Silicone has been the undisputed champion material for medical applications for more than fifty years. This inert, flexible and resilient polymer possesses unique properties that have made it a staple in everything from contact lenses to surgical implants.
However, working with silicone has always proved notoriously tricky due to its chemical makeup. Traditional manufacturing methods like injection moulding require complex tools and processes that restrict geometric freedom. This has limited silicone’s full potential – until now, thanks to the development of Silicone 40A Resin by Formlabs for its LFS 3D printers.
The Form 3, Form 3+, Form 3B, and Form 3B+ with the Form 3/3B Resin Tank V2.1 can fabricate intricate structures once impossible to produce by harnessing ultra-fine lasers to solidify liquid silicone layer-by-layer. This ground breaking capability stands poised to revolutionise the creation of medical devices.
Another game changing 3D printer range is the Lynxter S600D and S300X. These FFF 3D printers stand out with industry-leading technology – the S600D has a volumetric dosing pump system to precisely deposit two-part silicone beads layer-by-layer, and the S300X has an Independent Dual Extrusion (IDEX) system: the LIQ21 two-component for creating the main part and the LIQ11 single-component for water-soluble support structures.
We reveal all below.
Understanding SLA 3D Printing of Silicone
SLA 3D printing utilises a tank of liquid photopolymer resin selectively cured by a laser layer-by-layer to build a part. Silicone 40A contains photo-initiators that react to light wavelengths, causing the liquid silicone to solidify. Tracing each layer with ultrafine laser precision can produce even tiny complex structures.
After printing, silicone parts are then rinsed to remove excess resin, and finished.
Silicone 40A parts must be thoroughly washed in a solvent bath of 80% IPA and 20% n-butyl Acetate, and you must allow parts to fully dry before post-curing.
You post-cure parts in water inside the Form Cure according to recommended time and temperature settings. Post-cured parts will have a harmless odour that dissipates over time – this can be masked by adding Febreze HD to the water. Before applying adhesives, ensure the parts are clean and dry. Use a primer like DOWSIL 1200 before applying a silicone adhesive like DOWSIL 734 for the best bond.
Proper post-print processing is essential for Silicone 40A parts to achieve optimal mechanical properties.
Silicone 40A Resin
Silicone 40A Resin is the first accessible pure silicone 3D printing material, enabled by Formlabs’ patent-pending Pure Silicone Technology.
With superior stretch, rebound, and durability, Silicone 40A Resin produces flexible parts ideal for functional prototyping and low-volume manufacturing.
The chemical and temperature-resistant material enables applications like automotive seals, wearables, moulds, grips, and medical devices.
Compatible with the Form 3+ and Form 3B+ SLA printers, Silicone 40A Resin unlocks high-quality silicone 3D printing without casting or expensive silicone 3D printers.
Here’s how Silicone 40A Resin compares to another popular soft material, Elastic 50A Resin:
Silicone 40A Resin
- Softer and more flexible with 40A Shore hardness.
- Higher tear strength (12 kN/m) and elongation at break (230%).
- Better fatigue resistance (>500,000 cycles).
- Wider thermal stability range (-25°C to 125°C).
- Suitable for wearables and flexible consumer products, custom prosthetics and orthotics, human-machine interaction devices, soft moulds, and fixtures.
Elastic 50A Resin
- Harder, less flexible with 50A Shore hardness.
- More affordable and transparent.
- It is not as durable or as fatigue-resistant as Silicone 40A.
- Lower elongation at break and tear strength is expected.
- Good for early-stage prototyping like proofs of concept and looks-like prototypes.
Silicone 40A Resin is better for final prototypes, end-use parts, and applications needing durability and flexibility. Elastic 50A is suitable for early prototypes, prioritising low cost and transparency over functionality.
Understanding FFF 3D Printing of Silicone
Traditional fused filament fabrication 3D printing has limitations when working with silicone materials. FFF relies on heating and extruding thermoplastic filament, but silicone cannot be processed this way.
Instead, silicone parts are traditionally manufactured by injection moulding or casting processes, requiring extensive lead times and upfront costs for custom moulds and tooling.
FFF printing of silicone remained an unsolved challenge until Lynxter’s S600D system was introduced with a volumetric dosing pump to deposit two-part liquid silicone in layers precisely. The silicone has optimised rheology to hold its shape when printed, then crosslinks to become an elastomeric solid part.
The S600D unlocks new potential applications for the medical industry and streamlines production workflows. Patient-specific silicone parts like customised orthotics, prosthetics, or medical devices can be 3D printed on-demand. Lead times shrink from weeks or months with traditional processes to hours or days with the S600D. Healthcare providers gain the flexibility to iteratively refine and print devices to optimise fit and function.
The S600D’s precision dosing allows the mixing of customised silicone grades and durometers layer-by-layer within a single print, enabling digitally sculpted mechanical properties into the printed part, like strategically placing softer silicone onto weight-bearing areas of an orthotic. Healthcare providers can also validate and standardise devices by digitally storing and reproducing the exact 3D model file.
Overall, the S600D brings game-changing capabilities to fabricate complex customised silicone parts efficiently.
The S300X industrial silicone 3D printer enables free-form fabrication using elastomers like silicone and polyurethane. It features independent dual extrusion (IDEX) with two tool heads – LIQ21 for two-component printing of the main part and LIQ11 for laying down water-soluble support material.
This allows for unlimited design freedom and printing of complex geometries. The removable, hot-swappable, machined build surface, combined with a heated build plate (20°C to 160°C) and enclosure (20°C to 40°C), allows consistent printing of high-quality parts.
With a maximum build volume of 300 x 250 x 200 mm, high precision (12.5 μm XY resolution), and speeds up to 500 mm/s, the S300X is ideal for efficiently producing end-use silicone parts for industrial and medical applications. Its safety features, connectivity, and customisable firmware provide a reliable, industrial-grade 3D printing experience.
Transforming Medical Device Development and Manufacturing
The capability to rapidly 3D print functional silicone parts promises to transform every medical device development and production stage.
Silicone’s unique properties are ideal for short-run medical components like customised prosthetics and audiology products. Now, 3D printing further enables:
Faster Design Iteration
Engineers can print multiple design variations overnight rather than waiting weeks for outsourced injection moulding. Quickly testing prototypes leads to better product performance. Bespoke silicone parts tailored to patient anatomy, like prosthetic liners, are now viable to produce. This facilitates a shift toward personalised medicine.
Just-in-Time Manufacturing
Hospitals can quickly print emergency supplies like masks and tubing on-demand, saving lives during shortages. Less inventory waste also lowers costs. Silicone’s optical clarity is ideal for fabricating miniaturised diagnostic chip devices with complex internal geometries that are impossible to manufacture otherwise.
Improved Surgeon Training
Realistic 3D-printed silicone organs and tissues enable surgeons to practice procedures and develop skills safely and affordably before operating. This technology enables the rapid in-house production of short runs of intricate silicone parts catered to medical needs, creating a new way for surgeons to train.
The Future of 3D Printing in Medicine
Silicone additive manufacturing promises to usher in a new era in medical technology centred around customisation and on-demand production.
We see this unfolding in three ways:
Rapid Prototyping
Silicone 3D printing could enable medical companies to iterate and test new versions of products like wearables, grippers, and robotics components faster and for lower costs compared to traditional manufacturing methods.
Manufacturing Aids and Tooling
Companies that need custom manufacturing aids like fixtures or tools could benefit from printing them in-house on demand with silicone 3D printing, reducing machine downtime and costs compared to outsourcing custom silicone parts, which can take weeks.
Low Volume or Custom Manufacturing
Silicone 3D printing allows manufacturers to produce customised and personalised silicone products like wearables, grips, medical devices, etc., in low volumes.
Summing up
The introduction of silicone resins for SLA 3D printing marks a pivotal moment for the manufacturing of medical devices. Formlabs‘ Silicone 40A Resin provides an accessible and affordable way to produce highly elastic and intricate silicone parts with the geometric freedom of 3D printing.
Lynxter’s FFF contribution stands to transform how medical experts and engineers approach the design and prototyping of medical devices at scale.
This technology disruption will accelerate innovation in medical device design and manufacturing. Silicone’s unique properties of flexibility, durability, and softness perfectly match the needs of the medical industry, enabling the creation of novel devices and treatments to improve patient outcomes.