Screen printing 1000 questions (130-141)

â–¼130. How to choose the frame size?
The size of the frame area is generally twice the area of ​​the printed matter. If the screen frame is too small, the accuracy of the printed matter will be reduced. To ensure the printing quality, it cannot be less than 1.8 times the printing area.

â–¼131. How to store the screen frame?
Placed horizontally and vertically, it cannot be heavily compressed to prevent deformation, such as deformation, which can be diagonally corrected on the platform.

â–¼132. When it is apparent, there are several reasons why it cannot be seen.
Partial morphological failure can not be seen, mainly, in the drying process, especially the hair dryer and electric oven drying, local overheating, resulting in thermal cross-linking, photographic film and screen printing film surface is not compacted caused by light cross-linked, so Drying must strictly control the temperature can not be greater than 40 degrees.

â–¼133. The peeling of the exposed film during processing is mainly caused by the following reasons:
(1) Underexposure ensures that the exposure effect reaches the entire screen coating, and the exposure time must be increased in the dyeing screen and the copper screen. (2) Insufficient sensitization of the sensitizer must ensure that sufficient amount of sensitizer is thoroughly mixed with the emulsion. (3) Photosensitizer failure

â–¼134. There are several reasons why the fine pattern lines cannot be washed out:
(1) Overexposure (2) Uneven coating - Check if the tension of the tension net is sufficient (3) Refraction - Use of dyed mesh if making fine pattern (4) Uneven contact - Use single layer as much as possible Picture, and make sure that the vacuum suction box can tightly attach the positive image to the template

â–¼135. The pattern cannot be flushed out completely due to the following reasons:
(1) Excessive light exposure (2) The coated wire mesh is dried at an excessively high temperature and should be dried at a temperature not exceeding 40 °C (3) Irradiated by light when dry. Should be dried in a yellow safety light or under soft light (4) The coated screen has been stored too long

â–¼136. Premature peeling of the film is caused by the following reasons:
(1) The screen is not stretched (2) The exposure is insufficient (3) The screen is not handled properly

â–¼137. Pinholes on the screen are caused by the following reasons:
(1) Dust particles on the glass or the positive picture (2) The latex has been soiled. Remember to keep the working environment clean and cover the unused photosensitive adhesive.

â–¼138. The sawtooth line is caused by the following reasons:
(1) The mesh is too thick or non-stained - fine lines require fine mesh, and meshes exceeding 196/inch (77 cm/cm) require dyed mesh (2) Improper flushing - do not use excessive flushing Pressure. Wet the mesh on both sides. Allow the cream to soften for about 60 seconds. Rinse the bottom of the wire with normal water.

â–¼139. The main reasons for stencil are:
(1) Improper flushing - Make sure the image is completely clear (2) Absorb excessive water after washing

â–¼140. Printing pad performance and characteristics

The plastic head is one of the necessary raw materials for the pad printer. The plastic head is divided into two types: white and blue. The raw material of the white plastic head is from France and the raw material of the blue plastic head is from Japan. From the shape of the A, B, C, S four series. According to the specific printing requirements of the user to make a specific type of plastic head. Divided from the hardness of the standard (conventional supply), special soft, special hard three. The standard hardness is approximately 20 °C Shore, and special soft and special hard are supplied according to the user's needs. The rubber head has ideal elasticity and flexibility. For the printing of fine line patterns on flat and irregular surfaces, it can ensure a clear printing effect. The rubber head is completely covered with ink, and it is easy to deink and transfer. The residual ink is easily removed and the service life is long.

â–¼141. What is "printing" printing?

The principle of pad printing is to use the method of photographic plate making the desired printing pattern first, and then make the steel plate into a gravure and transferring it onto the object to be printed via a special adhesive printing head, and can be used for different purposes according to the material of the product. Ink, so that the quality is guaranteed. The flow of the printing machine is divided into the following four points: 1. The ink is evenly covered by the brush on the steel plate. 2. The excess ink is scraped off by a doctor blade. 3. Decrease the ink from the print head to the steel plate. 4. Drop the print head down until the product covers the pattern. Pad printers for the industry: plastics, toys, glass, metal, electronics, sporting goods, stationery, optical industry, IC packaging industry. Pad printer application scope: ruler, pen, ball, doll eyes, watches, cameras, hair dryer shell, ceramics, medical equipment, rackets, tapes, electronic components, IC, CPU, DRAM, computer shell, buttons, decorative signs , Brother big case printing.

---Qi Lu Graphic Arts