Automatic screen printing machine printing static phenomenon and cause
Automatic screen printing machine printing can be said to be universal printing, but the static phenomenon in the printing process is a very difficult problem, especially the phenomenon of printing plastic products or PET products is more obvious, then the automatic screen printing machine printing phenomenon is How did it happen?
Automatic screen printing machine printing electrostatic phenomenon performance
In the screen printing, the performance of printing failure caused by static electricity, etc. is:
1。 After the screen printing of the automatic screen printing machine, the ink on the imprinting is pulled up with the screen plate, and the phenomenon of "flying hair"-like ink is broken after the workpiece is taken out;
2. When the automatic screen printing machine is overprinted, the ink color and the edge of the pattern of the previous color and the latter color are mutually exclusive, which cannot be well matched, so that no ink can be printed between the two color inks;
3。 In silk screen printing, the workpiece sticks to the screen, especially to the screen position where the scraper moves to the end;
4。 After the automatic screen printing machine is printed, the printing materials are glued together and cannot be separated;
5. During the process of the automatic screen printing machine, the ink is flattened on the screen and the cakes are stuck together;
6. The substrate absorbs dust, and the ink is damaged after the silk screen, pitting, rough surface, etc.
Since the automatic screen printing machine printing static electricity will cause so many printing failures, how are those static electricity generated? Let's talk about it.
From the atomic point of view: all neutral materials, such as plastics, paper and other insulators, that is, the positively charged nuclei in each atom and the negatively charged electron cloud in the surrounding, when the materials are separated by frictional contact, in the insulating material The electrons are released to the surface of the material。 For example, in the middle school physics, the glass rod is rubbed with silk, and static electricity generated on the glass rod can suck up the paper scraps。 The surface of the electron-reduced material is positively charged, and the surface of the material with excess electrons added by electrons is negatively charged。 If the material with reduced electrons is supplemented with negative electricity and the material with increased electrons is positively charged, then the positive and negative charges of the two materials are balanced。 Then the two materials are neutral。
Especially in the automatic screen printing machine in the printing of the optical disc, the so-called silk printing is a process of transferring the ink onto the substrate under a certain scraping pressure by the relative movement of the screen and the squeegee。 The screen (screen) and the squeegee (polyurethane squeegee) are all insulators。 In the silk screen, they are relatively scraped and rubbed at the position, especially in low humidity, which will cause static electricity to affect the surface charge of the substrate。 Distribution status。 In particular, insulating materials, such as PC substrates for optical discs, PET sheets for touch-opening, and PVC for plastic and plastic bottles, PEs, etc。, which are used for name and sign, are basically insulators, and do not pay attention to static electricity during silk screen operations。 Will happen。 For example, when the silk screen switch is used to decorate the ink, the surface of the PET film is coated with a layer of PVC and other self-adhesive film to protect the surface, so that it is not scratched in the cutting and packaging。 However, the protective film must be removed before silk screen printing。 Some operators often peel off the protective film when the film is peeled off。 I don’t know that the film is quickly separated from the PET film at the moment of quick film uncovering。 In the process, static electricity is generated especially on the surface of the PET sheet under low humidity, and as a result, the ink on the edge of the silk screen has flying hair, and the quality of the fluffy ink on the transparent PET sheet, etc。, has been a problem。 There is a lot of confusion about the screen printing shop of the membrane switch unit。
The use of automatic screen printing machine can avoid the generation of static electricity during printing due to the cause of static electricity。 Now there is a device for static elimination that can be used together when printing。