Civil Engineering Reference
In-Depth Information
17
Design for Manufacture and Maintenance
“To be a machine, to feel, to think, to know how to
distinguish good from bad, as well as blue from yellow, in
a word, to be born with an intelligence and a sure moral
instinct.”
—
LaMettrie (1748). By considering the
constraints in machine operation, one can also learn about
human needs
—
as we will demonstrate below.
17.1
INTRODUCTION
Human factors professionals in manufacturing have mainly focused on two areas: design
of industrial workstations and design of products to meet customer's needs and improve
functionality and usability. The design of products has broader implications. It affects the
types of jobs created in the assembly of the product and in the maintenance of the
product. Products that are well designed will be easy to assemble. The manufacturing
tasks may be distributed in an optimal fashion between manual labor and automated
processes. The allocation of tasks to people or machines should be beneficial for the
company, and should also create satisfying jobs for the employees. In the first part of this
chapter we will address design for manufacturability. In the second part of the chapter,
we will analyze how products should be designed in order simplify maintainability:
design for maintenance.
It may seem that most of these issues are of engineering interest. Maybe so, but
unfortunately engineers rarely deal with theses issues. HFE experts are required, and
whether they come from psychology or engineering is not very important.
17.2
THE DESIRE TO AUTOMATE
During the last 20 years, manufacturing engineers vigorously pursued opportunities to
automate, and sometimes the results were very disappointing. In the 1980s when robots
suddenly became popular, General Motors invested U.S. $80 billion in automated
manufacturing, but at least 20% of their spending on automation technology failed; the
money was lost (
The Economist,
10 August, 1991). Other major companies had similar
experiences. In many cases the reason was surprising: manual labor, with its greater
flexibility and adaptability, will outperform automation. The focus on automation,
particularly by engineers, does not necessarily lead to increased productivity. We must
understand how different work functions should be allocated between humans, machines,
and computers, something that is not well understood by the engineering community. The
issue of task allocation has since long interested
