For engineers and researchers working at the intersection of optics, microfluidics, and precision manufacturing, one limitation has persisted for years: truly transparent 3D printing at the micro scale has been out of reach. Existing options either fall short on optical clarity, require extensive post-processing, or simply can’t achieve the feature resolution that demanding applications require.
That changes today. Boston Micro Fabrication is launching BMF Clear — an ultra-high-transparent photopolymer resin engineered specifically for micro-precision 3D printing, delivering greater than 90% light transmittance alongside the micron-level accuracy that BMF’s platform is known for.
The Optical Clarity Challenge
Achieving true optical clarity in 3D printed parts is not simply a matter of using a clear material. At the micro scale, two physical phenomena work against you: material absorptivity and surface roughness. Even minor imperfections in surface finish cause light to scatter and diffract, which can reduce transmission performance in applications like optical waveguides, microfluidic channels, and integrated photonic devices.
BMF Clear has been formulated and optimized specifically to address both of these challenges. The result is a material with industry leading transparency — not the translucency that “clear” resins have historically delivered — combined with the superior surface quality achievable through BMF’s Projection Micro Stereolithography (PµSL) technology.
BMF offers an ultra-high-transparency material with greater than 90% light transmission and a refractive index of the printed/fully cured material of 1.5375 @ 589nm. This combined with the superior surface finish provides an unmatched solution for micro-precision transparent components.
Understanding Haze and Geometry
Independent testing under ASTM D1003 using 400-780nm light source and a 0.1mm thick samples measured a haze value of 5.45% for BMF Clear — a result that’s worth understanding in context. Haze relevance depends heavily on geometry and optical path. Flat surfaces — the top and bottom faces of a printed part — are formed directly against BMF’s smooth membrane/window interface, replicating a glass-like finish with excellent clarity straight off the printer. Curved and vertical sidewalls behave differently: even at fine layer thicknesses, some degree of layer stepping is inherent to any additively manufactured part, even at micron-layers which can scatter light and increase apparent haze on those surfaces.
For many micro-scale applications — microfluidic devices, light guides, transparent housings, inspection features, fluid chambers, and medical device prototypes — this distinction works in BMF Clear’s favor, since the relevant optical path (observing fluid movement or internal geometry, for example) typically runs through the flat top and bottom faces rather than the sidewalls. For applications that demand true image-forming performance — low-scatter waveguides or high-sensitivity optical sensing, for example — geometry, wall thickness, curved surfaces and orientation should be evaluated for the specific part in question.
Platform Compatibility and Post-Processing
BMF Clear is designed for seamless integration with BMF’s 10-micron and 25-micron systems, printing at layer heights between 10 and 50 microns. Compatibility spans BMF’s full platform range — from high-end production systems to the compact, benchtop microArch® S150 series — making it accessible whether you’re running a research lab or scaling toward production.
The combination of ultra-high-resolution printing and BMF Clear’s material properties supports fine feature fidelity and strong optical performance on flat and near-flat geometries straight from the printer, without mandatory post-processing. For parts with curved or sidewall surfaces in the optical path, secondary finishing may further improve apparent clarity, and BMF can work with customers to evaluate options on a case-by-case basis as part of ongoing application development.
Applications Unlocked
The more significant implication of BMF Clear is what it unlocks for applications that have historically been difficult or impractical to manufacture at scale.
Microfluidics and lab-on-a-chip development. Transparent perfusable channels enable precise visualization and analytical reliability — critical for applications like high-resolution droplet generation and cell culture assays. Until now, many researchers have relied on PDMS soft lithography, a method that limits scalability, durability, and design flexibility. For teams specifically exploring PDMS alternatives for microfluidic fabrication, BMF Clear offers a compelling path: the design freedom of additive manufacturing, the dimensional accuracy of micro-precision printing, and none of the mold-making overhead.
Micro-optics, photonics packaging, and optical sensing. BMF Clear combines high optical transparency with micron-scale manufacturing precision, making it well suited for transparent micro-scale components such as optical alignment features, sensor housings, microfluidic devices, lens mounts, and photonics packaging structures. Its ability to produce complex geometries and fine features enables rapid prototyping and low-volume production of components that are difficult or costly to manufacture using conventional methods. For applications involving light transmission, imaging, or optical sensing, application-specific testing is recommended to validate performance for transmission, scattering, and other optical requirements.
Biomedical devices. BMF Clear has passed rigorous biocompatibility testing for skin irritation, sensitization, and in vitro cytotoxicity, opening additional possibilities in device miniaturization — including endoscopic systems, intraocular tools, and minimally invasive drug delivery applications where internal visibility and dimensional fidelity are non-negotiable.
From Prototype to Production
One of the more practical advantages of BMF Clear is that it doesn’t just serve early-stage research. By pairing Ultra-high-transparency with micron-level precision and BMF’s established manufacturing platform, it provides a credible path from proof-of-concept to scalable production. As John Kawola, CEO of Boston Micro Fabrication, puts it: “BMF Clear resin directly addresses this challenge, bridging the gap between prototyping and production-level micro-manufacturing.”
That bridging capability is what makes this more than a materials announcement. For teams working on next-generation optical components, microfluidic devices, or integrated photonic systems, it represents a meaningful expansion of what’s achievable with additive manufacturing.
Intersted in learning more? Check out our on-demand webinar, Engineering with Clear Materials: Applications, Tolerances, and Design Considerations in Micro-Precision 3D Printing.
