How Unilever and Serioplast developed new bottle designs with 3D printed molds

Posted by FIT THAI on July 6, 2026

As one of the world’s largest fast-moving consumer goods (FMCG) companies, Unilever is constantly developing new products for everyday use. From personal care to home care, nutrition, and beyond, it’s quite likely you have one or more of their products in your home right now, as the company owns Dove, Domestos, Cif, Knorr, Axe (Lynx), Ben & Jerry’s, and dozens of other global and local brands.

FMCG is an industry where constant consumer demand drives intense competition, so brands need to continuously innovate and adapt their product strategies. One key area of innovation is packaging. Bottle design can sometimes influence customer perception as much as the contents themselves. Brands like Unilever have to consider material usage, aesthetic appeal, safety, and sustainability for a large variety of packaging types and the products they contain. But for a “simple” plastic bottle, the journey from on-screen design to on-line filling traditionally takes many months.

“A consumer goods company like Unilever needs to get to market as fast as possible, or before your competitors. You need to provide the best possible product at the best possible price in the shortest possible time to consumers. 3D printing helps us to make this process faster.”

Stefano Cademartiri, CAD & Prototyping Owner, Unilever

Learn from Stefano Cademartiri, CAD & Prototyping Owner at Unilever and Flavio Migliarelli, R&D Design Manager at Serioplast Global Services, how they collaborate closely to test the feasibility of 3D printed molds for low-volume stretch blow molding (SBM) to accelerate prototyping and pilot testing, reducing lead times by six weeks and cutting costs by up to 90%.

Traditional workflow for new bottle design development and testing

Plastic products like food and beverage containers, cosmetic packaging, and medical packaging are commonly produced using blow molding, a broad family of fast and long-established mass production methods for high-quality, thin-walled parts. Blow molding has very short production cycle times, typically between one and two minutes, and is extremely cost-effective for high-volume production, typically used for producing millions of identical parts at a low per-unit cost.

Blow molding works by blowing air into a heated plastic tube, called a parison or an injection-molded preform, inside a mold until it forms the desired shape. There are three types of blow molding processes: extrusion blow molding (EBM), injection blow molding (IBM), and stretch blow molding (SBM). SBM is commonly used to produce high-quality, glass-like transparent PET containers, such as water bottles.

Serioplast is a global manufacturer of rigid plastic packaging for the FMCG industry and one of Unilever’s main partners for packaging development and production for the home and personal care market. “We produce four billion bottles per year, in PET, HDPE, and PP materials,” said Migliarelli.

The Seriomac UNIX 4 Cavities SBM machine from Serioplast at their R&D center in Italy. They developed a new workflow with Unilever for using 3D printed molds in this large industrial production equipment.

Traditionally, Serioplast either 3D prints mock-ups for direct prototyping or produces those prototypes via blow molding. Traditionally, 3D printed mock-ups do not represent accurate haptics or transparency and are not reliable enough to be put in the hands of consumers. However, producing production-quality samples via SBM requires expensive metal mold tooling, adding six to nine weeks of lead time to a typical pilot testing phase due to process complexity and outsourced mold production.

“We have to wait six to 12 weeks before we can give our customer a physical sample. So we are losing a tremendous amount of weeks just to try a new bottle design. Sometimes it is a heavy, frustrating job because maybe you have to start all over again,” Migliarelli said.

SBM molds are traditionally made from metal by CNC machining, which requires specialized equipment, CAM software, and skilled labor. Metal mold tooling production is typically outsourced to a service provider, which offers four- to eight-week lead times and costs anywhere from $2,000 to over $100,000, depending on part complexity and the number of parts per mold. Even in-house CNC machining of metal molds takes six weeks, typically, due to the many steps involved: lead time for material orders, CAM and machine setup, manual polishing, and waiting time for machine availability.

As a result, blow molding low volumes of parts for prototyping and pilot testing has not traditionally been economically viable. Companies like Unilever therefore had to plan with longer timelines and make final design decisions based on looks-like prototypes in different materials, often leading to obsolete tooling and sunk costs.

Blow mold real bottles 70% faster and 90% cheaper

3D printing is a powerful solution for producing tooling rapidly and at a low cost. It requires very limited equipment, freeing up CNC capacity and skilled operator time for other higher-value tasks. By bringing 3D printing in-house, manufacturers and product designers can bring rapid tooling into the product development process to validate the design and the manufacturing process before moving to mass production. 3D printed molds are already used in processes such as injection molding or thermoforming to rapidly iterate and improve, accelerate product development, and bring better products to market.

Stereolithography (SLA) 3D printing technology is an excellent choice for mold making. It features smooth surfaces and high accuracy, which the tool transfers to the final part, and also facilitates easy part release from the mold. The Form 3L is a large-format SLA 3D printer that enables the production of large parts and molds, while still being compact enough for the office.



Molds 3D printed on the Form 3L with Rigid 10K Resin.	After washing, supports are removed, and the molds are post-cured.

Material selection is crucial for mold making. Unilever and Serioplast needed a material that could withstand the internal pressures and temperatures of the SBM process, while maintaining good accuracy and dimensional stability.

“With the help of Formlabs engineers, we have identified a material that can give us the possibility to have a certain amount of bottles in the real material, to make our tests,” Cademartiri said.

Rigid 10K Resin is the Formlabs recommended material for SBM, as it combines strength, stiffness, and high heat resistance. It is a highly glass-filled, industrial-grade material with an HDT of 218°C @ 0.45 MPa and a tensile modulus of 10,000 MPa. Tooling printed with Rigid 10K Resin has good dimensional stability and is suitable for hundreds of blow molding cycles with high repeatability.

With Rigid 10K Resin, Serioplast produced accurate molds with a smooth surface that can incorporate fine details, including holes as small as 0.5 mm. They post-processed the mold tooling with polishing or manual sanding to achieve the critical dimensions required. Textured surfaces were incorporated into the mold cavity’s CAD.

“We have really fine-tuned the details for the mold, especially for bottles with some specific logos or things like lemon details, which require very high accuracy. The Formlabs machine, together with the Rigid 10K Resin, gives the possibility to have very fine details that can then be transferred to the real bottle,” Cademartiri said.

3D printed molds in Rigid 10K Resin are manually polished and then assembled into the metal frame.

With SLA 3D printing, a set of molds can be created in two days. 3D printed molds reduce lead times for starting pilot testing from six weeks to two weeks, while also enabling the creation of realistic pre-production parts that are very close to production quality and are molded using the same materials and machinery as the eventual actual production units. Furthermore, 3D printed molds allow operators to pilot test multiple designs simultaneously.

3D printed molds in Rigid 10K Resin are manually polished and then assembled into the metal frame.

Production of 200 parts	Machined metal molds	3D printed molds
Equipment	In-house CNC machine or outsourcing	Form 3L Rigid 10K Resin
Lead time for pilot testing	6-8 weeks	2 weeks
Mold tooling costs	$2,500-$10,000	$500-$1,000

“With 3D printed molds, we can save up to 70% of time and 90% of cost compared to standard molds. In the past, [customers] had to wait up to 12 weeks, just for one design. Now we can do five.”

Flavio Migliarelli, R&D Design Manager, Serioplast Global Services

Conducting such extensive testing with traditional methods would be virtually impossible. They would have to invest in metal molds for each design, with no benefit from economies of scale, and would never recoup the tooling costs.

From consumer testing to fine-tuning the production line

The 3D printed tooling is primarily used to produce samples for consumer testing. These samples are representative of the final product in terms of haptics, aesthetics, and functionality, and are perceived as real products in the eyes of the consumer.

“You can have the real bottle before you are making the real mold. So you can identify immediately if you are on the right path in your development, or if you need to change something to avoid a mistake that could be more costly.”

Stefano Cademartiri, CAD & Prototyping Owner, Unilever

Bottles produced with 3D printed tooling are virtually indistinguishable from final products produced through traditional metal mold processes. From left to right: Two-part mold 3D printed in Rigid 10K Resin, bottle produced with 3D printed mold in Rigid 10K Resin, bottle produced with metal mold, and labeled prototype bottle for consumer testing.

A secondary application of the modular molds is to validate the SBM process, including the PET preform that will be blown, by looking at the process windows, stretch ratio, and material distribution that can be achieved. Serioplast produces preforms in-house via injection molding. While some preforms are custom-made for a specific bottle, they typically work with standard off-the-shelf parts. The Serioplast team wanted to understand the range of capabilities available through this stock preform. Knowing this helps them determine if a given preform is suitable for blow molding a specific bottle before going into production.

“We are using the same process window as standard pilot molds. This is very good, because we can test the final process windows and see what happens with the bottle. We are talking about pressures up to 30 bar. It’s absolutely good and reliable on that. We are also talking about heating 100 °C for the preform without any kind of wear and tear on the 3D printed mold cavity. We can produce very easily 100, 200 bottles every day. We can go up to 1000 bottles with more time,” Migliarelli said.

A third application for rapid mold production is to test certain aspects of the production line early on. Because bottles molded with 3D printed molds are so close to the actual production units, they can be used to conduct some initial validation of the filling line, such as line movement, star wheel operation for bottle filling machines, capping, or robotic case packer operation. Early line validation helps plants anticipate spare parts, prepare the production line for mass production, and accelerate time to market.

Bringing better products to market faster

Cademartiri and Serioplast have already tested about 15 different bottle models with this new process.

With Formlabs SLA printers and Rigid 10K Resin, Unilever and Serioplast are able to reduce lead times by up to 70% and mold tooling costs by up to 90% to produce pilot runs of 200 pieces in as little as two weeks.

“In Formlabs, we found a very good partner, not only for selling machines but also for supporting us in discovering the properties of these materials. This partnership enabled me to identify the possibility of starting this path with 3D printed molds,” Cademartiri said.

This new workflow will enable Unilever to bring better products to market faster, and significantly reduce the risks and costs associated with packaging development.

“The big impact we have with 3D printers is the possibility to make your dreams come true. Something that is on your screen comes into your hands in a few weeks. A real product, with a real bottle, with a real cap, and a real label,” Cademartiri said.

Do you have questions about using SLA printers for blow molding or other engineering and manufacturing applications? Download our white paper for a detailed workflow, contact our solutions experts, or request a free sample part printed in Rigid 10K Resin.