Almost all sand used for 3D printing today comes from Central Europe and above all from Germany. But the Swedish sand works better than the Central European sand in 3D printing. This is stated by researchers from RISE and representatives from the foundry industry in a recently completed project. Using Swedish sand leads to lower costs, less environmental impact and higher quality of the products.
Since the first Swedish sand printer was installed in the RISE test bed for cast products, the technology has become well established in Swedish foundries and in demand by designers and designers of cast products. Within RISE, a network for industry has been formed to pursue common issues. One of the most important is to find economically and environmentally sustainable solutions for the most important raw material in the process, the sand. Another is to adapt technology and raw materials to Swedish conditions.
Swedish sand has many advantages
Almost all sand used for 3D printing today comes from Central Europe and above all from Germany. The reason is that the printers are manufactured in Germany and sold together with the sand used there. During the supplier's warranty period, the printer user - from a business point of view - is obliged to use the materials determined by the supplier. Now that the warranty period for the sand printers used in Swedish industry is about to expire, it opens up for a change of sand. In connection with this, the SANDBOX project has looked at the possibility of using Swedish sand in the printers instead, and the benefits are many.
– We tested Swedish sand in our printers during the project and it worked really well, says Robert Andersson, process technical manager at Volvo GTO in Skövde. The Swedish sand is of much better quality. Product quality improves, molds and cores become stronger and have better dimensional stability. In addition, we can reduce the binder content. Proximity to the supplier is another important factor for us.
The short transports will be more economical for the companies and it will of course also be a benefit for the environment
Fewer defects with swedish sand
The Swedish sand is mined at southern Lake Vättern and has the properties that the Swedish foundries demand. The grain shape, grain sizes and mineral content fit better than the European sand. The Swedish sand consists of 80% quartz and 20% feldspar, in contrast to the German sand, which consists of 100% quartz. The sand's content of feldspar makes the Swedish sand more flexible when you heat it up.
– When you heat the Swedish sand, it becomes a little softer and there are fewer cracks in the cores. The cracks can cause the metal to penetrate the core and then defects occur that must be cleaned away - and this is difficult because they occur inside the castings. These defects do not occur at all to the same extent in our Swedish sand as in the German quartz sand, says Ulf Gotthardsson, researcher and project manager at RISE. In the rest of Europe, the foundries add additives to the core sand to get the same properties that the Swedish sand has directly at the quarry, he continues.
The successful trials within the project have contributed to the Volvo GTO in Skövde now having replaced the sand and only using the Swedish in its printer. Sibelco, which manufactures and delivers the Swedish sand, also participated in the project.
– The foundries use the Swedish sand in other production and are thus used to working with it and it becomes more sustainable to buy a local sand. The short transports will be more economical for the companies and it will of course also be a benefit for the environment, says Niclas Raunegger, sales manager at Sibelco.
The SANDBOX project has been carried out by five companies together with RISE within SIP “Metallic Materials” and made possible through funding from Vinnova, the Swedish Energy Agency and Formas.
– RISE came out extremely well through this project, they were involved from the beginning in learning new technology and then it was obvious for us to be involved. For us, networking is also a big part of participation. We want to be the first to acquire knowledge about new technology, concludes Robert Andersson, process engineering manager at Volvo GTO in Skövde.