Information Technology Reference
In-Depth Information
14
Intelligent Analysis of Utilization of Special
Purpose Machines for Drilling Operations
Majid Tolouei-Rad
School of Engineering, Edith Cowan University, Perth,
Australia
1. Introduction
Drilling and drilling-related operations constitute more than 60% of all machining processes
in manufacturing industries. Consequently, it is important to know how to perform these
operations properly. With availability of many machining processes capable of performing
drilling operations sometimes it is difficult to decide which process would result in a higher
profit or a lower unit cost for a given task. Due to increasing global competition,
manufacturing industries are now more concerned with their productivity and are more
sensitive than ever to their investments with respect to flexibility and efficiency of
production equipment (Boothroyd and Knight, 2005, Wecka and Staimer, 2002). Researchers
(Ko
et al
., 2005) believe that increasing the quality of production and reducing cost and time
of production are very important factors in achieving higher productivity. Achieving this
goal requires reconsidering current production methods that could lead to introduction of
new production techniques and more advanced technologies.
In traditional drilling processes a sharp cutting tool with multiple cutting edges is used to
cut a round hole in the workpiece material. In non-traditional drilling processes various
forms of energy other than sharp cutting tools or abrasive particles are used to remove the
material. The energy forms include mechanical, electrochemical, thermal and chemical
(Groover, 2010). Generally non-traditional processes incorporate high capital and operating
costs. Therefore, when machining economy is of concern manufacturing companies focus on
traditional processes. Even within this category, a machining specialist has the choice of
using conventional drilling machines, CNC machines, and special purpose machines
(SPMs). According to the literature (Groover 2008) when production quantity and variety
are low, universal machine tools give the best result. When various components should be
produced, CNC is the best option. For the condition of high production quantity with low
variety, SPM gives the highest productivity and is considered as the most economic
production method. Accordingly, Tolouei-Rad and Zolfaghari (2009) believe that SPMs are
superior to computer numerical control (CNC) machines for producing large quantities of
similar parts; however, most manufacturers still rely on well-known CNCs for large volume
production tasks. This is mainly attributable to the fact that both SPMs and CNCs
incorporate high capital costs; SPMs are more productive and CNCs are more flexible. When
the part in production is no longer in demand due to frequent market changes, SPMs
