3D printing unlocks new applications for silicone materials

The daily maintenance of the German railway is a very headache for engineers.

With more than 100 years of railway history, there are more than 100 trains on the German railway network, and a wide variety of spare parts have become a heavy burden for the maintenance department. However, due to various reasons, some spare parts have been discontinued, and the parts supply chain has been severely broken. In order to solve the problem of the supply of parts, Deutsche Bahn AG thought of 3D printing technology.

3D printing technology has many unparalleled advantages of traditional injection molding. It can directly convert digital models into real objects without using any tools or molds, which can greatly shorten the process cycle and reduce production costs, especially for modeling or small batches. produce.

In 2015, Deutsche Bahn AG launched a company-wide 3D printing project, one of which was installed in the train brake control valve with a thickness of only 4 mm, which required very high strength and flexibility. In the repeated market screening process, Deutsche Bahn has selected WACKER's brand ACEO®, whose silicone materials and 3D printing technology meet the requirements of diaphragm products.

Why is ACEO® silicone material favored by the demanding Deutsche Bahn AG? How does silicone relate to 3D printing?

The name of silicone is polydimethylsiloxane, which is a general term for a class of polymers in which the main chain is alternately composed of silicon oxide atoms. According to Liu Lijun, senior technical manager of Wacker Chemicals, “organic silicon materials are derived from nature's silicon ore (sand). Compared to most synthetic rubbers derived from crude oil, silicones have a silicon-oxygen chain structure compared to carbon. The carbon chain has a higher bond energy and can withstand higher temperatures and environmental aging such as UV radiation. Its free-rotating side chain structure allows the material to remain soft in environments as low as -50 degrees Celsius. In addition, due to the absence of any plasticizer added to the formulation, silicone materials have good food safety and biocompatibility and can be widely used in food contact or medical devices, which is unmatched by many synthetic rubbers.

The superior performance of silicones is an important prerequisite for approval by Deutsche Bahn AG. Of course, this is also inextricably linked to Wake Chemical's advance layout in silicone 3D printing.

Create the world's first 3D printing elastomer service online store

The combination of 3D printing technology and silicone materials has made it impossible to meet the needs of many traditional injection molding applications, such as in the industrial fields of transportation or mechanical equipment and in the medical field. Rapid modeling, small batch production and on-demand production of spare parts are very important. .

Based on this market demand, Wacker Chemie exhibited at the 2016 Chinaplas, the world's first industrial silicone 3D printer, and a new business model – for all elastomers. 3D printing services created the ACEO® brand, so Wacker Chemie became the first company in the world to produce elastomers through 3D printing.

In order to promote the development of 3D printing technology, WACKER built a 700-square-meter additive manufacturing technology center near the Burghausen production site. “Unlike the rigorous WACKER traditional business, the atmosphere of the ACEO® team is very open,” said Liu Lijun.

The ACEO® sales model is also very different from WACKER's traditional business. Liu Lijun pointed out that "ACEO® 3D printing does not sell materials, equipment or software separately, we provide customized solutions."

The sales model of ACEO®3D printing service is mainly through the online store. Users can get in touch with the customer service personnel in Germany and upload the design drawings to the customer service server. The special development engineers will review the user's development needs and evaluate the solution. Sex. After the screening is passed, the development engineer prints out the product according to the design drawing, and finally delivers the product and the design plan to the user. The design plan is owned by the user himself.

In addition to this online store-based digital business model, WACKER also launched the "Open Print Lab", where customers can receive personal training on the site, which is the first in the industry.

Power automation revolution

The WACKER ACEO® campus in Burghausen is quiet, only to hear the hum of the copier-sized box. This buzzing box is the world's first industrial grade silicone 3D printer developed by WACKER engineers.

Since its inception, it has successfully turned many clever ideas into tangible objects, one of which is the robotic claw developed by Formhand in Braunschweig, Germany. The elastic clamp is made of silicone and uses WACKER ACEO® 3D technology.

This inconspicuous part is only one thumb size and shaped like a cylindrical container: the top is closed, the bottom is open, and the interior is hollow. However, although it seems to be unremarkable, it is the result of many years of hard work, courage and perseverance.

According to the technology inventor Holger Kunz, "That night, my entrepreneurial partner Christian Löchte mentioned this unresolved problem at the time: how to develop a robotic grip that can pick up very thin materials." It can be used to grab any object that needs to be moved, saving the company a lot of time and cost for retrofitting the automatic control unit. After determined to put the idea into practice, Kunz came to WACKER and hoped to expand the application of the product. His USB flash drive contains an electronic version of the blue silicon cap design, which is a sketch of a new size adsorption pad. The purpose of developing this new shape is to enable the vacuum gripper to grasp eight objects of similar size to table tennis and move it to another position.

With the help of the ACEO® team, Kunz's vision became a reality. “Here, we can see another advantage of 3D printing in practice, namely prototyping. The 3D printing process can help amateurs and startups like Formhand to quickly produce unique parts and, most importantly, cost. It is also relatively low," said Seitz, mechanical engineer at ACEO®.

Expanding the application of medicine

In addition to industrial application development, the combination of good biocompatibility of silicones and customized features of 3D printing technology has helped Wacker Chemie expand its application market in the medical field.

According to Liu Lijun, customized anatomical models have significant advantages in today's medical applications. They are useful in clinical training, surgical plan visibility and simulation, condition notification, and simulation in medical device development, and can be used as a custom model for precision prosthetics.

Silicone elastomers offer excellent flexibility and elasticity, and can be cut and stitched, especially for copying soft tissues such as blood vessels, heart, muscles or skin, while ACEO® silicone-based “on-demand inkjet” The technology can be used to print complex three-dimensional anatomical models, and the combination of the two makes the fidelity of simulated biomechanics reach an unprecedented level.

3D printed silicone anatomical models play an increasingly important role in clinical applications, universities and research institutions.

According to Egbert Klaassen, Director of Global Marketing at ACEO®, “The anatomical model printed with true silicone elastomers demonstrates the ultimate fidelity of anatomical models. WACKER works with experts from universities, clinics and research institutions. A basic product line including vascular, aortic arch, aortic valve and tricuspid valve models has been developed and is planned to be promoted in the mass market."

It is understood that a series of models developed by WACKER and the University of Erlangen-Nuremberg are now officially available.

Liu Lijun, who is in charge of the ACEO® China market, said, “The current Chinese medical market has great potential, but Chinese users have low awareness of silicone materials and the market still needs to be expanded.”

At present, the ACEO® team is working hard to open up the Chinese medical market. Its silicone 3D equipment debuted in Germany at the China International Import Expo, which was just concluded, attracting a large number of industry people. "I believe that with the deepening of the understanding of silicone elastomer materials in the medical industry, silicone rubber will become more and more widely used in the medical industry," said Liu Lijun.