Matching inks for the most popular pad printing eq

2022-07-25
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Pad printing machine is a kind of printing equipment, which is mainly used for plastics, toys, glass, metal, ceramics, electronics, IC seals, etc. Pad printing is an indirect gravure printing technology. It is a main method for printing and decorating various object surfaces

the process of pad printing is to etch the designed pattern on the printing plate, coat the etching plate with ink, and then transfer most of the ink to the printed object through the silicone head

what types of inks are there?

general purpose inks are often used. This type of ink and additives can print character patterns on plastic rubber, metal glass, nylon canvas and other materials. It is characterized by low cost, strong adhesion and ideal color. However, it is not applicable to PE/PP and baked ceramics. The corresponding diluent should be selected according to the pattern, size and adaptability of the substrate. Generally, the standard type should be selected

how to design a fixture

a special fixture should be designed and made according to the shape of the substrate, so as to firmly clamp the substrate, ensure the printing accuracy and repeatability in the printing process, and make the operation convenient, simple and safe. For a large number of prints, in order to improve efficiency, the assumption is not zero, the conveyor belt structure can be designed

the model of the rubber head

the rubber head should have good ink absorption and deinking, good resilience, fatigue resistance, solvent resistance and other properties. The size, shape and hardness of the rubber head shall be selected according to the chart or physical model provided by the supplier, and then a model specification shall be determined according to the actual use and service life

the contact deformation between the rubber head and the substrate should be as small as possible, and its diameter is about 3mm larger than that of the word case. If there are many thin lines in the printing plate, the glue head should be relatively soft. The extrusion depth between the rubber head and the substrate shall not exceed 1/3 of the height of the rubber head, otherwise the rubber head is easy to be damaged, and the ink case becomes indistinct in the shape of the gapless ball screw. There is a layer of release agent on the surface of the newly purchased rubber head, which should be wiped with a clean cloth dipped in ethanol or plate washing agent before use

composition of electric pad printing machine

the main composition of electric pad printing machine includes: rubber head, oil pan, scraper piece group, stepless speed regulation device, switch (operation/manual), fixture lifting table, etc. Because it does not need the traditional air pump air source, and adopts the mechanical transmission system of 220V power supply and electronic stepless speed change, the equipment has good stability, controllable precision, low cost, small volume, convenient use and reliable quality

the quality evaluation indexes of scraper mainly include hardness, thickness, elasticity, straightness of knife edge, etc

generally, 0.25mm flat steel strip with good elasticity is used as scraper. The cutting edge shall be sharp, smooth, straight and can closely match with the steel plate. If the blade edge of the scraper is not sharp or damaged, it will cause unclean scraping and adhesion to the edges of the text or generate scraper marks, and serious printing plates will be scratched. When in use, the doctor blade should be at a certain angle with the printing plate to avoid the falling of the doctor blade into the concave of the printing plate, and excessive scraping will damage the image and text. The length of the scraper shall be greater than the width of the pattern text close to the steel plate. The pressure of the scraper should be as small as possible on the premise of scraping the non graphic ink on the printing plate

I. control of process conditions

operation of the printing press

you should be familiar with the working status of the main mechanism at each stage and the operations that can be selected in turn. After the pilot test is normal, in principle, you should only pay attention to the printing surface, keys and display lights

installation of printing plate

fix the printing plate in the middle of the ink tray, and then adjust the fixture of the substrate so that the glue head is aligned with the center of the plate and the printing center of the substrate. The installation of the printing plate is completed

adjustment of glue head and control of machine speed

during pad printing, the falling and lifting of glue head determines the transfer rate of ink to some extent and affects the image and text forming. Therefore, under the premise that the glue head, substrate and ink flow are adjusted in place, properly slowing down the machine speed is conducive to improving the print quality

add solvent and control the ink flow

prepare the ink solvent at one time according to the printing volume. Generally, the ratio of the ink to the solvent is 1:2 (winter, spring and Autumn) and 2:5 (summer) which is also made of the panel with PMMA trademark. That is, use slow release agent when it is too hot or fast drying; On the contrary, if it is too cold or dry slowly, use quick drying agent. At certain intervals, add a certain amount of diluted ink in advance according to the amount of ink used for the substrate

wet temperature control

the essence is to make the ink 7 Maximum change angle: the solvent in 99999 ° has a relatively stable volatilization rate. A simple way to control temperature and humidity is to print in an air-conditioned workshop

II. Problems and handling suggestions

image and text deformation and distortion

are mainly caused by the deviation between the load, hardness, surface radius of curvature of the rubber head and the thickness, size, depth of the image and text and the two relative center positions between the transfer. Select more rubber heads of several specifications and models, or use the normal steel plate in the past to eliminate the fault source and select the correct process

light and open ink transfer

is mainly caused by improper ink selection and use. The ink should not be too thin or thick color paste should be added

rough mark edge

check whether the scraper is sharp or notched, whether the ink is too thin, and whether the rubber head and steel plate are worn

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