Types Of Drilling Machine:
Drilling is an operation of making a circular hole by removing a volume of metal from the job by cutting tool called drill. A drill is a rotary end-cutting tool with one or more cutting lips and usually one or more flutes for the passage of chips and the admission of cutting fluid. A drilling machine is a machine tool designed for drilling holes in metals. It is one of the most important and versatile machine tools in a workshop. Besides drilling round holes, many other operations can also be performed on the drilling machine such as counter- boring, countersinking, honing, reaming, lapping, sanding etc
TYPES OF DRILLING MACHINE
1. Portable drilling machine
2. Sensitive drilling machine
3. Upright or column drilling machine
4. Radial drilling machine
5. Gang drilling machine
6. Multi-spindle drilling machine
7. Vertical drilling machine
8. Automatic drilling machine
9. Deep hole drilling machine
Classification of drilling machines.
(a) General purpose drilling machines of common use
1. Table top small sensitive drilling machine
- These small capacity (Equal Or More Than 0.5 kW) upright (vertical) single spindle drilling
machines are mounted (bolted) on rigid table and manually operated
using usually small size (φ More than 10 mm) drills. Fig. typically shows one
|Table top small sensitive drilling machine
2. Pillar drilling machine
- These drilling machines, usually called pillar drills, are quite similar to the
table top drilling machines but of little larger size and higher capacity
(0.55 – 1.1 kW) and are grouted on the floor (foundation). Here also, the
drill-feed and the work table movement are done manually. Fig. typically shows a pillar drill. These low cost drilling machines have tall
tubular columns and are generally used for small jobs and light drilling.
| Pillar drilling machine
3. Column drilling machine
- These box shaped column type drilling machines as shown in Fig. are much more strong, rigid and powerful than the pillar drills. In column
drills the feed gear box enables automatic and power feed of the rotating
drill at different feed rates as desired. Blanks of various size and shape
are rigidly clamped on the bed or table or in the vice fitted on that. Such
drilling machines are most widely used and over wide range ( light to
| Column drilling machine
4. Radial drilling machine
- This usually large drilling machine possesses a radial arm which along
with the drilling head can swing and move vertically up and down as can
be seen in Fig.. The radial, vertical and swing movement of the
drilling head enables locating the drill spindle at any point within a very
large space required by large and odd shaped jobs. There are some
more versatile radial drilling machines where the drill spindle can be
additionally swivelled and / or tilted.
|Radial Drilling Machine
5. CNC column drilling machine
- In these versatile and flexibly automatic drilling machine having box column
type rigid structure the work table movements and spindle
rotation are programmed and accomplished by Computer Numerical
Control (CNC). These modern sophisticated drilling machines are
suitable for piece or batch production of precision jobs.
(b) General purpose drilling machines with more specific use.
1. Hand drills
- Unlike the grouted stationary drilling machines, the hand drill is a portable drilling device which is mostly held in hand and used at the locations where holes have to be drilled as shown in Fig. The small and reasonably light hand drills are run by a high speed electric motor. In fire hazardous areas the drill is often rotated by compressed air.
2. Gang drilling machine
- In this almost single purpose and more productive machine a number (2 to 6) of spindles with drills (of same or different size) in a row are made to produce number of holes progressively or simultaneously through the jig. Fig. schematically shows a typical gang drilling machine.
|Schematic view of a gang drilling machine
3. Turret (type) drilling machine
- Turret drilling machines are structurally rigid column type but are more
productive like gang drill by having a pentagon or hexagon turret as
shown in Fig. The turret bearing a number of drills and similar
tools is indexed and moved up and down to perform quickly the desired
series of operations progressively. These drilling machines are available
with varying degree of automation both fixed and flexible type.
|Schematic view of turret type drilling machine
4. Micro (or mini) drilling machine
- This type of tiny drilling machine of height within around 200 mm is
placed or clamped on a table, as shown in Fig. and operated
manually for drilling small holes of around 1 to 3 mm diameter in small
|Photographic view of a micro (or mini) drilling machine
5. Deep hole drilling machine
- Very deep holes of L/D ratio 6 to even 30, required for rifle barrels, long
spindles, oil holes in shafts, bearings, connecting rods etc, are very
difficult to make for slenderness of the drills and difficulties in cutting fluid
application and chip removal. Such drilling cannot be done in ordinary
drilling machines and b ordinary drills.
- It needs machines like deep hole
drilling machine such as gun drilling machines with horizontal axis which
are provided with
- high spindle speed
- high rigidity
- tool guide
- Pressurised cutting oil for effective cooling, chip removal and
lubrication at the drill tip.
Deep hole drilling machines are available with both hard automation and CNC system.