fundamentals of Tool Design,

American Society of Tool and Manufacturing Engineers,

FIGURE 25-32 Stresses in die cutting

Shearing (Fig 25-30):

Shearing force

The stripper pressure or force

The formula used to compute the force (or pressure)

ð25-145Þ where his shown in Fig 25-30

Neutral axis

Initial length of strip of metal (Fig 25-35)

Bending allowance for right angle bend to take into

account reduction of length K and T (Fig 25-35)

The bending force

Planishing force

where

b¼ bend allowance (arc length of neutral axis),

mm (in)

ri¼ inside radius of bend, mm (in)

t ¼ metal thickness, mm (in)

Kn¼ constant for neutral axis location

¼ 0:33 when riis less than 2t

¼ 0:50 when riis more than 2t

b¼ ðriþ tÞ tan

2
360



riþ t 2



ð25-149Þ where

b¼



3 tan 2

t

r i

FIGURE 25-35

V-PunchVee die

KnurledpinSpring

The bending punch

Spring loaded padDie

FIGURE 25-36 Bending methods

The force/pressure required for V-bending (Fig.

25-36a)

The force required for U-bending (channel bending)

The force required for edge-bending (Fig.25-36b)

Drawing (Fig 25-37):

Force required for drawing

Empirical formula for pressure (or force) for a

A tentative blank size for an ironed shell can be

obtained from equation

The blank size taking into consideration the ratio of

the shell diameter to the corner (d=r) which affects

the blank diameter.

Fv¼ KLt2 sut

where

F ¼ V-bending force, kN (tonforce)

L ¼ length of part, m (in)

W ¼ width of V- or U-die, m (in) sut¼ ultimate tensile strength, MPa (tonf/in2)

K ¼ die opening factor

¼ 1:20 for a die opening of 16t

¼ 1:33 for a die opening of 8t

d
c



ð25-158Þ where

D ¼ diameter of blank

d ¼ diameter of shell

h ¼ height of shell

r ¼ corner radius

T ¼ bottom thickness of shell

t ¼ thickness of wall of shell

C ¼ constant which takes into account friction and bending

For die clearance for different metals

For nomograph for determining draw-die radius

For chart for checking percentage reduction in

draw-ing of cups.

For clearance between punch and die

For draw clearance

For design of speed-change gear box for machine

tools, kinematic schemes of machine tools, layout

dia-grams or structural diagram for gear drives, version of

kinematic structures in machine tools, etc.

For fits and tolerances

For surface roughness and surface texture

For tool steels and die steels

ð25-160dÞ when d=r is less than 10

Refer to Fig 25-38 Refer to Fig 25-39 Refer to Fig 25-40

Refer to Fig 25-29 and Table 25-52 Refer to Table 25-53

Refer to subsection ‘‘Designing spur and helical gears for machine tools’’ from pp 23-109 to 23-138 of Machine Design Data Handbook, McGraw-Hill Pub- lishing Company, New York, 1994.

Refer to Chapter 11 on ‘‘Metal fits, tolerances and surface textures’’, pp 11.1 to 11.32.

Refer to Chapter 11 on ‘‘Metal fits, tolerances and surface textures’’, pp 11.26 to 11.32.

Refer to Chapter 1 on ‘‘Properties of engineering materials’’, Tables 1-31 to 1-36 for tool steels and Tables 1-49 and 1-51 for die steels.

TABLE 25-49

Metal removal rate in milling operation, Q

Material Metal removal rate,Q, mm3

/kW minCast iron, gray 12600

Average unit power Pu, for grinding

Unit powerPu, kW/cm3/minDepth of grinding, mm per pass

TABLE 25-52

Clearance between punch and die (Fig 25-29)

Location of the proper clearance determines, either hole or blank size, punch size controls hole size, die size controls blank size 2C ¼ clearance ¼ dp
ddi

Clearance between punch and die, mmSheet thickness,

mm Mild steel Moderately hard steel Hard steel Soft brass Hard brass Aluminum

TABLE 25-54

Shear strength of various materials

Ultimate strength,sut Shear strength,s

Ferrous alloys

TABLE 25-54

Shear strength of various materials (Cont.)

Ultimate strength,sut Shear strength,s

Blank and perforate hot

Group 3 materials, 7.5% + average clearance

Group 2 m aterials, 6.0% + average clearance

Group 1 materials, 4.5% + average clearance0.001

Group 1: 1100S and 5052S aluminum alloys, all tempers

An average clearance of 41per cent of material thickness isrecommended for normal piercing and blanking

Group 2: 2024ST and 6061ST aluminum alloys; brass, alltempers; cold rolled steel, dead soft; stainless steel soft Anaverage clearance of 6 per cent of material thickness isrecommended for normal piercing and blanking

Group 3: Cold rolled steel; half hard; stainless steel, halfhard and full hard An average clearance of 71per cent isrecommended for normal piercing and blanking

Courtesy: Frank W Wilson, Fundamentals of Tool Design,ASTME, Prentice-Hall of India Private Limited, NewDelhi, 1969

Thickness of stock, mm Drawing radius, mm

Blank holder force in drawing

Thickness of stock,t, mm Force, N per mm

Recommended die plate thickness

(a) For dies with cutting perimeter less than 50 mm

Die plate thickness,

(b) For dies with cutting perimeter greater than 50 mm

thickness Alclad Alclad (1hard) bend formed Annealed a 12hard annealedb

FORMING PROCESS:

Note: The Symbols, Equations and Examples given in

the book entitled ‘‘Mechanical Presses*’’ by Professor

Dr Ing Heinrich Ma¨kelt and translated by R

Hard-bottle, are followed and used in Symbols, Equations

and Examples with reference to Figs 25-41 to 25-49

in this Machine Design Data Handbook.

The minimum ram force in mechanical presses

The maximum ram force

The press work

The volume of the workpiece before and after forming

The force required to trim the forging

For chart for calculating ram path and velocity versus

crank angle

For calculation chart for blanking and piercing with

full-edge cutting tool.

For calculation chart for rectangular bending (a)

V-bending on a fixed die, (b) U-V-bending with back-up

For calculation chart for deep drawing and redrawing

where Prat¼ tonnage rating, tonneforce (tf)

For determination of blank-holder force for deep

drawing

For chart for extrusion molding and impact

extru-sion: a, extrusion molding of hollow bodies in

direction of punch travel (forward extrusion); b,

impact extrusion (tube extrusion) against direction

of punch travel (backward extrusion)

For determination of multiplication factor for impact

extrusion and cold extrusion, and also for stamping

and coining

For chart for calculating stamping and coining

For chart for calculating hot upsetting and drop

forging

For penetration of sheet thickness before fracture,

suggested reductions in diameters for drawing, mean

values for m and suggested trimming allowances

Refer to Fig 25-45

Refer to Fig 25-46

Refer to Fig 25-47

Refer to Fig 25-48 Refer to Fig 25-49

Refer to Tables 25-60, 25-61, 25-62 and 25-63

TABLE 25-60

Approximate penetration of sheet thickness before fracture in blanking

TABLE 25-61

Suggested reductions in diameters for drawing

Blanking and piercing (full-edge)

Making V- and U-bends

Deep-drawing and re-drawing 0.63Impact extrusion and extrusion forming 1.00

Hot, first upsetting operations 0.71

Refer to Chapter 11 on ‘‘Metal... 25 -38 Refer to Fig 25 - 39 Refer to Fig 25-40

Refer to Fig 25- 29 and Table 25-52 Refer to Table 25- 53< /h2>

Refer to subsection ‘‘Designing spur and helical gears for machine. .. 1 -31 to 1 -36 for tool steels and Tables 1- 49 and 1-51 for die steels.

TABLE 25- 49< /h2>

Metal