Technical standards and acceptance of flexographic printing machines Understanding the technical standards of flexographic printing machines is of great significance for scientifically and rationally purchasing machines and for correct acceptance of machine performance, safety, and quality. On the basis of the basic type printing machine, the multi-functional unit type flexographic printing machine is combined with several additional functional units to make the machine play a complete functional role.

The technical standards of flexographic printing machines should mainly include: the assembly quality of the main parts such as feeding unit, printing unit, die cutting unit, slitting unit, feed tension control, and printing, glazing, die cutting, rewinding, and Operation, noise, safety requirements, electrical quality and appearance quality, etc. Limit values ​​are specified for quantifiable characteristics, and non-quantifiable characteristics can be checked by specific test methods. Among them, the inspection of the assembly quality of the main parts can test the core reference components of each functional unit that affects the main mechanism, operating performance, accurate handover, and paper transfer handover accuracy of the flexographic printing machine. The specified limit value.

The dry running test of the machine requires starting from low speed under low pressure and without feeding, running at low, medium and high speed, and each stage of speed is tested according to the specified time: running at 40% of the maximum speed of the machine is not less 1 hour; running at 60% of the maximum speed of the machine is not less than 2.5 hours; running at the maximum speed of the machine is not less than 0.5 hours to conduct the dry running test, and the temperature rise of the bearing should not be higher than 35 ℃. Inspection content of the safety performance and electrical quality of the machine The content of the safety inspection includes the exposed transmission parts, printing, die cutting and other partial pressure points; the safety protection of the drying system and the ultraviolet curing device. Electrical quality inspections include electrical systems, protective earth circuits, insulation resistance, and withstand voltage tests. Conditions and requirements of machine test Ambient temperature 23 ℃ ± 5 ℃; relative humidity 60% ± 5%; one of three printing papers: 60g / m² ～ 100g / m² double-sided coated paper; 80g / m² mirror coated Self-adhesive; 230g / m² ～ 250g / m² white cardboard; the paper roll used in the test should not have defects such as dampness, curling, uneven thickness, drop deformation, uneven tightness and excessive joints; printing plate size Not less than 75% of the maximum printing width of the machine, and the length is not less than 254mm (10in); glazing printing uses a printing plate with a pattern or full version, whichever is one of the two; the thickest paper for noise test, at the highest speed of the machine 80% for printing; paper feeding, die cutting and cutting single sheet test; paper feeding, die cutting and slitting test at not less than 50% of the maximum speed of the machine, continuous sampling of 100 sheets, measuring with a ruler and scale magnifying glass According to calculation, the left-right error of the cut single paper is not more than 0.50mm.

The machine's printing test includes registration error test, imprint uniformity and imprint stability test, dot quality check, graphic printing test, printing and die cutting combined test, glazing test, rewind test, etc. The inspection method is realized through physical and chemical inspection, sensory inspection, and printing plate printing. There are overprint lines on the test printing plate that reflect the register of the machine, on-site measurement bars that reflect the running stability, a large network line area that reflects the quality of the dots, a cutting line that reflects the cutting error, and illustrations of the printing effect text. For registration error checking, multi-color products with more than 2 colors are printed at a time at not less than 50% of the maximum speed of the machine. 100 consecutive samples are taken, measured and calculated with a graduated magnifier, and the printing registration error is within 0.25mm. The pass rate of continuous samples shall not be less than 96%; the imprint uniformity and imprint stability inspection shall be printed at not less than 50% of the maximum speed of the machine. For each printing plate, in continuous printing, each item shall be separated by 10 sheets , Take 1 sheet, sample 20 pieces of each printing plate, and measure the solid density value on each piece of the specified sample sheet with a density meter; printing and die-cutting combined test, continuously sample 100 sheets, measure and calculate with a magnifying glass and ruler, print The registration error of the screen and die-cutting should be within 0.50mm, and the passing rate of continuous proofs should not be less than 96%.

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