Optimizing Thermoplastic Processing with Sheet-Metal Molds

As detailed by Academia in their article “Sheet-metal based molds for low-pressure processing of thermoplastics,” current mold technology used in thermoforming processes, such as vacuum forming, often suffers from inefficiencies in material and energy usage. Traditional molds, typically milled from solid blocks of aluminum, are time-consuming and costly to produce. Additionally, these molds require significant energy for tempering due to their large mass, leading to higher overall costs for the formed products.

Challenges are being addressed by developing and validating faster, cheaper, and more efficient molds made from plastically deformed metal sheets. These new molds are designed to meet specific criteria: they can be produced using appropriate sheet metal forming techniques, achieve the necessary structural stiffness, and maintain the desired thermal patterns. A notable technique in this context is Single Point Incremental Forming (SPIF), which allows for the creation of generic, freeform shapes using a standard, spherical CNC-controlled tool. SPIF is characterized by its short lead times, making it highly suitable for producing thin, thermally efficient metal plates.

However, due to their thinness, these metal plates need additional support to withstand the forces during the thermoforming process. The development of these molds is particularly advantageous for producing small series of plastic or composite products, where mold cost and production time are critical factors.

Low-pressure forming processes, such as thermoforming, rotational molding, and resin transfer molding, typically use molds with complex, deep forms but have limited mechanical stability requirements. There is a significant demand for improved manufacturing techniques for these molds from both the plastics and composites processing industries and mold manufacturers seeking to diversify their technologies. The research underlying this paper focuses on new types of molds based on 3D-shaped metal sheets, promising cheaper and faster production for thermoforming processes, especially vacuum forming.

Thermoforming involves shaping a plastic product from a heated polymer sheet, which is then stretched onto a cool mold and cooled to retain the mold’s shape. This process includes various techniques, such as vacuum forming, where a vacuum draws the sheet against the mold surface, creating a differential pressure that presses the sheet into the desired form.

This innovation is at the forefront, utilizing advanced sheet metal forming techniques to create efficient and cost-effective molds for low-pressure thermoplastic processing. Expertise and cutting-edge technology ensure high-quality and economically viable solutions for the industry.

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Article with all rights reserved, courtesy of academia.edu