Page 7 - Welding Robots Technology, System Issues, and Applications

Preface

Modern manufacturing faces two main challenges: more quality at lower prices
and the need to improve productivity. Those are the requirements to keep
manufacturing plants in developed countries, facing competition from the low-
salary regions of the world. Other very important characteristics of the
manufacturing systems are flexibility and agility of the manufacturing process,
since companies need to respond to a very dynamic market with products
exhibiting very short life-cycles due to fashion tendencies and worldwide
competition. Consequently, manufacturing companies need to respond to market
requirements efficiently, keeping their products competitive. This requires a very
efficient and controlled manufacturing process, where focus is on automation,
computers and software. The final objective is to achieve semi-autonomous
systems, i.e., highly automated systems that work requiring only minor operator
intervention.

Robotic welding is one of the most successful applications of industrial robot
manipulators. In fact, a huge number of products require welding operations in
their assembly processes. Despite all the interest, industrial robotic welding
evolved only slightly and is far from being a solved technological process, at least
in a general way. The welding process is complex, difficult to parameterize and to
monitor and control effectively. In fact, most of the welding techniques are not
fully understood, namely the effects on the welding joints, and are used based on
empirical models obtained by experience under specific conditions. The effects of
the welding process on the welded surfaces are currently not fully known. Welding
can in most cases impose extremely high temperatures concentrated in small zones.
Physically, that makes the material experience extremely high and localized
thermal expansion and contraction cycles, which introduce changes in the materials
that may affect its mechanical behavior along with plastic deformation. Those
changes must be well understood in order to minimize the effects.

The majority of industrial welding applications benefit from the introduction of
robot manipulators, since most of the deficiencies attributed to the human factor is
removed with advantages when robots are introduced. This should lead to cheaper

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