Drilling Operation in Manufacturing Technology

 

Drilling

Drilling is a metal removing process in which a drill bit to cut a hole of circular cross-section in solid materials. The drill bit is usually a rotary multi-point cutting tool.

A machine consists of a spindle that provides rotary motion to the drilling tool, which finally makes the hole in the workpiece is called drilling machine.

Parts of Drilling Machine

A drilling machine is usually composed of several or all of the following parts.

Base: generally bolted with the ground to support the weight of the drilling machine.

Column: located on one side of the base, can carry the load of the arm and drill head, with a sliding table mounted on it.

Arm: at the top of the column, carries the drill head and the housing of the driving mechanism.

Drill head: mounted on one side of the arm, consists of feed and driving mechanism. It can slide up and down.

Worktable: mounted on the column, can move vertically and horizontally.

Feed mechanism: hand and automatic feed by an electrical motor.

Spindle: holds the drill or cutting tool and revolves in a fixed position in a sleeve. 

Chuck: situated on the spindle, holds the drill jig.

Electric Motor

 

Classification of Drilling Machine

1. Portable drilling machine: generally small in size and contains a universal motor, used for drilling holes on the rocks or any rigid surface, suitable for any location. The piece to be drilled is held in a vice.

2. Bench drilling machine: perfect for producing small holes at high speeds, usually consists of a base, worktable, spindle, drill head, driving mechanism and column. The work is started from the drill fed into the piece by hand.

3. Radial drilling machine: mainly for drilling large and heavy workspaces, the table can be adjusted to suit different heights. It allows the operator to make the spindle directly over the workpiece rather than move the part to the tool, and also capable to create intersecting or angular holds in one setup. 

4. Upright drilling machine: larger and stronger than sensitive drilling machine, designed for handling medium to large-sized holes.

5. Gang drilling machine: can be used for drilling, reaming, counter boring and tapping, just need to move the machine back and forth.

6. Deep mole drilling machine: special type that is designed to drill deep holes in the connecting rods, spindles and others, with high cutting speed and less feed.

7. Multiple spindle drilling machine: with several spindles, perfect for drilling a large amount of holes into a part and drilling same holes on identical workpieces. 

8. CNC drilling machine: computer numerical control drilling machine can automatically change tooling with a turret or automatic tool changer. The program controls the speeds, feeds and table position.