German scientists have used three-dimensional printing technology to print out some very sophisticated objects, including a pretzel. In the future, this technology may be used for more useful things in 3D printing, such as composite lenses, filters and even decorations that usually require highly skilled craftsmen.According to a study published today in the Journal Nature, researchers used a "liquid glass" to make complex shapes that are smooth, transparent and have very high resolution. More importantly, these glasses are made with standard, ordinary 3D printers. But the technology also requires a high-temperature oven, which you may not need to use when baking cakes at home. In any case, this study opens up the possibility of using one of the most revolutionary technologies of our time to make very important materials.Now, 3D printers can be used to make everything from shoes to aircraft components. Of course, the materials used are different, usually plastic, but sometimes metals and ceramics are also used. Glass has some unique properties, such as high hardness, durability, heat insulation and insulation. It is the key material for making high quality lenses for glasses and cameras. But this material is difficult to use in 3D printing because it melts at very high temperatures.Bastian Rapp, a researcher at the Karlsruhe Institute of Technology, said: "Glass is one of the oldest materials known to mankind. It has been ignored by the 3D Printing Revolution in the 21st century."Scientists have previously printed glass objects in 3D. MIT scientists have made transparent glass with a special 3-D printer that can raise the temperature to 1900 degrees Fahrenheit (1038 degrees Celsius). Scientists in other places have also made attempts in this regard. As a result, the glass products produced are not very strong and transparent. But according to Leip, the technology mentioned in today's study published in Nature is somewhat different, because it uses 3D printing technology that is already very popular.The secret is the materials used by Leip and his team. The "liquid glass" they use is a mixture of glass powder and liquid polymer. Specifically, a standard 3D printer prints out objects using liquid glass. The glass particles will melt together and become transparent when they are treated in a high temperature furnace. Researchers have used this technology to create objects such as castle gates, pretzels, and millimeter-scale honeycomb structures. If a 3D printer with higher resolution is used, the resolution of the items produced by this technology will also be higher. These items can also withstand 1472 degrees Fahrenheit (about 800 degrees Celsius)."This allows us to use one of the oldest materials with the most amazing optical, mechanical and physical properties to have an artistic appearance with the processing of modern 3D printing devices," said Leip. Our goal is to fill the material gap.Leip said the technology could be used in the future to print composite lenses in smartphone cameras in 3D and components of next-generation microprocessors. But its application potential is infinite, from glass ornaments to glass panels of various complex shapes used in buildings can be manufactured.