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drilling machine:



A device, usually motor-driven, fitted with an end cutting tool that is rotated with sufficient power either to create a hole or to enlarge an existing hole in a solid material. Also known as driller.
a machine for making holes with removal of chips. Drilling machines are used for drilling, boring, countersinking, reaming, and tapping. Several types are used in metalworking: vertical drilling machines, horizontal drilling machines, center-drilling machines, gang drilling machines, multiple-spindle drilling machines, and special-purpose drilling machines.

Type of drilling machine:

Vertical drilling machine: Vertical drilling machines are the most widely used in metalworking. They are used to make holes in relatively small work-pieces in individual and small-lot production; they are also used in maintenance shops. The tool, such as a drill, countersink, or reamer, is fastened on a vertical spindle, and the work-piece is secured on the table of the machine.
Horizontal drilling machine: horizontal drilling machines are usually used to make deep holes, for instance, in axles, shafts, and gun barrels for firearms and artillery pieces

Centre drilling machine: Center-drilling machines are used to drill centers in the ends of blanks. They are sometimes equipped with supports that can cut off the blank before centering, and in such cases they are called center-drilling machines. Gang drilling machines with more than one drill head are used to produce several holes at one time.
Static and dynamic force analysis:
It is proposed that the dynamic quality of machine tools, in particular of radial drilling machines, be measured by the coefficient of merit. This coefficient is a product of the static stiffness between tool and workpiece, in the direction of the cutting thrust, and a non-dimensional ratio determined from the harmonic response locus of the machine structure.
The determination of the coefficient of merit in the case of radial drilling machines is discussed in details and its relationship with the stability chart of the drilling process is elucidated. It is shown that the coefficient of merit is proportional to the maximum drill diameter which is stable at all speeds and that its increase signifies a contraction of the speed ranges over which the machine chatters.

Drilling Machine…


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Drilling

Drilling is the operation of producing circular hole in the work-piece by using a rotating cutter called DRILL.
The machine used for drilling is called drilling machine.
The drilling operation can also be accomplished in lathe, in which the drill is held in tailstock and the work is held by the chuck.
The most common drill used is the twist drill.

Drilling Machine

It is the simplest and accurate machine used in production shop.
The work piece is held stationary ie. Clamped in position and the drill rotates to make a hole.
Types :-
a) Based on construction:
Portable, Sensitive,Radial, up-right, Gang, Multi-spindle
b)Based on Feed:
Hand and Power driven

Drill Materials

The two most common types are
1. HSS drill
- Low cost
2. Carbide- tipped drills
- high production and in CNC machines
Other types are
Solid Carbide drill, TiN coated drills, carbide coated masonry drills, parabolic drills, split point drill

Tool Holding devices

The different methods used for holding drill in a drill spindle are
By directly fitting in the spindle hole.
By using drill sleeve
By using drill socket
By using drill chuck

Precautions for Drilling machine

Lubrication is important to remove heat and friction.
Machines should be cleaned after use
Chips should be removed using brush.
T-slots, grooves, spindles sleeves, belts, pulley should be cleaned.
Machines should be lightly oiled to prevent from rusting

Safety Precautions

Do not support the work piece by hand – use work holding device.
Use brush to clean the chip
No adjustments while the machine is operating
Ensure for the cutting tools running straight before starting the operation.
Never place tools on the drilling table
Avoid loose clothing and protect the eyes.
Ease the feed if drill breaks inside the work piece.