PUprint revolution in 3d printing

As a specialist in thermoset Polyurethane resin formulation, Synthene’s strength is to benefit from its extensive expertise in the fabrication of rapid prototyping resins and  injection-moulding thermoset PU rubber.

This opens the door to adapting injection and molding elastomers into two-components 3d-printable PU products.

We obtain mechanically strong and functional parts, with a high structural integrity. The PU part is as strong as a molded part, that can be used not only as a prototype but also as a final part with high durability.

The PUprint materials are 2K thermoset polyurethane elastomers.

Unlike TPU (Thermoplastic Polyurethane), thermoset materials benefit from a very stable chemical structure, providing high performance and durability.

The chemical nature of thermoplastics and thermoset plastics is different. When exposed to high temperatures, TPU are subject to melting. A thermoset polymer will often show a higher temperature resistance. When exposed to very high heat, the material will be degraded, but is not likely to melt.

The 2K PU part also shows better isotropy with similar properties in all printing directions.

This range of thermoset PU for printing is completely different from Stereolithography, Digital Light Processing or Selective Laser Sintering.

With the technology of Material Extrusion (MEX), a two-component liquid polyurethane is printed on the build plate of the 3D-printer.

The process is somehow similar to FDM, with some major differences, particularly about the printing head involving two pumps and a static mixer. No filaments are used in the process and the material is not melted.

Instead, 2 syringes with liquid materials are plugged on the top of the printing head, compressed air push these materials through the pump that precisely dose the requested material quantity. Once pushed, the material get mixed into the static mixer to initiate the chemical reaction. It is then printed through the nozzle and on the build plate.

The deposition of material, layer after layer, involves a chemical reaction between each stratum, creating a strong bonding and adhesion. The 3d-printed part is therefore highly isotropic. Its durability is remarkable compared to photopolymerizable systems like SLA or DLP.

Yes, the PUprint system can be used in combination with support material, to get full printing possibilities.

The machine contains several nozzles, one for the thermoset PU product and another one for the support material. The two printing heads are alternating during the printing process to extrude the part layer by layer.

Additive Manufacturing opens the field of possibilities in terms of project realization.

First, it allows one to create an infinite combination of shapes, without the restrictions imposed by injection-moulding.

It is also a way to get rid of the tooling material. An aluminium mold often represents a high cost in a project budget, and often involves a certain rigidity in terms of design and flexibility. A silicone mold allows more possibility to change, but has a limited lifetime. 3D-printing polyurethane is therefore a more cost-efficient solution, that allows more creativity in the testing process and in the production phase.

The advantages that Additive Manufacturing brings to the equation are endless. The production process is more environmental-friendly with no tooling material and less waste: each drop of PU material is carefully used during the printing process.

It is also possible to print lighter parts, by optimizing the infill rate of material inside the part. The same STL file can be used to make parts with different hardnesses and lightness by using the slicer.

The use of a 3d-printer can indeed allow specific shapes that are technically not possible with the process of injection moulding, thus increasing the possibilities tenfold, without compromising the mechanical performance.

Another asset of this technology is to reduce the number of parts in a mechanical assembly.

This unique technology is the fruit of a close partnership between Synthene and Lynxter, a French company that manufactures 3D printers capable of printing polyurethane and silicone. Our PUprint resin is specifically formulated for their machines. The printing process perfectly adapts to the deposition of two-component liquid materials, with the possibility to use a support material.

The PUprint system is ideal for high-tech, high-demand industries looking for the agility of 3D printing without compromising on mechanical performance and wearproofness. It can be used in any sector, all the more that it is not dedicated to the prototype field only.

Because it delivers properties equivalent to traditional industrial casting polyurethanes, it has become a go-to solution in the following sectors:
– Automotive & Transportation: for fluid-resistant under-the-hood parts, custom seals, bellows, silentblocks, or short-run interior components
– Aerospace: for lightweighting initiatives through complex lattice structures (impossible to mold) and for functional cabin parts
– Robotics & Industrial Tooling (MRO): for custom robotic grippers that won’t mark delicate parts, as well as high-abrasion-resistant wear parts like rollers and gaskets
– Defense & Security: for shock-absorbing tactical equipment and operational maintenance, allowing spare parts to be printed directly on-site and on-demand
– Medical & Paramedical: for custom parts that are not in contact with human body, offering superior tailored comfort and durability compared to other printing technologies

To sum up, if you need to produce functional, flexible to semi-rigid parts with high fatigue and thermal resistance, and traditional molding is too costly or complex for your production volumes, PUprint is the ideal technology for your application.

The printing speed of the SYNTHЭD+ PUprint system is adjustable. It can be configured to approach the speed of standard rigid FDM printing, making it a highly productive option for reactive manufacturing.

PUprint allows you to print at a fast pace while maintaining a completely satisfactory level of precision. This balance makes it highly effective not only for standard components but also for smaller, intricate parts. It provides a reliable, efficient alternative when you need to produce functional elastomer parts rapidly without the lead times and technical contraints of traditional molding.

Yes, there are several ways to see the PUprint system in action:

At trade shows: Synthene exhibits every year at FORMNEXT in Frankfurt. On our booth you can see live printings demonstrations.
We are also showcase our technology at several trade shows worldwide, either directly or alongside our official distributors.

At our facility: You are welcome to visit the Synthene factory in France upon request. We have a Lynxter S300X machine on-site and we can print functional parts directly during your visit.

Online: you can also watch printing videos of thermoset PU on SYNTHENE’s official LinkedIn and YouTube channels.

Yes, we offer custom, in-house 3D printing services. If you have a project in mind, simply send us your STL files. Our technical team will review your designs, assess the manufacturing feasibility, and provide you with a tailored study and quote.

Because our material is a thermoset polyurethane, achieving its peak mechanical and thermal stability requires a thermal post-curing process in the oven.

Unlike standard thermoplastic FDM printing, where parts achieve their final properties immediately upon cooling, thermoset materials rely on a chemical cross-linking network. Post-curing the printed parts in an oven is a mandatory step to fully mature the polymer chains and unlock the product’s ultimate performance specifications (such as tear resistance, elasticity, and temperature limits).

To obtain the full properties of the materials as indicated in the TDS, we recommend to carry out the folloowing post-curing process: 16-24h at room temperature (23°C -10-30% R.H.) + 7h at 40°C + 12h at 100°C + 24h at 23°C.

Due to the exceptionally high abrasion resistance of thermoset polyurethane elastomers, machining parts with a hardness below 90–95 Shore A is highly complex. Because the material is flexible, it tends to flex and deflect rather than shear cleanly under standard cutting tools.

However, certain specialized machining professionals with specific expertise in elastomers are capable of successfully performing cutting and machining operations on these parts.

To ensure the best workflow, we highly recommend accounting for all your final tolerance and geometric constraints directly within your CAD design. Leveraging the design freedom of 3D printing from the very beginning is the most effective way to minimize or eliminate the need for post-machining.

Due to the layer-by-layer nature of this additive technology, visible layer lines are a standard characteristic of the printed parts.

At Synthene, our technology and material formulations are engineered first and foremost for functional, high-performance applications. We have made a deliberate choice to prioritize industrial durability, mechanical strength, and elastomeric integrity over purely cosmetic smoothness.

While the as-printed surface finish is perfectly suited for technical and industrial environments, post-processing workflows to enhance aesthetics are currently being optimized and can be evaluated depending on your specific project needs.