This article on molding processes used for reusable packaging, based on an interview with James Riegleman of ORBIS Corporation, marks the first installment of our Reusable Packaging Insights from Experts series.
Based on an interview with James Riegleman of ORBIS Corporation, this article on molding processes used for reusable packaging, marks the first installment of our Reusable Packaging Insights from Experts series.
When we think about reusable transport packaging, we often focus on its durability, cost savings, and sustainability benefits. But what goes into making these plastic bins, pallets, and bulk containers? For this installment of Reusable Packaging Insights from Experts, I spoke with James Riegleman, Senior Product Manager at ORBIS Corporation, to break down the basic molding processes that shape reusable transport packaging.
Plastic molding is more than pouring molten plastic into a mold and waiting for it to harden. Different products require different processes to balance strength, weight, cost, and durability. Here’s a look at some of the most important molding methods and how they impact the performance of reusable packaging.
High-Pressure Injection Molding: Speed and Precision
“High-pressure injection molding is probably the most common process that people are familiar with,” says Riegleman. This method involves injecting molten plastic into a mold under extreme pressure. benefits? Fast cycle times, precise molding, and a great strength-to-weight ratio.
This process allows manufacturers to create thin-walled, lightweight, yet strong plastic parts. That’s why high-pressure injection molding is gaining traction in the industry. “You’re still getting a high-performing part, but at a lower cost per unit due to faster production cycles,” he explains.
However, there’s a trade-off. The tooling costs for high-pressure injection molding are higher because the molds must withstand intense heat and pressure. Specialized metals are required, making the upfront investment significant. But for long production runs, the cost efficiency of the process outweighs the initial tooling expense.
Low-Pressure Structural Foam Molding: Strength and Impact Resistance
“Traditionally, ORBIS has been a structural foam company,” Riegleman notes. Structural foam molding uses a lower pressure process incorporating a gas into the plastic material, creating a cellular core structure that enhances impact resistance and durability.
This method results in thicker walls than high-pressure injection molding, making products highly resistant to impact and extreme temperatures. “It’s great for applications where you need toughness—think bulk bins that take a beating in the field or pallets that handle heavy loads.”
However, structural foam parts are heavier, and the process has slower cycle times than high-pressure injection molding. “That’s why we see a market shift towards more high-pressure molding where it makes sense,” he says. ORBIS has been investing heavily in injection molding, especially with new plant expansions that focus on both high-pressure and structural foam capabilities. The company carefully evaluates whether each new product would benefit more from one process or the other.
Thermoforming: Cost-Effective and Versatile
Thermoforming is another widely used method, particularly for lightweight, large-format plastic products. This process involves heating a plastic sheet until it becomes pliable, then forming it over a mold and trimming the excess material.
Thermoforming is commonly used for manufacturing lightweight pallets, top caps, dunnage trays, and protective covers. It is a cost-effective process that works well for low- to medium-volume production runs where complex mold designs are not required. Since thermoforming uses relatively inexpensive tooling, it allows for faster turnaround times and lower upfront costs compared to injection molding.
A specialized variation of this process, twinsheet thermoforming, involves heating two plastic sheets simultaneously and fusing them together in a single step. This method creates hollow or double-walled structures, enhancing strength, durability, and impact resistance while keeping products lightweight. Twinsheet thermoforming is often used for pallets, bulk containers, and material handling trays that need added structural integrity without the added cost of higher-pressure molding techniques.
| Molding Process | Main Benefits |
|---|---|
| High-Pressure Injection Molding | Fast production cycles, precise molding, excellent strength-to-weight ratio, cost-efficient for long runs. |
| Low-Pressure Structural Foam Molding | High impact resistance, thicker walls for durability, good for bulk bins and heavy-duty pallets. |
| Thermoforming | Cost-effective for low- to medium-volume production, lightweight products, fast tooling turnaround. |
| Twinsheet Thermoforming | Creates double-walled structures for added strength, reduces material costs, common for reusable pallets and bulk containers. |
| Extrusion | Ideal for corrugated plastic sheets and profile materials, used in reusable totes and bulk bins. |
| Compression Molding | Produces extremely strong parts, commonly used for heavy-duty pallets. |
| Blow Molding | Best for hollow plastic tanks for IBCs, cost-effective for mass production. |
| Rotational Molding | Creates seamless, thick-walled products like bulk containers and tanks; very durable. |
Extrusion: The Backbone of Plastic Corrugated Packaging
If you’ve seen corrugated plastic sheets used in reusable packaging, they were likely made through extrusion. This process involves melting plastic and forcing it through a die to create continuous shapes.
“Extrusion is becoming more popular as we move away from single-use corrugated cardboard to reusable plastic versions,” Riegleman says. Corrugated plastic totes and bulk bins are lightweight, durable, and resistant to moisture—ideal for supply chain applications where reusability is key.
Some plastic and composite pallet manufacturers also use an extrusion process to create profile material to be assembled into pallets. Additionally, plastic thermoformers also use an extrusion process to create the plastic sheets or blanks used in the thermoforming process.
Other Molding Processes Worth Noting
While high-pressure injection, structural foam, thermoforming, and extrusion dominate the industry, there are other methods worth mentioning:
- Compression Molding: Often used for making heavy-duty pallets, this process applies pressure to preheated plastic inside a mold. It’s slower but produces exceptionally strong parts.
- Blow Molding: Common in hollow plastic containers like bottles and some IBCs. Air pressure expands the plastic into the shape of a mold.
- Rotational Molding: Used for large, hollow, and seamless products like bulk containers and tanks. This process results in thick, durable walls but has longer cycle times and higher costs per unit.
Optimizing Cost Through Tooling Innovations
One key factor influencing costs in plastic molding is tooling. Riegleman notes the increasing use of multi-cavity molds and stack molds to improve efficiency. Multi-cavity molds allow multiple parts to be produced simultaneously, reducing cycle times and making production more cost-effective. “Being more creative on our tooling side has definitely been a focus area,” he says. This approach helps ORBIS reduce material waste and energy consumption while keeping costs manageable for end users.
Material Matters: PE vs. PP and Recycled Content
Choosing the right plastic resin is as important as selecting the molding process. Riegleman highlights the two most common materials used in reusable transport packaging: high-density polyethylene (HDPE) and polypropylene (PP).
- HDPE: “High-density polyethylene offers excellent impact resistance and works well in cold environments,” says Riegleman. It’s commonly used in freezer applications because it stays strong in low temperatures.
- PP: “Polypropylene, on the other hand, holds up better in high-heat applications,” he notes. It’s lighter than HDPE, making it an attractive option for reducing material costs.
And then there’s the push for recycled content. ORBIS, like many industry leaders, is focused on maximizing post-industrial and post-consumer recycled materials in their products.
“Most of our bulk containers use 75% recycled material while maintaining the same performance as virgin plastic designs,” Riegleman explains. “It’s all about balancing performance, cost, and sustainability.”
Real-World Example: Redesigning a Bulk Bin for Agriculture
To illustrate the impact of choosing the right molding process, Riegleman shares a case study from the agricultural sector. ORBIS had long provided a structural foam bin used to harvest and process leafy greens, but customers were experiencing plastic contamination issues when the bins broke under heavy impact.
“We redesigned the bin with a high-pressure injection molded base while keeping the structural foam panels,” he says. The result? When the bins took damage, they broke in a way that minimized contamination risks in food processing environments.
This kind of design innovation—choosing the right molding process for the right application—is key to extending product life, improving safety, and maintaining efficiency in logistics and supply chains.
Molding the Future of Reusable Transport Packaging
Understanding the various molding processes behind reusable transport packaging isn’t just a technical exercise—it’s critical for making smart decisions about durability, cost, and sustainability. Whether it’s the speed of high-pressure injection molding, the resilience of structural foam, or the adaptability of thermoforming and extrusion, each process has its place.
As manufacturers push for greater automation, lighter materials, and more recycled content, the evolution of molding technologies will continue to shape the future of reusable packaging. With companies like ORBIS investing in innovation, the industry is moving toward smarter, more sustainable solutions that redefine efficiency in logistics and material handling.
“This market is always looking for innovation,” Riegleman adds. “We’re constantly trying to push the envelope, whether that’s increasing the use of recycled content, finding new sustainable materials, or designing products that solve real-world challenges for our customers. At the end of the day, it’s about creating solutions that work better and last longer.”
Rick LeBlanc, EMBA, is the founder and editor of Reusable Packaging News (subscribe to the free newsletter) and editor of Western Pallet Magazine. A supply chain journalist with more than 30 years of experience, he specializes in pallets, reusable packaging, material handling and related operations. Rick is co-author of Pallets: A North American Perspective and Pallets & Progress: A Collected History of Pallets and Palletized Handling 1922–1945. He is also an advisory board member of the Virginia Tech Center for Packaging and Unit Load Design. Read Rick’s full bio.
