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| Deep Hole Boring Or Drilling |
A manufacturer or an engineer will define a deep hole by its depth-to-diameter ratio (D:d). Typically, holes larger than 10:1 depth to diameter ratio are considered as deep holes.
Deep hole boring or drilling into metal has a wide range of applications across several industries, with its origin tracking back to the need for straighter, accurate gun barrels, and expanding to modern deep hole drilling processes for improving the efficiency of their applications.
Deep hole drilling is a simple process, employed on machining a variety of materials from aluminium to superalloys. The process can effortlessly bore or drill to achieve:
- Tight diameter control
- Straightness
- Superior surface finish into workpieces
Deep hole boring/drilling tools
Gun drill Tooling
- Utilized for smaller hole drilling, ranging from 1 to 50mm in diameter
- High-pressure coolant is provided through the centre of the gun drill and spindle
- Chips are removed through a v-shaped groove in the length of the tool
BTA Tooling
- It’s used for more broader hole drilling range from 20 to 200 mm in diameter
- High-pressure coolant is provided through the pressure head assembly.
- Chips are discharged through the tool centre.
Note: BTA drilling or boring performs 5-7 times faster than gun drilling and requires higher power.
Deep hole boring/drilling process
- Rotating Tool: used to machine non-symmetrical components, or round parts with off-centre holes.
- Rotating Workpiece: used for round parts with a deep and on-centre hole
- Counter-rotating Tool and Workpiece: Accurate process for round parts with a deep and on-centre hole.
After Processes of Deep Hole Machining
After boring or drilling, additional methods are performed to further improve the bore/hole concentricity, surface finish, straightness, and add other complex features.
These after processes machine the inside surface of the hole, similar to other machining processes, and most of them can be performed on BTA deep hole drilling equipment.
Many of these deep hole machining processes are optimized for particular applications, such as bottle boring for landing gear actuators, or skiving machines for the hydraulic cylinder industry.
