Cooling the chip Improved chip control Improved chip transport
D3-0047-0008-E-p
Precision Cutting Tools
Case study
MegaJet vs. Twist drill with external coolant
Coolant pressure:
10 bar (142 psi)
20 (66)
10 (33)
Twist drill DIN 1897 TIN-coated A 6292 TIN MegaJet
0 vc = 37 m/min (SFM 122) vc = 42 m/min (SFM 138) f = 0.2 mm/rev (.0078 inch/rev) f = 0.3 mm/rev (.0118 inch/rev)
Alloyed steel
D3-0039-0008-E-p
Precision Cutting Tools
Spectrum of Materials
50 45 40
Ni- and Cobased alloys Stainless steels Steels up to 700 N/mm2 Cast Iron (GG/GGG) AlSi
0 150 300 450 600
Difficult to machine materials
Elongation A5 [%]
35 30 25 20 15 10
Titanium alloys
5
0
Steels up to 1000 N/mm2
750 900
High tensile steels Hardened steels
1050 1200 1350 1500 1700 1850
Tensile Strength Rm [N/mm2]
B9_091_E.ppt D3-0041-0008-E-p
Precision Cutting Tools
Forms of wear.
Clearance wear
Land wear
Crater wear
Step drill for machining with minimum burr formation.
90° ... 130° d2 = d1 + 0,5...1 d1
D3-0031-0008-E-p
Precision Cutting Tools
Axial forces.轴向力
60 - 70% 30 - 40%
D3-0032-0008-E-p
Precision Cutting Tools
The influence of tip-angle on the cutting forces. 钻尖角度对切削力的影响。
Soft Materials 软材料
90°
118°
130°
140° Hard
Materials 硬材料
Precision Cutting Tools
BASIC NOMECLATURE ROTATING TOOLS.
DRILLING 钻头
D3-001-0008-E-p
Harald Preusser
Precision Cutting Tools
硬质合金钻头材料
钻头采用硬质合金材料制造，是一种钨钴类合金，是以碳化钨（ WC）粉末为基体，以钴（CO）作粘接剂，经加压烧结而成，它 具有高硬度，非常耐热，有较高的强度，适用于高速切削。但韧 性差，非常脆。硬质合金材料的技术数据如下： 碳化钨 WC 90-94% 钴CO 6-10% 硬度 91.8-94.9HRA 密度 14.4-15.0g/cm2 抗弯强度 3200-4300N/mm2 WC颗粒度 0.4-1.0μm 可根据不同的材料配制，制造出不同技术参数的钻头出来，使钻 头发挥作用更大
Web taper.
d
钻心直径逐渐增大，保证钻心强度越来越 大。（并方便加工刀具过程中砂轮退刀）
100
d + 1 - 2 mm
1 : 50 1 : 50 1 : 80 1: 100
heavy normal
small
D3-0010-0008-E-p
Precision Cutting Tools
Different drill shanks.不同的钻头柄部模式
Typ H
brittle Materials 短削材料
类似直槽钻，适合加工硬材料
Typ W
soft Materials 软材料
D3-0025-0008-E-p
Precision Cutting Tools
Profile of a twist drill.
Profiles of the types N and UFL
60 (197)
50 (164)
Type of hole: Diameter: Depth: Material:
40 (131)
Tool life [m] (feet)
30 (98)
Through hole 12.2 mm (.48") 30 mm (1.18") 1.2713 = 55NiCrMoV6V (toolsteel L6) Rm = 970 N/mm2 (141.000 psi)
D3-0012-0008-E-p
Precision Cutting Tools
Clearance angle.后角
a
a = clearance
angle
D3-0014-0008-E-p
Precision Cutting Tools
Drill points.钻尖
Style A and C B D E U
High grade steels
Unalloyed high grade steels
Structural steels with > 0.5% C Tool steels 1. to 3. grade
AБайду номын сангаасloyed high grade steels
Structural steels, wear-resistant and bearing steels Tool steels, HSS Corrosion resistant steels, stainless and heat-resisting steels
D3-0033-0008-E-p
Precision Cutting Tools
Steel grades.
Structural steels
Structural steel grades
Rm < 690 N/mm2 (100,000 psi) and lower than 0.05% P and S
Precision Cutting Tools
Forms of wear.
Pushed swarf
Build-up edges
Excessive feed or incorrect drill geometry
D3-0045-0008-E-p
Precision Cutting Tools
Recommended cutting data for drilling.
D3-0022-0008-E-p
整体硬质合金钻头刃口结构
Precision Cutting Tools
普通钢韧性大，不易 断屑，要求刀具锋利 、强度大。
D3-0023-0008-E-p
Precision Cutting Tools
Basic drill types.基本钻头形式
Typ N
general Purpose 通用型
Plain cylindrical 圆柱柄
Morse taper莫式柄
Standard shank标准柄
D3-0011-0008-E-p
Precision Cutting Tools
麻花钻切削部分结构
• /view/e0703521482fb4daa58 d4b29.html?from=related&hasrec=1 PCD刀具
Diagram or table Feed vf = n · f f = mm/U
n=
D3-0046-0008-E-p
Precision Cutting Tools
Internal coolant supply.
Oil feed
Cooling the cutting edge
Higher cutting data, improved tool life
500
Number of drilled holes
Constructional steels
Unalloyed constructional steels
General structural steels with Rm < 500 N/mm2 (73,000 psi) Other steels up to > 0.55% C or Rm > 700 N/mm2 (102,000 psi)
Chip formation 铁屑形成
Sources: Sandvik Coromant
B4_001_E.ppt
D3-008-0008-E-p
Precision Cutting Tools
Back taper.
d
100
d – 0.02 ... 0.08
D3-009-0008-E-p
Precision Cutting Tools
Feed rate
0 (0) 200 (7.87) 400 (15.78) 0 (0) 200 (7.87) 400 [mm/min] (15.78) (IPM)