Rail engineers can face significant challenges in defining components for space-restricted applications and managing the overall weight of a solution.
Where conventional manufacturing machines such as lathes, mills, and drills produce results by subtracting material from an original billet, additive manufacturing (3D printing) involves manufacture by the addition of material.
This process offers considerable benefits for the rail industry including significant cost savings, the virtual elimination of waste materials typically produced from material cutting processes, and the freedom of design without many of the traditional process restraints.
Why is additive manufacturing so cost-effective?
The preparation and availability of a prototype at the early stages of a project will save time and cost and allows for any required modifications to be made prior to the metal being cut or plastic being molded, which could be expensive to correct afterward. The use of 3D models offers clarity on the design through a true visualisation, minimising costly corrections or drawing errors.
By manufacturing a prototype from engineered materials, which can often be functionally tested, the concept and ultimate product performance can be proven. Plus any modifications can be made before serial production starts. With traditional manufacturing techniques, prototyping and subsequent design changes add significant time pressures and can jeopardise project deadlines.
What’s in it for the rail industry?
Traditional manufacturing techniques often use more material due to process restrictions, whereas additive manufacturing delivers solutions with optimised designs using lower material quantities to achieve the required product characteristics. By using modern engineered materials--non-metallic materials that are lighter than traditional metals--the overall vehicle weight will be reduced, improving efficiencies.
Aside from the advantages of new design projects, additive manufacturing provides crucial benefits for refurbishment projects. Whilst the new rolling stock is appearing across the rail network, there remains a significant number of vehicles that have been in service for long periods. For rail operators to ensure that their service runs reliably and on time, the aging stock has to be regularly maintained and refurbished. However, this maintenance requires components designed and manufactured a long time ago, making the procurement of direct replacements or obsolete parts quite difficult. Additive manufacturing addresses this issue.
If parts are remanufactured using the same materials and processes it will become too cost-prohibitive, since production tools, methods and drawings may no longer be available. Also, small production runs and sporadic usage patterns make planning difficult. Prototyping and additive manufacturing reduce that problem as the process can be focused on reverse engineering of legacy components.
In contrast to traditional manufacturing techniques, tooling doesn’t have to be commissioned and short batch runs can be manufactured quickly and cost-effectively. These revolutionary methods are already being used to help reduce maintenance times and refurbishment cycles, satisfying the need to keep rolling stock in service and meet service demands.
What methods can be utilised?
Parker utilises a range of additive manufacturing processes including stereolithography (SLA), fused deposition modeling (FDM) and selective laser sintering (SLS) to engineer and manufacture prototypes and production parts for customer-specific application needs. These innovative techniques deliver cutting edge products in a cost-effective way and to very short timescales, ensuring rail operators can deliver exceptional service, keep costs down and minimise disruptions.
This article contributed by Dave Walker, market development manager for rail, Parker Hannifin.