Control of flexographic printing parameters
Mr. Mike Huey of Harper graphic solutions listed several uses of striped rollers in flexographic printing
striped roller has always been used by printers, and its role is reflected in many aspects, such as determining the ink volume of four-color printing, determining the optimal number of lines and hole volume of striped roller during spot color printing and combined printing, and determining a reasonable inventory of striped roller, etc. These are the most common applications of striped roller. Now its use has gone beyond the above scope and extended to other fields
for example, it is used in some occasions to determine the hardness of the printing plate, the density of the double-sided tape and the ink supply system used. Using the Striped roller can also determine the specific parameters of each process to ensure the daily printing quality. These are very good methods
flexographic printing is both an art and a science, but in the actual production and processing, we need to optimize the process flow to obtain the maximum profit. As we all know, the corrugation roller is a very key component in flexographic printing, which is called the heart of flexographic printing. In this article, I would like to introduce some flame retardant schemes with nitrogen and phosphorus systems that have been widely developed and utilized at home and abroad. Common and uncommon uses of corrugated rollers. No matter which market field you belong to, I hope to help your enterprise reduce production costs and improve profits through this article
determine the best ink volume for line draft, level draft printing and line image comprehensive draft
pre plan:
we all know that in order to ensure the stability of daily printing operation, we must determine various parameters and strive to adopt the best method to ensure printing quality. These are very easy to achieve using striped rollers. But first of all, we should gather relevant personnel, the suppliers of printing plates, inks, plate pasting tapes and embossing rollers. Of course, the printer must participate. The printer should involve the printer operator and his supervisor, as well as a manager and project leader. This meeting should determine the parameters of the corrugated roller used, the hardness of various printing plates, and the type of ink and double-sided tape. All variables that need to be tested should be listed to determine the test plan and collect relevant data
one thing to remember is that the ultimate goal is to determine the minimum amount of ink when the line manuscript, four-color layered manuscript and complex manuscript reach the required field density, so as to expand the reproduction range of tones. This means that in order to obtain the smoothest, thinnest and most stable field density, plates and tapes with different hardness are required
test log:
the printing of any work is the same. Prepress preparation is to ensure that all materials are ready before the start of the test. The average annual growth rate of the approved test from 2015 to 2020 is 7%. The list should ensure the accuracy of each step, just like the daily printing operation, list the parameters to be tested and the samples to be saved according to the time sequence of the test. The printer, ink, tension, temperature and all other control parameters should be the same as usual. If the usual ink viscosity is 24s (2 Zahn cup), it cannot be 28s during the test. The quality standard of printing is also the same as that of ordinary printing operations. Usually, there are control belts at both ends of the wrinkle roll. The control belt is a section of width at both ends of the fingerprint roller with the same number of lines and hole volume. It can print simple detection items at both ends of the substrate to check whether the axial pressure of the wrinkle roller is balanced. Once it is determined that the pressure setting reaches the normal operating conditions, all equipment operating parameters can be recorded, and the printed samples can be labeled/coded for future reference and detection. Specific test parameters, such as marked samples and recorded printing conditions, are critical to the success of the test. The preservation of samples, parameter testing and charts are shown as follows:
the density obtained under the condition of 800lpi line number and 1.9bcm hole volume is the closest to the requirements. Although the point enlargement is slightly larger than the 900lpi, 1.7bcm corrugation roll at this time, we still decided to use the 800lpi, 1.9bcm corrugation roll, because the point enlargement can be solved by compensation. After the completion of the test, all parties involved should discuss and determine specific standards, that is, the conditions necessary to achieve the desired results. The printing conditions of each type of work should include ink, embossing roller, printing plate, double-sided tape, etc. Maybe we often participate in or implement this type of test. In fact, the key is to list all the data and determine the final cost/benefit ratio. It depends on your core business, customer needs and expectations, and then decide what kind of tape, printing plate, ink, etc. to use to meet the business requirements of both parties
test of striped roller for white ink printing
above, we briefly discussed the most common uses of striped roller. Through the standardization of printing process, it helps printers improve the stability of printing quality, reduce downtime, and minimize the impact of uncertain factors. Using striped roller to print white ink is not as common as the above applications, but experiments have proved that it is indeed effective in determining the minimum ink layer thickness when the cost of white ink is reduced, that is, the opacity requirement is met. Like the above experiments, we also need to hold a team meeting to determine various parameters. The key of this test is to determine the appropriate hole volume, as well as the printing plate and double-sided tape with corresponding hardness, so as to ensure a uniform, pinhole free field. Based on years of experience, we know that the less pinholes, the more uniform the ink layer and the higher its opacity. I also know that many printers can reduce costs by not testing opacity in other ways. Why don't we use a corrugated roller with a hole volume of 7bcm, 8bcm or 9bcm to achieve the corresponding opacity? If we replace the 9bcm corrugated roller with 8.5bcm, it means that we can save 5.5% of the ink cost. After simple mathematical calculation, you can understand the impact on profits within a year, because all inks and prices depend on their dosage and ink type. For the sake of long-term cost, the use of striped rollers and other rollers for white ink testing must be worth it
whether narrow width printing or wide width printing, white ink is the most commonly used ink in printing plants, and it is also a part of the high cost. Although the applications are different, there is no doubt that if handled properly, the production cost can be reduced, that is, the opacity required by customers can be achieved while reducing the thickness of white ink. The cavity volume of the corrugated roller is not the only factor determining the cost. Many related tests are still in progress or have passed, such as using double-sided tapes and printing plates with different hardness to obtain the corresponding opacity. In a printed image, the opacity depends entirely on the number of pinholes. If the number of pinholes is reduced, the opacity can be increased accordingly
the key to reducing costs is to optimize the parameters of printing elements: double-sided tape, printing plate and embossing roller (number of lines, hole volume and hole shape), so as to achieve the best ink release and spreading in a given area, so as to avoid light passing through the ink layer. The following is about using the LCD large screen LCD full picture to display the experimental data, consequences, curves, the same number of lines, the same hole volume and hole shape of the wrinkle roller, but the hardness of the printing plate and the double-sided tape is different, and finally a completely different opacity is obtained
is the Striped roller used for coating test
there is an occasion where banded roller is rarely used, but it is possible to greatly reduce the coating cost for the company. Compared with the past, the application of coating in flexographic printing is significantly reduced. Now coating is more used in special printing. At present, the park consists of fluorine mining, anhydrous hydrogen fluoride, 3 chloromethane, 4 fluoroethylene, 6 fluoropropylene, and poly 4 fluoroethylene. For example, there are coatings that change color with temperature, safety coatings and special coatings used on batteries in the market
in fact, almost all imaginable prints need paint. UV, water-based and solvent based adhesives are used in almost every material. In short, if you don't have a special coating equipment at present, I believe you will buy it soon
in order to make the material achieve the function required in the design, the coating amount must reach a specific thickness
most paint manufacturers have a recommended range, that is, the coating amount required for specific occasions, and the key to the problem is to find the minimum coating amount on the premise of meeting customer requirements. For example, if the recommended range of coating amount is 1.0-1.25 pounds/3000 square feet, we should design a roller to reach this range. According to the performance of the coating, the cavity volume of the corrugated roller required to achieve this coating amount can be determined. Then, when we design the Striped roll, we can use the Striped roll that is slightly higher or lower than this value to test to determine the best coating amount for specific occasions. According to the test results, we can take some samples to test the specific performance required by the customer, so as to determine the minimum coating amount under the condition of meeting the customer's requirements
for example, if the 4.5bcm corrugated roller is too small and the 5.5bcm corrugated roller is slightly higher, then the 5.0bcm corrugated roller should be the best choice. The cost of the processor can be greatly reduced compared to the coating amount of 1.25 pounds/order with a 6.25bcm corrugated roller. Although the coating effect obtained by using a 6.25bcm corrugated roller can also meet the standard, why apply 20% more adhesive/coating? You should not think that saving 20% of the adhesive is not worth paying attention to. This is a common example. On the premise of ensuring the coating performance, the Striped roller is used to reduce the coating amount. If other parameters change in the actual printing, the printer should be responsible for monitoring, testing and recording the coating amount to ensure that the reduction of coating amount will not cause quality problems and cause customer dissatisfaction
through the above introduction, we can see that the banded roller is widely used. It can be used to improve the printing quality and standardize the printing process. Of course, the most important thing is to reduce the cost, so as to maintain competitiveness. Finally, it should be reminded that after the test is completed, the printer needs to maintain the Striped roller well. My suggestion is to clean it thoroughly and store it in a safe place. The Striped roller may be used frequently, such as the newly launched printing plate, ink, double-sided tape, coating, etc. we can use the Striped roller for testing, and at the same time, it can also be used as a quality control equipment to determine the stability of all material properties during daily printing. If some parameters are found to be different, they can be re verified according to the data recorded during the test