UNDERSIZED TAPPING ELECTRODES
ELECTRODES WITH ENGRAVING –ROUND TYPE–
Packed Product
EMTA EMTWA
EMLM
× P
M
8 °
E
（ ） ℓ
P
t
5
± 0.05
25
B
0 ＋ 0.3
45
＋ 0.2 ＋ 0.1
L
• EMTA • EMTWA
M Material Tough pitch copper (C1100) M Material Tungsten–copper (Cu30%–W)
M Material Tough pitch copper (C1100)
[ EMTWA ] Even a work made of carbide can be processed since it contains tungsten. (An electric discharging machine capable of using a copper tungsten electrode is required.) [ EMTB ] Has a through hole for water circulation that enables higher processing speed and helps reduce secondary electric discharge. E 2 pitches or less from the tip is considered as an incomplete thread and out of scope of tolerance guarantee.
■ Character size
EMTB (Through hole type)
M × P
W
Q 10
a
a =
one side 10 ‒ 12°
Q 10
t =
+ 0.2
B
＋ 0.2 ＋ 0.1 L
M Material Tough pitch copper (C1100)
Part Number
V (EMTB only)
Q
W
Part Number
D
d
P
L
B
Type
M
Characters for engraving (Round Gothic type)
Numerals alphabetical characters
Numerals alphabetical characters
+ – /
＜ ＞ /
ℓ
＜ ＞
+
3 4 5 6 8
2.2 3.0 3.9 4.7 6.4 8.2
0.5 0.7 0.8 1.0
0.5 0.7
Type
P
50
15
EMTA EMTB (Prepared hole type) EMTWA (M3–12)
5
* 0.8A
1
11.4 11.4 10.7
0.4 0.6 0.7 1.0 1.2 1.6 2.0 2.5 3.5
0.36 0.53 0.62 0.88 1.06 1.42 1.77 2.22 3.11
0.23 0.35 0.41 0.58
0.23
0.185
0.23 0.35 0.41 0.58 0.70 0.93 1.16 1.46 2.04
60
20
1.2
0.8 1.0 1.2 1.5 2.0 2.5 3.0 4.0
8
0.3 0.4 0.6 0.7 1.1 1.4 1.7 2.4
0.27 0.31 0.44 0.53 0.71 0.89 1.11 1.57
1.25
2
10 12 16 20
1.5
2.5
12
70
30
10.0 13.6 17.1
1.75
3 3 3
10
16 20
2.0 2.5
EMLM
80
40
8.9 7.1 5.3 3.6
0.7
0.93 1.16 1.46 2.04
Part Number EMTA4
Note 1
Note 2
Order
–
Delivery Quotation
＊ When 0.8A (P ＝ 0.8), only character size becomes small.
What is copper tungsten? ■ Characteristics • The composition and alloy structure are optimally adjusted to extend life of an elec- trode and to raise efficiency of electrical discharge machining at the same time. • It is possible to increase the machining speed, and reduce the wear of the electrode itself. Tungsten is very hard, permitting accurate electrical discharge machining.
E Concentricity between the engraving character and the shank is about 0.1. E Note 1 / : Use ¥ for designating / (slash) ; Note 2 : Use # for － (minus).
■ Undersized Tapping Electrodes This electrode is used when forming a female thread in hardened steel by electrical discharge machining.
Example
Characters for engraving
Part Number –
Order
EMLM0.8A – A EMLM2.0 – /
■ Characteristic values Characteristics
Copper tungsten
Specific gravity Hardness (HRB)
14.0 93.5
Delivery Quotation
EMTA EMTB EMTWA
Conductivity (IACS%)
50 60
Tensile strength (kgf/mm 2 )
Transverse rupture strength (kgf/mm 2 ) ■ Comparison of machining data Work: Carbide V3 Machining condition: 14–16 μm settings ＊ Wear–out ratio = Wear–out rate of electrode ÷ Wear– out rate of work
125
Machining speed (g/min.) Wear–out ratio
E Tip diameter (d) is smaller than the screw size (M). Insert an undersized tapping electrode in the low screw hole (low hole diameter reference value D P.1225) , and perform electrical discharge machining while rocking X / Y directions. • Swing amount = M–d–0.1 (Target) • Clearance for electro discharge = on one side 0.1–0.5
Copper tungsten products Conventional products 0
50 100 150 200 250 300
0
25 30 5 10 15 20
Part Number
PACK
Type
M
Packed Product Information on pack sales Customers can buy the same size in bulk for a good price.
EMTA EMTB EMTWA
10 PACK
3 4 5 6 8 10121620
Part Number
Delivery Quotation
Order
PACK Type 10 PACK – EMTA3
739
740
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