Silicone is a relatively new material in 3D printing, though not due to a lack of demand as its mechanical properties are ideal for countless applications. The technology took some time to develop because silicone has a very high viscosity, making it difficult to extrude in a precise manner. Silicone is an elastomer, and unlike thermoplastics it cannot return to a liquid state after it’s been solidified.
An elastomer is a polymer with viscoelasticity (viscosity and elasticity); it’s the technical name for rubber. The first rubber came from the sap of hevea trees in the Amazon rainforest, which are now more commonly known as rubber trees. Rubber has a lot of things going for it, most notably of which is the fact that it can be stretched and will return to its original shape when released. Silicone, being a synthetic rubber, shares that trait but it boasts several other appealing characteristics as well, including:
Properties & Applications of Silicone
- Excellent thermal stability, up to 200°C and as low as -80°C, with certain formulations able to go higher and lower
- Repels water and is resistant to steam
- Ideal compression set for forming tight seals
- UV resistant
- Electrical insulator, even under water
- Tear resistant
- Transparent, ideal for optics
- Can be sterilized
- Flame retardant
- Food safe
Those properties lend silicone to be found in a wide range of industries, such as manufacturing, energy, food production and handling, automotive, aerospace, consumer goods, healthcare, electronics and agriculture. Everything from gaskets and tubes to keypads and switches are made from silicone rubbers. The sound dampening devices in cars and the black boxes in airplanes are also made from the material. That flexible non-stick bakeware in your kitchen can go in the oven, freezer, and dishwasher because it’s made of silicone. And your snorkel keeps water out of your nose thanks to silicone. With all these uses, it’s no wonder engineers wanted to be able to 3D print with it.
Silicone 3D Printing Companies
Wacker Chemie ACEO
The first company to achieve silicone 3D printing was Wacker Chemie, a global chemical company. They market their DOD (drop-on-demand) technology under the ACEO trademark. Their ACEO Imagine Series K LSR (liquid silicone rubber) 3D printer features a dispenser that can rapidly deposit and shear tiny drops of silicone into precise patterns without touching the object. A UV light cures each layer to solidify it before the next layer is deposited. ACEO silicones include no acrylates or urethanes so they’re true elastomers. And multi-material printing is possible because their K2 3D printers can work with multiple silicones at once. Support materials are dissolvable in water and parts are finalized with a vacuum post-cure treatment at 200°C for four hours.
ACEO Use Case
One of ACEO’s silicones is electrically conductive and can be used in all sorts of electronic applications, like sensors, heating elements, switches, and complex circuits. A real-world use case of the material is the CINOGY PlasmaDerm therapy device for wound care, where the electrically conductive areas are produced by ACEO. Here, the material needed to be biocompatible, electrically conductive, and flexible so it’s an ideal scenario for silicone 3D printing.
The adhesives company LOCTITE (Henkel) has also developed silicone 3D printing, though theirs is based on resin 3D printing. They’ve launched an open-source DLP 3D printer and a line of resin materials, meaning their silicone and other materials can be used on ‘any’ resin-based 3D printer. Henkel is also working with HP to develop materials for their 3D printing platforms.
Henkel LOCTITE Use Case
When a respirator manufacturer needed 100 translucent, tough but flexible 1.5-inch tubes, they received a quote from an injection molder for $19,000 to fabricate the molds. Oh, and it would take four weeks. But LOCTITE supplied the silicone resin to print the parts for only $19 each, ten times less than the injection mold quote. And the parts were printed and delivered in four days.
EnvisionTEC has both a 3D Bioplotter (that works like the ACEO machine) and a silicone resin 3D printer (like that of LOCTITE). They produce gaskets, biocompatible dressings, and surgical planning models.
EnvisionTEC Use Case
Their E-Silicone is predominately used for fabricating cocoon molds hearing aids. Medical-grade silicone can be injected into the molds to produce high-quality shells with improved acoustic sealing, more gain before feedback, and better retention.
PICSIMA’s silicone 3D printing technology works by using a 3D plotter to inject a catalyst into a vat of unpolymerized liquid silicone. Wherever the catalyst is applied, the silicone solidifies. Their method requires no support material because parts are supported by the liquid bath.
PICSIMA Use Case
Here, they 3D print a custom earbud in silicone.
Spectroplast Use Case
Using 3D printed silicone for soft robotics makes them more durable and flexible, and more geometries are unlocked as well.
The world of 3D printed silicone is growing just like metal 3D printing: rapidly. Curious about how 3D printing can benefit your business?
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