1
Grouping Parts for Cellular Manufacturing with CADFind
Doug Love
Applied Search Technology Ltd.
Birmingham, U.K.
www.sketchandsearch.com
Introduction
This paper briefly reviews the nature of cellular manufacturing and examines the reasons why Group
Technology (GT) cells have become very popular in recent years. It goes on to examine one of the core tasks
faced by the cell design engineer – identifying the family of parts around which the cell will be designed. The
recent development of a ‘GT’ version of the CADFind graphical retrieval system has meant that this process
has been made faster and easier than was previously possible for coding and classification based
approaches. Traditionally coding and classification systems (like Opitz or CAMAC) used manual methods to
encode the properties and characteristics of parts into a numerical or alpha-numeric ‘code’. Parts with similar
codes were likely to be geometrically similar. Thus once all a company’s parts had been coded, simple
searches or sorts could be used to identify groups of parts with similar codes that would form the basis of the
cells’ families. These systems worked well but suffered from the long delays and costs associated with the
manual coding stage. In my experience manual coding rates rarely exceeded 100 parts per day per engineer
(a rate also confirmed by academic studies) and at this rate an engineer would take over a year to code even
a modest range of, say 25,000 parts. Such delays (or the costs associated with extra manpower) have often
proved unacceptable given the tight timescales that commercial realities frequently require of manufacturing
system redesign projects. This meant that other, less effective methods have often been used. The automatic
coding ability of CADFind can cut the time to code the parts range to a few days and thus for the first time
makes grouping based on coding and classification a viable option for any GT cell design project.
Design of Cellular Manufacturing Systems
The idea th