Page 159 - Welding Robots Technology, System Issues, and Applications

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Robotic Welding: Application Examples

5.1 Introduction

When robots are used on the shop floor to perform welding tasks, users expect
massive improvements in terms of flexibility, productivity and quality. But that
outcome is not an easy task, since a considerable amount of additional setup and
programming work is necessary to guarantee that robots perform as expected with
the required quality. This process is time consuming and requires skilled personnel,
which means that robots take longer to be programmed and set up than really doing
some interesting work, introducing an overhead cost on time and personnel that
must be considered. And that is a major problem, since actual concepts like
availability and agility [1],[2] are key issues of modern manufacturing. In fact,
those concepts are fundamental to have robot automation take a more important
part on the shop-floor, cooperating with humans, which is decisive to help modern
country companies fight the low salary trap. Machines that store high levels of
flexibility, like robot manipulators, but fail in terms of agility because automation
integrators and machine builders were unable, when designing a specific machine,
to expose that flexibility to the users may become less interesting. Also, for SMEs
robot automation becomes uninteresting since all these companies work with small
series, under contract by customers, which means several models of products.
Knowing that the big majority of the production workforce is represented by
SMEs, this scenario constitutes a big problem. Consequently, solving these issues,
reducing setup and programming times, is one of the major problems that robot
manufacturers must address clearly in the near future.

The welding quality is closely related to the weld bead shape which is regulated by
the selected welding parameters (see Chapter 2). Consequently, several databases
have been developed, such as those from the Welding Institute – UK [3], to help in
selecting the parameters more suitable for the particular situation under
consideration. In these databases the input data is generally the type of weld (butt
weld or fillet weld), the welding position (flat, horizontal, vertical or overhead),

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