Today, the most common printing presses use flexographic printing processes. Flexo printing is a rotary printing method that prints patterns on various substrates on the surface of the raised pattern. That is, the non-printing area of ​​the rubber plate or photosensitive resin plate is withdrawn and lowered, and the desired printing pattern is generated on the printing plate. The printing plate is connected with rotating cylinders with different diameters to obtain patterns of various sizes. The ink is transferred to the printing plate surface by an ink measuring roller called an anilox roller with a mesh structure. Generally, inkjet devices work in conjunction with a doctor blade to supply ink to the anilox roller. The above system operation can be repeated for each printing color printing machine. Currently, the average number of printing stations on a printing press is 10, and the web width is 6 to 136 inches. Main types of movement in printing applications Printing applications are diverse, ranging from simple monochrome printing to the need to locate complex multicolor printing. Most printing applications use a rotary inkjet head containing the pattern to be printed. The printing surface is usually a web that directly contacts the inkjet head. Roll paper is often linear and can be composed of any kind of material, including paper, plastic or resin film, corrugated paper, etc. The printing ink is directly supplied to the inkjet head, and when the inkjet head comes into contact with the roll paper, the pattern is transferred to the roll paper. The main type of motion in printing applications is spindle / slave motion-the web to be printed on is the master axis and the inkjet head is the slave axis. Traditional printing press roll paper and inkjet head are mechanically connected. Now, considering high-performance motion controllers can perform electronic cam profiling, and printing end users increase machine flexibility, and hope to shorten production time and achieve rapid For production conversion requirements, servo mechanisms are usually used. This is especially true for inkjet heads, which also have this requirement for the web spindle. Multi-color printing applications include multiple inkjet heads. Each inkjet head corresponds to a color and becomes a master axis and a slave axis. Each inkjet head must be aligned with each other. It is rare in other types of sports printing applications, such as moving the inkjet head in and out of the adjustment shaft for machine maintenance and product switching. Typical printing applications require the use of multiple motion control components, including feedback components such as encoders or resolvers, servo motors, speed reducers, servo amplifiers, and high-performance motion controllers. The motion control method used in printing can also be used in other paper processing applications where the rotary slave shaft and the linear web are in contact. Main problems in motion control There are several problems in implementing motion control in printing applications. The first is that when the inkjet head is in contact with the web, it is very important to control the speed of the inkjet head accurately. The speeds match each other, but the inkjet head speed will be higher or lower. When the speed matching is inaccurate, the printing quality will be reduced, which may cause material damage. The circumference of the inkjet head is the same as the length of the product, so the motion relationship is a transmission ratio between the two, and there is also a position synchronization relationship (for example, they are proportional, but the slave axis is locked at a specific spindle position, printing occurs on the web In the correct position). The circumference of the inkjet head is different from the length of the product. When the inkjet head is in contact with the roll paper, the speed will match. The remaining length of the product. The inkjet head must be accelerated or decelerated. The appropriate position is in contact with the roll paper to process the next product. In addition, when the motion curve is executed, speed synchronization and position synchronization are also required. In this way, the relationship between the master and slave axes can be made effective from stop to full speed at all spindle speeds, and the scrap rate can be minimized. The speed depends on the substrate, the label printing speed is usually 300 ~ 1000 FPM, the central impression cylinder flexo printing on plastic (the roll paper is wound around a large central impression cylinder, and the inkjet head is positioned around the cylinder) The speed is 1000 ～ 2000 FPM, and the speed of embossing roller type flexo on paper can exceed 3000 FPM. There are, of course, exceptions. The web and plate speeds do not match, and one of these speeds can exceed or be less than the 2% repetition length of the plate roller. The final customer can make the size as close as possible to the actual needs, and accept the production capacity of the machine, which can save the plate cylinder / sleeve and save material greatly. Most printing applications also require positioning, and the difference between different positioning is very large. The best positioning should be within 0.0005 inches, the center embossed cylinder flexo is 0.002 inches, and the line printing is 0.003 inches. The motion curve needs to be dynamically adjusted to compensate for small changes in the distance between the positioning marks on the web. This situation is especially seen in multi-color printing, where accurate color registration must be maintained so that the final printed pattern has good quality. It is also important to design the motor / amplifier combination over the entire length of the product. At design time, the smallest and longest products may not represent the worst case. It is generally recommended that this design be completed for several product lengths (such as 5 or 10) to ensure a suitable motor / amplifier combination for the entire product range. The specifications of force and torque randomizers vary greatly, and the load inertia also varies with the design. The motion control components are designed to meet 10: 1 to 200: 1 inertial mismatch. How to apply motion control technology to improve pre-press and post-press printing, and quantify when possible The success of high-speed product positioning printing is crucial. To achieve high-speed positioning, it is necessary to provide high-speed position lock input to the drive or motion controller, and capture the precise spindle position when encountering the positioning mark. The difference between the two positions before and after is used to calculate the actual distance between the positioning marks. That is, the distance is compared with the theoretical distance between the marks, and a correction amount is calculated. Subsequently, the correction amount is substituted into the slave axis motion curve. From the detection to the positioning mark to the time required to apply the correction amount, it is important to produce high-quality products. This time depends entirely on the motion controller used for the application, and will also be affected by the technology used (for example, some digital motion control networks have a delivery delay that must be compensated, which may not be acceptable in some applications). Certain applications require the use of special positioning algorithms, such as averaging the corrections of several or many products, filtering the corrections, or requiring that no corrections are applied to certain segments of the motion curve. The motion controller should also be able to properly handle web splicing and missing positioning marks. Typical basic configuration The 10-color printing machine production line has more than 65 closed-loop motion control axes. In larger production lines, there are usually more than 100 axes. In the past, each axis was driven mechanically, but now, the updated control system improves the positioning performance and reduces the positioning accuracy to half the value of the old system. These control systems are highly flexible, can handle special tasks, and provide infinitely variable repetitions. Used to replace the speed matching method discussed earlier, it enables the user to increase or decrease the speed of the plate roll web to change the repeat length. These improvements can also make the speed faster, increasing the maximum speed from 1200 FPM to 2000 FPM, and the flexographic printing process can reach higher speeds. The time for a printing press to switch from one job to the next has been shortened from an average of 4 to 6 hours to 30 minutes, and in some cases even shorter. The use of motion control and printing drive positioning system manipulator has a great influence on the switching time. In application, the entire control system provides better diagnostic information and the machine production time is extended. Compostable Knife,Bioplastic Knife,Bioplastic Knife Cutlery,Compostable Cornstarched Knife Anhui Jianfeng Environmental Protection Technology Co., Ltd , https://www.ahbiocutleries.com