Trimming the Bowl While It Is Still Hot In-Line Die Cutting for Vacuum Formed Molded Pulp Containers

This application covers a way of making plastic-replacement fibre containers where the trimming step is folded into the drying press: a moulded pulp part is compressed between heated plates that carry their own integrated cutting blades, so the part is pressed, dried and die cut in one in-line operation. The applicant is Footprint International, the Arizona materials science company founded by former Intel engineers to eliminate single-use plastics from food packaging.

The Problem

The background section frames the commercial reality bluntly: sustainable solutions for reducing plastic pollution must not only be good for the environment, they must be competitive with plastics on both cost and performance. Molded pulp is the leading candidate. Made from old newsprint, corrugated boxes and other plant fibres, it already protects electronics, household goods, automotive parts and medical products in shipping.

The specification walks through the two standard processes. Type 1, or dry manufacturing, dips a screened mould into a fibre slurry, pulls a vacuum to draw the pulp onto the mould, ejects the part and sends it through a drying oven; it yields thick-walled support packaging. Type 2, or wet manufacturing, transfers the wet part to a hot press that compresses and dries it, producing the thin, smooth-walled containers used for food and consumer goods.

What neither process contemplates, the document says, is in-line die cutting of the container. Trimming flash from the edges, punching holes, and other finishing work sits outside the forming line as a separate downstream operation, extra handling and extra cost for a product that has to beat plastic on price.

What This Invention Does

The invention integrates the cutting die into the drying press itself. In the overall process, a wire mesh mould is immersed in a slurry of water and fibre particles, a vacuum drawn across the mesh accumulates fibre into a moulded part, and the part is transferred to a die press assembly where it is dried and die cut in the same station.

Claim 1 captures the press step precisely: a method for simultaneously pressing and cutting a moulded fibre container, comprising receiving at a first plate a moulded fibre part having a moisture content below 10 percent, compressing the part against the first plate with a second plate, and cutting the compressed part with a die cutting blade integrated into at least one of the plates. Dependent claims add the practical details: the blade removes excess flash, the plates carry vent holes that pass heated air through the part to keep drying it, and cutting happens at 150 to 250 degrees Centigrade while the part is compressed. Cutting is defined broadly to include trimming, punching, forging and forming.

The specification is candid about the engineering trade-off at the heart of the idea. A part must be dry enough to hold its shape under the blade, but the wetter it is, the easier it cuts: a still-moist part can be die cut with around twenty tons of force, while a fully dried, rigid part can demand in the range of one thousand tons. Cutting inside the drying press lets the manufacturer pick the point on that curve.

Running blades inside a hot press creates its own problem: the plates, springs and blades are machined at room temperature but operate at oven temperatures, and mixed stainless steel and aluminium components grow at different rates. The design compensates for the differential thermal expansion of the metals so the cutting edges still land where they should. The same tooling does double duty for product features: one illustrated embodiment punches a ring of steam holes into the base of a moulded fibre steamer bowl during the die cut, using spring-loaded blades and punch forms built into the die plates.

Key Features

• Cutting die inside the drying press. The die cutting blade is integrated into the heated press plates, so pressing, drying and trimming happen in one in-line station instead of a separate downstream operation.
• Moisture window for cutting. The claimed method cuts a part with moisture content below 10 percent, balancing structural rigidity against cutting force.
• Hot cutting at oven temperature. Cutting can occur at 150 to 250 degrees Centigrade while the part is compressed, so drying never has to pause for trimming.
• Twenty tons instead of a thousand. Cutting while the part retains some moisture reduces required press force from around one thousand tons for a bone-dry part to roughly twenty tons.
• Thermal expansion by design. The tooling compensates for the differing expansion of stainless steel and aluminium components heated far above the temperature at which they were machined.
• Punching features, not just trimming. The integrated die can punch functional openings, such as steam holes in the base of a food steamer bowl, in the same stroke that trims the part.

Who Is Behind It

Footprint International, based in Gilbert, Arizona, was founded in 2014 by former Intel engineers Troy Swope and Yoke Dou Chung to engineer fibre-based replacements for single-use plastic. The company makes moulded fibre bowls, trays, cups and meat trays for major food brands and retailers, and its history includes naming rights to the Phoenix Suns’ arena, the Footprint Center. Footprint has been repeatedly recognised for sustainability innovation, including a CNBC Disruptor 50 listing.

The two named inventors are Yoke Dou Chung, the company’s co-founder, and Michael Theodore Lembeck. The application is a divisional of Australian application 2024203692, filed 31 May 2024, itself a divisional of 2018271916, filed 23 May 2018 as the Australian entry of PCT/US2018/034176, which claims priority from two United States applications, 15/606,988 and 15/606,992, both filed 26 May 2017. The specification also incorporates by reference Footprint’s 2016 US application on fibre-based produce containers.

Why It Matters

Moulded fibre only displaces plastic where it can match plastic’s economics, and thermoformed plastic packaging comes off high-speed lines with trimming built in. Folding die cutting into the fibre drying press attacks the cost gap directly, removing a handling step, a separate trimming machine and floor space from the line. It is manufacturing process engineering in service of sustainable packaging, the least glamorous and most decisive part of the plastics transition.

The steam hole embodiment shows where the technology points: not just clamshells and corner protectors but microwaveable and steamable food containers, where vent placement is a product feature and a secondary drilling operation would be prohibitive. That is the premium end of the moulded fibre market, and the one where performance parity with plastic is hardest won.

The filing pattern, a 2017 US priority carried through a PCT into Australia and kept alive through successive divisionals into 2026, signals that Footprint regards its process patents, as much as its materials, as the moat around its business. For a company whose pitch is that fibre can beat plastic on cost, the production line is the invention.

Related Concepts

• Molded pulp – the recycled fibre packaging material the process forms and trims.
• Die cutting – the trimming and punching operation moved in-line by this invention.
• Vacuum forming – the forming principle used to draw fibre slurry onto the wire mesh mould.
• Thermal expansion – the effect the hot press tooling must compensate for across mixed metals.
• Sustainable packaging – the market this manufacturing economics play is aimed at.
• Paper recycling – the source stream, newsprint and corrugated boxes, feeding the fibre slurry.

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AU 2026202110 was published in the Australian Official Journal of Patents on 9 April 2026 and is open for public inspection. Patent applications represent inventions that are sought to be protected and do not necessarily reflect commercially available products.