Several key problems in improving the cutting and cutting of gravure printing machine
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Several key issues
Cutting precision At present, the cutting precision of the imported gravure printing machine is about ±0.15. Due to the low level of domestic machining technology and equipment, the accuracy of our design of the new system should be set at ±0.20mm. The cutting accuracy is related to the measurement error of the original gear and the paper feed roller. The error of the tooth tip circle diameter and the helix angle of the gear affects the cutting accuracy of the measurement. The diameter of the paper feed roller is generally large, generally about 200mm, and the measurement error of the large diameter also affects the cutting precision. The cutting accuracy is related to the machining error of the gear and the paper feed roller. Gear dimensional tolerances and machining can affect the cutting accuracy. The processing of gears in China is limited to hobbing machines, gear shaping machines and gear grinding machines, and it is rarely processed by CNC machine tools. Such a large processing error will eventually affect the accuracy of the transmission system, and the machining error of the paper feed roller diameter will also affect the accuracy.
Several parameters of gear processing
The modulus is selected from the gravure printing machine imported from Europe. The modulus M or MN of the transmission system gear can be calculated according to the international calculation, according to the international GB-1356-88 series.
According to international regulations, the helix angle of the domestic gear is generally 8 degrees - 16 degrees. The imported equipment is to increase the longitudinal coincidence of the gears, so that the gears run more smoothly. The generally selected gear helix angle is 19 degrees-20 degrees.
Pressure angle The pressure angle of the imported gear is the same as that of the domestic gear. The general pressure angle is 20 degrees.
Material selection and heat treatment The material of the imported gear is good, and the gear has high hardness after heat treatment. When processing new gears, try to choose the hinged material, such as 40CR after quenching and tempering, roughing. The hardness of the gears thus processed can generally reach about HRC48.
The machining precision grade imported gears are mostly made of CNC machining centers, and the machining precision is high. When processing new gears in China, it is generally required that the machining level of the gears is above 6 and can reach 5, and the machining error of the gears is minimized.
The paper feed roller has a large diameter, and generally has a diameter of about 200 mm and a length of about 1000 mm. Therefore, the rollers of this array are easily deformed during processing, and the bD work is difficult. Generally, the 40CR material well can be selected for quenching and tempering treatment. After roughing, the plant is planted. At the same time, it is necessary to pay attention to the coaxiality of the paper feed roller, and the reference is selected at the support position of the two shafts.
Design case
Take ATN's 660 gravure printing machine as an example. The original large-size sheet is 789mm. In order to save the cost of making the embossing, indentation and die-cutting cylinders when making the flip-top cigarettes, the products are cut into large sheets after printing on the gravure printing machine. Embossing, indentation and die cutting are then performed on the platform die cutter. The flap cover has a width of 98 mm. Due to the limitation of the maximum printing cylinder circumference of 640mm, the printing cylinder is rotated for two weeks, and the slitting cylinder is cut once every 4/3 weeks. The printing plate is arranged in 2 rows and 4 rows, leaving 5mm waste edges on each side. Thus, the circumference of the printing plate cylinder was calculated to be 402 mm. The printing is cut once every two weeks, and the size of the large sheet is 802 mm. By comparison, the 802mm large sheet size differs from the original 789mm slit size by 13 mm, which is not too big.
The transmission gear of the partial paper feed roller is printed. The transmission gear of the partial discharge roller is printed, the transmission gear of the slitting unit, and the diameter of the paper feed roller of the slitting unit. When the gear is processed, the parameters such as the modulus helix angle, the tip height coefficient and the installation size are all referred to the original gear machining. The material is made of 40CR, and the heat treatment is quenched and the hardness reaches HRC48. The trial cutting accuracy meets the quality requirements.