The article presents the assessment of the quality of operation of devices, which comprise a processing line in SAATNAU Sp. z o.o. in Środa Śląska. The following devices were researched: the unit for cleaning cobs, a chamber drier, a threshing unit, a cleaner, cylinder calibrators, a weight selector and a bagging machine. Cobs leaving the units, which separate covering leaves, were clean in approx. 95%. Moisture of cobs upon drying did not exceed 14%. The quality of operation of the threshing unit was at a very high level. Slight fluctuations of the quality of operation occurred in case of cylinder calibrators. The weight selector was of high degree of selection. In case of the bagging machine operation, declination was never exceeded.