Definition of Drilling Machine
With the aid of drill bits, it is a machine used to drill holes in parts or workpieces.
A single-point cutting tool, such as the one used in a lathe machine, can remove material slowly. In contrast, a multipoint cutting tool removes material more quickly and thus increases MRR. This is why drill bits are also known as multipoint cutting tools.
Line Diagram of Drilling Machine
Below is a line diagram of a drilling machine.
Parts of Drilling Machine
- Base
- Vertical Column
- Swivel Table
- Power Transmission system (Stepped Cone Pulley)
- Drill Feed Handle (Hand Wheel)
- Chuck
- Table Clamp
- Drill bit
- Spindle
Base
The base, which serves as the drilling machine's base, is made of cast iron, which has high compressive strength, good wear resistance, and good absorbing capability (i.e., the ability to absorb vibrations induced during working conditions).
Vertical Column
It is precisely positioned in the base's middle and acts as both a holding mechanism for the power transmission system and support for the rotation of the Swivel table.Swivel Table
Due to its attachment to the column that can hold the machine vice in its grips, the workpiece is fixed in the machine vice in order to perform the drilling operation.
The Swivel table can move up and down due to its rotational motion, and a locking nut can be used to secure it to the column.
Power Transmission system
This part comprises the motor, stepped pulley, V-belt, and spindle. Power transmission is explained by how the drilling machine operates.
Drill Feed Handle
Rotation of the handwheel causes the spindle to move vertically up and down, feeding the work as needed.
Here, rotational motion is changed into linear motion by a Rack and Pinion mechanism, which is described below.
Chuck
Therein is held the workpiece. Circular components are typically held with a 3-jaw chuck, while rectangular components are typically held in place with a 4-jaw chuck.
Table Clamp
It is utilized to lock the swivel table in place.
Spindle
It is used to hold the drill bit along with jaws.
Drill bit
It serves as the machine's main part and removes material from the workpiece's surface by creating holes in it.
Working Principle of Drilling Machine
When the motor is turned on, the spindle rotates, which causes the stepped pulley that is attached to it to also rotate. The other end is connected to another stepped pulley that can be inverted to change the speed of the rotation.
The stepped pulley gap is now filled with a V-belt that drives the power transmission. A V-belt rather than a flat belt is used in this situation to increase power efficiency.
The drill bit, which was attached to the spindle and inserted into the chuck, is now rotating. Along with the Pulleys, the spindle rotates as well and has the ability to turn the drill bit.
Now, the rotation of the handwheel causes the spindle to rise and fall.
Drive Mechanism of Drilling Machine
This drive mechanism is based on the rack and pinion mechanism.
When the handwheel is turned, a rack and pinion transform rotational motion into linear motion.
The set-up consists of a Rack with fine grooves, a Pinion, a Chuck, and a Drill bit. The pinion is inserted into the rack grooves [shown in the figure below] when the hand wheel is turned while the drill bit is in the chuck and the chuck is connected to the rack, changing rotational motion to linear motion. Because it uses these two parts to function, this mechanism is known as a rack and pinion mechanism.
Types of Drilling Machines
- Radial drilling machine
- Upright drilling machine
- Multiple Spindle drilling machine
- Deep hole drilling machine
- Sensitive drilling machine
- Portable drilling machine
- Gang drilling machine
Radial Drilling Machine
A radial drilling machine is used to drill holes in the components, which is very different from a typical drilling machine. The radial drilling tool has an arm that can rotate in a predetermined radius.
The operation must be performed while the radial arm is rotating if the component is too large to fit on the worktable and must be placed on the ground.
Upright Drilling Machine
A wide range of spindle speed and feed options are available for various types of work.
The upright drilling machine has a drilling capacity of up to 75mm.
Multiple Spindle Drilling Machine
As their name implies, these drilling machines have many widely spaced spindles.
This machine is utilised when making separate workpieces or drilling numerous holes on a single workpiece.
This operation will result in an increase in production rate.
Deep Hole Drilling Machine
Sensitive Drilling Machine
The operator of a sensitive drilling machine can "feel" or "sense" the workpiece's cutting action as it relates to the tool when it is fed into the workpiece, which is how the machine got its name.
As was mentioned at the beginning of the article, another name for it is a bench drilling machine.
Portable Drilling Machine
While the portable drilling machine performs similarly to the bench drilling machine, its name derives from the fact that you can transport it to various workplaces.
Contrarily, the bench drilling machine is more adaptable but is limited to a single location in the workplace.
Gang Drilling Machine
As the name implies, it has a gang of drill heads with individual motors attached to the vertical column and executes several operations simultaneously.
It typically has four to six drill heads arranged side by side, capable of drilling, boring, reaming, tapping, and other operations.
No matter how big or small you want the hole, the numerous spindles can create it.
Drilling Machine Operations
The drilling machine's functions are as follows.
- Drilling
- Boring
- Reaming
- Tapping
- Spot facing
- Trepanning
- Honing
- Counter boring
- Counter Sinking
An Explanation for the Operations to be performed on Drilling Machines
The explanation is as follows.
Drilling Operation
The term "boring operation" refers to enlarging an existing hole. The drilling operation produced the current hole.
Boring Operation
Reaming Operation
Reaming operation uses a reamer to size and finishes an existing hole.A reaming tool has multiple cutting edges to smooth the surface and is multipoint.
Tapping Operation
The process is known as "tapping operation," and it entails using a cutting tool called a tap to create internal threads.
Spot Facing Operation
The chips on the hole's surface must be removed for the bolts to be properly seated. This can be done using an end mill cutter and a drilling machine.
Trepanning Operation
A Trepanning operation is used to create a large-size hole larger than 50mm in diameter without drilling. Blind holes are not suitable candidates for this Trepanning operation.
Honing Operation
The tool will rotate and reciprocate around its axis during this process to create incredibly smooth holes.
The IC Engine cylinder holes are primarily finished during this honing process.
Counterboring Operation
A specific hole area is made larger using the boring counter operation.
The end of the hole is enlarged during the countersinking operation to give it a conical shape for a shorter distance.
These are the different tasks that are carried out using drilling machines.
Let's discuss the uses of the drilling machine and its benefits and drawbacks.
Advantages of Drilling Machine
- The advantages of the Drilling Machine are as follows.
- Bench drilling machines require the operator to maintain high precision and accuracy, whereas automatic drilling machines rely on the machine to maintain high accuracy.
- It is simple to use.
- Low maintenance is required.
Disadvantages of Drilling Machine
The Disadvantages of the Drilling Machine are as follows.
- Since drilling produces ragged holes. Consequently, it is possible to anticipate a medium surface finish rather than a high surface finish.
- A small workpiece that fits the worktable can be machined, but larger components cannot.
- .If the workpiece and drill clamping are incorrect, the drill bit has a chance of breaking.
Applications of Drilling Machine
- Surface mining
- Counter boring
- Countersinking
- Underground mining
- Tapping etc.
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