HPF The Mineral Engineers, a division of German minerals company Quarzwerke Group, is reportedly working on developing functional fillers for 3D printing. According to Compounding World, mineral fillers for additive manufacturing materials could lead to faster and higher-quality printing.
For those not well-versed in plastics and compounds, mineral fillers are a common ingredient in polymer compounds, and they can be used for many ends. Often, mineral fillers are incorporated into polymer materials to reduce the cost of the material.
Perhaps more interestingly, certain mineral fillers can be added in order to modify and improve the properties of a material. Dubbed “functional fillers,” these mineral-based materials can be used to increase the stiffness or strength of a polymer material.
The plastic molding compounds industry typically uses such minerals as calcium carbonate, talc, silica, wollastonite, clay, calcium sulfate fibers, glass beads, alumina trihydrate, and more as fillers.
Péter Sebö, the head of marketing and market development at HPF The Mineral Engineers, spoke about his company’s 3D printing filler research at the AMI Compounding World Congress this past April and explained that HPF was working with various 3D printing technologies, including fused deposition modeling (FDM) and stereolithography (SLA).
Notably, both 3D printing methods use polymer-based materials, making them suitable for use with mineral fillers. For FDM 3D printing, the company explored using mineral fillers like wollastonite, mica, kaolin, and others with ABS polymers.
Part of the research depended on finding the right particle size, shape, and surface modification for the minerals in order to make them usable for 3D printing filaments. And one of the most important aspects of developing the mineral fillers for FDM 3D printing was “constant grain size distribution.” This, explained Sebö, is due to the diameter of the die.
For stereolithography 3D printing, HPF has been working with epoxy and acrylic based photopolymers. Soon, it says it will begin exploring new FDM materials including PLA, PA6, and PA12, and will even begin research on producing mineral fillers for selective laser sintering (SLS) 3D printing.
So far, HPF has developed a number of hybrid filler blends for 3D printing, each with specific properties. These filler materials are already available for resin and compound producers, as well as for filament extruders. The mineral fillers are said to decrease risks of shrinkage and warpage in 3D printed parts.
Still, there is work to be done, as Sebö indicates that HPF is currently working on improving the “mechanics of the final part and the adhesion of the [3D printed part’s] layers.” For this, HPF is currently seeking to establish partnerships with polymer materials manufacturers.