When doing glass screen printing, sometimes may occur: bubbles sometimes appear on the ink after printing. What is the principle of this phenomenon and how to deal with it?
The main reasons for bubbles are as follows:
1. Poor pre-printing treatment of the substrate. In order to remove these bubbles, defoamers should be used. The amount of defoamers added to the ink is generally about 0.1-1%. If it exceeds the specified amount, it will play a foaming role. Even if the ink foams after transfer, as long as the wettability of the substrate and the fluidity of the ink are good, the bubbles on the surface of the printed ink film will gradually disappear, and the glass screen printing ink will form a flat printed ink film. If the bubbles in the glass screen printing ink are not eliminated, the ink film will form a ring-shaped uneven film surface. Generally, bubbles in glass screen printing ink can be degassed due to the effect of the screen when passing through the screen;
2. Excessive printing speed or uneven printing speed will also produce bubbles. The printing speed should be appropriately reduced to maintain the uniformity of the printing speed;
3. Static electricity fault The static electricity current is generally very small, but the potential difference is very large, and attraction, repulsion, conduction, discharge and other phenomena may occur at the same time;
4. The adverse effects on screen printing. The screen during printing is charged due to the pressure and scraping of the scraper rubber, making the rubber part and the screen charged. The screen itself is charged, which will affect the normal inking and cause the plate blocking fault; the screen will be sucked by the screen at the moment of output of the substrate;??
5. Methods to prevent static electricity. Methods to prevent static electricity include: adjusting the ambient temperature and increasing the air humidity. The appropriate temperature is generally around 20℃ and the relative humidity is around 60%; static electricity can be transmitted in humid air; reduce the mesh distance and reduce the printing speed.
Gloss characteristics:
1. Print and bake immediately to show flat ink;
2. Print and bake for 3 hours to make it bright ink;
3. Add a little more diluent and bake it for bright ink.
Drying:
1. After adding 8:1 hardener, dry naturally, surface drying for 40-60 minutes; actual drying takes 12-24 hours;
2. After adding 8:1 to 10:1 hardener, it can be baked at 80-120 degrees for 30 minutes. If it is baked at 120-150 degrees for 10-30 minutes, its solvent resistance and adhesion will be better. ??
Printing method: silk screen printing, pad printing.
Resistance:
1. After the ink is completely dried, the ink film shows good adhesion, alcohol resistance and wear resistance.
2. Because it can be baked-free and low-temperature baked, it is suitable for printing on reinforced acrylic, mobile phone lenses, plastic electroplated surfaces, and plastic UV spray surfaces.
3. For special materials, products with high requirements for alcohol resistance, sweat resistance, wear resistance, etc., such as machine metal knobs, anodized aluminum digital camera shells, glass cosmetic bottles, metal eye legs, etc., the effect will be better after baking at 120-150 degrees for 10-30 minutes.
Scope of application: metal, electroplating surface, ceramic, paint surface, reinforced acrylic, hardened acrylic, UV spray surface, flame-treated PP, PE, etc.; has a good adhesion effect on hard materials.
For more details and information, welcome to send requirement to sales@paiouscreenmesh.com, or you can reach us at Tel/Whatsapp/Wechat: +86 19932893768
