Designing For Additive Manufacturing: Serial Production

Designing For Additive Manufacturing: Serial Production

Manufacturing for production has for a long time been seated in well-established methods and processes. Machining processes like milling, turning, drilling, and Injection Molding have been tried, tested, scrutinized, and reworked over hundreds of years and today, they make up a body of manufacturing know-how that is used and trusted by thousands of companies worldwide. So when a technology as potentially disruptive to the existing state of manufacturing as AM comes along, there is a natural hesitancy to rework processes, redefine manufacturing logistics, and fully adopt and trust this new technology. 

In the world of manufacturing, AM is the (relatively) new kid on the block, with its earliest formulations dating back to the 1980s. But because of technical and material limitations, the technology has for a long time remained synonymous with rapid prototyping — it was primarily a means to quickly develop and test early versions of parts or products before investing in full-blown manufacturing processes for end-use and production purposes. 

But today, with distinct technologies and a growing materials portfolio made up of metals, polymers, ceramics, and composites, faster printers, and more elaborate software solutions, Additive Manufacturing for serial production has arrived. AM is no longer the technology of the future, it is the technology of today. 

This article will look at the role that AM plays in serial production and how it’s replacing or supplementing conventional manufacturing methods. Specifically, we will examine two paths to production AM: mass customization and mass production.

1. Product Life Cycle and Mass Customization with AM 

Businesses understand that the products they manufacture have a limited shelf life. When a new product is introduced to a market, it follows a growth trajectory as interest in the product heightens until it reaches a peak and inevitably declines either due to new market players saturating the market, a change in consumer desire, or a number of other market factors. As a result, there’s constant pressure on businesses to continually invest in new product development and take new products to market in order to remain viable. This is especially true with market trends indicating that typical product life cycles are seeing a significant reduction in lifespan.

Product customization significantly extends a product’s lifespan — that is, the manufacturing of products that are personalized for the end-user with functional or aesthetic modifications or a mix of the two. 

One of AM’s core benefits is that it can easily accommodate a growing desire for products personalized specifically for each customer. AM also allows companies to quickly adapt to new market trends by offering more variations in their product lines and modifying their manufacturing processes for smaller batch sizes. 

Where the focus of conventional manufacturing is on simplifying products to reduce costs, AM’s nature opens the door for businesses that design products specifically for the end-user, allowing them to provide customized solutions at a premium price and extend the product’s shelf life. 

Perhaps there is no better example of personalization at scale than inStryde’s insoles which use each individual customer’s unique footprint to create the perfect orthotic solution, offering both comfort and affordability. The insoles, which are made using the Carbon DLS process, are printed and shipped on-demand.

Because of inherently large setup and tooling costs, customization like this in conventional manufacturing is unheard of — the marginal costs associated with adding customized features to a product are significant. The large initial investments can be economical in a mass production scenario where the investment is distributed over the total units of products made. And it’s because of this, that product complexity is kept to a minimum to enable higher production rates and reduce costs. 

With Additive, everything is done on the same software, using the same printers, allowing for an agile response to consumer demand; the marginal costs associated with product customization are minimal. With the processes in place, printing a custom part becomes as simple as using a different CAD file.

But what about larger production? Is AM a viable solution for replacing or supplementing existing processes and making parts at scale? Yes it is. Companies like BMW are using Additive technology — like HP’s Multi Jet Fusion — to optimize their manufacturing lines to produce better, more functional products at scale for their customers.

Over the last decade, BMW has used Additive technology to produce over a million parts for its vehicles.

2. Considerations For Large-Scale Production With Additive Manufacturing 

To accrue the largest benefits from AM, engineers and product designers should adapt to designing specifically for Additive Manufacturing and really consider the unity of design, technology, and process simultaneously to determine which parts are a good fit for the technology. 

Small parts that would typically require tooling, for instance, can make for good candidates as a DLS printer can replicate those parts in large batches and shorter time than it would take to mold or machine the parts. The money-savings here are seen primarily in eliminated or minimal post-processing requirements or material savings, as might be the case with subtractive processes.

Small parts that may have conventionally required molding and machining can be produced using a DLS printer creating near-net-shape parts and maximizing the printer’s build plate capacity.

This multi-function fishing tool by FinMan Fishing Innovations is a great example of this. The product, designed to slice, snip, and stow fishing gear, has a complex design and demands materials that are tough enough to withstand rigorous use. What would typically have been a molding and machining process was designed for AM using Digital Light Synthesis technology. This saves the company money on tooling costs and cost-per-part and results in a quicker time-to-market than would have otherwise been possible.

FinMan’s fishing tool’s design included precise features, undercuts, thru-holes, and surface textures and required a solution capable of accommodating its complexity. Producing the part with Injection Molding would have required a re-design to simplify manufacturing, something FinMan wasn’t willing to compromise on. The final part was printed using Digital Light Synthesis process using an RPU 70 polymer.

Rethinking legacy designs can also draw tangible benefits from the technology. For example, topology optimization software can be used to reduce the mass of a part using complex lattice structures otherwise not feasible with conventional manufacturing methods and produce weight savings and more economical final assemblies. Consolidating multiple parts into a unified design can eliminate the need for post-processing activities such as welding and machining and produce parts with better mechanical fidelity. 

Although Additive is most beneficial when used to make a part designed specifically for AM, making use of benefits that only AM can bring like complex geometries, light-weighting, and no tooling, there are instances where AM may be able to deliver lower-cost solutions for existing parts — parts that don’t undergo any design changes and benefit simply from moving over from a conventional process to an AM process. Here the savings are typically seen in minimized material waste and machining. Boeing did just that with its titanium door latch fitting for the Boeing 787

This access door latch for a Boeing 787 is the same part design previously produced through machining and an example where simply switching to AM have resulted in cost-savings. The Additive version of this part is produced using a deposition process to fuse titanium together and some machining for post-processing.

With pre-tooling all but eliminated from AM processes, businesses can shave weeks, if not months, off their lead times, enabling them to take products to market at a much faster rate than previously possible. “Quick-to-market” also goes hand-in-hand with faster product development — conventional product prototyping gives you an idea of what the end-use product will look and function like. With AM, though, you can print a part with its final properties and quality standards in place early in its prototyping stage, making it easy to quickly iterate design changes and test ideas and accelerate your product development process significantly. 

It’s no surprise that nearly 90% of respondents to a 2021 survey by ASME indicated they use Additive Manufacturing in the development cycle. 

In some cases, AM can be used as a “bridge production” tool to manufacture the initial run of a product while tooling is being secured.

Additionally, where conventional manufacturing plants require large investments, in many cases, decentralization becomes economically unfeasible. With AM, businesses can work with one or multiple global (or national) production partners with distributed manufacturing centers closer to where their customers are, saving money within their supply chains and getting products in their customers’ hands quicker. 

3. Conclusion 

Whether you’re moving legacy parts to an additive process or altogether designing new parts, specifically designing for additive is pivotal for bringing about the most benefits from the technology. In some cases moving a part from a conventional process to an additive process can result in immediate cost savings and improved functionality, but this is the exception, not the rule. In addition to benefits such as cost-savings, faster production runs, minimal tooling and post-processing, and decentralized distribution channels, customization – which is a distinct benefit of additive – can help businesses create parts and products unique to their individual customers and prolong the shelf life of those product lines. The two paths to production AM – mass customization and mass production – both start with designing for additive.

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