Formlabs Functional Prototypes and Small-Batch Manufacturing Case Study
Form 4L and Tough 1500 Resin Conquer the Mint 400 Desert Off-Road Race
Sirris used large-format SLA 3D printing to complete the design, functional testing, and production of end-use parts for electric off-road motorcycle fork guards in just a few weeks.
In 2024, the 120-mile Mint 400 off-road race opened to electric off-road motorcycles for the first time. As a pioneer manufacturer of high-performance suspension systems for electric off-road motorcycles, Sirris needed to upgrade the motorcycle's fork guards to withstand the harsh desert terrain.
Due to limited prototyping and production time, Sirris ultimately chose 3D printing technology, combining the robust and durable Tough 1500 Resin with the Form 4L large-format stereolithography (SLA) 3D printer to avoid the high upfront costs of molds.
"What makes this project truly unique is its astonishing speed from concept to execution. Similar projects at other companies might take 6 to 12 months, while this project went from idea to race in just a few weeks."
Josh Doolittle, Creative Director at Sirris
"We can now bridge the gap between prototyping and full production, delivering functional parts to customers without waiting for molds."
Jon Howard, Co-founder and Head of Operations at Sirris
Accelerating Functional Prototyping with Form 4L
Off-road motorcycles require precisely designed suspension systems to handle rugged terrain, jumps, and heavy impacts. Fork guards protect the fork tubes from rocks and debris, preventing seal damage, oil leaks, and suspension failures.
Therefore, fork guards must possess sufficient strength, flexibility, and impact resistance to withstand flying rocks, collisions, and continuous vibrations in desert racing conditions.
Why Switch from FDM and SLS to SLA?
Sirris initially attempted to use Fused Deposition Modeling (FDM) for prototyping and had previously used Selective Laser Sintering (SLS) 3D printing. However, early parts made with SLS and FDM failed the functional tests for off-road motorcycles.
SLA parts possess more uniform isotropic mechanical properties, reducing performance differences between different print orientations. Combined with tough and durable engineering resins, they are better suited for high-impact and functional testing under actual loads.
"3D printing technology allows us to immediately obtain functional prototypes. Our products need to withstand harsh off-road environments, and being able to iterate based on actual test results in days, rather than weeks, is crucial."
Jon Howard, Co-founder and Head of Operations at Sirris
Multiple Design Iterations per Day
The Formlabs large-format SLA 3D printer, Form 4L, offers sufficient build volume to produce a pair of fork guards in a single print.
With its high-speed printing capability, Sirris could perform two to three design iterations daily, installing them on the actual vehicle for off-road testing immediately after completion.
This rapid iteration process allowed Sirris to validate part fit, durability, and functional performance in a very short time.
"The Form 4L is just the tip of the iceberg of what we can do. The ability to rapidly customize and iterate gives us a significant advantage in the market."
Jon Howard, Co-founder and Head of Operations at Sirris
Tough 1500 Resin: Durable Enough for the Race
Tough 1500 Resin combines impact resistance and flexibility, providing the durability required for real-world applications.
Sirris initially used Tough 1500 Resin to create functional prototypes. With the upgraded Tough 1500 Resin launched in March 2025, the team transitioned to the higher-performance V2 material.
Tough 1500 Resin V2's mechanical properties are comparable to polypropylene, with 10 times the work to break of Tough 1500 Resin V1 and 3 times the Gardner impact strength of its predecessor, meeting Sirris's stringent requirements for high-impact parts.
With this durable material, Sirris can not only produce functional prototypes but also directly manufacture custom or small-batch end-use parts.
Can withstand flying rocks, debris, and collisions in desert off-road environments.
Reduces the risk of rigid parts breaking under repeated vibrations and impacts.
Suitable for customized, small-batch, and functional parts that may still be adjusted.
Small-Batch Manufacturing Directly Replaces Early Tooling
Injection molding requires significant upfront tooling costs. Depending on part complexity, mold costs range from $6,000 to $28,000, in addition to longer production cycles and minimum order quantity restrictions.
Sirris needs to produce about 50 fork guards per week, while designs may still be adjusted based on testing results. For such needs, direct 3D printing reduces upfront risks and maintains the flexibility to quickly modify designs.
| Manufacturing Method | Lead Time | Modification Flexibility | Material Used |
|---|---|---|---|
| 3D Printing with Form 4L | Approx. 1 day | Can be modified directly before each print | Tough 1500 Resin |
| Injection Molding | Approx. 8 to 10 weeks | Difficult, expensive, or impossible to modify | Polypropylene |
"With 3D printing technology, we can produce protective guards on demand without waiting for molds. A single batch takes about 13 hours to print, meaning we can meet small-batch production needs in days, not weeks."
Jon Howard, Co-founder and Head of Operations at Sirris
120-Mile Race: Mint 400 Field Test
The Mint 400 is one of America's toughest off-road races, covering 120 miles through rugged and sandy desert terrain.
In 2024, electric off-road motorcycles participated in this event for the first time, with some of them featuring custom Sirris F43 forks and 3D printed fork guards.
Post-race inspection revealed no significant wear on the fork guards after the 120-mile course. The Tough 1500 Resin parts successfully withstood the harsh demands of the desert race.
"Formlabs' 3D printing technology allowed us to manufacture custom plastic fork guards. This critical component not only helped the motorcycles compete but also ensured they successfully completed the challenge in this landmark race."
Jon Howard, Co-founder and Head of Operations at Sirris
Looking Ahead: More Materials and Process Applications
After successfully producing custom suspension parts using the Form 4L, Sirris is further expanding its customized manufacturing options.
The team plans to explore manufacturing parts using Nylon 12 Tough Powder and Selective Laser Sintering (SLS) technology, and will also investigate using Rigid 10K Resin to print molds to support small-batch production.
Through a combination of different processes such as SLA, SLS, and 3D printed molds, Sirris can establish a more flexible digital manufacturing workflow based on part requirements, material performance, production volume, and lead time.