Classification of silicone key printing defects and solutions
Silicone keys are widely used, not only for TV, air conditioner and other remote controls in daily life; Mobile phones, small appliances, cars and other buttons are also common. They all need to use surface screen printing to screen characters. If there is production, there will be defects. What are the defects of these silicone key screen printing? How did they come into being? How to solve it?
1. Silica gel printing is simply to say that the screen printing method is used. The screen printing part of the screen can pass through the silica gel printing ink, and the screen printing part of the screen can not pass through the silica gel printing ink. The basic principle of printing is that the screen printing part of the screen can not pass through the silica gel printing ink. Use the squeegee soft scraper to apply a certain pressure on the screen, so that the silica gel ink can be squeezed from the screen holes of the graphics and text part to the surface of the silica gel keys.
2. The silicone key printing generally has these defects through classification: deviation, oil accumulation, dirty screen, diffusion, color difference, pinhole, thin oil (pitted surface), ghosting, burr (saw edge), deformation, missing printing and poor adhesion;
3. The causes and treatment methods of various defects are as follows:
1. Position deviation. The reasons for position deviation are: a. The film is inconsistent with the fixture; b. The fixture is too loose, and the key is on the side; c. The fixture is too tight, and the key cannot be covered when printing; d. The tension of the screen is unstable or the screen and the screen frame fall off slightly or are damaged slightly; The above defects can be solved by adjusting the film fixture.
2. There is oil accumulation, which is caused by: a, the key surface has radian, the net spacing is too high, b, the key surface has radian, and the rubber scraper pressure is too small; c. The key surface has radian, and the rubber scraper is too soft; d. The rubber scraper is not long enough or deviates; e. The rubber scraper has a gap; The above defects can be adjusted and improved by adjusting the height of the screen spacing and the hardness, softness, slope and pressure of the rubber scraper.
3. The screen is dirty. There are two reasons for the dirty screen. The product is stuck to the screen or the ink is too dirty because the roller is not clean. Just improve the above two points.
4. Diffusion (bold font) may lead to oil accumulation due to: a. The ink is too thin; B. Too large squeegee pressure; c. The net spacing is too low; d. Wire mesh aging; e. The rubber scraper is too hard; The above can be improved by adjusting the ink, pressure, squeegee, screen spacing, etc.
5. Color difference. The possible reasons for color difference include: a, the proportion of printing ink preparation formula is inconsistent; b. The ink is too thin or too thick; c. The rubber scraper used is too hard; d. The rubber scraper has been used for too long and has no elasticity; e. Take the wrong color with other color numbers; It is enough to improve the above problems.
6. Pinholes. Possible causes of pinholes include: a. Problems with the screen film itself; b. Wire mesh aging; c. The screen is used up last time or has been used for a long time, and the printing ink is solidified; Clear the above problems to solve them.
7. The oil is thin (pitted surface), and the possible causes of pinholes are as follows: a. The problem of the screen film itself; b. Wire mesh aging; c. Printing ink is too thick; d. The rubber scraper is too hard; e. The squeegee is too straight; f. The squeegee pressure is too low; g. The net spacing is too high; h. The printing ink has bubbles; i. The die surface of oil pressure product is too thick; The above problems can be solved through adjustment and improvement.
8. Ghosting. Possible causes of pinholes include: a, problems with the screen film itself; b. Wire mesh aging; c. Printing ink is too thin; d. The rubber scraper is too soft; e. The rubber scraper is too short; f. Too high squeegee pressure; g. The net spacing is too low; h. Too much printing ink flows to the middle; i. The rubber scraper position is not aligned with the product center; It can be solved by finding problems that may cause problems and adjusting them.
9. Burrs (sawing edges) may cause pinholes: a. The rubber scraper position is not aligned with the product center; b. Screen film itself; c. Wire mesh aging; d. Printing ink is too thick; e. The mesh number of screen cloth is too low; The problem can be solved by solving the above problems in an appropriate way.
10. Deformation. The possible causes of deformation include: a, the problem of the screen film itself; b. The printing fixture is too tight; d. The rubber scraper is too hard; e. The lower part of oblique key fixture is not leveled; f. Too high squeegee pressure; g. The net spacing is too low; The above problems can be solved in a controllable way.
11. Missing printing. The possible reasons for missing printing are: a. The screen film itself is defective; b. Wire mesh aging; c. The printing fixture is too tight, and the Key is not put on; d. Unplug the product and accidentally touch the printed pattern; e. Error during blocking; The above problems have been solved.
12. Adhesion. The possible causes of poor adhesion are as follows: a. The printing ink takes too long, and the auxiliary curing agent or catalyst is volatilized; b. The ink used is not matched, and it is not the special ink for silica gel printing; c. The surface of the product is polluted during production (oil, water, mold release agent); d. Insufficient baking temperature or time; e. The ambient humidity is too high; f. The product surface is polluted by hand cream in winter. The problem of poor adhesion can be solved by adjusting and improving the above problems.
Nantong Boxin Electronic Technology Co., Ltd., a professional full process production team, pays attention to the development of corporate culture and is also building a wolf team. We have participated in the customer's preliminary design, understood the customer's various requirements for the product, paid attention to every detail in the process of customized processing of each section of silicone keys, and customized high-quality silicone products for customers.