Difference between Positive & Negative Vacuum Membrane Press Machine And Negative Only

Machine Principle

In layman's terms, the positive and negative pressure laminating machine not only has a negative pressure (vacuum pressure) at the bottom, but also a positive pressure at the top. When the machine is running, the bottom is pumped and the top is pressed. Not only is the negative pressure at the bottom vacuumed, but positive pressure is also applied at the top, so it becomes positive and negative pressure. The negative pressure machine only vacuumizes at the bottom, and there is no pressure at the top, so it is called a negative pressure machine. Vacuum forming machine and negative pressure machine are different names for the same concept. Of course, the machine will not only go through the "pressing" step, but also have to cooperate with heating and other processes to become a complete laminating process.

Finished product effect

The three-dimensional sense of the workpieces made by the positive and negative pressure laminating machine will be stronger, such as the angular corners, concave and convex surfaces, groove surfaces, and corners. Because the negative pressure machine only has the function of negative pressure, there is no pressure added on it, and it can only be pulled down by airflow, so the three-dimensional sense of the corners, grooves and other positions of the workpiece after processing is not strong.

The products processed by positive and negative pressure can be kept from peeling off for a long time. Because the temperature of the negative pressure machine can only be transmitted on the surface of the workpiece, the temperature transmission of the side and groove is not comprehensive compared with the positive and negative pressure, so the relative adhesion will be poor, and the product will easily fall off after 2-3 years. The positive and negative pressure is transmitted to every part of the workpiece through the positive pressure and heated airflow. The airflow brings temperature when pressurized, and the transmission is more in place, making it difficult for the workpiece to peel off.

                                      

Positive and negative pressure can make the highlights. Because the highlight film is relatively thick, generally 45 threads, the temperature must be relatively high if it is made by a negative pressure machine. In this way, due to the high temperature, the highlight film will be too soft, which is easy to cause film burning (the film is deformed by heat, and uneven chicken skin patterns appear on the surface). The products made in this way are not accepted on the market. Therefore, it is recommended that users who need to make highlights purchase positive and negative pressure. Positive and negative pressure do not require very high temperatures. They will be pressurized at a uniform speed through an airflow of about 70 degrees, which can ensure the gloss, the softening of the film, and the adhesion of the glue.

So under what circumstances is it suitable to purchase positive and negative pressure or negative pressure machines? If the customer manufacturer is positioned at the high-end route, and has requirements for three-dimensional sense, gloss, etc., you can purchase a positive and negative pressure laminating machine. If the project has just started, users in the trial and exploration stage can consider purchasing a negative pressure machine. Generally speaking, negative pressure machines are suitable for the transition period, and positive and negative pressure laminating machines are basically the main ones.