|Drilling machines or drill presses are one of the most common machines
found in the machine shop. A drill press is a machine that turns and
advances a rotary tool into a workpiece. The drill press is used primarily
for drilling holes, but when used with the proper tooling, it can be used
for a number of machining operations. The most common machining operations
performed on a drill press are drilling, reaming, tapping, counterboring,
countersinking, and spotfacing.
There are many different types or configurations of drilling machines,
but most drilling machines will fall into four broad categories: upright
sensitive, upright, radial, and special purpose.
SENSITIVE DRILL PRESS
Figure 1 Upright sensitive
| The upright sensitive drill press (Figure 1)
is a light-duty type of drilling machine that normally incorporates
a belt drive spindle head. This machine is generally used for
moderate-to-light duty work. The upright sensitive drill press gets its name
due to the fact that the machine can only be hand fed. Hand feeding
the tool into the workpiece allows the operator to "feel"
the cutting action of the tool. The sensitive drill press is
manufactured in a floor style or a bench style.
The upright drill press (Figure 2) is a heavy duty type
of drilling machine normally incorporating a geared drive spindle head.
This type of drilling machine is used on large hole-producing
operations that typically involve larger or heavier parts. The upright drill press
allows the operator to hand feed or power feed the tool into the
workpiece. The power feed mechanism automatically advances the tool into
the workpiece. Some types of upright drill presses are also
manufactured with automatic table-raising mechanisms.
Figure 2 Upright drill press
ARM DRILL PRESS
The radial arm drill press (Figure 3)
is the hole-producing work horse of the machine shop. The press is
commonly refered to as a radial drill press. The radial arm drill
press allows the operator to position the spindle directly over
the workpiece rather than move the workpiece to the tool. The design
of the radial drill press gives it a great deal of
versatility, especially on parts too large to position easily. Radial
drills offer power feed on the spindle, as well as an automatic mechanism
to raise or lower the radial arm. The wheel head, which is located
on the radial arm, can also be traversed along the arm, giving
the machine added ease of use as well as versatility. Radial arm
drill presses can be equipped with a trunion table or tilting table.
This gives the operator the ability to
drill intersecting or angular holes in one setup.
Figure 3 Radial arm drill press
PURPOSE DRILL MACHINES
There are a number of types of special purpose drilling machines. The
purposes of these types of drilling machines vary. Special purpose drilling
machines include machines capable of drilling 20 holes at once or
drilling holes as small as 0.01 of an inch.
Figure 4 Gang drill press
|The gang style drilling machine (Figure 4) or gang drill press has
several work heads positioned over a single table. This type of
drill press is used when successive operations are to be done. For
instance, the first head may be used to spot drill. The second head
may be used to tap drill. The third head may be used, along with a
tapping head, to tap the hole. The fourth head may be used to
Spindle Drilling Machine
|The multiple spindle drilling machine is commonly refered to as a
multispindle drill press. This special purpose drill press has many
spindles connected to one main work head (Figure 5).
All of the spindles are fed into the
workpiece at the same time. This type of drilling machine is
especially useful when you have a large number of parts with many
holes located close together.
Figure 5 Multispindle drill press
| The micro drill press is an extremely accurate,
high spindle speed drill press. The micro drill press is typically
very small (Figure 6) and is only capable of handling very small
parts. Many micro drill presses are manufactured as bench top
models. They are equipped with chucks capable of holding very small
Figure 6 Micro drill press
Type Drilling Machine
| Turret drilling machines are equipped with several drilling
heads mounted on a turret (Figure 6). Each turret head can be
equipped with a different type of cutting tool. The turret allows the
needed tool to be quickly indexed into position. Modern turret
type drilling machines are computer-controlled so that the table can be
quickly and accurately positioned.
Figure 6 CNC Turret type drilling