4. General structure

As with all material-removing machine tools, the structure is made up of fixed and moving elements. In this case, the structure is highly stressed by the particularities of broaching machining: interrupted work, jerking and vibration. As a result, broaching machines are massive in design, with very high work rates. The main frame is usually cast-iron, obtained from a foundry and stabilized over time, before being machined and assembled. The various casings making up the frame are reinforced to withstand stresses under load. Mechanically-welded frames are rarely used, except for small units or machines built in small numbers, and therefore not justifying the creation of a foundry model. For the other constituent parts: tables, slides, mounts, cylinders, etc., cast iron and steel are used, with the introduction of composite materials, as in the case of slides, for example.