BIG DAISHOWA High Performance Tooling Solutions Vol 4

KAISER BORING CUTTING CONDITIONS

CUTTING SPEED SELECTION GRAPH FOR CUTTING STEEL

Chatter is always an issue in boring. The figure at right shows how the cutting speed (rotational speed) inevitably decreases as the bar becomes longer. Refer to the cutting conditions listed in this graph and on the previous pages when selecting the optimum cutting conditions. For cast iron, 10-20% longer projection length is generally permissible.

260 240 220 200 180 160 140 120 100 80 60 40 20 Cutting Speed Vc (m/min)

Diameter

ø20-26mm CK1 ø25-33mm CK2 ø32-42mm CK3

70 80 100 130 160

ø41-54mm CK4

ø53-100mm BBT40-CKB5/6 ø53-70mm BBT50-CKB5

200

Reference Example

260

Indicated by

in the graph at right

ø100-150mm BBT50-CKB6

Reference example shows the projection length A of 182mm; and the diameter of ø45mm (ø41-54mm CK4). The recommended cutting speed is 118m/min. Select an appropriate cutting speed based on this reference example.

320

ø68-100mm BBT50-CKB6 ø100-150mm BBT50-CKB7

400

500

600

Projection Length A = 7.165

• Please note: Cutting Speed indicated is expressed in (m/min), Projection Length A in (mm), and Diameter in (mm)

The insert nose radius and boring bar length (machining depth limit) are closely related. Refer to the graph below when selecting a CK Shank. Depths 1.1 - 1.3 times greater than listed in the graph are possible for cast iron (FC). Refer to the cutting conditions table on the previous page for information about cutting conditions. The cutting speed, in particular, inevitably decreases when the bar projection length increases. Refer to the above graph for details.

Relationship between Nose Radius and Effective Boring Depth

Effective Boring Depth A

90 CK7

BBT50

64 CK6 50 CK5 39 CK4 31 CK3 24 CK2 19 CK1

Selection example BBT50, øD 1 = 50mm R = .4mm A = 200mm

Taper BBT40

65 80 100 130 160 200 260

65 80 100 130 160 200 260 320 360

460

560

Effective Boring Depth A (mm)

503