New high-performance OMD grinding machines

Since 1993 OMD Officina Meccanica Domaso SPA has introduced the forced air ventilation system in grinding machines with the target of cooling the abrasive, while improving the cutting capacity and the service life, and of avoiding the overheating of the springs under machining. Over the years the fluid-dynamic analyses, carried out to study air motions inside the grinding chamber, and the practical experiences gained on the field have allowed implementing a “theoretical model” of the air flow inside the grinding chamber. In the new series of grinding machines, two fundamental aspects rule the air flow: the machine geometry and the surrounding conditions. The machine geometry has been designed to reduce drastically both the zones with low air speed, with flow stagnation and consequent possibility of dust accumulation, and vortical motions, main cause of the escape of solid particles. Once fixed the machine geometry, the surrounding conditions are two: the incoming air (forced) and the outgoing air (intake). The incoming air is used for: the special cooling system among the wheels to optimize the abrasive efficiency; cooling the spindles to exploit the highest nominal power also in heavy-duty situations; providing a sufficient air delivery, through apposite pipes, inside the grinding chamber to reduce the overheating of springs under machining; keeping clean, by means of special nozzles, the loading table from grinding dusts, thus reducing the wear of the spring sliding plans; creating a barrier, through apposite slots in the machine bed, to hinder and to reduce the escape of dusts and sparks; avoiding the material accumulation inside the machine. The optimization of the air nozzles, the oriented deflectors and the regulation of the flow adapted to the real needs, depending on the springs to be ground and the focal points to be cooled, allow achieving the best efficiency and drastically reduce useless dispersions. The air flow optimization has brought further productive advantages, besides notably reducing costs, thanks to an inferior consumption of abrasive wheels, then an inferior number of dressings and a minor consumption of chutes, to full advantage of the production. Concerning the outgoing air, they have optimized the nozzle sizing and calibrated, depending on grinding requirements, the suction system, drastically reducing the dust dispersions and notably improving operators’ working conditions.