Vacuum thermoforming is a relatively simple manufacturing method where atmospheric differences—vacuum pressure—are used to push or pull a heated and malleable plastic sheet flush against a mold—the thermoform. Thermoforms are often made from several types of materials, including wood, but aluminum vacuum forming molds bring some unique advantages to high-production thermoforming that is used to produce simple items, like kiddie pools, but also heavier duty products like car dashboards and office equipment.
Understanding Vacuum Thermoforming
Vacuum thermoforming is a tried and true process that dates back to the second half of the nineteenth century when it was used to form cellulose nitrate into toys and bottles. The molds today can be made of wood, sometimes covered in plastic for a smoother finish, plastics or resins supported by steel framing, or rough cast aluminum whose selling points include a porosity that means dedicated air holes to draw air away from the plastics’ surface aren’t necessary. In other words, this industry doesn’t require a lot of precisely machined surfaces or potentially expensive labor.
However, there is also a range of industries whose aluminum vacuum form molds are constructed for heavy-duty use. These molds are CNC machined from high-quality MIC-6 or a MIC-6 alternative aluminum tooling plate. This is an expensive material and an expensive process that is used to create these particular aluminum vacuum forming molds. However, the properties of aluminum can speed up the production process to offset costs, and the aluminum lends the finally formed plastic some unique properties that may be a requirement for the industry it will be used in.
When to Use Aluminum Vacuum Forming Molds
One of the most common, and certainly most prolific, uses of aluminum vacuum forming molds is in the packaging industry. High-quality cast aluminum plates are one of the best choices in this industry due to the high degree of precision that it allows over both the mold and the molding. The thermal conductivity of the aluminum causes all the heat to move swiftly out of the plastic product and the product to quickly become firm enough to move on to the next step in the process. Thermoforming is also a less pressure-intensive means of molding plastic than injection molding which eliminates one of the disadvantages of aluminum vs. steel injection molds from consideration in vacuum forming. Aluminum vacuum forming molds are a long-lasting, high-volume solution in this application.
Cast aluminum tooling plate has another potential advantage as an aluminum vacuum forming mold in industries like food and beverage or pharmaceuticals. As a class of materials, cast aluminum plate offers exceptional surface flatness, and newer alloy formulations like ACP 5080 and Alca 5 have exceptionally fine grains and low-surface porosity. In industries like food and pharmaceuticals where sanitation is vital, the potential to mold flat and clean plastic surfaces easily is ideal since crevices in the mold can trap chemicals and microbes. These new formulations of aluminum share the existing advantages of aluminum tooling alloys like MIC-6 including:
- Durability: Aluminum is one of the most durable vacuum forming mold materials available. Lasting longer than wood or composite materials aluminum is an excellent choice for high-volume, long-term production that requires quick cycle times.
- Consistency: CNC machined cast aluminum tooling plate offers a high degree of consistency throughout the material. Far more than rough cast aluminum, wood, or steel-reinforced composites.
- Cost-effective: The combination of durability and consistency offers extraordinary cost-effectiveness over the lifespan of an aluminum vacuum forming mold. While the initial material and cost to work it into a mold may be expensive, the benefits of long-term, high-volume production more than makes up for the initial upfront costs.
- Less porosity: Cast aluminum boasts a low porosity which serves vacuum forming molds well, especially in the food and beverage and pharmaceutical industries. The fewer pockets of air or tiny holes in the metal means less of a chance to harbor any contaminants and affect the resulting product.
Combined these advantages make machined aluminum one of the best options for vacuum forming molds, and thermoforming more generally. In industries such as food and beverage and pharmaceutical packaging, there aren’t many alternatives to machined aluminum that offer the same advantages or the same cost benefits. New 5000 series blends of machined cast aluminum tooling plates can potentially offer still greater cost benefits for those that are willing to pioneer their use, and with high-speed fast prototyping widely available for aluminum vacuum forming molds, it has never been as easy to develop new production processes and gain a competitive edge in thermoforming.