Additive Manufacturing
Will Aid and Accelerate
the Circular Economy

MATERIAL

Reimagine the Feedstock

When companies implement additive manufacturing for existing products, one of the first challenges they must face relates to materials. While additive manufacturing’s material portfolio is growing, equivalency with conventional injection molding resins, casting alloys or machining stock is not guaranteed.

At the same time, moving from a conventional process to an additive manufacturing one offers an opportunity to rethink the material. Titanium, for instance, is difficult to machine but easy to print; a part that might previously have been milled from steel could perhaps more easily be 3D printed in titanium with powder bed fusion. Or maybe that machined part doesn’t need to be metal at all; perhaps it could be made lighter and more easily from 3D printed plastic instead.

AM’s design benefits also have a role to play in informing material selection. 3D printing enables the many pieces of an assembly to be consolidated, often into just one part. This kind of consolidation simplifies production and limits labor, but also reduces the use of fasteners and the number of materials used. An assembly that involved tool steel and aluminum welded together could be replaced entirely with nylon parts, for example. The resulting product could be lighter and easier to make but also simpler to recycle, as it would not need to be broken down into separate materials first.

In addition to these benefits, 3D printing provides some unique material opportunities. A growing number of manufacturers are providing plastics for 3D printing made from recycled sources (which can be every bit as good as, if not better than, polymers made from virgin stock) as well as bio-based polymers like PLA made from renewable plant sources.

Composites reinforced with recycled carbon fiber and biodegradable material such as wood fiber are also in development. In metals, options for recycled materials are fewer, but technology and materials suppliers are coming up with new ways of mechanically recycling metals into brand-new alloys, 3D printing with machining chips, and atomizing scrap into metal powder in small batches near where it will be used. A company committing to a new additive manufacturing workflow has a diverse range of material options, and if the door is already open, why not consider one made from a recycled or renewable feedstock?

Background photos: GreenGate3D; Armor Group; Carpenter Additive

DESIGN

Optimization Supports More Efficient Products

Design for manufacturing (DFM) is best practice in product development, but additive manufacturing engineers are concerned with something broader. Design for additive manufacturing (DFAM) does not just consider the manufacturing step — that is, the 3D printing step — for the part in question; it must also take into account the material (since material properties are largely set during the printing process), build parameters, part orientation, support structures, build envelope nesting and any necessary postprocessing. AM substantially expands the scope of design, and asks engineers to follow their designs through a longer chain. This is a mindset change as much as it is an organizational and technological one.

While the design stage becomes more complex with additive manufacturing, AM also brings new possibilities. Advanced software tools for topology optimization, generative design and simulation help engineers arrive at better designs that can be produced only with an additive process. While 3D printing’s first use was as a rapid prototyping tool, finite element analysis (FEA) and print simulation tools are pointing toward a future of more sustainable manufacturing that relies on digital prototyping, where fewer physical items are needed to arrive at a final design.

With 3D printing and software-driven design, material can be applied exactly where needed, and manipulated with features such as lattices to impart different properties in different areas. The concept of “digital foam” relies on this ability; an entire shoe insole for instance can be made of just one material, but printed using different lattice geometries to impart cushioning or rigidity in the regions where these properties are needed.

Design features like lattices and honeycomb structures can also be applied to limit the amount of material required and reduce a part’s weight. In a process like machining, where stock is removed from a larger piece of material, the goal is to minimize the machining process; removing more material only increases lead time, cost and waste. But with additive manufacturing, minimizing the material used also minimizes these other factors. When applied to products such as cars and planes, optimized 3D printed parts designed this way contribute to reduced fuel consumption and allow for a smaller carbon footprint.

Indeed, some next-generation electric vehicles and aircraft will only be made real with the lightweighting and optimization that additive manufacturing and design software can produce together. These lightweight components will be the enablers to extended battery life, longer flight ranges, and farther space travel. Human endeavors like travel and exploration will become more energy efficient and sustainable with new designs made possible through additive manufacturing.  

As parts or whole products are reinterpreted for additive manufacturing, DFAM also presents an opportunity to reconsider what will happen to the objects at the end of their usable life. Decisions made in the design stage, such as the use of fasteners, replaceable parts and diversity of materials, will have an impact on how easily the product can be remanufactured or broken down for recycling later.

Background photos: Staff; XponentialWorks | ParaMatters

MANUFACTURING

Digital, Distributed and On-Demand

Conventional manufacturing that relies on molds, dies or other tooling typically takes place in one centralized location. The investment that a manufacturer has made in this infrastructure makes it practical to keep production in this one location, store items in inventory until they are needed, and ship them to retailers or customers once ordered.

This model, however, stretches the supply chain in a way that can handicap it. As we saw throughout the COVID-19 pandemic, centralizing production in one area makes it more difficult to respond quickly and flexibly to needs in other parts of the world, especially when travel and trade are restricted. Manufacturing can only happen at a scale commensurate with the tooling it requires; once a given plant reaches its capacity, it can neither add more nor outsource easily. And in times of business-as-usual, this model leads to waste. Manufacturers must predict what will be needed, make it and hold it in inventory; this leads to shortages in some cases and surpluses in others that will eventually need to be scrapped.

Additive manufacturing, however, is digital manufacturing. A 3D printer does not require a mold, or cutting tools, or workholding solutions. All it needs to make a given part is the proper material and the digital file to do so. Products can therefore be held in digital inventory as files, and made on demand in direct response to customer orders and trends. Production can be “right sized” to make just the quantity required, reducing inventory and scrap.

What’s more, digital manufacturing can be distributed manufacturing. Part files can travel easily across borders even when goods and people cannot. An enterprise that has 3D printers and materials located around the globe can easily shift production in response to a crisis, increased demand or simply open capacity. Or, many manufacturers with the proper equipment can be mobilized to produce together, as we saw with nasopharyngeal swabs used for coronavirus testing.

The flexibility enabled by digital manufacturing also has another benefit: the ability to manufacture locally, near where customers are. Rather than one long supply chain with all a company’s products coming from one location, manufacturing can be spread throughout markets, creating many short, more resilient supply chains.

This distributed manufacturing model allows customers faster, easier access to products, and means fewer delays and shortages in the event that production is disrupted in one or more locations. From the manufacturer’s perspective, the payoff is a more secure and flexible workflow that can handle fluctuations in market demand and enable production to continue uninterrupted, even in the face of emergency.

Additionally, additive manufacturing distributed across physical locations can be a more environmentally friendly means of production. Manufacturers depending on 3D printing can often occupy much smaller facilities than conventional, centralized ones; an entire production line can fit on a tabletop (as at Spectrum Dental, pictured). And, producing local to customers means less shipping and a reduced carbon footprint.

In some cases, the 3D printing technology may even be more energy efficient than a conventional manufacturing process.

Background photos: Flowbuilt Manufacturing; Staff

PRODUCT

Digital Workflows Create Better, Longer Lasting Goods

Historically, bespoke items were the norm (think: shoes, furniture, jewelry), but since the Industrial Revolution we have grown accustomed to mass produced goods. Manufacturers offer products in predetermined sizes, colors and configurations not because these are the best options for every customer, but because they are the most effective to make at large scales. Numerical sizes for rings, shoes and everything in between are relics of this standardized model, where consumers fit their needs to the product instead of vice-versa.

When a product like a line of athletic shoes must be made with molds, it makes sense to limit the number of size selections because each one will require its own set of mold tooling. To produce custom shoes for every wearer would require too much time, cost and/or manual skill to be feasible, and simply producing more variations on the same product would undoubtedly lead to even worse problems with inventory and waste.

The digital, toolingless nature of additive manufacturing breaks free from these hurdles. Rather than a mold, a 3D printer operates on 3D data. If sufficient data can be gathered from the customer, it’s only a matter of software manipulation to convert that information into a part file that the printer can produce. Companies created in recent years can use customer input in conjunction with AM to produce items ranging from rings and furniture created with parametric design tools in a browser, to glasses frames and shoe insoles based on biometric measurements of the intended wearer.

This digital workflow is not just a different way of making products and fulfilling orders; it is a way of making better products. Custom insoles or bespoke glasses will fit the customer better straight out of the box, and are more likely to last longer. Even aesthetics that don’t affect the function of a product, like the color of a table or embossed design of a ring, impart greater value to the custom object than its mass-produced counterpart.

Many of AM’s product benefits also translate to more standardized goods. Additive manufacturing supports ongoing product development and flexible changes so that designers can arrive at better products more quickly. Its digital process allows manufacturers to offer more variations on a given product without additional investment in tooling or other infrastructure.

As described above in the DESIGN section, AM also makes it possible to realize designs that support more efficient and sustainable new products, such as electric vehicles. Software-driven design and simulation support rapid development of products that function better. Parts can not only be made lighter and with less material; they can actually be made to consume less energy in use.

Background images: Model No.; Staff; XponentialWorks | ParaMatters

END OF LIFE

Opportunities Through and with 3D Printing

A conventional, linear approach to manufacturing doesn’t often take into consideration the end of a product’s life. The manufacturer’s commitment and oversight ends once the item is sold and shipped; from there it is up to the user to deal with reuse or recycling, or as is more likely the case, disposal. But discarding unneeded products is quickly becoming unsustainable. China, for instance, previously purchased the bulk of the world’s plastic waste, but is now turning this material away; used plastic from the U.S. is being diverted to other Southeast Asian countries where it can be recycled (at best), incinerated, buried in landfills, or dumped (at worst). The end for a plastic part is a question that cannot be answered until luck or chance determines its fate.

But a truly circular economy does not leave this question unanswered, for any product, part or material. Sustainability requires closing the loop and providing pathways for unneeded parts and goods to be transformed back into feedstock, conserving their material for future applications. Ideally, this transformation does not diminish the value of the material, and allows it to be reborn at equal or greater value.

Compostable materials that can be converted back into organic matter provide for one kind of end-of-life scenario, but repurposing, remanufacturing and recycling goods are other valid options. 3D printing materials such as filaments and powder are arguably the most versatile feedstock, and a worthy reincarnation for unneeded industrial scrap, post-consumer waste or products at the end of their lifespan. A manufacturer that can recapture its materials and transform them into printing feedstock can continue manufacturing sustainably, or even find new avenues of revenue.

But 3D printing isn’t just a destination for recycled material; it also supports and enables this kind of material regeneration. The design advantages discussed above encourage products that use fewer materials, depend on fewer assemblies and involve fewer fasteners — all characteristics that make an object easier to recycle. 3D printing also supports the inclusion of features such as QR codes and embedded sensors that can hold information about a product’s material make up, use history and lifespan, all valuable data points that can indicate when an item is ready to be recycled, how this step should be executed, and the kinds of materials that can be reclaimed.

AM’s capacity to manufacture what is needed, where it is needed, and on demand also reduces the amount of material that must be recaptured, conserving the resources needed to do so. More custom, distributed and just-in-time manufacturing means less waste, and better use of the materials already in the system. Over the long term, a circular model in which the manufacturer assumes responsibility for its products across their full lifecycle, from material through end of life, will lead to more careful use of resources, and a more sustainable system of both producing and consuming.

Background photos: 3DEVO; GreenGate3D