Designing for Additive Manufacturing: Light-weighting in Electric Vehicles

Additive Design

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Published on 

March 29, 2022

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6 minute read

SUMMARY

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Electric vehicle (EV) manufacturers are leading the manufacturing revolution by adopting additive manufacturing processes that enable them to build more ergonomic, lighter weight, better functioning, and more cost-effective vehicles.

EVs are widely considered the vehicles of the future. While many EVs are more economical for the end user, they all take on a principled role as an eco-friendly option for consumers who want to do their part to help the environment.

One of the core objectives for EV manufacturers is overall weight reduction. This ‘light-weighting”, implemented in cars, buses, shuttles, trucks and e-bikes, can have a significant impact on battery life, and by extension the vehicle’s range. All EV manufacturers recognize that extended vehicle range will equate to wider consumer acceptance and increased sales.

In this article, we’ll look at two light-weighting techniques as well as some specific AM material applications in e-vehicles.

Light-weighting Through Parts Consolidation

Perhaps the single biggest advantage of AM is its ability to create geometries that are too complex, or too costly, for existing legacy manufacturing processes. This paves the way for thinking about design in innovative and unorthodox ways. With AM, combining the assembly of four or eight or twelve components into a single part is not out of the realm of possibilities. Cost is a fundamental governing factor for any assembly, and the benefits from part consolidation are readily apparent.

What Are The Benefits of Parts Consolidation?

Parts Consolidation Helps Trim Down Your Supply Chain

Consolidating multiple parts into a single part helps minimize the number of manufacturers and suppliers involved in its production. When innovation and consolidation is part of your design process for the entire assembly, it makes way for cost savings up and down the supply chain. Not to mention minimizing the risk involved in one or more of your suppliers being unable to supply any given part for any reason.

Parts Consolidation Results in Improved Performance

AM allows you to design and create geometries that are desirable but that are limited by traditional subtractive and formative processes (either due to costs or feasibility). These complex designs allow for the production of consolidated parts with high strength-to-weight ratios and - where it’s desired - higher surface areas, excellent shock absorption, vibration and noise cancelling, among other mechanical properties.

Parts Consolidation Makes For Easier Assembly

Consolidation results in fewer parts. Fewer parts means faster assembly. Faster assembly equals faster product dispatching. Win, win, win.

All of these elements play a role in cost savings and business profits. By consolidating your parts you are using less material, trimming down your supply chain, and producing better products for your customers.

A great example of this is Proterra, the electric bus maker that used the Carbon DLS™ process, a breakthrough additive technology,  to consolidate two products for its buses into a single dual-purpose handle that functions both as a door switch and a tool to open access panels.

This particular shift to AM from what has previously been an IM process allowed Proterra to save over 95% on its handles (most of which was spent on tooling costs) bringing the unit cost down from $2,500 to $22.50, and resulting in a more ergonomic part for its buses.

Another example of part consolidation using AM is General Motors’ and Autodesk’s generative design experiment that consolidated a seat bracket for one of its vehicles down from eight components to a single component. Parts consolidation can help you tackle high production costs by facilitating lighter products and a shorter supply chain.

GM claims to have reduced a total mass of 5,000 pounds across 14 of their vehicle models since 2016, with most models shedding more than 300 pounds.

The design complexity afforded by AM allows for more opportunity to consolidate multiple parts, effectively reducing cost per part

Light-weighting With Lattice Structures

Designing using lattice structures is nothing new, but the inherent limitations typical to traditional subtractive and formative methods hinder product design. The more complex the designs, the less feasible they are, due to the complexity of setup and tooling required, cost, or the fact that it’s impossible to create. But with additive manufacturing comes the flexibility needed to produce complex lattice structures in a cost-effective manner, the benefits of which are important to note.

What Are The Benefits of Designing With Lattice Structures?

Good strength-to-weight ratio results in lightweight parts that are just as strong or stronger than comparable counterparts, and with the right materials you get comparable (or better) mechanical fidelity needed for your particular project. Take Carbon EPX 82 material for example – this rigid polymer is similar to lightly filled PA or PBT and passes every validation test required of automotive grade material. In combination with the design flexibility afforded by AM, you can use a material like EPX 82 to consolidate or reimagine existing parts and further lightweight it with new and innovative lattice designs.

Lattice structure being printed using the Carbon DLS process

High surface area can be desirable in applications that require good heat transfer efficiency such as heat exchangers used in computers, or cylinder heads used in automotive engines. Lattices can dramatically increase the surface area available or produce that surface area more affordably by eliminating complex tooling procedures.

FIT West Corp reimagined the cylinder heads in their sports vehicles using AM and a lattice structure that produced 66% weight reduction and an increase in surface area from 823 cm2 to 6,052 cm2.

FIT West Corp's lattice structure used in cylinder head design

Excellent shock absorption is another benefit of good lattice design. Elastomeric polymers like Carbon EPU 40 and EPU 41 materials are well suited for products where high resiliency is needed. Think something like bike saddles, handle grips for your e-scooters, or dampeners around critical components in an electric module.


While lattice design has been traditionally limited in scope due to limitations in technology, with AM we’re starting to see unprecedented geometries make their way into various assemblies. Combine that with the material flexibility of high-performance polymers and you can design and build lattice structures that have superior properties to solid materials and conventional structures. The only limitation becomes your imagination as the technology continues gaining ground.

Material Applications in E-Vehicles

While traditional resin-based 3D printing produces weak and brittle parts, the Carbon DLS process results in functional parts that can meet stringent, industry-specific criteria, with surface finishes comparable to injection molding. Carbon offers best-in-class 3D printing materials for the most rigorous of applications:

EPX82

This workhorse material combines functional toughness, stiffness, and temperature resistance - with T1 and T2 capabilities, with some applications up to T3 - making it useful for a variety of automotive and consumer applications.

EPX82 is a cross-linked aromatic epoxy/amine, which leads to excellent retention of material properties during high temperature aging, temperature/humidity cycling, and thermal shock. EPX82 can retain function with minimal property degradation after aging tests required for automotive and industrial brackets/mounts/housings.

EPU40

EPU 40 offers a combination of tear strength, energy return, and elongation making it perfect for impact absorption, vibration isolation, gaskets, and seals. It is a good choice for applications where high elasticity and tear resistance are needed. In combination with complex lattice structures, its uses are endless.

RPU 130

RPU 130 is strong, tough, and heat resistant with an impact resistance of 76 J/m and heat deflection temperature of 119 °C. RPU 130 is composed of 30% Susterra® propanediol, a bio-based material that combines performance and sustainability. RPU 130’s unique combination of performance attributes makes it comparable to an unfilled thermoplastic like nylon and polypropylene.

This material is suitable in applications ranging from automotive, to industrial, to consumer products.

Conclusion

Light-weighting is undeniably important for the future success of electric vehicles. As new materials and design technologies for additive manufacturing continue to be developed, the bar continues to rise in terms of ways to reduce vehicle weight. Incorporating the design techniques discussed in this article into your design process - from parts consolidation to lattice structures - results in better products that weigh less, meet functional requirements, and are more cost effective. As AM continues to take technological strides, it increasingly becomes the best option for product designers and engineers everywhere to create better and more economic products at any scale.

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