Are you looking for the Drilling Machine? So today we will study in details the Definition, Main parts, Types, Operation, Twist drill Nomenclature, Advantages, Disadvantages, and Application of Drilling Machine. Here you will get the articles of Mechanical Engineering in brief with some key points and you will get to know an enormous amount of knowledge from It. So If you find this articles helpful, please let us know in the comment box, either if any correction required too, also let us know in the comment box.
- Drilling is a material removing or cutting process in which the tool uses a drill bit to cut a hole of circular cross-
section in solid materials. Or
- This is the most common machining process, one estimate is that 75% of all metal cutting material removed comes from the drilling operation.
- While performing drilling operation the tool we use is Twist Drill, the nomenclature has shown below.
Drilling Machine Main Parts:
- The base is made up of the steel or iron. The main function of the base of the drill press is used to support the column and stabilize it.
- With the help of the base or the foot, the drill press can be placed in the upward direction.
- The column of the drilling machine is used to tie the table. The work is held in place by the table during the drilling process.
- This is a long rod in shape that stands vertically with the table. Both the column and the tables are placed at the 90 degrees with each other.
- You can adjust the work table up or down the column to reach the proper height. If required, it can also be swiveled around the column to the intended working position.
- A whopping majority of worktables have slots, holes and other structures and other work holding accessories. Certain tables can also be rotated around the horizontal axis.
- The head part of the drilling machine houses the spindle as it is attached at the top region of the spindle.
- It is responsible for the spindle movement because the spindle can only move upward or downward.
- The spindle is the most important part of the drilling machine that is used to hold the tool and is responsible for its rotation.
- The spindle of the tool is held with the help of arm that is gripped with the column.
- In order to keep the spindle in its place, the manufacturer has used a spindle return spring and the spindle moves up and down easily. The weight of the spindle is very useful in the performance of the drill press as counterbalances the spindle spring. At the bottom side of the spindle, chuck is placed and this chuck is used to hold the drill bit in place.
- An angle plate is usually known to support the action by its edge.
- These very accurately align the work in a perpendicular fashion to the surface of the table, and they usually have holes and slots to help in clamping it to the table and holding the workpiece together.
- Drill jigs are used for multi-tasking. That is when several holes need to be made in one particular place.
- It has got quite a few functions. It clamps, works in a firm manner and locates it in the correct or favorable position required for drilling.
- The last, but not the least important function of the drill jig is to guide the drill straight through with the help of ‘drill bushings’.
- The power transmission in the drilling machine used to transmit the power for its working is known as the power transmission. This power is supplied from the electric motor. The process of transmission takes place with the help of the v-bolt and the pair of pulley stacks opposite to each other. The speed of the spindle is fixed or controlled with the help of the pulley stacks.
- The above-provided figure shows the all the main parts of the drilling machine. All the important parts are highlight by labeling them. You can see the figure and get the idea of the parts of the drill press.
- Using the drilling machine is very easy if you know all the parts of the tool and their functions. In a case, if your tool is not working properly and having some problem you can find out easily that which part of the tool is not working properly or creating problems. You can de-attach that part of the drill press and replace it with the new one. This is the best way to operate your drill press in a quick and a good way.
Types of Drilling Machine:
Sensitive Drilling Machine:
- This is the same diagram the above-mentioned which is sensitive drilling machine.
- The machine has only a hand feed mechanism for feeding the tool into the workpiece. This enables the operator to feel how the drill is cutting and accordingly he can control the down feed pressure.
Vertical or Pillar:
- This drilling machine is free standing and is of a far heavier construction able to take larger drills.
- It has a heavy frame to support a wider range of work.
- The table height is adjustable and power speed and feeds are available.
- The larger drills normally have taper shank which located within taper bore in the spindle end. These tapers are standardized as Morse tapers.
- The radial drill is free standing and the workpiece is clamped in the position on the base. It is used for heavy large and heavy work.
- The arm is power driven for the height location. The drill head is positioned using motorized drives and it transverse the swinging arm.
- The workpiece remains stationary o the machine base or worktable.
- The machine spindle is moved to the location required.
- In this type, several spindles/ or stations are mounted on one long table as shown in the figure.
- There are many spindles mounted on one head to allow many holes to be drilled simultaneously.
Numerical Control Drilling Machine:
- The machine can automatically change tooling with a turret or automatic tool changer.
- Speeds, fee, and table position are controlled using a computer program.
Twist drill nomenclature:
- It is designed with cones like internal structure, narrow at the top or the web with a gradually increasing thickness to the shank.
- Axis: The imaginary straight line which forms the longitudinal centerline of the drill.
- Back taper: A slight decrease in diameter from front to back in the body of the drill.
- Body: The portion of the drill extending from the sank or next to the outer corners of the cutting lips.
- Body Diameter clearance: That portion of the land that has been cut away so it will not rub against the wall of the hole.
- Chisel Edge: The edge at the end of the web that connects the cutting lips.
- Chisel Edge Angle: The angle included between the chisel angle and the cutting lips as viewed from the end of the drill.
- Clearance Diameter: The diameter over the cutaway portion of the drill lands.
- Drill Diameter: The diameter over the margins of the drill measured at the point.
- Flutes: Helical or Street grooves cut or formed in the body of the drill to provide cutting lips, to permit removal of chips and to allow cutting Fluids to reach the cutting lips.
- Flute Length: The length from the outer corners of the cutting lips to the extreme back and of the flutes; it includes the sweep of the tool used to generate the flutes and, therefore does not indicate the usable length of the flutes.
- Helix Angle: The angle made by the leading edge of the land with a plane containing the axis of the drill.
- Land: The peripheral portion of the body between adjacent flutes.
- Land Width: The distance between the leading edge and the hill of the land measured at the right angle to the leading edge.
- Lead: The axial advance of leading edge of the land in one turn around the circumference.
- Lips: The cutting edge of a two flute drill extending from the chisel edge to the periphery.
- Lip Relief: The axial relief on the drill point.
- Lip Relief Angle: The axial relief angle at the outer corner of the lip; it is measured by projection onto a plane tangent to the Periphery at the outer corner of the lip.
- Margin: The cylindrical portion of the land which is not cut away to provide clearance.
- Neck: The section of reduced diameter between the body and the shank of a drill.
- Overall length: The length from the extreme end of the shank to the outer corners of the cutting lips; it does not include the conical shank end often used on a straight shank drill, nor does it include the conical cutting point used on both straight and taper shank drills.
- Point: The cutting end of the drill, made up of the end of the lands and the web; inform it resembles a cone, but departs from a true cone to furnish clearance behind the cutting lips.
- Point angle: The angle included between the cutting lips projected upon a plane parallel to the drill axis and parallel to the two cutting lips.
- Shank: The part of the drill by which it is held and driven.
- Tang: The flattened end of a taper shank intended to fit into a driving slot in a socket.
- Tang drive: Two opposite parallel driving flats on the extreme end of a straight Shank.
- Web: The central portion of the body that joins the land; the extreme end of the web forms the chisel edge is on a two flute drill.
Operation on Drilling Machine:
There are total 9 operations in drilling machine:
- When sand castings are made, cores are used to displace the metal where holes are desired. When cast the molten metal flows around the core. After the metal solidifies the casting is removed from the mould and the core disintegrates leaving the desired holes. the holes are usually quite rough and require heavy body drill to clean up the side wall of the whole.
2. Step Drilling:
- The above figure shown is also step drilling operation.
- More than one diameter can be ground on the drill body which saves an extra operation.
- It is the process of enlarging a hole. It is done with the help of a single point cutting tool which is usually held by a boring bar.
- It is an operation of finishing a drilled hole. A finished hole has the specified diameter size, is perfectly round, the diameter is the same size from end to end, and it has it has a smoothly finished surface. A drill hole is seldom accurate enough in size or sufficiently smooth to be called a precision hole. When greater accuracy is required the whole must be drilled undersize by a certain amount and finished by the reaming
5. Counter Boring:
- It is the operation of boring a second hole, larger diameter than the first but concentric with it. When this operation is done on a drilling machine a tool known as counterbore is used. The small diameter on the end of the tool known as the pilot keeps the counterbore concentric with the original hole. Pilots are interchangeable with others of different size to fit the various size of holes.
6. Counter Sinking:
- It is the operation of producing an angular surface at the end of a hole. A countersink is used. Countersink are made in many diameters size and several angles. The angle size depends upon the reason for countersinking. Flathead screws require a countersink with an 82 included angle, where is a Centre hole must be 60. Various types of rivet heads have included angles of from 90 145.
7. Spot Facing:
- It is the operation of machining a flat, circular surface around a whole to provide a seat for a Bolt head, nut or washer. It is usually performed on casting. A Counter bore may be used for spot facing. The Surface machined should be a square with the hole.
- Holes that are to be tapped(threaded) are first are drilled to a specified size. In order to tap holes on a standard drilling machine, a tapping attachment must be used. This attachment is held in the spindle of the drill press by a tapered Arbor, who drives the friction type mechanism. The tap holding chuck accurately centers the tap on the round part of the shank and floating jaws hold the tap on its square end in a firm, rigid grip, which prevents the tap from pulling out of the chuck when reversing.
- It is a hole making operation where an annular groove is produced leaving a solid cylindrical core in the center. In Trepanning a cutter consisting of
One or more cutting edges placed along the circumference of a circle is used to produce the annular groove. Trepanning is feasible if the hole has a diameter of more than 50 mm. Hole depth of 160 times the diameter can be obtained in Trepanning.
Advantages, Disadvantages, and Application:
Advantage of Drilling Machine:
- This machine is needed to mark on the end of components of dresses especially for setting pocket, dart & so on.
- It can make the hole permanently for a long.
Dis-advantage of Drilling Machine:
- The use of a machine is limited.
Application of Drilling Machine:
It is used to make a hole in the fabric for button attaching and to make a reference mark for attaching different small components on the garments.
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