Screen printing squeegee selection method

With the rapid development of the printing industry, screen printing is an important point in the printing industry. No matter what the industry is, screen printing is indispensable. The most important part of screen printing is how to analyze and select the squeegee and use the squeegee. The use of squeegee and selection is critical to the quality of screen printing. How do we choose and use the squeegee as follows:

First, squeegee it has four roles

1. Can make ink flow through the screen.

2. Can make the screen contact with printing materials.

3. Can ensure that the screen and the surface of the printing material adapt.

4. Can remove the excess ink on the screen.

Second, choose two standards for squeegee

1. Squeegee hardness The hardness of the squeegee is usually expressed in terms of Shore hardness. The hardness range is between 55 and 95 Shore. In the screen printing line, this range is also used as a measure of hardness. The 5 Shore hardnesses from the highest to the lowest hardness of the squeegee reduce the difference, ensuring the stability of the printing quality. The hardness of the squeegee changes the degree of deformation and bending of the squeegee, and the coefficient of squeegee characteristics varies depending on the squeegee maker, and this can be expressed at the time of printing. The hardness value of the squeegee affects how the squeegee aligns with the substrate and determines how much pressure should be applied to the squeegee to allow the ink to flow through the screen plate. The softer the squeegee, the better the fit of the squeegee to the surface of the screen, and the lower the required printing pressure, the opposite.

2. The shape of the squeegee in the squeegee shape of the squeegee refers to the shape of the cross-section of one end of the squeegee that contacts the screen plate. All of these surface shapes determine the pressure on the surface of the substrate. Different sections can make the ink flow more or less, affecting the thickness of the printed ink layer. The squeegee shape of the squeegee also determines the adaptability of the squeegee to the surface of the substrate, and directly affects the printing ink volume and the fineness of the printed image. The sharper the print end of the squeegee is, the less the ink flow is, the better the resolution of the printed image is, the better the printability is, and the thicker the printed ink layer is.

Third, how to choose the right part of the squeegee squeegee is the print end of the squeegee. During the printing process, the squeegee print end contacts the screen plate. The hardness or softness of the squeegee is critical to the entire printing process. That is, the squeegee determines the print quality.

1. The hybrid squeegee has a solid support, and the hardness of the print end of the squeegee can vary. Because the squeegee bends in the printing, this reduces the pressure of the screen, and the contact area with the surface of the printing material increases, and the printing ink is more evenly coated on the surface of the printing material. Hybrid squeegee is an ideal choice for high-speed printers. It can print flat glass, solder resist, and make the multi-color printing ink layer and UV varnishes uniform. Some prints do not require such a hybrid squeegee, but with the increase in customer demand for high-quality prints, it is necessary to select a suitable squeegee.

2. The flat mouth type squeegee is widely used for the printing of ordinary materials such as paper and textile printing. Suitable for a variety of printing materials and ink printing. This type of squeegee is compatible with printing materials and has the highest pressure. The ink is scraped off the screen plate instead of flowing through the screen under pressure. Therefore, the amount of ink is minimal, and the flat-type squeegee is thick line printing and dot printing. The ideal choice. The smaller the ink ink layer, the finer the printed image.

3, sharp-edged squeegee when printing glass and plastic bottles can well control the flow of ink. The double blunt squeegee can control the printing angle better, and the pointed squeegee is also suitable for fine printing on textiles.

4. Groove type squeegee is used in container printing. The contact complex with the irregular surface is particularly good, controlling the ink flow excessively.

Fourth, the hardness of squeegee divided into three categories

1. Soft squeegee is generally used for moderate pressure on the squeegee, soft squeegee is used for large screen openings and low ink viscosity. Soft squeegee is the best choice for printing on irregular objects and uneven printing platforms. The use of soft squeegee printing, ink accumulation, printing image fine degree of moderate, generally used for large area printing and glass, ceramic printing.

2, when the hardness of the medium-hardness squeegee printing pressure is large, the medium-hardness squeegee is used, and any screen mesh and ink can be selected in the middle hardness squeegee, line printing. The use of medium hardness squeegee printing, ink accumulation is good. Image resolution is good, suitable for all types of printing materials printing.

3. Hard squeegee Use hard squeegee when the printing pressure is maximum and the ink viscosity is high. The amount of oil accumulation is small, the image resolution is quite normal. Fine screen printing can choose hard squeegee, it produces thin ink layer.

Fifth, the distinction between Shore hardness and scratch hardness

1,55 Shore to 65 Shore is a soft squeegee.

2,65 Shore to 75 Shore is medium hard squeegee.

3,75 Shore to 95 Shore is a rigid squeegee.

Sixth, squeegee squeegee squeegee print end will eventually be damaged due to friction with the screen. Using a scraper can make the edge of the squeegee sharper. We need to pay attention to a few things when we are doing squeegee grinding:

â—‹1 Grinding with a finer grinding wheel to minimize the loss of the squeegee material during grinding. Ensure that the edge of the squeegee is clean, free of spots, does not melt, and the rotational speed of the grinding wheel is low.

â—‹2 When you need to quickly wear out a large piece of squeegee material, you can use rough grinding wheel to scrape. â—‹3 If you only need to smooth the squeegee, use very fine sandpaper.

â—‹4 When using a cutting knife to cut away a part of the adhesive, when re-grinding is required, make sure that the trimmed wiper is clean and free of gaps.

â—‹5 After the squeegee is printed, do not grind it immediately. After the printing, the squeegee should be left for 24 hours until the solvent completely evaporates.

â—‹6 In addition to ensuring that the edge of the squeegee is straight, the free height of the squeegee is kept uniform along the entire length of the squeegee.

Seventh, squeegee maintenance storage

â—‹1 When the library is stored, the squeegee should be laid flat. Do not place it in a roll.

â—‹2 After opening the entire roll bar, place it for 24 hours so that the bar can be stretched and then used again.

â—‹3 When storing the squeegee without removing the handle, the squeegee should be used upwards. The squeegee cannot touch any object.

○4 The temperature of the storage squeegee should be kept away from the ink in a dry environment of 20°C to 25°C, because the squeegee can absorb the moisture and solvent in the air.

â—‹ 5 Squeegee or handle with ink cannot be stored overnight.

â—‹ 6 Squeegee Do not soak in the solvent for a long time, although some squeegee can resist a variety of solvents, but a long soak will temporarily scratch the squeegee, lose their elasticity.

â—‹7 The squeegee should be flushed immediately after use to prevent the ink from drying on the squeegee. There is no trace of any ink left on the cleaned squeegee handle and squeegee, otherwise the squeegee will have an impression on the next print.

â—‹ 8 Use a soft cloth to clean the squeegee and clean it along the squeegee direction, otherwise the reverse cleaning will damage the print edge of the squeegee.

In general, we hope that the selection and use of squeegee among screen printers will be of great importance to the vast majority of screen printing and printing staff. We choose the squeegee according to the different printing materials in our printing process, and choose the squeegee for the wire. Web printing quality plays a big role.