Rapid Liquid Printing: Redefining How We 3D-Print Large Objects
- Nathan Griese
- May 19
- 11 min read
3D printing has long promised quick, on-demand manufacturing, but in practice it often struggles with speed, size, and material limitations. Rapid Liquid Printing (RLP) is an emerging technique that addresses these challenges. Developed at MIT’s Self-Assembly Lab (with partners like furniture maker Steelcase) and now spun off as the company Rapid Liquid Print, RLP lets printers “draw” entire 3D shapes within a tank of gel. Instead of layering plastic or resin, RLP injects a liquid (often silicone, rubber, or foam) into a specially engineered gel bath. The gel holds each extruded line in place (as if in zero gravity) while the material cures. In minutes, a full-sized part emerges – no supports needed, no gluing, and minimal cleanup .
This gel-based process is dramatically faster than traditional methods and can use “industry-standard” materials like silicones and foams. In other words, RLP turns the printer bed into a supportive suspension. As VentureBeat describes, the printer “draws” a liquid object in 3D space within a container of engineered gel, holding the object in suspension (as if in zero gravity) while it cures. Because the gel supports overhangs, RLP eliminates the need for extra support scaffolds (and their tedious removal). The part simply solidifies in place and, once lifted out of the gel, it is ready to use after a quick rinse.
How Rapid Liquid Printing Works vs. Conventional 3D Printing
To understand RLP’s advantage, consider how it differs from common 3D printers. Fused Deposition Modeling (FDM) uses a heated nozzle to extrude plastic layer by layer, and SLA printers cure resin with lasers or LEDs, also building up thin layers. Both processes often require support structures for overhangs and tend to be slow for large builds. By contrast, RLP “draws” material freely in all directions because the gel bath holds each segment until it hardens.
In practice, an RLP machine works like this: A CAD model is sliced into 3D toolpaths, and a gantry system moves the nozzle through a tank of viscoelastic gel. As the nozzle extrudes liquid (silicone, rubber, or other fast-curing material) into the gel, the material instantaneously cures or crosslinks. The gel “self-heals” behind the nozzle, closing any path so printed lines stay in place. When printing is finished, the whole object – now solid – is lifted out. The suspension gel is simply rinsed away with water. There’s no blasting with heat or UV and no post-curing required.
This fundamentally changes the fabrication process. For example, BMW’s investment arm notes that RLP “eliminates the geometric constraints of traditional layered 3D printing” bmwiventures.com. Without gravity pulling on uncured material, you can print complex, soft shapes (even long overhangs or lattice structures) without collapse. A Steelcase/MIT demo showed a lattice-topped table printed in about half an hour – a job that took 50+ hours with standard 3D printing. MIT’s Skylar Tibbits reports parts printed in minutes instead of days, since the gel-supported lines cure almost as fast as they’re extruded steel.
In short, RLP trades layer-by-layer building for a free-form, gravity-free deposition. The gel suspension supports each line, effectively acting like an invisible scaffold. This yields printed parts that often have better structural integrity than if they were built in unsupported layers. As one review notes, RLP allows “the creation of complex, soft shapes that were thought to be impossible” by conventional methods, and the parts “become ready to use” immediately, with no extra work or wasted support material.
Advantages: Speed, Scale, Materials, and More
RLP’s strengths come in several key areas. First, speed. Because the printer isn’t slowing down to add and remove supports, RLP can operate at high rates. Reports show parts printing in minutes: an intricate table top in ~28 minutes, or a component in just 10 minutes that took ~50 hours on a different machine. VentureBeat notes that the nozzle is fed molten material like “opening a faucet” – once the flow is on, geometry prints very quickly. Studies with liquid metal RLP (a related technique) achieved at least 10× speedup over other metal AM process, illustrating the time advantage even when using molten aluminum.
Second, large scale. Because there’s no collapse risk, RLP can print very big. An example from BMW’s investor note: RLP has “the ability to print large objects, such as a hammock structure in an eight-feet diameter tank”. In theory, with a big enough gel tank, you could print an entire piece of furniture or car interior component in one go. This overcomes the size limits of desktop 3D printers and many industrial machines that cap out at meter-scale.
Third, material flexibility. RLP uses industrial-grade elastomeric materials (silicones, rubbers, foams) that are normally hard to 3D-print. FDM is usually stuck with PLA/ABS plastics, and SLA resins often aren’t very tough. But RLP can use any curable liquid that will set in the gel. BMW notes it can handle “soft rubber, silicone and foams” with properties akin to molded parts. In fact, the print materials are off-the-shelf polymers from known suppliers, yielding the expected softness and durability of genuine elastomers. This means parts can be used as functional prototypes or even end-use products, not just brittle models. The method even allows multi-material blending on the fly – printers can switch liquids to make parts with gradients of hardness or color.
Fourth, no support structures. We cannot overstate this: RLP requires zero internal supports. The suspension gel itself is 100% safe and reusable. When the part is done, you simply pull it out and rinse off the gel with water. There’s no cutting away scaffolds or chemical bath needed. The Rapid Liquid Print company calls it “Zero post-production. Zero waste.”. This saves not only time but also materials and labor, boosting overall efficiency.
Finally, customization and design freedom. Because objects are drawn in continuous curves, RLP often produces organically flowing, smooth geometries. Designers note that the printed “lines” have an almost natural, brushstroke quality. Think personalized lattice patterns or sculptural shapes that would be impossible to mold. Speed and material flexibility together enable on-demand customization (one of the big selling points of 3D printing in general). For example, a lattice cushion could be customized to a user’s ergonomics and printed in minutes rather than months of mold-making.
In summary, RLP packs speed, scale, and strength in one package. As Steelcase’s write-up puts it, the new process “breaks the three constraints of traditional 3D printing – slow speed, small size, and poor material quality”. By contrast to slow prototyping machines, RLP can mass-produce soft parts rapidly using familiar materials.
Real-World Applications
Because of these benefits, RLP has caught the attention of industries from furniture design to healthcare. Below are some notable examples:
Design & Furniture: Steelcase and designer Christophe Guberan demonstrated RLP by 3D-printing a customizable table top at Milan Design Week. Their Bassline table design took only ~28 minutes to print. RLP enables rapid tailoring of aesthetic patterns (e.g. lattice surfaces) for each customer. More broadly, RLP was initially pitched for interior design/furniture, letting firms produce one-off “3D printed furniture” without molds. The technique is well-suited to ergonomic lattice chairs or desks that blend style and function. As one lab researcher put it, RLP could use “materials with the same properties as real world products,” promising genuine comfort and durability.
Fashion & Consumer Goods: In a striking proof-of-concept, French fashion brand Coperni used RLP to print a silicone handbag. Dubbed the “Ariel Swipe” bag, it was printed in silicone underwater (within a gel) as a special Disney-themed edition. Rapid Liquid Print’s founder says the company now offers custom 3D-printed objects (like fashion accessories) from its Boston facility and will soon sell printers for such jobs. Footwear is another area – RLP’s investors explicitly mention “footwear” as a target, enabling custom insoles or shoe components printed in soft foam or rubber. Using RLP, shoe designers could fabricate test soles or midsoles without months of tooling.
Automotive: Car makers are interested in RLP, especially for soft components. BMW i Ventures led a funding round for RLP in 2021, noting that the process could 3D-print “large-scale, high-resolution, soft and stretchable products” like seat cushions. In fact, Rapid Liquid Print’s founders had already prototyped silicone seat cushions for BMW. More recently, Hyundai showed off “SPACE” adaptive seating at CES 2024, featuring 3D-printed lattice cushions made via RLP . These cushions – customized for comfort – were ready in minutes without any molds, tools or toxic processing steps. Even auto trim or gasket parts are in play: RLP can make flexible “bladders” or seals with multiple hardness zones. The key attraction for automotive is quick iteration on soft, large parts that are hard to mold.
Aerospace & Transportation: Though less publicized, RLP’s ability to print soft, complex parts appeals to aircraft interiors and related fields. For instance, custom flexible gaskets and seals for aviation could be printed on-demand. 3D Printing Industry notes RLP serving “aviation” needs. Envision on-demand inflatables, duct linings, or ergonomic panels in aircraft or trains. The technology’s scalability means large cab components (e.g. seat cushioning, panel padding) could be made as one piece. While airplane-grade materials require certification, RLP could prototype them quickly.
Healthcare & Wearables: This is a fast-growing domain. RLP’s strength in customizable soft parts is ideal for medical cushions and prosthetics. A standout example: Australian firm ProMotion Prosthetics uses RLP to print custom silicone liners for prosthetic limbs directly from patient scans. These liners (a kind of socket cushion) traditionally cost $360–500 and take weeks to make. RLP produces one in just minutes for about $250, dramatically cutting cost and delivery time. In one case study, a tailored 3D-printed silicone liner and even a myoelectric prosthetic finger (“i-digit”) were successfully created for an amputee using RLP. Other medical uses include custom inflatable bladders (for example, patient-specific cushions or respiratory devices). RLP can also print soft surgical models or orthotic devices in biocompatible silicones. In short, any healthcare component needing patient-specific geometry and elastic materials is a natural fit.
Art & Fashion Tech: RLP even blurs the line between industry and art. The early MIT/Steelcase tests involved designer Christophe Guberan, and one of his RLP-printed objects was acquired by MoMA. This shows that RLP can create iconic, bespoke items that last – the lab notes that an RLP-printed piece from five years ago still looks “impeccable” today. Fashion shows, furniture fairs, and design museums have featured RLP prints, highlighting its creative potential beyond pure function.
In summary, RLP is already raising eyebrows across sectors. Its fans include tech accelerators and magazines (it’s been covered by Wired, Fast Company, etc.), and the spin-off startup has reported customers in medical, automotive, aerospace, apparel and more. This wide interest underscores RLP’s versatility: from chair armrests and handbag prototypes to knee braces and car seats, the same gravity-free gel printing can apply.
Challenges and Limitations
Despite its promise, Rapid Liquid Printing is not a cure-all (yet). The process has constraints to be aware of:
Resolution and Surface Finish: RLP generally trades off fine detail for speed and scale. The extruded lines (often millimeters in diameter) don’t achieve the microscale accuracy of SLA or multi-jet printers. The MIT news on liquid metal RLP explicitly notes it “sacrifices resolution for speed and scale”. In practice, RLP parts have a characteristic tubular/striated texture; thin features below the nozzle diameter aren’t possible. For many applications (like cushions or frames) that’s acceptable, but it’s a limitation for highly detailed parts.
Material Scope: Currently RLP shines with soft, curable materials – silicones, urethanes, gels, certain waxes – that cure at room temperature or by catalysts. It cannot print rigid thermoplastics (like ABS/PLA) or metals without significant adaptations. A metal version (MIT’s “LMP”) is under research, but standard RLP systems focus on elastomers. Some biocompatible resins or catalysts might be adapted in future, but the material palette is narrower than the broad polymers of FDM. Designers should also note the final parts are inherently soft or semi-flexible. You won’t print a PLA gear wheel, but you might print a rubber-like gasket.
Post-Processing Needs: While supports are eliminated, there is a cleanup step: removing the gel. The reusable gel must be washed off (usually water-soluble) or drained out of internal channels. BMW’s documentation mentions simply rinsing with water, but for intricate lattice there may be trapped gel to clear. This step is trivial compared to dissolving support, but it is a process to factor in. Also, the gel itself, while reusable, will need replenishing or filtering after many prints, adding some consumable cost.
Equipment and Scale: Large-scale RLP requires a large tank of gel and a stiff gantry or robot arm. Current machines are still in the engineering/demo stage; there’s no off-the-shelf RLP printer (the startup is preparing one for release). Building and maintaining such rigs is more complex than buying a hobbyist FDM unit. For smaller businesses, the price point and form factor of RLP systems may be prohibitive at first. As of now, RLP services are mostly provided by the specialized startup or research labs.
Speed vs. Control: The process of extruding liquid in free space is inherently tricky. As one researcher noted, once the material is molten, controlling its flow is “like opening a tap”. This can lead to overshoot or difficulty with very fine movements. Engineers are still fine-tuning software paths and material viscosities to balance speed with accuracy. Until those kinks are fully worked out, extremely delicate or thin prints might be challenging to execute reliably.
Limited Mature Ecosystem: Finally, RLP is still emerging. There aren’t as many material suppliers, user communities, or proven design guidelines as with FDM/SLA. Designers and engineers may need to experiment more to understand the specific tolerances and best practices of RLP. (For instance, surface imperfections like tiny bubbles or layer seams can be different, and certain geometries may require special infill patterns in the gel.) Over time this will improve, but early adopters should be prepared for some trial and error.
In short, RLP isn’t a blanket replacement for all 3D printing. It excels at large, soft, complex parts – particularly prototypes or customized products – but it won’t obsolete fine-detail micro-printing or simple rigid parts anytime soon. For example, trying to print a thin plastic spoon with RLP would be silly; that’s better left to an FDM machine. Instead, RLP complements existing technologies, filling a niche where other methods falter.
Looking Ahead
Rapid Liquid Printing is still in its infancy but advancing quickly. The spin-off Rapid Liquid Print recently raised a $7M Series A to develop commercial machines. They’re also working on new models (e.g. the upcoming “Levity” printer) to bring RLP to market. Large investors (BMW, Germany’s HZG, etc.) and press coverage in outlets like Popular Science and Design Boom suggest the industry sees real potential.
Moreover, ongoing research at MIT is pushing RLP further. The Self-Assembly Lab continues to refine the process, experimenting with new gels, multi-axis robots, and even combining RLP parts with high-resolution components (for a hybrid approach). Other labs are exploring RLP-like ideas for bioprinting or composite materials.
As the technology matures, we expect to see RLP enter production workflows. For instance, a furniture company might use it to quickly 3D-print customized soft padding or connectors in their chairs. Automotive suppliers could print bespoke seals or custom-insulation panels on demand. Healthcare providers might offer tailored orthopedic or cushioning devices made via RLP right in the clinic. Even aerospace manufacturers could find uses in prototyping cabin interiors or ground-support equipment.
For 3D printing enthusiasts and professionals alike, RLP is an exciting new tool. It doesn’t replace FDM or SLA, but it breaks new ground by combining fast throughput with true industrial-grade materials. In the words of one RLP proponent, it “scales without the support struggles”, letting designers focus on ideas instead of engineering workarounds.
Michigan Prototyping Solutions (like many other prototyping shops) will be watching RLP closely. In an era where customization and speed are king, gravity-free 3D printing could unlock capabilities we’ve only dreamed of. As RLP moves from lab demos to real workshops, it may soon be one of the “conversational tools” – to borrow a term – that shape how products, apparel, and parts are made in the future.
Sources: The above draws on MIT Self-Assembly Lab descriptions and publications selfassemblylab.mit.edulink.springer.com, industry analyses 3dprintingindustry.com3dprint.com, and news articles covering RLP developments venturebeat.com3dprint.com.
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