Method of generating a tool path

Apparatus for depositing material to a material receiving surface of an aerofoil, aerofoil having a leading edge, a trailing edge and suction and pressure surfaces extending between the leading and trailing edges, the apparatus comprising a laser for generating a beam onto the surface at a predetermined location, a movement mechanism for traversing the beam relative to the surface, and processing apparatus, wherein the processing apparatus

• a) assigns a deposition plane to the aerofoil;
• b) determines for the deposition plane points corresponding the leading edge, the trailing edge and the centre of a circle constrained by both the suction surface and the pressure surface when the suction surface and the pressure surface are the greatest distance apart from each other;
• c) determines the position of the centre point of a circle the edge of which passes through the deposition plane points;
• d) determines a trailing edge reference line extending from the centre point of the circle through the trailing edge point, a leading edge reference line extending from the centre point of the circle through the leading edge point and one or more mid reference lines extending from the centre point of the circle through one or more mid reference points between the leading edge point and the trailing edge point;
• e) trims each mid reference line to the bounds of the suction surface and pressure surface and determining the length of each mid reference line;
• f) applies an adaptive factor to the length of each mid reference line to provide an adaptive point for each mid reference line;
• g) determines a spline extending through the leading edge point, the trailing edge point and each adaptive point;
• and
• h) causes the movement mechanism to traverse the beam along the spline or a path offset from the spline by a predetermined factor.