Section J 25-26

Deep Hole Drilling XHGS / PHT

■ Recommended Drilling Method

(1) Make a guide hole using the PHT  Select the same nominal diameter for the PHT type dedicated guide hole drill as the XHGS type deep hole drill. (The guide drill diameter is designed to be 0.02 mm to 0.05 mm larger than the long drill diameter.)

H = Drill diameter × 1.5 to 2.0 times the depth

H

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(2) Feed the XHGS deep hole drill through the guide hole at low rotation speed  Spindle Speed: 500 RPM  Feed Rate: 39 to 78 IPM

* If the drill is inserted into the guide hole at the set cutting speed, peripheral run-out may cause damage to the drill's peripheral edges.

Stop 0.04" away from the guide hole depth

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(3) Increase rotation speed until the set cutting speed is reached, then start normal drilling operation

* On some NC machines, the feed command may be activated before the set spindle speed is reached, so it is recommended to enter a dwell sequence before the feed command.

Increase rotation speed

(4) After drilling, rotation speed is reduced and the drill is retracted from the work material  Spindle speed: 500 RPM Feed rate: 39 to 78 IPM

* Retracting a drill from the work material at a high rotation speed is dangerous as doing so may result in breakage due to runout.

Change rotation speed to 500 RPM

(5) Other notes  A flat base should be prepared first if the entry side is a non-flat surface (slanted surface, cylindrical surface, etc.).

Spot facing using an endmill or flat MultiDrill MDF type (see page J44)

Concave ended endmills cannot be used.

 If the exit side is a non-flat surface, reduce the feed rate to f=0.002 IPR immediately before the breakthrough point to prevent the drill from breaking or burrs from forming. (1) Internal coolant supply  Use coolant equivalent to JIS A1-1 (emulsion).  Pump pressure Steel: 1. 5 to 2. 0MPa (higher pressure results in a stronger cooling effect, which affects chips and wear) Cast iron and aluminum alloy: 4. 0 to 6. 0MPa (prioritize cooling performance) (2) Internal MQL  Air pressure : 0.5MPa or greater  Evacuation volume : It is recommended to set the maximum evacuation volume for your equipment. *Consult the manufacturer if you intend to machine aluminum alloy. (3) Internal dual-fluid mist  Air pressure : 0.5MPa or greater  Evacuation volume : It is recommended to use the optimal setting for your equipment. ■ Coolant

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