Information Technology Reference
In-Depth Information
2. Fundamentals of SPM technology
Groover (2008) has defined the term ”production automation” as the application of
electrical, electronic, mechanical, hydraulic and pneumatic systems for rapid and quality
productions in large volumes. Automated production techniques are widely used in
manufacturing industries for dealing with issues such as high cost of labour, shortage of
skilled people, low interest of labour to work in production firms, safety, high cost of raw
materials, improved quality, uniformity in the quality of products, low inventory, customers
satisfaction, and performing difficult operations. Figure 1 shows a SPM as an example of
utilization of automated production techniques in manufacturing. This machine has two
work stations, one for drilling and one for tapping. The machine is used for machining the
parts shown in the Figure.
Fig. 1. A two station SPM for drilling and tapping operations with parts being produced
(Photo: Suhner, 2001)
Generally SPMs lack the high rigidity found in conventional and CNC machines.
Consequently, majority of these machines are used for performing drilling and drilling-
related operations such as tapping, reaming, counterboring and countersinking on
machinable materials where the magnitude of machining forces is relatively low. This
eliminates excessive vibrations of the machine tool due to high cutting forces. However, it
should be noted that SPMs are also capable of performing milling and some other
machining operations that would result in high cutting forces. In such cases there is a need
for stronger chassis, stronger machining and sliding units, and use of special accessories in
order to eliminate vibrations when possible.
2.1 Machining and sliding units
The units used in SPMs can be divided into two main groups: machining and sliding. A
machining unit is equipped with an electro-motor that revolves the spindle by means of pulley
and belt systems in order to rotate the cutting tool. Like other machine tools, the connection of
cutting tools to the machining unit is accomplished by standard tool holders. Machining units
