The Converting market, as generally understood, embraces all applications in which the processing of a material starts with its unwinding. Further subdivisions are possible on the basis of the different materials involved (paper, board, plastic films, etc.), their specific characteristics and the individual processes they undergo, but as far as brakes are concerned, converting can be discussed in the broad sense of the term.
Coremo Ocmea has been working on this market for a long time, especially with pneumatic brakes installed on machines of various kinds: flexo and rotogravure printing machines, cutting machines, laminating machines, coating machines, embossers, labelling machines, rewinders, corrugated board making machines, etc.
Brakes are normally installed on pay-off reels to provide a torque resistant to unwinding of the reel and keep the unwound material at the correct tension. The tension on the material must be constant throughout the unwinding phases, to ensure that the downstream printing, lamination, gluing, cutting and embossing steps can take place correctly. What’s more, as the reel’s diameter decreases, the resistant torque applied by the brake must be reduced accordingly.
Brakes operate in continuous slipping mode where the working pressure decreases while the rpm increases constantly due to this reduction in diameter. In these working conditions it is vital for the effective value of the friction coefficient, a specific characteristic of the material, to remain more or less stable as the temperatures and speeds vary.
In applications where the working speed or torques are particularly high, as in the case of slitter-rewinders or corrugated board machines, brakes are fitted with special fans to increase their thermal capacity and prevent vitrification of the linings.
Coremo pneumatic caliper brakes are also used for other purposes: for example, for braking the central drum, as in flexo printing machines, for braking rolls, and in special applications, to slow down, stop or hold moving parts of machines.