Production Technology

-VW VW Ao
A1
O Z

-VW
V= VW+VT

N Workpiece

Chip

VT
Cutting tool

X Y

Ao

b=f

N

VT
Absolut velocity

a

VW = f (x, y, z)

VT = f (x, y, z)

Basic condition of cutting

Forces in the material of workpiece and tool makes strain that makes elastic and plastic deformation.

(σ1 ) W ≥ (R m ) W (σ1 )T ≤ (σm )T
HVT ≈ ( 3 ÷ 5 ) ⋅ HVW Main parameters of cutting procedure

V V

Vc=Vy
Chip

Vc=Vy

O Z

VZ
X Y

N N

VX VX
Cutting tool

Workpiece

VZ

N

VW , = VW − VW = 0 VT , = VT − VW = V
V ≅ VC
Calculation of the main cutting velocity 1. By broschure Manufacturer’s brosschure contains cutting parameters (cutting velocity, feed, depht of cut, material workpiece ect.,) In this case the tool life is T=60min. 2. Empiric approaches Kronenberg-method T= 60 min, r =45° for HSS tool

 m  CV V60,  =ε  min  V A 

A=Ao [mm2] .. normal crossection of chip in starting phase

CV [m/perc]….cutting velocity (1.1. table)

εV, ………..experimental data (1.1.table)

1.1. table
TOOL WORKPIECE BRASS BRONZ HSS

εV
1,65 2,23 2,75 500 N/mm2 Rm=500600 N/mm2 Rm=600800 N/mm2

CV
112 80 28,7 50 35 20

ALLOY STEEL Rm=300-

STEEL

2,4

CAST IRON-MILD CAST IRON-MIDDLE
CAST IRON-HARD

3,6

42 26 15

 m  , V60   = V60 ⋅ ξk ⋅ ξ m  min 

ξκ modification factort of setting angle of main edge of tool (1.2. table) ξW modification factor that depend of material of cutting edge and workpiece (1.3. table) 1.2. table
Setting angle of main edge of tool modification factor

κ

20

30

40

50

60

70

80

90

κ 1,27 1,17 1,05 0,95 0,86 0,79 0,75 0,74

1.3. table
Material of workpiece STEEL CAST IRON

Carbon tool steel HSS
0,25 0,3 1 1

Carbid cut
4…8 5 and more

Walich-method T= 60 min, r =45° for HSS tool

This equation regarding the HSS tool. This method is more accurate than KRONENBERGmethod. Because this respect not only the normal cross-section of chips but