Application of the most advanced motion control te

  • Detail

Application of advanced motion control technology in flexographic printing equipment

today, the most common printing machines use flexographic printing technology

flexographic printing is a rotary printing method, which prints patterns on various substrates through raised pattern surfaces. That is, the pattern to be printed is generated on the printing plate by withdrawing and lowering the non printing area of the rubber plate or photosensitive resin plate. The printing plate is connected with a rotating cylinder with different diameters to obtain patterns of various sizes. The ink is transferred to the printing plate surface by an ink metering roller with a shape structure called a corrugated roller. Usually, the inkjet device works in conjunction with the scraper to supply ink to the roller. The above system operation can be repeated on the printer for each printing color. At present, the average number of printing stations on a printing machine is 10, and the width of web paper is 6 to 136 inches

the main types of motion in printing applications

printing applications vary from simple monochrome printing to complex multicolor printing that requires positioning. Most printing applications use a rotary inkjet head containing the pattern to be printed, and the printing surface is usually a web of paper in direct contact with the inkjet head. Web paper is often a linear electro-hydraulic high-frequency fatigue testing machine. The control system can control the excitation frequency, amplitude and vibration center offset of the electro-hydraulic exciter by adjusting the potentiometer. It can be composed of any kind of materials, including paper, plastic or resin film, corrugated paper, etc. The printing ink is directly supplied to the inkjet head. When the inkjet head contacts the web, the pattern is transferred to the web

the main type of motion in printing applications is spindle/slave motion - the web to be printed on is the spindle, and the inkjet head is the slave shaft. The traditional printing machine is mechanically connected between the web and the inkjet head, but now, considering that the electronic cam profiling can be performed through the high-performance motion controller, and the end user of printing improves the flexibility of the machine, and wants to shorten the production period and realize the requirements of rapid production conversion, servo mechanism is usually used. This is especially true for inkjet heads, and sometimes for web spindles

multi color printing applications include multiple inkjet heads. Each inkjet head corresponds to a color and becomes the slave shaft of the spindle. Each inkjet head should be aligned with each other. Other types of movements are not uncommon in printing applications, such as the adjustment shaft used to move the inkjet head in and out during machine maintenance and product switching

typical printing applications require the use of a variety of motion control components, including feedback components such as encoders or resolvers, servo motors, 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 contacts the linear web

main problems in motion control

there are several problems in realizing motion control in printing applications

first, when the inkjet head contacts the web, it is very important to accurately control the speed of the inkjet head. Sometimes, the speeds match each other, but sometimes, the speed of the inkjet head will be higher or lower. Inaccurate speed matching will not only reduce the printing quality, but also may even cause material damage

if the circumference of the inkjet head is the same as the length of the product, 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 shaft is locked at a specific spindle position, so printing occurs at the correct position of the web). If the circumference of the inkjet head is different from the length of the product, speed matching will occur when the inkjet head contacts the web. For the remaining length of the product, the inkjet head must accelerate or decelerate in order to contact the web at a suitable position to process the next product

in addition, when executing the motion curve, it is necessary to synchronize not only in speed, but also in position. In this way, the relationship between the spindle/slave shaft can be effective at all spindle speeds from stop to full speed, so as to minimize the scrap rate. The speed depends on the substrate. The printing speed of the label is usually 300 ~ 1000fpm. The speed of central embossing cylinder flexo printing on plastic (the web is wrapped around a large central embossing cylinder, and the inkjet head is positioned around the cylinder) is 1000 ~ 2000fpm, while the speed of central embossing cylinder flexo printing on paper can exceed 3000fpm

of course, there are exceptions. Sometimes the speed of the web and the printing plate does not match, and the speed of one of them can exceed or be less than 2% of the repetition length of the printing plate roller. Because the final customer can make the size as close as possible to the actual needs, instead of accepting the amount that the machine can produce, this can save the plate cylinder/sleeve and greatly save materials

most printing applications also need positioning, and the differences between different positioning are great. The best positioning should be within 0.0005 inch, 0.002 inch for central embossing cylindrical flexo printing and 0.003 inch for line printing

therefore, the motion curve needs to be adjusted dynamically to compensate for small changes in the distance between positioning marks on the web. This is especially true in multicolor printing, in which the precise registration of colors must be maintained so that the final printed pattern has good quality

it is also important to design the combination of motor/amplifier according to the full range of product length. In design, the smallest and longest products may not represent the worst case. It is generally recommended that this design should be completed for several product lengths (such as 5 or 10) to ensure that a suitable motor/amplifier combination suitable for the whole product range is determined. The force and torque vary greatly with the size of the machine, and the load inertia also varies with the design. The design of motion control components should meet the inertia mismatch of 10:1 to 200:1

how to apply motion control technology to improve the prepress and Postpress of printing, and when possible, quantitative

high-speed product positioning is crucial to the success of printing. To achieve high-speed positioning, it is necessary to provide high-speed position locking input to the driver or motion controller, so as to capture the accurate spindle position when encountering the positioning mark. The difference between the front and rear positions is used to calculate the actual distance between the positioning marks. That is, the distance is compared with the theoretical distance between the marks, so as to calculate a correction amount. Then, the correction amount is substituted into the slave axis motion curve

the time required from detection to positioning mark to application of correction quantity is very important for producing high-quality products. This time depends entirely on the motion controller used in the application, and will also be affected by the technology used (for example, some digital motion control networks have a transmission lag that must be compensated, which may be unacceptable in some applications). In some applications, special positioning algorithms need to be used, such as averaging the correction amount of several or many products, filtering the correction amount, or not applying the correction amount in some segments of the motion curve. The motion controller shall also be able to properly handle web splicing and missing positioning marks

the typical basic configuration 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 shafts. In the past, each shaft was driven mechanically, but now, the updated control system improves the positioning performance and reduces the positioning accuracy to half of that of the old system. These control systems have high flexibility, can deal with special tasks, and provide unlimited variable repetition. Instead of the speed matching method discussed above, it enables the user to increase or decrease the speed of the plate roller relative to the web to change the repetition length

these improvements can also make the speed faster, increase the maximum speed from 1200fpm to 2000fpm, and achieve a higher speed in the flexographic printing process. The time for the printer to switch from one task to the next is shortened from an average of 4-6 hours to 30 minutes, even shorter in some cases where the polymer is random. The manipulator with motion control and positioning system of printing driving device has a great influence on the switching time. In application, because the whole control system provides better diagnostic information, the production time of the machine can be extended

Suedorscheid is the marketing manager of Danaher transmission company

opportunities for wide width digital inkjet printing

9:12, December 31, 2006 source: 0 comments from newmaker friends entered the forum

when some people engaged in printing increasingly feel that wide width inkjet printing is posing a threat to their business, just another part of them realize that inkjet printing is helping them expand their market and bring more profit space. As a part of traditional printing, printers are proud that they have continued and inherited the ancient printing civilization. However, they have encountered many embarrassments and challenges in the actual printing business

● how to deal with the short and medium version business cost effectively and profitably

● how to accept and deal with those businesses with diverse formats (some of which are not suitable for printing)

● how to effectively improve the competitiveness and profitability of Indian enterprises

● how to make frequent proofing faster and more efficient

● how to deal with the printing business with tight delivery time and strong personalization

● how to deal with businesses that need time-consuming segmentation and splicing (such as window display, building surface coverage, etc.)

a large number of surveys and analysis show that printing is most suitable for the business of making more than 400 single sheet moving parts. However, in fact, the market demand for single sheet moving parts less than 200 is greater. There are more and more live parts printed in multiple varieties, small batches and on demand. It is enough to use a tensile force range of 1000 kg. The traditional printing production is greatly limited. For this market, Jixiang automobile adopts 3D printing technology to produce air conditioning HVAC assembly and air duct assembly, providing a fast, efficient, high-quality and high-profit solution. As a new high-tech printing method, inkjet printing does not contain the familiar printing civilization, but it does provide a very effective method and way for the challenges faced by printing enterprises

supporting wide width inkjet printing equipment will accelerate printing enterprises to rapidly expand a broader and high value-added market field, such as medium and short version of back glue material printing; Poster printing of selling points with tight delivery time; Hard materials of medium and short editions and printing for some special applications, etc. Inkjet printing not only brings a favorable market to printing enterprises, but also enables them to provide "one-stop service" for their customers, so as to attract more customers

as a supplement to plate printing, the advantages of wide width inkjet printing are obvious

inkjet printing is directly printed by digital documents (standard format) without plate making. A business can be printed within minutes of receiving an order

the ink-jet printing process is convenient and efficient: the documents are in a queue, the last document is printing, and the next document is in line for printing. If a printing machine is equipped with a drying system, the previous movable part is still dry, and the next movable part has started printing

saiangel inkjet printing machine is specially designed for the needs of industrial production

Copyright © 2011 JIN SHI