laminating machine——SWFM-920A

What is function of laminating?

Laminating the surface of digital prints, printing a large area and then laminating will help to protect the photos during post-press processing, cutting or packaging. One-sided lamination of double-sided prints is not necessarily beneficial because the uncoated side may be more likely to peel off the printing colour due to friction in subsequent processing.

What are the principal machine parameters of this machine?

SWFM920A+, similar to SWFM520A+ and SWFM920A+, It's a sizeable hydraulic roll laminating machine with oil heating and slitting. But its max paper size is 885mm, more significant than 520A+, and the operating speed is 0-25m/min. Furthermore, the laminating temperature is 50-120℃. Besides, the total power is 4kW, and the dimensions(L×W×H) are 1.38×1.3×1.4m. lastly, the pressure is 3~8MPa.

How do we handle the everyday problems of papers after lamination?

1. After the film is covered, there are bubbles, wrinkling, and some even peeling off. After research and analysis, it is found that the reasons are rough as follows:

1. There is a problem with the printed material itself

If paper with poor uniformity is used for printing, the ink absorption amount and speed are inconsistent, which will cause quantitative changes in paper tightness, evenness, smoothness, and moisture. If the ink is too thick and the ink layer is too thick, the wetting, diffusion, and penetration of the adhesive will be poor, the molecular motion will not be very active, and the mechanical bonding force will be small. In addition, in printing, to avoid the paste of the printing sheet, drying oil is often added to the ink to make the ink layer quickly conjunct, resulting in the crystallization of the surface of the ink layer, the surface of the printed product is smooth and challenging, and the adhesion is lost. Wetting affinity seriously affects the bonding fastness, failing the lamination.

2. The influence of the operation process and printing environment on the quality of lamination

When laminating the printed matter, first apply a layer of adhesive on the surface of the plastic film. Although it has been dried, it still does not meet lamination requirements. At this time, the glue should be diluted with a solvent for quick drying. If the moisture content is too high, bubbles will likely appear when the film is pressurized, resulting in peeling and peeling. At the same time, if the laminating workshop does not control the temperature, airflow, and humidity, the film will easily absorb grease, moisture, dust, and other substances in the air, thereby reducing its surface energy. Excessive moisture will also affect the volatilization of the solvent in the adhesive. Too much residual solvent will create an air barrier in the film, preventing the film from sticking. The roller pressure is uneven, the rubber roller itself is not dry, and there is dirt on the rubber roller, which will also cause the film to wrinkle.

2. Poor adhesion and troubleshooting

1. When the adhesive is improperly selected, the amount of glue applied is not set correctly, and the proportioning measurement is wrong, the bond type and amount should be re-selected.

2. The diluent contains alcohol and water that consumes NCO groups so that the hydroxyl groups do not react. High purity ethyl acetate should be used.

3. There is powder spraying on the surface of the printed matter. Gently wipe off with a dry cloth.

4. The ink layer of the printed matter is too thick. The amount of adhesive applied should be increased, and the pressure should be increased.

5. The ink layer of the printed matter is not dry or completely dry. It should be hot-pressed again before gluing; choose a binder with high solid content; increase the coating thickness; increase the drying tunnel temperature, etc.

6. When the adhesive is absorbed by printing ink and paper, the coating amount is insufficient. The application amount should be reformulated and set.

7. The surface treatment of the plastic adhesive film is insufficient or exceeds the expiry date, which makes the treated surface invalid, and the sticky plastic film should be renewed.

8. The pressure is too low, the speed is fast, and the temperature is low. The film temperature and pressure should be increased, and the vehicle speed should be appropriately reduced.

3. The phenomenon of foaming occurs, which generally belongs to the following situations:

1. The printing ink layer is not dry. It should be hot-pressed again before gluing, and the lamination time should be delayed to allow it to dry thoroughly.

2. The printing ink layer is too thick. The amount of adhesive coating should be increased, and the pressure and compounding temperature should be increased.

3. The drying temperature is too high, and the surface of the adhesive is crusted. The drying temperature should be lowered.

4. The surface temperature of the composite roller is too high. The compound roll temperature should be lowered.

5. The film is wrinkled or slack, and the film is uneven or curled. The film should be replaced and the tension adjusted.

6. There are dust impurities on the surface of the desert. It should be removed in time.

7. The adhesive coating is uneven, and the dosage is small. The coating amount and uniformity should be improved.

8. The adhesive concentration is too high, the viscosity is large, and the coating amount is uneven. The diluent should be added to reduce the adhesive concentration.

Fourth, the film is wrinkled.

1. The film transfer roller is unbalanced. The transfer roller should be adjusted.

2. The two ends of the film are inconsistent or wavy. The qualified film should be replaced.

3. The adhesive layer is too thick, and the solvent is not evaporated completely, which affects the viscosity. It is squeezed by the pressure roller and slips between the paper and the film. The amount of glue applied should be adjusted, and the drying tunnel temperature should be increased.

4. The two ends of the electric heating roller and the rubber roller are unbalanced, the pressure is inconsistent, and the line speed is not equal. Both rollers should be adjusted. The problems often encountered in the lamination of packaging printed products include these categories. Lamination is a crucial post-printing process, and packaging printing is a comprehensive problem.

What should I pay attention to when I'm operating laminating machine?

1. When the machine is running, avoid putting your fingers into the two rollers to avoid sticking your hands. The temperature of the pressing roller of the device is high. Please do not touch it with your hands to prevent burns. The inner roller drags the cloth in his hand.

2. Glue, thinner, and washing machine are flammable products, so be careful about fire.

3. Electric thermocouples are used to detect the temperature when the sensor element of the temperature controller is used. Due to the significant influence of the position of the device and the surrounding air temperature and external wind flow, the temperature measurement accuracy has a significant error. The temperature is an absolute temperature, and the user should choose the temperature according to the actual processing experience and the guide value of the reference temperature table.

4. The machine used in the new installation should be more smooth to the device, and it is essential not to use the machine quickly during the running-in period of the machine transmission.

5. Strictly prevent tools, devices, and sundries from being placed on the machine. The air gap between the rubber roller and the rubber roller is tiny. Once any hard object is pressed into the surface of the rubber roller, it will leave a pressure pit on the rubber. The light one takes a long time to restore the natural elasticity, and the heavy one indirectly makes the rubber roller scrapped.

6. The main power switch should be closed when repairing and inspecting the machine. The machine's electrical system should be maintained in good insulation to avoid moisture. To prevent accidents, the power supply should be cut off when the device is stagnant.

7. When the machine is stopped, the hydraulic system must be unloaded, the pressing roller and the rubber roller are separated, and the scraper and the pre-pressing roller are loosened to avoid temporary pressure deformation and damage to the two rollers.

How do we solve problems in  winter?

Cold lamination in winter often causes shrinkage, fog, and non-stick edges. It is not difficult to find out through careful observation. The culprit that causes the poor adhesion of the picture is the ink. You can compare the dark colour picture and the light colour picture. The shrinkage or heavy fog is because the ink on the image is not completely dry during the cold lamination. In addition, the environmental humidity is too high, or the cold lamination humidity is too high, which causes the paper to absorb moisture and form "lotus leaf edges." It also causes the paper to wrinkle during the cold lamination process. Therefore, many friends will add plastic border strips after laminating to solve the problem of non-sticking the edge during cold lamination in winter. They will work harder and harder to solve the problem of shrinking and wrinkling. It is not difficult to find that if the pressure is not uniform, it will cause. The paper is to be wrinkled during the lamination process, and if the tension is too large, the film is wound and torn, which will also cause the paper to wrinkle during cold lamination.

In addition, with the development and application of digital printing technology, much of digital printing equipment currently uses electrostatic and toner imaging technology. When printing large-area dark patterns, the amount of silicone oil is large, and the anti-adhesion is strong. Traditional cold lamination technology ( Including water-based, oil-based, non-adhesive films, etc.) can not solve the phenomenon of low adhesion strength, air bubbles, white snowflakes, etc.

There is no need to be so troublesome in winter laminating. Since cold laminating machine lamination is prone to problems, we can choose hot laminating machine lamination. Jintu multifunctional laminating machines can do cold lamination, hot lamination, thermoplastic and other work. If cold lamination is not suitable, you can choose hot lamination.

Using the heating method to coat the film in thermal lamination is not simple. After hot mounting, the picture does not bubble, wrinkle, or delaminate. In winter, hot lamination has more advantages than cold lamination. Because the temperature of cold lamination is not enough, it is not enough to rely on cold pressing. Because the viscosity of the cold lamination film adhesive is too large to meet the requirements, wrinkles and blistering often occur, mainly. Many cold lamination machines still need to be operated manually. If replacing high-quality cold lamination film increases the Cost, you must know that the current market price of hard lamination film made of transparent PVC through adhesive backing is not low.

The warpage and deformation of single-sided thermal mounting are related to the printed paper's moisture and tension (humidity, flatness). We know that due to thermal expansion and contraction, too high and too low temperature will aggravate the expansion and contraction of paper. , affecting the lamination effect, so if the temperature, pressure, and speed are not adjusted well during the thermal lamination and the use of inferior thermal lamination pre-coated film, then the single-sided thermal laminating machine is prone to curling, warping, and other phenomena. Therefore, to solve the warping phenomenon of single-sided thermal mounting, it is necessary to control the heating temperature and working speed strictly; of course, high-quality pre-coated films such as single-sided thermal mounting films that are not easy to bend can also be used, but this further increases the potential Cost is just a helpless choice to treat the symptoms rather than the root causes.