The working principle of the thermoforming packaging machine is to use the preheating and softening characteristics of plastic sheets with tensile properties to blow or vacuum the packaging material to form a packaging container with corresponding shapes according to the mold shape, and then load the products and seal, automatically collect excess waste after cutting and forming. It mainly consists of the following parts:
Heating and forming area
Before molding, heat the bottom film to reach the temperature required for molding and soften it, ready for rapid forming. The molding method is different according to the technology of the manufacturer, the material of the film, and the depth of the forming container.
The following mainly introduces several of the most common and widely used forming methods in thermoforming packaging machinery:
1) Vacuum: Negative pressure forming, vacuum from the bottom of the mold to attach the sheet fit the mold to form a packaging container, which is suitable for thinner sheets and used for shallow stretched containers.
2) Compressed air. Positive pressure forming, adding compressed air from above the heating chamber. This method has high technical requirements and is suitable for stretching thicker sheets and forming deeper containers.
3) Add the auxiliary stretching mechanism based on 1 and 2. The main principle is that different air pressures are formed on both sides of the sheet. Under the action of differential pressure, the sheet is pressed down close to the bottom of the forming mold. If the difficulty of stretching or the depth of forming is particularly large, it is necessary to add an auxiliary stretching mechanism to help it form. This forming method has higher technical requirements for manufacturers. Before the compressed air is connected, the heated and softened sheet is pre-stretched by the stretching head, so that the formed container has a deeper depth and a more uniform thickness to meet the needs of more customers.
Stretching head auxiliary forming
Through the above three forming methods, the formed mold is cooled, and formed into a container similar to the shape of the mold.
After being fully cooled, it is formed into a container similar to the shape of the mold.
The working process of thermoforming packaging machine is shown in the figure below (flexible film):
1.Bottom film area: Install the film roll on the inflatable shaft as required, confirm the position is correct, and inflate to make it tight. Feed one side of the bottom film into the middle of the two clamping chains along with the drum.
2.Forming area: Conveyed by the chain, the bottom film reaches the forming area. In this area according to customer requirements, the sheet is heated and stretched through the above three forming methods (vacuum, compressed air, stretching head+compressed air).
3.Loading area: This area can be equipped with automatic weighing filling equipment or manual filling according to customer requirements.
4.Sealing area: The bottom film and top film are heated, vacuum and sealed in this area (add inflate function as needed), and the sealing temperature can be adjusted according to the properties of the sheet.
5.Cutting area: There are two cutting methods for this area according to the thickness of the film: Rigid film for pressure cutting, flexible film for transverse and longitudinal cutting. After products are sealed, they are sent to this area for cutting and output.According to customer needs, we can install auxiliary equipment such as sorting, metal detection, weighing detection and so on to form a complete production line.
After years of research and improvement, Utien Pack thermoforming packaging machine has successfully formed 150 mm deep containers, with high precision and uniform film thickness distribution. At the same time, our packaging speed has reached 6-8 times per minute, far ahead of domestic peers.
Post time: Dec-25-2021