ARE THERE BENEFITS to 3D printing bearings?


or bearing manufacturers, 3D printing provides the flexibility to produce

components with bespoke elements and enhanced performance. As the 3D printing process is relatively simple and doesn’t require expensive tooling, manufacturers and design engineers can experiment with design features that wouldn’t have been economically viable using conventional bearing manufacturing methods. They can also use an increasingly

diverse range of materials, with 3D printed reinforced polymers matching or enhancing beyond conventional properties. As an example, Bowman International of Oxfordshire used MJF technology to produce a bespoke ‘rollertrain’ retainer using PA11 nylon. The interlocking structure permits room for two to four more rollers, allowing for a 70% increase in load capacity, as well as greater elasticity, durability and functionality. 3D printing also removes the barrier of minimum order volumes,

allowing manufacturers to provide a cost-effective low-volume production service. Furthermore, 3D-printed moulds save time and money compared to expensive metal bearing moulds, as well as enabling

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Chris Johnson, managing director of SMB Bearings, looks into how 3D printing can help bearing production

a more agile manufacturing approach. While 3D printed mass-produced

bearings aren’t yet commonplace, polymer 3D printing is making an impact in the rapid prototyping world. For example, in a niche concept vehicle, 3D printing may be used to achieve fast and visually appealing prototyping. This would ensure that the smallest of mechanical elements, such as the bearings, functioned in unison with the entire system.

LIGHTWEIGHT DESIGNS In industries such as aerospace, automotive or medical technology, lightweight design can achieve better safety performance as well as vital

cost savings. For low load, low speed applications, plastic bearings not only offer high performance characteristics but they are already five times lighter than their steel counterparts. Using 3D polymer printing processes, it is possible to design a

component that is lighter still – by using honeycomb-like structures. This would be very difficult and time-consuming to achieve with traditional machining processes. Many industries may have historically chosen to rely on metal lightweight innovations – such as Schaeffler’s XZU conical thrust cage needle roller bearing, that can be used as an articulated arm bearing in lightweight portable robots. However, 3D printed high-performance thermoplastics such as carbon-fibre and polyether ether ketone (PEEK) offer a feasible alternative to metal. Opting for a 3D printed retainer in nylon (PA66) or another

polymer material can help to reduce the weight of the whole bearing. Carbon-fibre reinforced nylon is one of the most popular combinations for nylon printed materials. While offering many of the same benefits as standard nylon including high strength and stiffness, it produces significantly lighter components. A 3D-printed polymer cage may also reduce the wear on the rolling elements, compared to a conventional steel cage. A 2018 feasibility study assessed the friction performance of a

commercial deep-groove (6004) 3D printed ball bearing. The bearing was fabricated using the MJP process, using plastic material for the structure and fusible wax material for the support. The result demonstrated satisfactory durable life of the 3D-printed ball bearing at low loads and speeds.

ENSURING QUALITY In June 2018, the Additive Manufacturing Standardization Collaborative (AMSC) published an updated version of its ‘A standardisation roadmap for additive manufacturing’. Adopting standards to mitigate and control risks as well as allowing more consistent quality are important steps for the future of 3D polymer printing. This is especially important for components that are safety critical, such as bearings. As with traditionally manufactured components, 3D printed plastic bearings must undergo the same rigorous testing procedures to make sure they are fit for purpose. Polymer 3D printing can be used to supplement traditional bearing

manufacturing techniques, offering rapid prototyping and enhanced performance characteristics that have the potential to rival metals.

SMB Bearings 32 NOVEMBER 2020 | DESIGN SOLUTIONS 

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