DRILLING
MACHINE…
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
SENSITIVE DRILLING
MACHINE
• DRILL HOLES FROM
1.5 TO 15MM
• OPERATOR SENSES
THE CUTTING ACTION
SO SENSITIVE
DRILLING MACHINE
UP-RIGHT DRILLING
MACHINE
• DRILL HOLES UP TO
50MM
• TABLE CAN MOVE
VERTICALLY AND
RADIALLY
RADIAL DRILLING
MACHINE
• IT IS THE LARGEST
AND MOST
VERSATILE USED
FOR DRILLING
MEDIUM TO LARGE
AND HEAVY WORK
PIECES.
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
Drilling And Drills
Types of drills
– Twist drill: most
common drill
– Step drill:
produces holes
of two or more
different
diameters
– Core drill: used
to make an
existing hole
bigger
DRILL FIXED TO THE
SPINDLE
Drilling operations
Drilling Centre Hole
Drilling Deep Holes
Drilling Thin Material
Drilling Pilot Hole
TOOL NOMENCLATURE
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
WORK HOLDING DEVICES
DRILLING OPERATIONS…
• OPERATIONS THAT CAN BE PERFORMED
IN A DRILLING MACHINE ARE
DRILLING
REAMING
BORING
COUNTER BORING
COUNTERSINKING
TAPPING
OPERATIONS IN DRILLING
MACHINE
OPERATIONS IN DRILLING
MACHINE
TYPES OF CUTTERS
REAMERS :-
MULTI TOOTH CUTTING TOOL
ACCURATE WAY OF SIZING AND FINISHING THE PRE-
EXISTING HOLE.
ACCURACY OF 0.005MM CAN BE ACHIEVED
BORING TOOL:-
SINGLE POINT CUTTING TOOL.
BORING TOOL IS HELD IN THE BORING BAR WHICH HAS
THE SHANK.
ACCURACY OF 0.005MM CAN BE ACHIEVED.
TYPES OF CUTTERS
COUNTERSINKS :-
SPECIAL ANGLED CONE SHAPED ENLARGEMENT AT THE END OF
THE HOLE
CUTTING EDGES AT THE END OF CONICAL SURFACE.
CONE ANGLES OF 60°, 82°, 90°, 100°, 110°, 120°
COUNTER BORE TOOL:-
SPECIAL CUTTERS USES A PILOT TO GUIDE THE CUTTING
ACTION .
ACCOMMODATES THE HEADS OF BOLTS.
COUNTER BORE AND SPOT FACING
TYPES OF CUTTERS
COMBINED COUNTERSINKS AND CENTRAL DRILL :-
SPECIAL DRILLING TOOL TO START THE HOLE
ACCURATELY.
AT THE END IT MAKES COUNTERSINKS IN THE WORK
PIECE.
GUN DRILL :-
MACHINING OF LENGTHY HOLES WITH LESS FEED RATES.
TO OVERCOME THE HEATING AND SHORT LIFE OF THE
NORMAL DRILL TOOL
TYPES OF CUTTERS
TAPPING:-
FOR CUTTING INTERNAL THREAD
MULTI CUTTING EDGE TOOL.
TAPPING IS PERFORMED EITHER
BY HAND OR BY MACHINE.
MINOR DIA OF THE THREAD IS
DRILLED AND THEN TAPPING IS
DONE.
WORK HOLDING DEVICES
• 1. MACHINE TABLE
VICE
WORK HOLDING DEVICES
• STEP BLOCKS
• CLAMPS
• V-BLOCKS
• ANGLES
• JIGS
• T- SLOTS BOLT
DEFINITIONS
• CUTTING SPEED (V):-
IT’S THE PERIPHERAL SPEED OF THE DRILL
V = X D X N WHERE
D = DIA OF THE DRILL IN M
N = SPEED OF ROTATION IN RPM
FEED RATE (F):-
IT’S THE MOVEMENT OF DRILL ALONG THE AXIS
(RPM)
DEPTH OF CUT (D):-
THE DISTANCE FROM THE MACHINED SURFACE TO
THE DRILL AXIS
MATERIAL REMOVAL RATE:-
IT’S THE VOLUME OF MATERIAL REMOVED BY THE
DRILL PER UNIT TIME
MRR = ( D2 / 4) X F X N MM3 / MIN
MACHINING TIME (T) :-
IT DEPENDS UPON THE LENGTH (L) OF THE HOLE TO BE
DRILLED , TO THE SPEED (N) AND FEED (F) OF THE DRILL
T = L / F N MIN
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.
