Experiment # 07

Title:
To understand the working of Drilling Machine.

Objectives:
 To develop an understanding of Drill machines.
 To learn the functions of its various parts
 To observe basic operations performed on it
Apparatus:
 Drill machine
 Drill bits
 Reamer
 Countersink tool
 Counter bore tool
 Tapping tool (for internal threading)
 Work piece
 Cutting fluid
 Safety goggles
 Workbench or clamping device

Figure 1: Drill Machine

Theory Background:
Drill Machine:
A drilling machine, commonly known as a drill, is a versatile tool designed to create round
holes in various materials such as metal, wood, plastic, and masonry. It operates by rotating a
drill bit at high speeds while applying pressure to drive it into the work piece, resulting in precise
and clean holes.

Working Principal:
The working principle of a drilling machine involves converting electrical energy into
mechanical energy to rotate a drill bit and apply axial pressure, thereby creating holes in various
materials.

Figure 2: Working of Drill Machine [1]

Parts of Drill machine:

Base
The base of the drilling machine supports the machine and can either be fixed to a workshop
floor or mounted to a work table in the case of smaller machines. Some bases have slots to allow
for bolting and holding larger work pieces that cannot fit on the table.

Column
The column is usually a hollow, cylindrical structure that connects the base, table, and head of a
drilling machine. The column also serves as a linear slide on which the table moves up and
down. The table clamps onto the column once positioned as desired.
Arm
On larger drilling machines the arm is attached to the column and is used to support the spindle
and drill chuck. The arm also allows for some travel in a direction perpendicular to the column.
Smaller machines do not have an arm and instead, have the spindle positioned relatively close to
the column on the head assembly.

Drill Head
The drill head contains the spindle, feed mechanism, and drill chuck. The spindle is usually
driven by an electric motor via a gearbox. For larger machines with arms, the electric motor’s
power can be transmitted via a series of V-belts and pulleys.

Work table
Table provides a stable surface for the work piece. It can be raised or lowered to adjust the drill
bit's distance from the work piece. The table also has T-slots or holes to facilitate the clamping
of the work piece. A sensitive drill has a much smaller worktable when compared to a gang drill,
for example. A sensitive drilling machine worktable is not designed for heavy loads whereas a
gang drills worktable is.

Feed Mechanism
The feed mechanism is designed to control the rate at which the drill is lowered into the material.
The optimal feed rate and the speed of the drill bit are determined by the type of material being
drilled and the size of the drill bit.

Spindle
The spindle is a shaft assembly with bearings that connect the electric motor to the chuck.
Spindles are designed to have as little rotational eccentricity as possible to ensure that drilled
holes are concentric.

Chuck
The chuck is a mechanism used to grip the tool tightly enough to stop the tool from slipping
during drilling operations. A drill chuck typically has three jaws whose position can be adjusted
to account for different drill bit diameters. When adjusted, these jaws move either radially
inwards or outwards to account for different diameters.

Electric Motor
The electric motor drives the spindle either directly with a gearbox or with a series of belts and
pulleys. The electric motor can either be mounted to the base of the machine or at the top of the
column. Like the feed rate, the rotational speed can be adjusted for different drill bits and
materials.
 Figure 3: Parts of Drill Machine [2]

Operations Performed on Drilling:

Drilling
The creation of a hole into the work piece using drill tools is called drilling.

Figure 4: Drilling [3]

Reaming
Reaming is a machining operation in which a rotary tool takes a light cut to improve the accuracy
of a round hole and to reduce the roughness of the hole surface.

Figure 5: Reaming [4]

Counter Sinking
Countersinking is a process that creates a V-shaped edge near the surface of a hole. It is often
used to deburr a drilled or tapped hole or to allow the head of a countersunk-head screw to
sit flush or below a surface.

Figure 6: Counter Sinking [5]

Counter Boring
Counter Boring operation enlarges a pre-drilled bore. Usually counter boring is used when
machine power does not allow solid drilling of that size.

Figure 7: Counter Boring [6]

Tapping
Tapping in machining refers to the process of creating threaded holes in a work piece to
accommodate screws, bolts, or other threaded fasteners and attachments.

Figure 8: Tapping [7]

Applications:
 Manufacturing Industry: Drilling machines are essential for creating holes in metal
components, such as engine blocks and gearboxes, facilitating assembly and fabrication
processes.
 Construction Industry: Used for drilling into concrete, brick, and stone to install
anchors, bolts, and reinforcement bars, as well as for creating openings for plumbing and
electrical installations.
 Woodworking Industry: Employed to drill holes for dowels, screws, and other
fasteners in furniture assembly, as well as for crafting intricate designs and patterns.
 Automotive and Aerospace Industries: Utilized for drilling holes in components
like fuel injectors, landing gear, and structural parts, requiring high precision and
consistency.
 Oil and Gas Industry: Drilling machines are used to bore deep into the earth to
extract oil and natural gas, as well as for creating holes in pipelines and other
infrastructure.
 Electronics Industry: Applied in creating holes in circuit boards for inserting
components like resistors, capacitors, and connectors.
 Mining Industry: Used for drilling blast holes in rock to facilitate the extraction of
minerals and ores.
 Medical Equipment Manufacturing: Drilling machines assist in producing
surgical instruments and implants by creating precise holes in metal and plastic
components.

Comments:
Fundamental Operation: A drilling machine operates by rotating a cutting tool (drill bit)
against a stationary work piece, applying axial force to create holes. This process involves
converting electrical energy into mechanical energy to facilitate the cutting action.

Versatility: Drilling machines are versatile tools capable of performing various operations
beyond simple hole drilling, such as reaming, tapping, countersinking, and counter boring,
depending on the attachments and settings used.

Precision and Control: Modern drilling machines offer precise control over speed and
feed rates, allowing for accurate hole placement and consistency, which is crucial in
manufacturing and engineering applications.

Safety Considerations: Proper safety measures, including the use of personal protective
equipment and adherence to operational guidelines, are essential to prevent accidents and ensure
safe operation of drilling machines.
Remarks:
Efficiency: The efficiency of a drilling machine depends on factors such as the type of
material being drilled, the condition of the drill bit, and the appropriate selection of speed and
feed rates. Regular maintenance and correct usage enhance performance and longevity.

Technological Advancements: The integration of computer numerical control (CNC)

technology has significantly improved the automation, precision, and repeatability of drilling
operations, making modern drilling machines indispensable in industrial settings.

Material Considerations: Different materials require specific drill bits and operational
settings. For instance, drilling into metals necessitates different speeds and bit types compared to
drilling into wood or plastics. Understanding material properties is vital for optimal results.

Environmental Impact: Efficient drilling practices, including proper chip removal and
coolant usage, not only improve the quality of the drilled holes but also minimize environmental
impact by reducing waste and energy consumption.

References:
[1] https://www.google.com/imgres?q=The%20working%20principle%20of%20a%20drilling%2
0machine%20involves%20converting%20electrical%20energy%20into%20mechanical%20ener
gy%20to%20rotate%20a%20drill%20bit%20and%20apply%20axial%20pressure%2C%20thereb
[2] https://www.google.com/imgres?q=Parts%20of%20Drill%20machine%20LABEL%20DIGR
AM&imgurl=https%3A%2F%2Fextrudesign.com%2Fwp
[3] https://www.researchgate.net/figure/Scheme-of-movements-in-a-drilling-operation-
CustomPartNet-2007-Ft-f-D-us-2T-1_fig6_297213739
[4] https://www.google.com/imgres?q=reaming&imgurl=https%3A%2F%2Fwww.summaryplane
t.com%2Fengineering%
[5] https://www.google.com/imgres?q=Counter%20Sinking&imgurl=https%3A%2F%2Fengineer
ing.myindialist.com%
[6] https://www.google.com/imgres?q=Counter%20Boring%20&imgurl=https%3A%2F%2Fengi
neering.myindialist.com%2Fwp
[7] https://www.google.com/imgres?q=tapping%20operation&imgurl=https%3A%2F%2Fengine
ering.myindialist.com%