Drilling Operation

Drilling is a cutting process that uses a drill bit to cut or enlarge a hole of circular cross-section in solid materials. The drill bit is a rotary cutting tool, often multipoint. The bit is pressed against the workpiece and rotated at rates from hundreds to thousands of revolutions per minute. This forces the cutting edge against the workpiece, cutting off chips (swarf) from the hole as it is drilled.

Titanium drilling

Drill bits are cutting tools used to create cylindrical holes, almost always of circular cross-section. Drill bits come in many sizes and have many uses. Bits are usually connected to a mechanism, often simply referred to as a drill, which rotates them and provides torque and axial force to create the hole.The shank is the part of the drill bit grasped by the chuck of a drill. The cutting edges of the drill bit are at one end, and the shank is at the other.

Twist drill bits

Drill bit

The twist drill bit is the type produced in largest quantity today. It comprises a cutting point at the tip of a cylindrical shaft with helical flutes; the flutes act as an Archimedean screw and lift swarf out of the hole.

Drilling machine Drilling is the machining operation used to create a round

hole in a workpiece.

Drilling is done with a rotating cylindrical tool having two cutting edges on its working end.

The tool is called as a drill or a drill bit.

The rotating tool feeds into the stationary workpiece to take care of the depth of the hole,

The hole diameter will be equal to the drill-bit diameterCan a 8 drill bit make a hole of exactly 8.000 mm?

Note that the straight shank drills will need a drill chuck to mount into the spindle of drilling machine.l

Types of Drilling machine:

Upright drill press

Bench drilling m/c.

Radial drilling m/c.

gang drill

multiple spindle drill

Upright drill press

Radial Drilling machine (RDM)

Types of Drilling machine..contd

Gang drill Has a series of 2 to 6 drill heads connected together in an in-line

arrangement.

Each spindle is powered individually.

But they share a common work table.

A single job can be processed sequentially to do centering, drilling, reaming, tapping..), but one by one.

Application: Many Fastening holes to be drilled, counter sunked and tapped on a Cylinder head.

Multiple spindle drill Several drill spindles are connected to a common drill head.

Each spindle will carry its own tool.

In one stroke a batch of workpieces can be drilled. All spindles move down simultaneously to do the drilling.

Now a days NC drill presses are available too.

Multiple spindle drill press

Gang drill press

Through hole, and Blind hole

Other Operations that can be done on a drilling m/c