Pasting plate refers to the phenomenon that the through-hole portion of the mesh screen printing plate can not transfer the ink to the substrate during printing. The occurrence of this phenomenon will affect the printing quality, and even in severe cases, normal printing cannot be performed.
The reasons for the phenomenon of scumming during mesh screen printing are intricate. There are the as following:
① Causes of substrates. Mesh screen printing substrates are diverse, and the texture characteristics of the substrates are also a factor that causes the phenomenon of scumming. For example: paper, wood boards, fabrics and other substrates have low surface smoothness and poor surface strength. During the process, it is easy to produce powder and hair loss, which will cause pasting plate.
②Causes of workshop temperature, humidity and ink properties. Mesh screen printing workshops require a certain temperature and relative humidity. If the temperature is high and the relative humidity is low, the volatile solvent in the ink will evaporate quickly, and the viscosity of the ink will become high, thereby blocking the mesh. Another point to note is that if the downtime is too long, the phenomenon of pasting will also occur. The longer the time, the more severe the pasting. Secondly, if the ambient temperature is low, the ink fluidity is poor and it is easy to produce offsets.
③ Reasons for mesh screen printing plate. The prepared mesh screen printing plate can be washed with water and dried before use. If it is left unprinted for too long after the plate is made, dust will stick to it more or less during the preservation process. If it is not cleaned during printing, it will cause the pasting plate.
④ Causes of printing pressure. Excessive embossing force during the printing process will bend the squeegee.The squeegee is not in line contact with the mesh screen printing plate and the substrate, but in surface contact.In this way, the ink cannot be scraped clean, leaving a residue Ink, after a certain period of time, it will condense and cause paste.
⑤ Reasons for improper clearance between mesh screen printing plate and substrate. The distance between them should not be too small. After the mesh screen printing plate cannot be separated from the substrate, when the mesh screen printing plate is photographed, a certain ink is adhered to the bottom of the printing plate, which is also easy. Caused by misprints.
⑥ The reason for the ink. When the particles of pigments and other solid materials are large, it is easy to block the mesh screen printing. In addition, the number of screen meshes and through-hole areas selected is smaller than the particle size of the ink, and it is also one of the reasons that it is difficult for coarser inks to pass through the mesh and cause network sealing.
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