Post on 18-Jan-2016
………..Continued
- Parts of Radial Drilling Machine
-Functions
- Classifications
Drilling Machine – Operations
Unit 4Unit 4Machine Tools Machine Tools
Machine Tools (Basic Elements, Working principle
and Types of Operations)
Lathe Machine – Centre Lathe
Drilling Machine – Radial Drilling Machine
Grinding Machine -Surface grinding, cylindrical grinding, centerless grinding, All operations
Operations performed on the Drilling Machine –
1. DRILLING OPERATION: In this process, a cylindrical hole is produced by removing metal
by the rotating edges of a cutting tool called as drill. Before drilling the centre of the hole is located on the work piece. Then the centre punch is used to produce an indentation at the centre. The drill point is pressed at this centre point to produce the required hole.
2. REAMING OPERATION – It is an operation of sizing and finishing a hole which has been
previously drilled. In order to finish a hole and to bring it to the accurate size, the hole is drilled slightly undersize. The speed of the spindle is made half that of drilling and automatic feed may be employed. The tool used for reaming is known as reamer which has multiple cutting edges. Reamer cannot originate a hole. It simply follows the path which has been previously drilled and removes a very small amount of metal.
Operations performed on the Drilling Machine –
3. BORING OPERATION: This operation is used for enlarging a hole to bring it to the required
size and have a better finish. This operation is also used to machine the internal surface of a hole which is already produced in casting.
4. COUNTER BORING OPERATION: It is the operation of enlarging the end of a hole cylindrically. The
enlarged hole forms a square shoulder with the original hole. This is necessary in some cases to accommodate the heads of bolts, studs and pins.
5. COUNTERSINKING OPERATION: It is the operation of making a cone shaped enlargement of the end of
a hole to providea recess for a flat head screw or countersunk rivet fitted into the hole. The tool used for is called as countersink. Standard countersinks have 60o, 82o included angle.
Operations performed on the Drilling Machine –
6. TAPPING OPERATION: It is the operation of cutting internal threads in already
produced hole by means of cutting tool called as a tap.7. GRINDING OPERATION: This operation is performed to finish hardened hole by a
revolving grinding wheel fitted on a spindle and fed up and down.
Operations performed on the Drilling Machine –
TrepanningTrepanning
• Trepanning is the operation of producing a Trepanning is the operation of producing a hole by removing metal along the hole by removing metal along the circumference of a hollow cutting toolcircumference of a hollow cutting tool
• Trepanning is performed for producing largeTrepanning is performed for producing large holes which can not be produced by any holes which can not be produced by any drilling operationsdrilling operations
WP
Guide
Cutting Edges
DRILLING
9
Reaming
10
11
12
13