What is Thermoforming?

Thermoforming is a process of heating thermoplastic sheet and placing it over a mold until cooled. Its primary forms include the thin gauge thermoforming process used extensively in producing disposable packaging for retail applications and thicker gauge forming commonly used to mold everything from shipping trays to permanent components in refrigerators, automobiles, etc.

Business Units Supported

Sinclair & Rush originally invested in thermoforming primarily serving the VisiPak business unit by producing a wide variety of clear plastic packaging including its signature line of stock clamshells. The business grew organically expanding to include production of blisters and packaging trays, further enhancing the clear packaging line for customers. Strategic acquisitions led to innovative mold-base technology and continues to be a source for increasing packaging solutions. Visit Indepak for precision thermoforming details.

The StockCap business unit utilizes thermoforming to support its client’s need for protective shipping and work-in-process trays used in a wide variety of industries to store, protect and efficiently transport high-value components.


Our thermoforming operations are located in ultra-clean, modern facilities in the suburbs of St. Louis, MO and Portland, OR, allowing us to better serve our customers across the United States through both location and operational redundancy.

The combined square footage of both facilities exceeds 200,000 square feet. Each facility houses administrative, warehouse, engineering (including in-house tooling design and development) and manufacturing capabilities.


Our thermoforming operations are supported worldwide by our experienced VisiPak sales and engineering teams. These specialists aid customers with sizing, design and more, to find the best solutions for their specific application. Armed with the latest CAD and 3D printing technology, custom packages and trays can move from concept and design to prototyping and production in the most efficient and cost-effective manner. All locations benefit from the company’s extensive experience in materials and design innovation, automation and quality control while conforming to the unique needs of their specific markets.


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