The challenge was to provide a needle winding solution specifically to manufacture DC armatures. The requirement was for a solution that would enable unskilled or semi-skilled operators to achieve consistent quality without specialised tooling and operator intervention.
A risk assessment was carried out which showed the key to the process was the control of the wire loops for commutator terminations. A separate design study invented the ‘hedgehog’ which was then used in the final solution.
The machine is PC controlled enabling patterns to be stored and called up when necessary. Patterns can be edited or new patterns created upon demand. The machine uses high power brushless servos, belt drives and linear slides to provide tensions up to 1000N at 10g acceleration and phase locked speed of 4m/s. This is achieved whilst guiding the needle and wire in the stator slot with only 0.2mm clearance.
A manufacturing automation solution delivering consistent quality for products ranging from 25mm diameter to 200mm and up to 600mm long. A secondary development to enable direct welding of the wires to the commutator also achieved significant labour savings.