Talking about several technical problems existing in screen printing of steel drums (1)

Talking about several technical problems existing in screen printing of steel drums (1)

Xin Qiaojuan

In recent years, with the rapid development of the packaging industry, users are increasingly demanding steel drums for metal packaging containers. For this reason, steel drum packaging companies are beginning to adopt new technologies in the manufacture and painting of steel drums. New technology to improve product quality. In addition to painting paint on the surface of steel drums, users now have added advertising on the surface of steel drums in order to promote their products. The traditional production process can not meet the requirements of users, so the screen printing technology with beautiful, generous, convenient plate making, cheap price, various printing methods, flexible and easy to master technology is quickly applied in steel drum enterprises. It has become a beautiful landscape on the steel drum. However, since most steel drum companies lack the technology of screen printing, there are often some technical problems in the actual production operation. The following questions are analyzed and explored for common problems.

First, the steel drum is easy to seal when printing (blocking the net)

Sealing refers to the phenomenon that the screen printing text cannot be transferred to the steel drum through the printing part. This phenomenon will affect the quality of the screen printing of steel drums, because the text and graphics will be incomplete and so unrecognizable. There are several reasons for this phenomenon:

(1) The influence of temperature, humidity and ink properties at the production site

When screen printing, there is a certain temperature and humidity requirement for the printing production site. If the production site temperature is high and the relative humidity is low, the volatile solvent in the ink will quickly evaporate, and the viscosity of the ink becomes high, thereby blocking the net. In addition, if the residence time is too long, the paste blocking phenomenon will occur. The longer the time is, the more serious the paste is. Secondly, if the ambient temperature is low, the ink flowability is poor, and it is easy to produce paste and block. Most of the steel drum manufacturers use screen printing when their work sites are open-air, and the temperature and humidity of their production sites are affected by local natural weather conditions. Especially in the northwestern part of China, the natural climate is dry, the solvent in the ink evaporates quickly, and the sealing phenomenon is easy to occur. Therefore, attention should be paid to such problems during operation.

(B), the impact of the screen version

The prepared screen plate is rinsed with water before use and dried before use. If the plate is left unprinted for a long time after the plate is made, the dust will adhere to it more or less during the preservation process, and if it is not cleaned during printing, it will cause the seal.

(3) Reasons for pressure during printing

Screen printing of steel drums, sometimes due to small batch size and frequent plate changing, is generally done by hand printing. In manual printing, the operator's arm is mainly used to adjust the embossing force. If the embossing force is small, the printing plate is not exposed to the surface of the steel drum and printing cannot be performed. If the embossing force is too large, the squeegee will be bent and deformed, and the contact between the squeegee and the wire mesh and the steel drum will not be in line contact, but will be in surface contact, so that the ink cannot be scraped clean every time the squeegee is printed, leaving Residual ink, after a certain period of time, will cause conjunctiva to form a seal.

(4) Improper gap between the screen plate and the steel drum

The gap between the screen plate and the steel drum should not be too small, the gap is too small, the screen plate can not be separated from the steel drum after the printing, and the steel plate is bonded to the steel drum. When the screen plate is lifted, the bottom of the plate adheres. A certain amount of ink, which is also easy to cause a seal.

(5) The influence of ink

Screen printing requires less ink and is suitable for all types of inks. Various inks such as oil, water, synthetic resin, and powder can be used. Therefore, the particle size of the pigment and other solid materials in the ink is not uniform. When the particles are large, the sealing phenomenon is likely to occur. In addition, the mesh size and the through-hole area of ​​the selected ones are smaller than the particle size of the ink, and it is also one of the effects that the coarse-grained ink is not easily passed through the mesh. The sealing plate caused by the large particles of the ink can be solved by selecting an ink of good quality, small particle size and fineness.

The ink dries too quickly during the printing process and is also prone to seal. To print graphics on the surface of steel drums, the most prominent feature is that drying is fast. Therefore, when printing the steel drum, it is best to use a volatile drying ink. In order not to seal the ink, an appropriate solvent must be selected during printing to control the drying speed. In the selection of inks, the effects of climatic conditions should be considered. In general, fast-drying inks should be used in winter; in summer, late-drying agents should be added to the inks. If the use of late-drying agents also occurs, the other must be replaced. Type ink.

In the process of printing steel drums, the viscosity of the ink should not be too high, because the viscosity is too high, the fluidity of the ink is poor, and the sealing is easy to occur. The graphic on the steel drum is generally small, and the screen is on the screen. The ink consumption is correspondingly small. If the ink is prepared too much at one time, the ink solvent evaporates, resulting in an increase in the viscosity of the ink, and the phenomenon of sealing the net is likely to occur, so that the ink should be prepared in an appropriate amount each time.

After a network failure occurs, scrub according to the nature of the ink on the screen plate with a suitable solvent. The main method of scrubbing is to start from the printing surface, gently wipe from the middle to the periphery, and then check the printing plate after wiping. If there is any defect, it should be repaired in time, and it can be reused after repairing. It should be noted that the screen plate cannot produce the sealing phenomenon many times, because the plate film is thinned every time it is scrubbed. If the film is seriously damaged due to wiping, the new plate is required to be printed.