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
(1) Choosing Cutting Oil ● If the cutting speed is more than 131 SFM, 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 131 SFM, sulfo-chlorinated oil (JISA1 type 1) is recommended as it has a lubricating effect and is non-water soluble. * Insoluble cutting oil may be ammable. To prevent re, 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 sufcient external supply of coolant at the hole position. Coolant pressure 0.3 to 0.5MPa, coolant volume 3 to 32 SFM is a guideline. ● Internal Coolant Supply For holes ø4 or smaller, the oil pressure must be at least 1.5MPa to ensure a sufcient 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
recommended, as the grip is strong and can be used with ease. 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 ute. If the drill ute 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 ute
■ Clamping of the Workpiece
■ Calculation of Power Consumption and Thrust
High thrust forces occur during high-efciency 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 rmly enough to withstand them.
Especially large drills
● Calculating cutting speed
X × DC × n 1,000
v c =
n
H
n = 1,000 × v c X × DC ● Calculating feed rate per revolution and per tooth DC
Deformation → chipping Support needed
■ Drill Regrinding
v c : Cutting speed (SFM) X : π ≈3.14 DC : Drill diameter (in) n : Rotation speed (min -1 ) v f : Feed rate (IPM) f : Feed rate per revolution (IPR) H : Drilling depth (in) T : Cutting time (min) HB : Work material Brinell hardness
● Tool life determinant
● 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
v f = n × f
f =
1 to 2 feed marks
T = H v f ● Calculation of Cutting Time
● How and where to regrind We recommend regrinding and recoating.
Regrinding alone may be sufcient, 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. ● Regrinding on your own Customers regrinding their own drills can obtain MultiDrill Regrinding Instructions from us directly or their vendor.
Appropriate Tool Life
Excessive marks
Power consumption (kW) = HB × DC 0.68 × v c ● Calculation of Power Consumption and Thrust <Experimental>
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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