FIGURE EIGHT MOVEMENT OF SPRAY GUN
A figure eight mechanism (12) moves a thermal spray gun (22) over a substrate (26) such that the deposit (27) pattern has a figure eight configuration. The mechanism (12) and thereby the thermal spray gun (22) and the pattern are traversed along the substrate (26). The mechanism (12) is such that, when driven by an input drive of constant speed, the deposit travels along the configuration at a non-uniform velocity. A drive system (16) provides an input drive with varying speed so as to reduce the non-uniformity of the velocity. In one aspect a motor (52) has varying speed, and in another aspect a linkage (54) between a constant speed motor (52) and the mechanism (12) provides the varying speed.