Formlabs Functional Prototypes and Small-Batch Production Case Study
Form 4L and Tough 1500 Resin Conquer the Mint 400 Desert Off-Road Race
Sirris used large-format SLA 3D printing to design, functionally test, and produce end-use fork guards for an electric off-road motorcycle in just a few weeks.
In 2024, electric off-road motorcycles were allowed to compete in the 120-mile Mint 400 off-road race for the first time. Sirris, a pioneering manufacturer of high-performance suspension systems for electric off-road motorcycles, needed to upgrade the motorcycle's fork guards to cope with the harsh desert terrain.
With limited time for prototyping and production, Sirris ultimately chose 3D printing technology. By combining robust and durable Tough 1500 Resin with the Form 4L large-format stereolithography (SLA) 3D printer, they were able to avoid the high initial investment in molds.
“The truly unique part about this project is the speed from concept to execution. Another similar project might take six to twelve months, but this project went from ideation to race in just a few weeks.”
Josh Doolittle (Creative Director, Sirris)
“We can now bridge the gap between prototyping and full-scale production, delivering functional parts to customers without waiting for molds.”
Jon Howard (Co-founder and Operations Manager, Sirris)
Accelerating Functional Prototyping with the Form 4L
Off-road motorcycles require a precisely engineered suspension system to handle rugged terrain, jumps, and heavy impacts. Fork guards protect the fork tubes from flying rocks and debris, preventing seal damage, oil leaks, and suspension failure.
Therefore, fork guards need sufficient strength, flexibility, and impact resistance to withstand flying rocks, collisions, and sustained vibrations on desert courses.
Why switch from FDM and SLS to SLA?
Sirris initially attempted to prototype with Fused Deposition Modeling (FDM) and had previously used Selective Laser Sintering (SLS) 3D printing. However, parts produced early with SLS or FDM could not pass the functional tests for off-road motorcycles.
SLA parts possess uniform and isotropic mechanical properties, reducing performance variations due to print direction. When combined with tough and durable engineering resins, they are even more suitable for high-impact and real-world load functional testing.
“With 3D printing technology, we can immediately get functional prototypes. Our products need to withstand harsh off-road environments, and the ability to iterate based on real test results in days, not weeks, is extremely crucial.”
Jon Howard (Co-founder and Operations Manager, Sirris)
Achieve multiple design iterations per day
Formlabs' large-format SLA 3D printer, the Form 4L, offers ample build volume, allowing for the production of one pair of fork guards in a single print.
Its high-speed printing capability enabled Sirris to perform 2-3 design iterations per day, allowing them to immediately mount the parts onto the motorcycle for off-road testing after printing was complete.
This rapid iteration process allowed Sirris to verify the fit, durability, and functional performance of the parts in a very short timeframe.
“The Form 4L is only showing us the tip of the iceberg of what we can do. The ability to customize and iterate quickly gives us a significant advantage in the market.”
Jon Howard (Co-founder and Operations Manager, Sirris)
Tough 1500 Resin: Superior Durability for Racing
Tough 1500 Resin combines impact resistance and flexibility, providing the high durability required for real-world applications.
Sirris initially prototyped with Tough 1500 Resin. When an upgraded version of Tough 1500 Resin was released in March 2025, the team transitioned to the higher-performance V2 material.
The mechanical properties of Tough 1500 Resin V2 are comparable to polypropylene (PP), with fracture toughness 10 times that of Tough 1500 Resin V1 and Gardner impact strength three times that of the previous generation, meeting Sirris's stringent demands for high-impact parts.
By leveraging this highly durable material, Sirris was able to not only produce functional prototypes but also directly manufacture custom parts and small batches of end-use parts.
Withstands flying rocks, debris, and collisions in desert off-road environments.
Reduces the risk of rigid parts breaking due to repeated vibrations and impacts.
Ideal for custom products, small-batch production, or functional parts requiring continuous specification adjustments.
Small-Batch Manufacturing Directly Replaces Initial Tooling Costs
Injection molding requires a significant upfront investment in mold manufacturing. Depending on part complexity, mold costs can range from $6,000 to $28,000, in addition to long manufacturing lead times and minimum order quantity (MOQ) restrictions.
Sirris needed to produce approximately 50 fork guards per week, and designs could also be continuously adjusted based on test results. For such needs, direct 3D printing allows for reduced upfront risk and ensures flexibility for rapid design changes.
| Manufacturing Method | Lead Time | Design Change Flexibility | Material Used |
|---|---|---|---|
| 3D Printing with Form 4L | Approx. 1 day | Direct modification possible before each print | Tough 1500 Resin |
| Injection Molding | Approx. 8-10 weeks | Difficult, expensive, or impossible to modify | Polypropylene (PP) |
“Thanks to 3D printing technology, we can now produce protectors on demand without waiting for molds to be completed. The print time per batch is about 13 hours, so we can meet small-batch production demands in days, not weeks.”
Jon Howard (Co-founder and Operations Manager, Sirris)
120 Miles of Grueling Racing: Real-World Testing at Mint 400
The Mint 400 is one of the toughest off-road races in the US, covering 120 miles of rocky, gravel-strewn desert terrain.
In 2024, electric off-road motorcycles participated in this race for the first time, with some vehicles equipped with custom-made Sirris F43 forks and 3D-printed fork guards.
Post-race inspection revealed no significant wear on the fork guards after 120 miles, proving that parts made with Tough 1500 Resin successfully withstood the harsh challenges of the desert course.
“Formlabs' 3D printing technology allowed us to produce custom plastic fork guards. This crucial part not only supported the bike's entry into the race but also played a significant role in its successful completion of this landmark race.”
Jon Howard (Co-founder and Operations Manager, Sirris)
Future Outlook: Leveraging More Materials and Manufacturing Methods
Following the successful production of custom suspension parts using the Form 4L, Sirris is further expanding its custom manufacturing options.
The team is exploring part manufacturing using Nylon 12 Tough Powder and Selective Laser Sintering (SLS) technology, as well as researching mold manufacturing using Rigid 10K Resin to support small-batch production.
By combining different manufacturing methods such as SLA, SLS, and 3D-printed molds, Sirris is establishing a more flexible digital fabrication process tailored to part requirements, material properties, production volume, and lead times.