A drilling machine which is also known as a drill press is a cutting process that uses drill bits of various sizes to cut a hole of circular-section in solid materials like metal, plastic, wood, rocks, etc.
The drill bit as the cutting tool rotates, is often multi-point. This drill which rotates from hundreds to thousands of revolutions per minute is pressed against the workpiece with force. The force applied causes the cutting edge to cut off chips from the workpiece.
Drilling is a common process in the manufacturing industry, which is why all mechanical engineers must know of them.
Now, let’s go deep to explain what a drilling machine is, its applications, parts, diagram, types, specifications, working, advantages, and disadvantages!
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What is a Drilling Machine?
Drilling is the process of making cylindrical holes of a specified depth and diameter on a workpiece. It is done by removing metal with the rotating edges of a drill. The equipment used to create the circular hole is known as a drilling machine.
A special tool known as drill bit is used to drill the hoes. These tools are used to drill holes of different sizes and different operations. Wood and metal are the common workpiece material that drilling operations are performed on, which is why it is one of the most important machine tools.
The machine tool was first invented to make cylindrical holes on metals, although there are different machine tools in the workship that are capable of creating holes.
Wilhem and Carl Fein of Stuttgart, Germany, in 1895 developed the first hand-held portable drilling machine. In 1917, Black & Decker patented the first pistol-grip portable drill with a trigger switch, which is still highly in use today.
Applications of Drilling Machines
Drilling machines are available in different shapes and sizes, varying from small hand-held power drills to bench-mounted and finally floor-mounted versions. They are used to carry out operations such as countersinking, counterboring, reaming, spot facing, as well as tapping large and small holes. Due to the fact that drilling machines can perform the operations, principles, and drill bits achieving them totally varies.
Applications of drilling machines with the use of drill bits with sharp cutting edges are used to achieve various hole sizes on operations mentioned above. The operator must know how to set up the work, set speed and feed, as well as coolant to obtain a quality hole.
However, drilling machines are used in various industries such as:
Construction and engineering to drill holes in materials such as concrete, wood or metals. They are used in mining industry to make holes in the ground for blasting and extration of minerals form the ground.
Drilling is perform in oil and gas industry, used to drill wells and extract oil and natural gas from underground reservoirs. Also, cordless drilling machine and magnetic drill press aer widely used in manufacturing industry for making holes in workpieces like metals, plastics, and wood.
In medical industry, drilling machine are used to make holes in bones during orthopaedic surgieries. Finally, in auto industry, the machine tools are used to drill holes for various parts, including chassis.
Drilling Machine Parts
The major part of a drilling machine are base, column, upper arm, worktable, drill head, feed mechanism, spindle, chuck, electric motor and pulley. Learn about the components of drilling machine here!
Diagram of drilling Machine
What are the Specifications of a Drilling Machine?
The specifications of a drilling machine include power source, motor capacity, drill chuck size, spindle speed, drill depth capacity, feed rate, drill bit compactibility.
Power Source
Most drilling machine predominantly rely on electricity as their source of energy, which ensures a reliable and consistent performance. Modern portable drilling machine are equip with battery which ease the usage in remote locations, adding to its convenience and flexibility.
Also some advanced models incorporate hydraulic systems to enhance power and precision for specialized applications.
Motor Capacity
Different motor capacity are incorporated on drilling machines, which caters for wide range of workloads and applications. The motor capacity varies from compact units suitable for light operations to robust machines designed for heavy operations.
The drilling machine motor capacity is typically measured in horsepower (HP) or Kilowatts (kW). With this, there is clear indication of the machine’s power output.
Drill Chuck Size
The Chuck size of a drilling machine is used to detemine the maximum diameter of the drill bit that the machine tool can accomodate. Drill chuch sizes are 1/2 inch, 3/4 inch, and 1 inch, allowing for various drilling requirements. This give the machine flexibility to handle different varietyof projects with varying hole diameter.
Spindle Speed
The spindel speed is measured in revolution per minute (RPM), which indicates the rotational speed of the drill bit. Different spindle speed is required for specific applications to achieve great result.
This is why drlling machines are designed to have adjustable speed settings, which allows the operators to customize the speed to meet the need of different materials, operations, and sizes.
Drill Depth Capacity
The drill depth capacity is the maximum depth a machine drill bit can penetrate into a workpiece material. It is required to choose a drilling machine with an appropriate depth capacity which is important for precise and efficient drilling operations.
With this machine tool specification, the drilling machine can meet the specific requirements of different drilling projects.
Feed Rate
Feed rate in a drilling machine is the speed which the drill bit make into the material during the operations. Drilling machines with adjustable feed rates gives the operator flexibility to control the drilling speed according the requirement of the materialwhich can determine the outcome of the project.
Drill Bit Compatibility
Drilling machines are designed to be incoporated with different types and sizes of drill bits. Drill bit types are twist drills, spade drills, hole saws, and step drills. Chuck size and machine configurations are used to determine the compactibility of the drill bits with the drilling machine.
Types of Drilling Machine
The various types of drilling machine are portable drilling machine, sensitive drilling machine, upright drilling machine, radial drilling machine, gang driling machine, multiple spindle drilling machine, deep mole drilling machine. Learn more about the types of drilling machines here!
Working Principle of a Drilling Machine
In the working of a drilling machine, the swarf is carried away from the tip of the drill bit by the fluting of the drill bit. The cutting tip produces more chips which continue the movement of the chips outwards from the hole. Cutting fluid or coolant is sometimes applied to prolong the tool’s life by cooling and lubricating the tip and chip flow.
When using a gun drill coolant may be introduced with the drill shank, it is used mostly while drilling aluminum. The cutting fluid help to ensure smooth and accurate cutting and prevent the metal from grabbing the drill bit while drilling the hole.
When cutting soft metals like brass that can cause grabbing of the drill bit and even causes chatter. 1-2 mm can be ground on the cutting edge to create an obtuse angle of 91 to 93 degrees. This prevents chatter and instead cuts the metal. The cutting tool edge pushes away the metal rather than grabbing the metal, creating high friction and hot swarf.
On heavy feeds and comparatively deep holes, oil-hole drills are used in the drill bit. It is designed with a lubricant pump to the drill head through a small hole in the bit and flowing out along the fluting. The arrangement of a conventional drill press can be used in oil-hole drilling. However, it is more common in automatic drilling machinery, because the workpiece rotates rather than the drill bit.
In computer numerical control (CNC) machine tools are also called peck drilling or interrupted cut drilling. It is used to keep swarf from detrimentally building up when deep holes.
This peck drilling involves plunging the drill partway through the material, which is more than five times the diameter of the drill. It then retracts it to the surface, which is repeated until the cutting is completed.
The Feed, Cutting Speed & Machining Time of a Drilling Machine
In the operation of a drilling machine, the feed, cutting speed, and machining time important to achieve the desired result. Operators are expected to know the equation of these terms.
Feed
The feed is the distance a drill bit travels into the workpice with each rotation. It is also called feed rate and is mostly measured in millimetres. The range of the feed is 0.05 to 0.35 mm. A drill bit can be maintained by employing the best feed rate, which to a lay man it is by not feed too hard ot too low.
Cutting Speed
The cutting speed is the rate at which the edge tool travel through rotation. Materials are highly imparted on the drill bit cutting speed, which is why cutting speed should be consider and recommended. The cutting speed typically range depending on the material from 10/ m/min to 90 m/min. This can have impact on how much meterial is removed.
Mathematically, v=πdN1000
Here,
v = Cutting speed, in m/min
d = Drill diameter, m
N = Number of rotations of cutting tool per min
Machining Time
The machining time is the total time taken by the drilling machine to achieve the desired hole on the workpiece. It can be calculated using:
T=LN×f
Here, f = feed in m.
Drilling Machine Operations
The operations that can be carried out with drilling machine are plane drilling operation, core drilling operation, step drilling operation, boring operation, counter boring operation, reaming operation, countersinking operation, Spot facing operation, tapping operation, and trepanning operation. Learn about drilling machine operations here!
Maintenance and Safety in Drilling Machine
One of the major maintenance of a drilling machine is by lubricating in between the drill bit and workpiece while working. This helps to dissolve heat and friction generated by the moving parts. Some manufacturers offer manuals for proper lubricating methods and cleaning methods.
The drilling machine is expected to clean after use and clear the chips to avoid damage to the moving parts. Ensure spindles and sleeves are free from grit to avoid damaging the precision fit. To prevent rust on the machine parts, especially the bed, the oil should be lightly coated on their surfaces.
Drilling larger holes requires some special care to avoid injuries to the operator. The part should hold one vice or join with other metal parts that will stop the workpiece from moving. It should be operating at slow speeds to avoid rapid abrasive wear on the moving parts. Lubrication should also be added more often.
When the machine is in extremely cold conditions, the machine should work at a slow speed. Allow the parts and lubricants to warm up before increasing the speed.
Safety precaution to be taken in drilling operation as it involves power equipment. It must be considered to prevent damage to the equipment, operator, and people nearby. To avoid this, serious care must be taken in maintaining and setting up the work and proper working tools should be selected. The holding device should also be in good condition to avoid damage.
Read: Power feed and hand-feed drilling machine
Types of Drilling Machine Tools
The types of drilling machine tools are Flat or Spade Drill, Straight Fluted Drill Tool, Twist Drill Tool , Taper Shank Core Drill , Oil Tube Drill , and Centre Drill.
Advantages of Drilling Machine
Below are the benefits of drilling machine:
- Drilling machine aer much faster than manual drills.
- They are designed to be precise and accurate with consistent size and depth.
- Modern drilling machines are automated, they are capable of making large holes of consistent side, shape, and depth.
- They are used to drill different materials like plastics, wood, metal, and composites, which is why they are used in various applications and industries.
- The machines are capable of drilling different sze of holes on different workpiece.
Disadvantages of Drilling Machine
Below are the limitations of drilling machine:
- Drilling machines can be so noisy and produce vibration.
- Drilling machines have limited depth of drilling
- Operator are exposed to injury if no careful
- Machine can be expensive to purchase and maintain
- Regular maintenance is required to prevent breakdown
That is all for this article, where i explained what a drilling machine is, its applications, parts, diagram, types, specifications, working, advantages, and disadvantages. I hope it was helpful, if so, kindly share with others. Thanks for reading, see you around!
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