Discussion on the screen printing process of steel drum surface

Discussion on the screen printing process of steel drum surface

The 200L steel drum is made of cold-rolled steel sheet or galvanized sheet. It is open and closed. It is a common container for liquid materials such as oil and solvent. For the cold-rolled steel plate type steel drum, in order to prevent the barrel from rusting, the finished surface should be painted to achieve a beautiful and practical effect. Generally speaking, the customer will also ask for the words or patterns (such as company name, trademark, media name, weight, etc.) printed on the barrel and barrel surface of the steel drum. These characters or patterns are often in the form of screen printing, etc. The quality of the steel drum has a great impact on the appearance quality of the steel drum, directly related to the customer's market image. This paper outlines the process and explains some of the key points in the process.

The screen surface of the drum is usually made of nylon mesh. After the plate making, the ink is screen printed onto the surface of the steel drum by a squeegee.
1, wire mesh
Nylon mesh has good elasticity and is an ideal plate-making material in screen printing. The screen is divided into various types according to the number of meshes, such as 120 mesh, 150 mesh, 200 mesh, 250 mesh, 300 mesh, 350 mesh, 380 mesh, etc. Different meshes have different permeability to ink. The smaller the mesh, the thicker the mesh and the stronger the permeability, and vice versa. When making a plate, first select a suitable wire mesh according to the pattern printing area and ink transmission performance. If the pattern area is small and the ink permeability is good, it is better to select a mesh with a higher mesh number to achieve a higher hiding rate. High, contoured appearance. If the pattern is large-area printing and the ink permeability is poor, it is better to use a lower mesh screen to ensure uniform pattern coverage, but the edges may have jagged edges.

The wire mesh has imported and domestically produced parts. The imported price is expensive, it is not easy to take off the wire, and the life is long; the domestic price is cheap, and it can be selected according to factors such as printing difficulty.
If you choose a good mesh, you need to pull the net nail net. It can be fixed by mesh nail or adhesive mesh glue. When pulling the net, it should be tightened and evenly applied. If it is too loose, it will produce defects such as ink leakage or sticky net.

2, printing version
After the screen is made, the plate is printed. Before printing, the screen should be washed with water or washing liquid, dried and coated with photoresist. The photosensitive adhesive should be evenly coated, and the coating should have a certain thickness. If it is too thin, the photosensitive film will fall off during printing, which will affect the production. After applying the photoresist, blow it dry to ensure that the photoresist is dry and prevent it from falling off.
After the photosensitive adhesive is dried, the printing plate is exposed, and the negative film is attached to the screen to avoid running light. The exposure time is 5-10 min (the specific length of time should be determined according to practice), and its length has an important influence on the life of the screen, which is directly related to The fastness of the photosensitive film to the screen and affect the exposure quality.
After the printing plate is finished, it should be carefully inspected, and the leaking point should be repaired with sealing net glue to facilitate the normal production, and avoid frequent leakage of ink to cause downtime trimming.
3, printing
After the screen is made, select the desired ink to print. The ink has different components, and it is necessary to select a suitable ink for the paint composition of the surface of the printed object. When the performance is not good, the affinity between the ink and the paint ink is poor, and it is easy to fall off. The fineness of the ink component affects its ability to pass through the screen, so a higher coverage can be achieved with a finer component ink.
For barrel surface printing, a flat scraper is usually used, and the barrel is printed with a V-shaped scraper. When printing, it is necessary to select a scraper with appropriate hardness. At the same time, it should be noted that the action surface of the scraper is smooth. If it is not smooth, scratches on the printed pattern may occur, which may affect the appearance quality of the pattern.
The above is mainly from a qualitative point of view. Quantitative analysis during the printing process such as mesh size and pattern relationship, ink fineness, blade hardness, sensitization time, film thickness, screen tension and print quality also need to be summarized by the operator in production.