Abstract
The TIM robot has been designed for use with high-precision welding using the TIG (tungsten-inert-gas) process. Details are given of the design and construction of a five degrees of freedom machine, having cartesian and wrist movements. Details are also given of the operating features and the microcomputer and electronic hardware necessary to achieve these design features. An Intel 8085 8-bit microcomputer was used to control the welding operation; the workpiece position and movement and the time sequence of the welding cycle could be controlled in accordance to a predetermined set of parameters stored in memory.
The approach adopted for software development is also described. Emphasis is placed on the use of a high-level language to achieve flexibility, with subroutines in assembly language for faster response. Path entry was carried out by moving the torch around the joint and recording by the point-to-point technique. Complex joint paths, for example circular, square and triangular paths, can be reproduced accurately, and such welds have been used as illustrations of the flexibility of the machine.
In designing the machine for TIG welding operations, the controller was fully protected against HF airborne noise present during arc initiation.
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