Today, we still use plastic products extensively for a wide range of applications. However, since our understanding of thermoformed products is limited, we often seek to learn more about them. Below, we’ll share some information on… Thick-sheet thermoforming Let me introduce the technical features of this knowledge. If you’re not familiar with it but are interested, we can take a look together.

　　Characteristics of Thick-Section Blister Forming Technology

　　The operating principle of thick-sheet thermoforming is to feed a rolled sheet into an electric oven, where it is heated until softened. While still hot, the sheet is drawn over a thermoforming mold; the mold then moves upward and a vacuum is applied, pulling the softened sheet tightly against the mold’s surface. Simultaneously, cooling water is atomized onto the molded sheet to harden it, after which the finished part is automatically conveyed to a storage bin. A pneumatic cutter separates the molded piece from the unformed sheet, completing the entire process. Most quality issues in thermoformed products typically arise during this stage:

　　1. Insufficient vacuum forming results in deformed shapes, producing parts that do not match the mold’s contour.

　　2. Excessive foaming indicates that the product is too thin;

　　3. Draw marks refer to unwanted linear defects that appear on the molded part.

　　4. Uneven thickness. These issues must be properly adjusted after the mold is installed, including: the timing of blank feed, the heating temperature and duration, the vacuum‑pulling intensity and duration, the position, timing, and depth of the upper die’s descent, as well as the alignment of the molds on the nesting plate and whether additional fixtures are used between the molds.

　　Thick-sheet thermoforming typically ranges from 0.14 to 8.0 mm in thickness, with products available in various materials and finishes. It is primarily used for refrigerator liners, advertising light boxes, product display racks, pet cage bases, rear-projection TV back shells, and a wide array of mechanical panels. These parts can serve as substitutes for injection-molded components. Key advantages include low tooling costs—about one‑twentieth those of injection molds—short production cycles, and rapid mold development, usually taking just 3–5 days.

　　The reason for classifying material types is primarily to take into account ordinary sheet thermoforming and… Thick-sheet thermoforming The materials used vary somewhat, but PVC, PP, PS, and PET account for the majority in both types of blister-pack products. One could say this is the “family” of plastic‑based materials!

　　PVC rigid sheet has moderate toughness and is not easily combustible. When burned, it releases emissions that can have a certain environmental impact. It is easy to heat-seal and can be sealed using sealing machines or high-frequency sealers. It is a primary raw material for manufacturing transparent plastic products.

　　PS hard sheets have low density, poor toughness, and are highly flammable. When burned, they release styrene gas—a harmful substance—so they are typically used to manufacture various industrial thermoformed trays.

　　PET rigid sheets offer excellent toughness and high transparency, are easily combustible, and do not release harmful gases when burned. They are an environmentally friendly material, though relatively expensive, making them suitable for plastic products. In Europe and North America, blister packaging typically requires PET rigid sheets; however, their poor heat‑sealability poses significant challenges to the packaging process. To address this issue, a PVC film is laminated onto the PET surface, creating a PETG rigid film, though at a higher unit cost.