Disc Screen Printing Process Discussion III

Three printing processes

The essence of screen printing is to use a squeegee to make the ink transfer to the substrate through the missing part of the printing plate. During printing, the screen plate and the substrate are kept at a certain distance. Under the pressure of the squeegee, the screen plate is in line contact with the surface of the substrate. When the line contact is displaced, the resilience of the screen causes the original line to spring up quickly. Separation of substrates to avoid imprinting, blurring, and clear markings. The ink is rapidly transferred by the squeegee during the movement of the press line, a part of which is printed on the printing material, and the other part is moved forward with the squeegee. When the squeegee stroke ends, the squeegee is lifted to complete a printing stroke.

The screen printing of the optical disc is carried out on a dedicated automatic multi-color disc screen printing machine, and the general printing speed can reach 1 sheet/second or even faster.

In the operation control of the printing press, the specific work has the following points.

1. Replacement and replacement screen

The screen of the special screen printing machine for optical disc is fixed by sucking the iron frame of the screen by the suction force of the magnet. When the plate is installed, the positioning holes on the frame must be aligned, and the screen plate and the fixed frame must be in close contact with each other. , reliable, otherwise the ink easily leaked from the gap.

2. Adjust the screen

Adjust the distance between the screen and the large rotary disk (printing platen). Generally, the thickness of the two disks is appropriate. Too high ink is not easy to print, and too low is easy to cause bad phenomena such as sticking and pasting.

3. Adjust the distance between the squeegee and the screen

According to the requirements of the printing effect, the angle between the knife and the scraper is adjusted. The distance between the squeegee and the screen is too small, and it is easy to scrape the screen. If the distance is too large, it will cause uneven printing and result in poor printing. In general, the squeegee pressure is high. When the angle is small, the amount of ink is larger and the color is darker. On the contrary, the amount of ink is less and the color is lighter.

4. Choose different hardness scraper

Generally, the three types of scraping adhesives with Shore hardness of 75, 80, and 85 are used for screen printing. Compared with soft scraping, the amount of ink scraped by hard scraping is less.

5. Timely replacement of worn squeegee

Damaged squeegee notches can not only leave scratches on the printing surface of the disc, destroy the overall effect of printing, and long-term squeegee will scratch the surface of the mesh, resulting in broken net.

6. Mixing ink

The deployment of ink in the process of optical disc printing is an often done but very high technical content work, in the general manufacturer of this work is done by experienced employees, because the deployment of color involves color, Ink manufacturing technology and other professional knowledge. The general operation mode of coloring is to determine the main color first, then select the matching color, then select the color background, and finally adjust the brightness to complete the color matching.

When preparing inks, records should be made, and the proportioning components and the used materials should be recorded in detail on the adjusted ink or sample label paper. This can provide convenience for repeated production. When adjusting the ink, the quantity should be estimated based on the quantity of the order, so as not to waste too much ink.

Printing technology is a difficult-to-learn, easy-to-learn technology. This is a consensus within the industry. With the continuous development of science and technology and industry requirements, customers have higher and higher requirements for optical disc printing. The mission of the practitioners who have given CD printing to the era must continue to develop and innovate.

(Text / Zhu Xin Guangdong Huawei Technology Co., Ltd.)
"Printing Technology"