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FAQ


Q Dull, not bright colors 2011-12-12 12:15:59

The reasons may be poor quality of the original, poor design of the plate-making curve, low density of the color separation film, false printing, too shallow imprint, insufficient printing pressure, aging printing machine, excessive dampening solution, rough paper, low whiteness, etc. .

Q Heat seal leakage problem 2011-12-12 12:15:59

Leakage is due to the existence of certain factors, so that the parts that should be melted and bonded by heating are not sealed. Leakage generally has the following reasons:

 

①The heat sealing temperature is not enough. The same packaging printing material requires different heat-sealing temperatures in different heat-sealing positions, different packaging printing speeds require different heat-sealing temperatures, and different packaging printing environmental temperatures require different heat-sealing temperatures. The heat-sealing temperature required for longitudinal sealing and horizontal sealing of packaging and printing equipment is different, and the temperature of different parts of the same heat-sealing mold may also be different. These are issues that must be considered in packaging and printing. For heat-sealing equipment, there is still a problem of temperature control accuracy. At present, the temperature control accuracy of domestic packaging and printing equipment is poor, generally there is a deviation of 10~C, that is, if the temperature we control is 140%. , In fact, the temperature is between 130-150~C during the packaging and printing process. Many companies use random sampling of finished products for air tightness inspection, but this is actually not a good method. The most reliable method is to take samples at the lowest temperature point within the temperature range, and the samples should be taken continuously so that the samples can sufficiently cover all parts of the mold vertically and horizontally.

 

②The sealing part is contaminated. In the filling process of packaging printing, the sealing position of packaging printing materials is often polluted by packaging printing materials, and pollution is generally divided into liquid pollution and dust pollution. Solving the problem of contamination of the sealing part can be solved by improving packaging and printing equipment and using anti-pollution and anti-static heat-sealing materials.

 

③ Problems with equipment and operation. For example, there are foreign objects in the heat-sealing mold, the heat-sealing pressure is not enough, and the heat-sealing mold is not parallel.

 

④ Problems with packaging and printing materials. Such as corona over the surface, too much lubricant on the heat-sealing layer, resulting in poor heat-sealing, etc.

Q Problems of heat sealing pressure penetration and pressure breaking 2011-12-12 12:15:59

Press-through refers to the formation of a penetrating hole or crack in the packaging printing material by the extrusion of an external force. The causes generally include:

 

①The heat sealing pressure is too high. During the heat-sealing process, if the heat-sealing pressure is too large or the heat-sealing molds are not parallel, resulting in excessive local pressure, it will often press through some fragile packaging and printing materials.

 

②The heat-sealing mold is rough, with edges and corners or foreign matter. Poorly made new heat-sealing molds often crush the packaging and printing materials, and some heat-sealing molds have sharp edges and corners after being damaged, and it is easy to press through the packaging and printing materials.

 

③The thickness of the packaging and printing materials is not selected correctly. Some packaging and printing machines have requirements for the thickness of the packaging and printing materials. If the thickness is too large, some parts of the packaging and printing bags may be pressed through. For pillow type packaging printing machines, the thickness of the packaging printing material should generally not be greater than 60um. If the packaging printing material is too thick, it will be easily broken in the middle seal of the pillow type packaging printing.

 

④The structure of the packaging and printing materials is wrong. Some packaging and printing materials have poor pressure resistance and cannot be used for packaging and printing some hard and angular things.

 

⑤ Improper printing of mold design for packaging and printing. In the design and printing process, if the die hole of the heat-sealing mold does not match the shape and size of the printed matter to be packaged, and the mechanical strength of the packaging and printing material is not high, it is easy to be crushed or cracked during the packaging and printing process. Material.

Q Heat sealing extrusion PE problem 2011-12-12 12:15:59

During the heat-sealing process of the composite film, PE is often extruded and stuck to the heat-sealing film, and the accumulation will affect the normal production. At the same time, the extruded PE will oxidize and smoke on the heat-sealing mold, giving off peculiar smell. Heat-sealing extruded PE can generally be solved to a certain extent by reducing the heat-sealing temperature and pressure, adjusting the formula of the heat-sealing layer, and modifying the heat-sealing film to reduce the pressure on the edge. But practice has proved that the best solution is to use extrusion compounding process to produce composite film, or increase the speed of packaging printing machine, so that PE can not be extruded onto the heat-sealing film.

Q Heat sealing problem 2011-12-12 12:15:59

The low-temperature heat-sealability is mainly determined by the performance of the heat-sealing layer resin, and it is also related to the pressure. Generally, the extrusion temperature is high during extrusion compounding, and the low-temperature heat of the material will be reduced if the corona treatment is too strong or the film is parked for a long time. sealing performance. Hot tack is used to describe the strength of the melting surface of the heat-sealing layer against external force peeling when it is not sufficiently cooled and solidified after heat-sealing: this external force often occurs in automatic filling packaging printing machines. Therefore, the composite film coils used for automatic packaging and printing should choose heat-sealing materials with good thermal viscosity. Anti-pollution heat-sealability, also known as heat-sealability of inclusions, refers to the performance of heat-sealability when the heat-face is adhered to the contents or other pollutants. Composite films choose different heat-sealing resins according to different printed materials to be packaged, regardless of packaging printing machinery and different packaging printing conditions (temperature, speed, etc.), and one heat-sealing layer cannot be used uniformly. For packaging and printing with poor heat resistance, low-temperature heat-sealing materials should be selected. For heavy-duty packaging and printing, heat-sealing materials with high heat-sealing strength, high mechanical strength and good impact performance should be selected. For high-speed packaging and printing machines, heat-sealing materials with low-temperature heat sealing and high thermal adhesive strength should be selected. For products with strong pollution such as powders and liquids, heat-sealing materials with good anti-pollution should be selected.

Q Coefficient of friction problem 2011-12-12 12:15:59

The friction force in the packaging and printing process is often both a drag force and a resistance force, so its size should be controlled within an appropriate range. Coil materials for automatic packaging and printing generally require a small inner layer friction coefficient and a suitable outer layer friction coefficient. If the outer layer friction coefficient is too large, it will cause excessive resistance during the packaging and printing process, causing the material to stretch and deform. If it is small, it may cause the drag mechanism to slip, resulting in inaccurate tracking and cutting positioning of the electric eye. However, the friction coefficient of the inner layer is eloquent and cannot be too small. Some packaging printing machines have too small friction coefficient of the inner layer, which will cause unstable stacking and misalignment during bag forming; for the composite film for strip packaging printing, the inner layer If the coefficient of friction is too small, it may also cause the tablet or capsule to slip, resulting in inaccurate positioning of the blank. The friction coefficient of the inner layer of the composite film mainly depends on the content of the anti-blocking agent and slip agent of the inner layer material and the stiffness and smoothness of the film. The corona treatment surface, curing temperature and time during the production process will also affect the product. coefficient of friction. When studying the coefficient of friction, special attention should be paid to the fact that temperature has a great influence on the coefficient of friction. Therefore, it is not only necessary to measure the coefficient of friction of packaging and printing materials at room temperature, but also to investigate the coefficient of friction at the actual ambient temperature.

Q Cursor problem 2011-12-12 12:15:59

In the automatic packaging and printing process of composite film coils, positioning heat sealing and positioning cutting are often required, and an electric eye cursor is required for positioning. The size of the cursor varies with different packaging and printing opportunities. It is generally required that the width of the cursor be greater than 2mm and the length be greater than 5mm. The cursor generally chooses a dark color that has a large contrast with the background color. It is best to use black. Generally, red and yellow cannot be used as the cursor, nor can the color scale of the same color as the photoelectric eye be used as the cursor color. For example, the light of the photoelectric eye is green. Light, you can not use light green color as the color of the electric eye cursor, because the green photoelectric eye cannot recognize green color. If the background color is a darker color (such as black, dark blue, dark purple, etc.), then the cursor should be designed and printed as a light-colored cursor that is hollowed out and white.

 

The electric eye system of a general automatic packaging printing machine is a simple identification system, which cannot have the function of intelligent fixed length like the bag making machine. Therefore, within the longitudinal range of the electric eye cursor, the roll film is not allowed to have any interfering words and patterns, otherwise it will be damaged. cause recognition errors. Of course, for some electric eyes with high sensitivity, the black and white balance can be adjusted precisely, and some light-colored interference signals can be removed by adjustment, but the pattern interference signals with similar colors to the cursor or darker colors cannot be removed.

 

The distance between the cursors is used to determine the length, so the error between the actual distance and the design printing value should not be too large, generally only 0.5mm error is allowed. For many automatic packaging and printing equipment, the tracking effect of negative deviation is better than that of positive deviation, so it is recommended to design and print with negative deviation.

 

Aluminum-plated or pure aluminum has strong specular reflection, which will affect the recognition of the electric eye. It is recommended that the composite film cursor be printed on a white background. For transparent composite films, due to the influence of the color of the items in contact with it, it is also recommended to print the cursor on a white background to reduce interference.

Q Paper pressure line burst 2011-12-12 12:15:59

Some paper will crack if the force is uneven or the pressure exceeds the limit.

 

Solution: Pay attention to ensure the humidity of the paper. Too dry paper has weak toughness and is easy to crack. The pressure on the paper should not be too high. Pay attention to test the tensile strength of the paper before purchasing the paper.

Q Blurred typography 2011-12-12 12:15:59

Generally, the printed characters are blurred, mostly because the ink is too dense and the viscosity is too high, which causes uneven ink rejection and ink connection effect.

 

Solution: Pay attention to the viscosity of the ink when adjusting the ink. Of course, you also need to pay attention to the pressure relationship between the printing cylinder and the pressure roller. In short, pay attention to some detailed debugging.

Q The size is wrong, and there is a shift phenomenon; 2011-12-12 12:15:59

Dimensional problems are generally caused by deviations in the position of the slotting knife, or small shifts during the operation of the machine, or irregularities in the paper, bending and other phenomena that cause deviations in the final packaging box size.

 

Solution: You can adjust the position of the slotting knife for proofing and debugging. If it is caused by paper bending, you can flatten the paper. Generally, the paper warehouse needs to ensure a certain humidity, which is more conducive to the storage of paper. Under environmental conditions, the part in contact with the air will absorb water and the part not in contact with the air will cause the paper to bend due to the evaporation of water.

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