Quality Control of Aluminum Printing Accuracy

Aluminum printing substrate is aluminum, in the printing process, aluminum printing overprint error is a major factor affecting the quality of aluminum printing. So how to improve the printing accuracy of aluminum version?

1. The baking temperature must be the same before and after printing

The printing ink used in aluminum printing is a baking curing type, which must be baked after printing. The curing process of the ink is a process in which the aluminum plate is heated and a thermal expansion and contraction occurs. The printing pattern on the aluminum plate also follows the thermal expansion and contraction of the aluminum plate. , change the relative position. If the aluminum plate is at normal temperature (25°C) before printing, the aluminum plate will undergo thermal expansion after the first printing and baking, and the second printing will occur. The secondary printing pattern opposite the side rule will appear within one printing pattern. Contraction phenomenon, because the pattern on the aluminum plate expands with the aluminum plate after one printing and baking, and the pattern transferred on the second printing plate does not change, and is printed on the heat-expanded aluminum plate in a relatively pre-expanded position. Therefore, the overprint deviation of the pattern occurs, and the higher the temperature, the greater the deviation. Therefore, the aluminum plate should be baked at the same temperature before printing so that it can fully expand. In order to ensure the accuracy of overprinting in the printing process, the process of coating the primer can be arranged before the printing, so that the paint is directly printed, which not only reduces the cost, but also solves the overprint deviation caused by the temperature difference.

2. Ensure the flatness of the printed aluminum plate

Due to the soft and low melting point of the aluminum plate, during the baking process, the temperature will be too high and deformation will occur, resulting in the curvature of the layout, making overprinting of the printing pattern inaccurate. Each type of aluminum plate has a different optimal baking temperature. Usually, the baking temperature of the aluminum plate in the southwest of China is relatively low, and it is baked at a constant temperature of 180±10°C for 10 minutes. The baking temperature of the aluminum plate in Harbin is high and the temperature is 190 Bake at ±10°C for 10 minutes. Therefore, according to the characteristics of different aluminum plates to find the best baking temperature, while maintaining the ink while maintaining the layout of the layout, but also for the protection of the subsequent printing accuracy.

3. The PS plate used for a printed pattern needs to be printed at one time

During the printing process, there is often no printing deviation in the first and second editions, but the phenomenon of large deviations in the third edition has been found to be eliminated. This type of register deviation phenomenon occurs mostly because the PS edition is not a one-time process. . Film at a different time, at different temperatures there is a small amount of stretching, not the same time drying the PS version, it is inevitable that this is affected by the printing process, the product volume is large, the interval is long, time, temperature changes, the impact is more pronounced. In order to prevent overprint deviations, PS plates used in one product should be dried at one time.

4. Aluminum push head should be synchronized

The aluminum plate pushing head of the printing machine feeding system is not synchronized, so that the aluminum plate mouth is in contact with the impression roller and the rubber roller one after the other, causing the position of the pattern on the aluminum plate to shift, affecting the overlay accuracy of the next printing. Therefore, the synchronization of pusher heads should be checked before each print to avoid unnecessary losses.

5. Aluminum version specifications to meet the printing requirements

Under normal circumstances, the printed aluminum plate is required to be rectangular or square, to ensure the synchronization of the mouth, and the side gauge should be at right angles to the mouth. However, inaccurate cutting boards can cause aluminum plate specifications to be unqualified and appear diamond or trapezoidal. Therefore, before printing, you should check whether the specifications of the aluminum plate meet the printing requirements and avoid causing the printing waste.