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13. BREAK-IN PROCEDURE
During transportation, storage or installation, the grease inside the bearings will settle. If the spindle is
suddenly run at high-speed, excessive heat may cause bearing damage. Before operating for the first
time after installation, repair, or a long period of non-operation, follow the break-in procedure detailed in
steps 1 to 4 of Table. 2.
Table. 2
Step
Rotation Speed (min
Rotation Time (min)
Items to Check
14. CAUTIONS WHEN USING CUTTING DRILLS
CAUTION
• Refer to the following formula for the maximum spindle rotation speed when using a
drill or an end mill.
• Keep the overhang length to a minimum when installing the cutting drill. If the overhang
length is too long, the cutting drill may bend and cause injury.
• When a long drill is used, increase rotation speed gradually to prevent damage.
• The longer the drill length, the greater the chance of runout damage. To prevent this
damage, do drilling after the center hole or guide hole is processed.
（1） The spindle RPM depends on the drill diameter and the workpiece material.
（2） Please follow the manufacturer's recommended feeds and speeds.
Using drills outside of the manufacturer's maximum recommended rotational speed may cause
damage to the spindle or injury to the operator.
（3） When increasing the cutting drill overhang, reduce the motor speed. (Table. 3)
（4） Always clean the drill shank before installing the drill in the spindle.
Foreign matter in the collet or collet nut may cause excessive
run-out that could damage the cutting drill or spindle.
（5） Use after checking for runout.
（6） Do not strike, drop or disassemble the spindle.
Table. 3 Relationship Between Drill Overhang Length
and RPM
Overhang Length (mm)
Drill diameter
10
Drill diameter
20
Drill diameter
20 or more
38
1
)
5,000
-1
5
Coolant is supplied at pressure of approx. 3 MPa
Rotation speed (min
100 % of the RPM
60 % of the RPM
30 % or less of the RPM
2
10,000
5
1,000
Cutting speed (m/min)
) =
-1
3.14
Cutting drill diameter (mm)
Max RPM
3
4
20,000
30,000
5
5
Overhang length
(mm)
Fig. 22
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