On May 23, 2019, WACKER Chem, a provider of silicone 3D printing solutions, shared a lecture on "Innovative Solutions for Silicone 3D Printing" at the 2nd Biomedical 3D Printing Development Summit Forum in Guangzhou. Hundreds of listeners at the scene benefited.
Knowledge background
Silicone is a kind of polymer elastomer widely used in the medical industry. Its biggest advantages are simple ingredients, safe and reliable, and good biocompatibility. Compared with other materials, it has unique advantages: compared with PVC materials, silicone materials can achieve a very soft effect without the addition of plasticizers; compared with latex materials, silicone materials have no risk of sensitization; Compared with thermoplastic elastomer materials, silicone materials have more reliable temperature and pressure resistance properties. At the same time, the silicone material itself has two solid and liquid forms, which are suitable for a variety of molding processes, and can well adapt to the complex and complex processing needs of the medical industry.
WACKER CHEMICAL is a supplier of silicone materials with a history of more than 70 years. It is also one of the companies that entered the development of silicones very early in the world. WACKER ACEO® 3D printing technology is the world's first industrial-grade technology for additive manufacturing of liquid silicone rubber components. With its unique "drop-on-demand" technology, ACEO® ensures full design freedom for printing highly functional parts while maintaining excellent properties such as high temperature resistance, radiation resistance and biocompatibility of silicone rubber . Silicone rubber components printed with ACEO® technology are widely used in many key industries such as automotive, aerospace, medical, equipment, and mechanical engineering.
In general, silicone molding mainly uses complex injection molding processes:
The manufacturer must first prepare the mold,
Liquid silicone rubber is then injected under pressure.
This method is too costly and is only suitable for large-scale production.
Silicone 3D printing enables a completely new part design:
It can cover different life cycles of products, and can directly convert digital models into physical objects without using any tools or molds.
This method reduces production costs, saves production time, significantly shortens the process cycle, and improves products quickly during product development. On the other hand, silicone 3D printing can also integrate functionally complex functional parts and prototypes.
By using support materials to produce complex structures such as eaves or holes, you can print three-dimensional objects layer by layer. After printing is complete, remove the object from the work platform and rinse the support material with water. The object is then secondary vulcanized to remove volatiles and achieve the final mechanical properties.
3D printed anatomical model in silicone
ACEO® 3D printing technology can be used to replicate human organs and make biocompatible silicone rubber components. The demand for such components in the scientific and medical industries continues to grow. Recently, the WACKER ACEO® team launched a series of anatomical models. It has developed a basic product line including vascular, aortic arch, aortic valve and tricuspid valve models with experts from several universities, clinics and research institutions, and plans to promote it in the mass market.
Anatomical models have significant advantages in today's medical applications. They are useful in clinical training, visibility and simulation of surgical plans, notification of conditions, and in the simulation of medical device development. They can even be used as customized models of precision prostheses. Because its appearance and touch are closer to the human body than other materials, anatomical models are playing an increasingly important role in clinical applications, universities and research institutions.
Silicone 3D printed dental applications
Recently, the dental laboratory of the Munich General Dental Prosthetics Hospital selected ACEO® in a project to further promote the application of artificial gums for additive manufacturing. Artificial gums are implants during the production of crowns. Both digital and physical imprints of the patient's mouth are available, but the softness and sensitivity of real gums cannot be digitally calculated. Therefore, creating a perfect crown requires a more realistic gum model, which should be softer than plaster and can change shape.
Silicone has properties similar to gums. They are impermeable and pass the Medical Category IIa test. They have different hardnesses and colors, so the shape and feel of the 3D printed parts are realistic. On the other hand, no subtractive manufacturing technology suitable for silicone processing has yet been developed. When acquiring data through a 3D intra-oral scanner, the only way to create a solid model is by milling or printing. ACEO® uses high-quality materials, is cured with ultraviolet light, and does not add plasticizers, so it does not affect the feel and mechanical properties. It provides the perfect solution for manufacturing artificial gums.
3D printed biological model
Biological models are medical engineering that explore anatomical structures and their characteristics. It can be divided into personal models and general models. Personal models can be used for purposes such as preoperative testing, prosthesis manufacturing, or corrective surgery. The general model is educational.
Surgeons such as hospitals and oral and maxillofacials are increasingly printing these models individually in 3D. To this day, the choice of 3D printed materials is still limited, so these models can only be used for limited purposes. At the same time, anatomical data provided by modern radiological programs such as magnetic resonance imaging (MRI) and computed tomography (CT) can also be used to create 3D printed silicone models.
3D printed biological models can be used to create organic structures with complex internal structures and have a wide range of applications. Silicone is also a great advantage because it is flexible, deformable, and easy to cut and stitch. With such models, doctors can show patients their internal organs and the treatments they need to take. For example, a surgeon can use imaging data to 3D print a patient's heart and preview surgical procedures under near-real conditions to predict and reduce unexpected problems during surgery.
Silicone 3D printed biological models based on MRI or CT data offer unlimited opportunities. In the future, various new applications will emerge endlessly. For example, 3D printed custom silicone breathing masks and hearing aids will soon be available.
Prospects and challenges
Silicone 3D printing is an emerging technology, but it has begun to be gradually applied, and it will become more and more widely used in the industrial field in the future. With the advantages of 3D printing being insensitive to complex shapes and eliminating the need for mold opening, more and more innovative designs are emerging and production efficiency has been effectively improved. The world is not only exploring the potential of 3D printing in prototype printing, small batches, and parts printing, but is also increasingly using the advantages of true 3D structures to achieve innovative designs, such as anatomical models, the use of lattice structures, and robotics Grab your hands and wait. Therefore, there is still huge room for development in silicone 3D printing.
However, the development of a new technology is always accompanied by obstacles. Due to insufficient market awareness of 3D printing and unclear qualification process standards, some low-performance products have appeared on the market, which has damaged the reputation of silicones. This is especially true for users who do not know about silicones from traditional processes. Therefore, professional organizations, industry associations and other organizations should actively solve the problem of standard setting for silicone 3D printing. Manufacturers should work closely with customers to use silicone 3D printing technology to make production more flexible and be able to respond quickly to different needs.