Technical Guidance MultiDrill Usage Guidance, Drilling Edition
■ Drill Maintenance
■ Using Cutting Oil
● External Coolant Supply
(1) Collet Selection and Maintenance ● Ensure proper chucking of drills to prevent vibration. Collet type chucks are recommended, as the grip is strong and can be used with ease.
(1) Choosing Cutting Oil ● If the cutting speed is more than 40m/min, cutting oil (JISW1 type 2) is recommended as its cooling effects and chip control capacity are good, and it is highly soluble. ● For optimum tool life at cutting speeds of less than 40m/min, sulfo-chlorinated oil (JISA1 type 1) is recommended as it has a lubricating effect and is non-water soluble. * Insoluble cutting oil may be flammable. To prevent fire, a substantial amount of oil should be used to cool the component so that smoke and heat will not be generated. (2) Supply of Coolant ● External Coolant Supply There must be a sufficient external supply of coolant at the hole position. Coolant pressure 0.3 to 0.5MPa, coolant volume 3 to 10M/min is a guideline. ● Internal Coolant Supply For holes ø4 or smaller, the oil pressure must be at least 1.5MPa to ensure a sufficient supply of coolant. For ø6 and above, if L/D is <3, the pressures should be at 0.5 to 1.0MPa. If L/D is >3, a hydraulic pressure of at least 1 to 2MPa is recommended.
● Vertical drilling
Collet
(
)
Drill chucks and keyless chucks are not suitable for MultiDrills as they have a weaker grip force.
N
Use high pressure at entrance
Easy to use
Drill Chuck
Collet Chuck
Collet
● When replacing drills, regularly remove cutting chips inside the collet by cleaning the collet and the spindle with oil. Repair marks with an oilstone. (2) Drill Mounting ● The peripheral runout of the drill mounted on the spindle must be within 0.03mm. ● Do not chuck on the drill flute. If the drill flute is inside the holder, chip evacuation will be obstructed, causing damage to the drill. (
● Horizontal drilling
Use high pressure at entrance
If there are marks, repair with an oilstone or change to a new one
● Internal Coolant Supply
● Coolant supply equipment
)
● Internal supply from machine
Peripheral runout within 0.03mm
Do not grip on the drill flute
■ Clamping of the Workpiece
■ Calculation of Power Consumption and Thrust
High thrust forces occur during high-efficiency drilling. Therefore, the workpiece must be supported to prevent fractures caused by deformation. Large torques and horizontal cutting forces also occur. Therefore, the workpiece must be clamped firmly enough to withstand them.
Especially large drills
● Calculating cutting speed
X × DC × n 1,000 1,000 × v X × DC c
c =
v
n
H
Deformation → chipping Support needed
n =
DC
● Calculating feed rate per revolution and per tooth
■ Drill Regrinding
: Cutting speed (m/min)
v
c
● Tool life determinant
X : π ≈3.14 DC : Drill diameter (mm) n
● When to regrind When one or two feed marks (lines) appear on the margin, when corner wear reaches the margin width or when small chipping occurs, it indicates that the drill needs to be sent for regrinding.
v
f n
f =
f =
v
n × f
1 to 2 feed marks
: Rotation speed (min -1 )
: Feed rate (mm/min)
v
● Calculation of Cutting Time
f
: Feed rate per revolution (mm/rev)
f
● How and where to regrind We recommend regrinding and recoating.
H v f
T =
: Drilling depth (mm)
H
Regrinding alone may be sufficient, but if the work material is steel, use recoating as well as regrinding to prevent shortening of tool life. Note: Ask us or an approved vendor to recoat with our proprietary coating.
Appropriate Tool Life
T : Cutting time (min) HB : Work material Brinell hardness
Excessive marks
Power consumption (kW) = HB × DC 0.68 × v c ● Calculation of Power Consumption and Thrust <Experimental>
● Regrinding on your own Customers regrinding their own drills can obtain MultiDrill Regrinding Instructions from us directly or their vendor.
1.27 × f 0.59 /36,000
Thrust (N)=0.24 × HB × DC 0.95 × f 0.61 × 9.8
Over-used
* When designing the machine, an allowance of 1.6 x power consumption and 1.4 x thrust should be given.
N63
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