Vacuum Casting Comprehensive Guide (2024)

Vacuum casting is an elastomer casting technique that injects liquid plastic or metal into a silicone mold under vacuum, effectively producing components made of both plastic and rubber. This innovative approach has numerous applications, yet many individuals remain unaware of the intricacies involved in implementing this process efficiently.

In exploring the details of vacuum casting, it becomes essential to review the fundamental principles, select appropriate equipment, understand the procedural workflow, and delve into the unique characteristics as well as the limitations of this technique.

Vacuum casting, often referred to as vacuum duplication with a silicone mold, merges two established methodologies: vacuum casting and flexible molding. This synergy was made feasible with the advent of silicone resin, the primary material for creating molds, supplemented by polyurethanes that replicate the qualities of materials utilized in mass production. Consequently, vacuum casting has gained popularity in pre-series manufacturing and small-scale productions for visual testing, assembly, functionality, and market analysis.

History of Vacuum Casting

The initial silicone resins were developed in the 1940s, although it was during the 1980s that the technology for plastic vacuum casting using silicone molds became prominent through academic advancements in Dresden and Cottbus, located in the former German Democratic Republic. This innovative process combined established technologies: vacuum casting had been employed for some time, while flexible molds like natural rubber had already aided artists and restorers in replicating reliefs or sculptures without causing damage. The heat resistance featured in silicone resin enabled a productive merger of these processes for effective vacuum casting.

Initially emerging in Japan during the 1980s, this technology was primarily adopted within the automotive industry before making its way back to Europe. Presently, it is extensively utilized across the R&D divisions of nearly all leading manufacturing companies in Europe. Following the development of thermosetting plastics in the late 1990s, these materials entered the realm of vacuum casting, perfectly imitating the aesthetics and functionality of mass-production materials. This breakthrough spurred a series of innovative developments, processes, and accessories, revolutionizing automation and simplifying system management—all contributing to the method's sustained success.

You will receive exceptional service from thingyfy.

Definition of Vacuum Casting

Vacuum casting, or vacuum duplication, commences with the creation of a model via stereolithography, CNC machining, or 3D printing. This model then serves as the basis for the silicone mold. Once crafted, the molding is executed by vacuum injection employing a vacuum casting machine where polyurethane resin is injected into the silicone mold and allowed to cure under heat. Following the curing phase, the mold is removed and the process can be replicated multiple times.

The primary advantage of this technique lies in the reusability of the silicone mold, allowing for the production of prototypes that are indistinguishable from the original model using materials that closely resemble the final product. Such capabilities make this method highly suitable for pre-series or small-scale production runs. The prototypes yield are not only identical in form but also of outstanding quality.

Additionally, vacuum casting offers a broad selection of hardness options and materials, along with the opportunities for dyeing, painting, or integrating inserts through overmolding. This technique is particularly advantageous when the component geometry poses challenges to molding, thanks to the flexibility of the silicone mold, ultimately making it a more cost-effective choice than traditional steel molding.