Техническая информация Sumitomo - страница 14

Basics of Drilling Drilling Edition

■ Parts of a Drill

Height of point Leading edge Margin width Back taper

Margin Lead

Body Neck Tang

clearance Flank Taper shank Flute

Land width e 先端角先端角

Point angle Heel Flut Helix angle

Chisel edge angle width Cutting Body clearance

edge

Overall length Chisel edge Straight shank Tang Depth of thickness Chisel edge corner body clearance

ke Diameter of Ra Chisel edge length angle body clearance Tang length Relief angle B

A

Web thinning Web Cutter sweep

A:B or A/B = Flute width ratio

• Point Angle and Force
• Minimum Requirement Relief Angle
• Relation Between Edge Treatment and Cutting Force

f: Feed rate (mm/rev) 8,000 T T

Ѳx f 6,000

Ѳ°

Md Md 4,000

DC πDX ・ 2,000 DX π DC 0

π DX * Large relief angle is needed at When point angle is large, thrust becomes the center of the drill. large but torque becomes small. 60

• Web Thickness and Thrust
• 40

Point Angle and Burr

20 0

0.8 ° 0.2 0.3 0.4

118 Feed Rate (mm/rev) 0.6 140° ° Drill : Multi-drill KDS215MAK

0.4 150 D ’ J ’

Width : 0.15mm 0.23mm

0.2 Work : S50C (230HB) Cutting Conditions : v =50m/min, Wet 0 c

0.05 0.10 0.15 0.20 0.25 Removed

Feed Rate (mm/rev) Work: SS41 Web thinning decreases the thrust concentrated Cutting Speed v =50m/min c at the chisel edge, makes the drill edge sharp, When point angle is large, burr height becomes low. and improves chip control.

• Decrease Chisel Width by Thinning Typical types of thinning

N

S type N type X type

S type: Standard type used generally. N type: Suitable for thin web drills. X type: For hard-to-cut material or deep hole drilling. Drill starts easier.