Exceptional demands are placed on HelioSprint high-performance engraving systems.

They engrave 8000 / 12000 cells per second at a depth of up to 70 µm and with a required precision of 1 µm. In this process, it isn’t just necessary to maintain the repeat accuracy for each individual repeat on the cylinder, but to ensure this precision is adhered to even after engraving over 10,000 cylinders.

An ideal engraving system would convert an image signal, e.g. the square wave signal of a black-and-white transition, 1:1 into a mechanical movement. However, no ideal engraving system exists in practice. The properties of materials, magnetic effects such as hysteresis and inevitable production tolerances always lead in practice to deviations from the ideal transfer behavior. This results in unavoidable errors in engraving such as bounce, drag, and thermal drift.

HELL has developed an adjustment process that uses digital signal processing to offset deviations from the ideal. This involves recording the engraving system’s characteristics using a large number of measurements and calculating a fingerprint. This fingerprint is stored in a memory chip in the engraving system. Before each engraving, the fingerprint is accessed and fed to the digital signal processors in the engraving machine. During engraving, the processors use the specific fingerprint to calculate a corrected image signal that counteracts the errors (see above) of the particular engraving system.

Engraving systems are subjected to a range of influences in day-to-day production that may impact negatively on their transfer behavior. Incorrect use, such as rough handling, damage, soiling, cooling problems and aging processes result in changes to the characteristics of engraving systems. Using non-certified engraving styli may also lead to these effects.

To ensure consistently high engraving quality at all times, it is essential to carry out regular service on engraving systems so as to return them to their original condition. To do this, engraving systems are dismantled and cleaned, faulty or worn parts are replaced, and the fingerprint is updated. Systems undergoing service are subjected to the same quality checks as new engraving heads. Service is concluded by performing another engraving process, with customer parameters also being used if requested.