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3D printing has long promised to solve a variety of engineering challenges. With its low startup costs, short lead times, and high level of geometrical freedom, additive manufacturing can help engineers find new and innovative solutions in prototyping and production.
Materials play a big role in the identification and execution of these solutions. However, few 3D printing materials are developed to fill a highly specific engineering need. Instead, most materials are designed to suit a range of applications and industries, promising broadly desirable attributes like tensile strength, printability, or flexibility. The few specialty materials on the market include products like ESD-safe powders and flame-retardant filaments.
Cologne-based plastics specialist igus is one company making 3D printing materials that solve a genuine engineering challenge. The bearings expert has developed a range of 3D printing filaments, powders, and resins with unique tribological properties. Solid lubricant additives make these materials exceptionally wear-resistant, giving them sliding performance unlike anything else on the additive manufacturing materials market.
This article serves as an introduction to 3D printing with wear-resistant plastics for motion and sliding applications, looking at why these products exist, how they can be exploited for maximum advantage, and the different technologies available for printing them.
In the not-too-distant past, 3D printing was considered first and foremost a prototyping technology. In some contexts, the term “rapid prototyping” was synonymous with 3D printing, with a focus on the speed and low cost-per-unit of the technology in small quantities. Today, additive manufacturing has reached a level of maturity where it is also considered a viable tool for production of end-use parts. This opens up many possibilities for engineers.
Several 3D printing materials are suitable for end-use parts. High-performance filaments like PEEK offer exceptional strength, while titanium alloy powders for powder bed fusion have been deployed in aerospace applications. However, in the area of moving parts like bearings, sliders, and rollers, only igus 3D printing materials have the wear resistance and low level of friction that can guarantee high performance over a long period of time. So, if an engineer requires both excellent sliding performance coupled with the inherent advantages of 3D printing — geometrical freedom, short lead times, one-off parts, and more — they require igus tribo-materials.
Before the development of igus 3D printing materials, the best options for sliding applications were nylons such as PA6 and PA66. However, the utility of these materials is limited by two factors. First, nylons have a higher coefficient of wear than genuine tribo-materials, giving them a relatively short service life. Second, they have substandard printability due to their hygroscopic nature: highly susceptible to humidity, they can produce printing defects if not fully dried before use. A better plastic for sliding applications is POM, but this material is almost impossible to print and is better suited to CNC machining, in which it does not need to be melted.
The benefits of 3D printable tribo-materials can be divided into two categories. First and foremost, there are the unique performance advantages of these specialist materials, such as the long service life for motion parts like bearings. Secondly, there are several important process advantages relating to the behavior of the material during the 3D printing process.
Performance advantages of igus 3D printable tribo-materials include:
Process advantages of igus 3D printable tribo-materials include:
High machine compatibility: open materials suitable for most 3D printing hardware; many materials even compatible with low-cost machines.
Printability comparable to standard materials: unlike many high-performance plastics, many igus tribo-materials require standard printing parameters with moderate temperatures.
Resistance to water absorption: unlike nylon, most igus materials are not hygroscopic, making them resistant to water absorption and unlikely to produce defects even in humid ambient conditions (iglidur A350 requires active drying).
3D printing tribo-materials from igus come in three formats for different additive technologies: filaments for fused filament fabrication (FFF), powders for selective laser sintering (SLS), and resins for digital light processing (DLP) and liquid crystal display (LCD). These technologies have their respective advantages and disadvantages when it comes to sliding applications. Depending on the application specifics, budget constraints, and availability of printing hardware, the most efficient solution may be an in-house print or a customized print order from the igus 3D printing service.
igus tribofilaments provide the widest range of end-use applications to the widest range of users, as many igus filaments can be processed on standard FFF machines that cost significantly less than other types of additive manufacturing hardware. Tribofilaments also represent the largest material category in the igus 3D printing product portfolio, numbering 10 unique formulations suitable for a range of applications.
For maximum compatibility with low-cost, open-frame 3D printing hardware and standard brass nozzles: iglidur i150 and iglidur i151
For medium temperature resistance (100 °C) and high dynamic applications: iglidur i180
For rigorous temperature resistance (170 °C) and flame retardancy: iglidur RW370
For structural components requiring maximum strength: igumid P150 and igumid P190
Tribological powders from igus are designed for use on SLS hardware. This technology offers advantages over FFF such as greater design freedom, no support structures, and near-isotropy, with no weakness along the Z-axis. As a result, hardware is more expensive and is typically operated only in industrial environments. Users of SLS hardware can choose between several igus tribological powders to suit their chosen application.
For good balance of wear resistance, strength, and processability: iglidur i3.
For reliable prevention of electrostatic discharge (ESD) and compatibility with widest range of SLS hardware: iglidur i8-ESD and igliduri9-ESD.
For abrasion resistance and use in worm gears: iglidur i6 and iglidur i6-BLUE.
Tribological resins from igus can be used on standard DLP 3D printers, which can be purchased at costs almost comparable to FFF. Resin 3D printing can produce exceptionally smooth surface finishes and a very high level of detail — ideal for fine-tooth gears. Furthermore, unlike many standard resins, igus DLP materials provide a high degree of strength and stiffness. Compatible with the majority of DLP and LCD 3D printing hardware, igus’ iglidur i3000 resin is the first to provide wear resistance up to 60x greater than standard 3D printing resins.
Explore the transformative world of 3D printing as we delve into the intricacies of using wear-resistant plastic materials. This guide offers engineers a comprehensive overview of material properties, applications, and best practices. Unlock the potential of durable plastics and revolutionize your manufacturing processes.