A molding method that changes the pressure difference by vacuuming to make the heated plastic sheet stick to the mold surface.

Basic Introduction

Vacuum molding is often called Vacuum Forming molding, which is a plastic processing technology. The main principle is to heat and soften the flat plastic hard sheet, then use vacuum to absorb it on the mold surface, and then cool it to form. It is widely used in plastic packaging, lighting, advertising, decoration and other industries.

Vacuum packaging: a general term for plastic products produced by Vacuum Forming molding technology and packaged with corresponding equipment.

Vacuum packaging products include: Vacuum Forming, tray, Vacuum Forming box, and synonyms include: vacuum cover, Vacuum Forming, etc.

The main advantages of vacuum packaging are saving raw and auxiliary materials, light weight, convenient transportation, good sealing performance, and meeting the requirements of environmentally friendly green packaging; it can package any special-shaped products, and no additional cushioning materials are needed for packing; the packaged products are transparent and visible, beautiful in appearance, easy to sell, and suitable for mechanized and automated packaging, which is convenient for modern management, saving manpower, and improving efficiency.

The vacuum packaging equipment mainly includes: Vacuum Forming forming machine, punching machine, sealing machine, high-frequency machine, folding machine.

The packaging products formed by encapsulation can be divided into: plug-in card, suction card, double bubble shell, half bubble shell, folding bubble shell, three-fold bubble shell, etc.

Vacuum forming is to reheat and soften the thermoplastic plastic sheet or sheet (thickness less than 6mm), place it on a mold with many small holes, and use the vacuum method to make the sheet tightly sucked on the mold for forming. This method has fast forming speed and easy operation, but the surface of the product is rough, and the size and shape errors are large.

Vacuum forming is widely used to produce calcium plastic ceiling decoration materials, washing machine and refrigerator shells, motor shells, artworks and daily necessities.

1 Vacuum forming

The so-called vacuum forming refers to a method of relying on a vacuum pump to draw a vacuum state between the mold and the heated thermoforming sheet (plate), causing a pressure difference between the upper and lower parts of the sheet (plate), so that the sheet is tightly attached to the mold surface for forming. Vacuum forming can be divided into several forms such as single positive mold (convex mold), single negative mold (concave mold), and moldless.

1. Single positive mold vacuum forming

Single positive mold vacuum forming is also called convex mold vacuum forming, covering vacuum forming or vacuum forming. The process is that the plastic sheet is clamped with a clamp frame and then heated, and a small hole for vacuuming is opened on the convex mold surface. After the sheet softens, the clamp frame moves down or the convex mold moves up to stretch the sheet. After the clamp frame and the convex mold are in contact and sealed, the convex mold is vacuumed, and the pressure difference causes the sheet to adhere to the convex mold surface for forming. After cooling and shaping, demoulding by blowing, and trimming, the product is obtained.

2 Single-mold vacuum forming

Single-mold vacuum forming is also called concave mold vacuum forming, direct or simple forming. The process is that the sheet is clamped on the concave mold, and a small hole for vacuuming is opened on the lower cavity of the concave mold. The concave mold is both a vacuum chamber and a molding cavity. After the sheet is softened by heat, the concave mold is evacuated. The pressure difference between atmospheric pressure and vacuum causes the sheet to be stretched and tightly attached to the concave mold cavity for molding. After cooling and shaping, it is demoulded by blowing, and the product is obtained after trimming.

3 Moldless forming

Vacuum forming without a mold is called moldless forming, also known as free forming. This molding method is used to blow various hood shapes

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