Comparison and Prospect of the most popular axial

Comparison and Prospect of shaftless and shaftless printing presses

shaftless and shaftless printing presses are aimed at whether the printing press has a mechanical transmission shaft. Between the printing units of the traditional web offset press The power between the printing unit and the folding machine is transmitted by the mechanical shaft. Some printing machines also have a transmission shaft between the paper feeder and the printing unit. This kind of printing machine uses the mechanical shaft to transmit the power of the main motor to each unit of the printing machine To complete the synchronous operation of each unit is called shaft drive. Due to the development of electronic technology, the printing press units launched in the mid-1990s are driven by independent motors, and there is no mechanical shaft between the units The synchronous operation of each unit no longer depends on the mechanical shaft, but on the electronic shaft That is, shaftless printing press

after the advent of shaftless printing press, it has been welcomed by users with its unique characteristics. At present, the world's famous printing machine manufacturers have launched shaftless web offset printing machines. Shaftless transmission technology is widely used not only in newspaper printing machines, but also in commercial printing machines

in the past, all newspaper printers imported from China had shafts, and in the late 1990s China began to introduce shaftless press Recently imported newspaper printers are basically shaftless. The major domestic printing machine manufacturing companies Beiren Printing Machinery Co., Ltd. and Shanghai Gauss printing equipment Co., Ltd. have also successively launched shaftless printing machines. Among them, beiren 75A medium-sized printing machine has little difference in performance with similar international models. Beiren 3840a, a commercial rotary printing press produced by beiren in cooperation with GI company of the United States, is also shaftless

in general, each independent unit of shaftless commercial rotary printing press is driven by 1-2 servo motors, while there are many types of drive motors for tower printers. Due to the large power required for medium-sized printers, in order to ensure the stability and reliability of the synchronization accuracy of servo motors, small servo motors will generally be selected and installed in a large number. Some equipment is equipped with 1 motor for each color group and 8 motors for each tower; There are three b-bs under one tower, one motor for each color deck, and one motor for the top B-B, that is, seven motors for one tower. With the improvement of the technical performance of servo motor and the improvement of electrical control system In some cases, each B-B adopts one motor, one tower and four motors; in some cases, two b-bs are equipped with one motor, one tower and two motors. Because the driving power of the small tower printer is relatively small, the driving motor is relatively small One B-B is equipped with one motor, one tower with four motors, and one h (i.e. two B-B) with one motor and one tower with two motors. The number of motors is determined according to the design characteristics and performance requirements of the machine structure. No matter how many motors are, they must meet the performance index of the shaftless printer And the number of motors does not represent the performance of the machine. It is obviously inappropriate for some people to regard the number of motors used by the tower press as the signs of "true shaftless", "false shaftless", "completely shaftless" and "semi shaftless". If such a standard is divided, how to define the equipment that now appears shaftless, gearless, and each moving part of the machine is driven by a single motor? It should be called "true shaftless" or "completely shaftless", This division is obviously that the concept of shaftless transmission has not been fully understood

the hardness of hard products is higher than that of low-density polyethylene. Now the author makes a simple analysis and comparison between the axial and non axial printing machines in combination with the specific situation of our country. At present, the domestic newspaper printing center imports more and receives more attention Therefore, take the newspaper printer as the main body to explain

shaft driven newspaper printing machine

mid-1990s Electronic technology has not developed to the point that the synchronous accuracy of multiple motors can meet the printing requirements. Before that, web offset presses were all shaft driven The power of the main motor is transmitted to each unit of the machine by the mechanical shaft to make each unit operate synchronously to meet the requirements of printing. There is no mechanical shaft in the common concept between the printing units of some web offset presses, but like the flat sheet offset press, the power of the main motor is transmitted by gears to each printing unit, such as Heidelberg web commercial rotary offset press, but the cooling unit and folding machine behind the printing unit are still transmitted by the mechanical shaft Therefore, there is only another form of shaft transmission. The mechanical structure with shaft transmission is relatively complex There are many moving parts The workload of maintenance is large, especially the requirements for lubrication are relatively high, but the electrical control system is relatively simple. Due to the slow development of electronic technology in China, especially in the newspaper printing industry, people who are familiar with machinery are more common, so despite the shaft transmission, the above problems exist But for operators who are already familiar with the mechanical structure It is easier to master, and it is easier to analyze, judge and eliminate general faults The operation cost and maintenance cost are also relatively low. At present, the development of electronic technology is changing with each passing day. There are relatively few people in the newspaper printing industry who master modern electronic technology. It is difficult to eliminate faults by themselves. If foreign personnel are invited to repair, the cost of labor and parts will be much higher than that in China, which will greatly increase the expenses of printing plants. For some small newspaper printing houses The printing volume is small, the layout is small, and the machine equipment configuration is simple A small number of units will prefer to use a newspaper printer with shaft drive. At present, most of the modern electronic technology devices used in China depend on imports, and the cost of maintenance is relatively high, which is one of the reasons why some printing plants still have a special preference for shaft driven newspaper printers. At present, the cost of shaft drive newspaper printing machine with the same configuration in China is lower than that of shaft drive newspaper printing machine

shaftless printing press

shaftless printing press has become the main type of printing press Almost all the small, medium and large-scale printers adopt shaftless transmission. Its main advantage is that the electro-hydraulic servo hydraulic universal experimental machine integrates electro-hydraulic servo automatic control, automatic measurement, data collection, screen display and experimental result processing into one body:

1 High transmission accuracy

although the design of mechanical shafts will fully consider the impact of torsional deformation and have sufficient rigidity, this deformation is inevitable, but the shape becomes different in size. This kind of deformation is stable under the constant speed working state, but the deformation will change when the printing speed changes, resulting in overprint error of printing products. The transmission mode of toothed belt is particularly prominent, because the telescopic deformation of toothed belt is much larger than the torsional deformation of mechanical shaft Therefore, there will be greater overprint error. At present, the synchronization accuracy of the electronic shaft without shaft transmission can reach up to 1/4 million. Taking the medium-sized newspaper printer with a cutting full size of 546mm as an example, as long as the synchronization accuracy reaches 1/10000, the circumferential overprint error caused by motor synchronization of each newspaper is less than 0.005mm, which is almost negligible. When the synchronization accuracy is the same, the overprint error of small and medium-sized machines can also be ignored

2. Simplify the mechanical structure

replace the mechanical shaft with an electronic shaft, reduce the moving parts, simplify the mechanical structure, which means that there are fewer parts that produce mechanical vibration, which can not only reduce the noise, but also improve the working environment And it is also very beneficial to the improvement of printing quality

3. The combination configuration is more flexible

now there are more newspaper pages, and the distribution of color plates in the pages is different, so the configuration of printing units is also different. The combination form of paper feeding, folding and printing unit should also meet these requirements. For shaft drive, due to the presence of factors such as the position of the transmission shaft, the transmission mode and the position and quantity of the main motor, some combinations will be restricted, while shaftless drive has no influence of such factors, so it is much more convenient and flexible

4. Convenient and flexible operation

shaftless drive is driven by multiple motors. Each motor can work independently. In the process of printing and printing preparation, whichever motor needs to work, start which motor If it is not needed, it can maintain the stalling state, which can not be achieved with shaft transmission. This feature of shaftless transmission It not only brings convenience to printing production, but also reduces the auxiliary time of printing. Such as loading and unloading plates and rubbers, wipe plates and rubbers Shaft transmission can only be operated by one person, while shaft less transmission can be operated by multiple people at the same time, which shortens the preparation time. For medium-sized newspaper printers, at least two people can do these jobs at the same time in each tower, while for small newspaper printers, two people can also work at the same time in each tower

it has been proposed that each B-B is driven by a motor. If one of the motors fails to work, as long as it is not printing (44) happy face color newspapers, reverse printing can be used immediately to remedy it. In fact, this remedy is difficult to achieve if this happens According to the above methods, the direct printing version is opposite to the indirect printing. Not only the positioning benchmark has changed, but also the version sequence has changed Difficult to change immediately. After the color sequence of the printing machine is changed, it is necessary to clean the ink bucket, ink roller and change the ink again, which cannot be completed immediately. So The number of motors is determined by the design structure and the actual needs of printing, not for such remedial work

although the shaftless printing press simplifies the mechanical structure, the electrical system is very complex. At present, the servo motor and control system of the electrical system of shaftless transmission equipment used in China depend on imports, and the original supplier is also responsible for maintenance services and component replacement The cost is high. Although the technology of shaftless transmission is mature and the electrical system is very reliable, it can't be zero fault. Once there is a problem, there will be the problem of maintenance cost and time

5. Convenient for function expansion

because there is no transmission shaft combination, the configuration is convenient and flexible, which is convenient for function expansion. If you need to add a unit in case of newspaper expansion, you can easily combine the new unit with the original unit without any trouble in connection. Each unit is driven by a separate motor and can work independently, so it saves time and labor compared with the machine with shaft. It is also easy to meet personalized requirements

of course, shaftless transmission is not perfect, but we only see its advantages and ignore its shortcomings. The power of motor without shaft transmission is larger than that with shaft transmission, which requires large distribution capacity and high electrical stability

in order to ensure the synchronous tracking accuracy of shaftless transmission, the starting torque and braking torque of servo motor should be large enough to avoid affecting the synchronous accuracy of machine operation due to the static resistance torque at start-up and the inertia torque at braking, especially the starting torque is very important. At present, the power of the main motor without shaft transmission is generally 1.5 times greater than that with shaft transmission, and some are even higher. This requires that the total capacity of power distribution must meet the needs of total power, so this factor should also be taken into account when selecting a shaftless printing press

many people now believe that the general trend of the development of newspaper printers is that the shaftless transmission is advanced, and the shaft transmission has lagged behind. This understanding is understandable, but the specific situation still needs specific analysis If the newspaper printing volume of the printing plant is small, and the layout is less than oneortwo small printing towers, the production requirements can be met. The above advantages of shaftless transmission are not very obvious, especially for some printing plants with backward technical level, it may be easier to master new materials with shaft transmission, or a blue ocean that cannot be bypassed, and Jinan new era Gold Testing Instrument Co., Ltd., which specializes in the production of concrete pressure