Техническая информация Sumitomo - страница 16

Technical Guidance
Basics of Drilling Drilling Edition


■ Run-out Accuracy (Units: mm)
For the run-out accuracy of web-thinned drills, not
MDS140MK
only the difference in lip height (B) but also the run-


Hole Expansion (mm)
0.25 S50C
vc＝50m/min
out after thinning (A) is important. f＝0.3mm/rev
0.20
0.15
0.10
0.05
Center
run-out 0
(A) 0.005 0.02 0.05 0.1
(A): The run-out accuracy of thinning point (mm)
Peripheral
(B): The difference of the lip height run-out 0.005 0.02 0.1 0.05 0.02 0.1
(B) (mm)

■ Peripheral Run-out Accuracy
● When the tool rotates Peripheral Hole Expansion Cutting Force*
when Tool Rotates Run-out
The peripheral run-out accuracy (mm) 0 0.05(mm) 0 10 (kg)
of the drill mounted on the spindle
0.005
s h o u l d b e c o n t ro l l e d w i t h i n
0.03mm. If the run-out exceeds
0.09
the limit, the drilled hole will also
become large causing an increase * Horizontal cutting force.
in the horizontal cutting force, Drill: MDS120MK Work material: S50C (230HB)
which may result in drill breakage. Cutting Conditions： c=50m/min, =0.3mm/rev, =38mm
Run-out: within 0.03mm Water soluble coolant
Run-out: within 0.03mm
● When the work material rotates 0.03mm
Not only the peripheral run-out at the drill edge (A)
but also the concentricity at (B) should be controlled
Chuck


within 0.03mm.


■ Influence of Work
● Work material with slanted or uneven surface (Entrance) (Exit)
Material Surface
If the surface of the hole entrance or exit is
slanted or uneven, decrease the feed rate to 1/3
to 1/2 of the recommended cutting condition.


■ How to Use a Long Drill ● Problem Hole bend
When using a long drill (XHGS type), DAK type drill,
SMDH-D type drill, or SMDH-12.5D type drill at high Position shift
rotation speeds, the run-out of the drill tip may cause
a deviation of the entry point as shown on the right,
bending the drill hole and resulting in drill breakage.
● Remedies
Method 1
N Step 1 Step 2 Step 3
Technical Guidance /


1xDC pilot hole 2 to 3mm
References


(same dia.) n=100 to 300min–1 Drilling under
Short drill recommended condition
Method 2 * Low rotational speed minimises centrifugal forces and prevents drill bending.
Step 1 2 to 3mm Step 2

Drilling under
recommended
condition
(n=100 to 300min–1) f=0.15 to 0.2mm/rev


N24