Chapter 18

Ten Impossible Designs Created Using Additive Manufacturing

Some designs would be impossible to produce via traditional manufacturing processes. In some cases, they’d be too expensive or difficult to manufacture. In other cases, the necessary technology doesn’t exist. Due to the unique layered process of additive manufacturing, many of these “impossible” designs have become reality. This chapter discusses ten unique products that are best produced with an additive manufacturing process.

Personalized Objects

At some pop-up events around the world, 3D printers are being used to personalize a cocktail drink order by being able to print on demand a simple cocktail stirrer in bio-plastic with the person's initials. Derived from contactless drink payment, a simple model is automatically generated and processed, sent to a 3D printer, and printed in minutes while the cocktail is being elaborately made by the bar staff. It would be impractical to have every combination of a person's initials made and in-stock via traditional methods of plastic injection molding. Using 3D printers to produce an object like this at the point of sale is still a waste of plastic and has questionable value as an ongoing enterprise, but as a marketing stunt and a way to promote your event, bar, or club, it could be quite effective.

More elaborate custom 3D-printed objects can often now be ordered online for delivery in a specific color, with added customer-specific requirements such as the spider web guitar shown in Figure 18-1. Details such as serial numbers or a maker's signature can be included in the printed design so that each printed object is created with its own identity.

Image courtesy of Olaf Diegel

FIGURE 18-1: This guitar has been customized with a spider-and-web motif.

Medical Implants

Unlike traditional implants, which use standard rods and other adjustable components, 3D-printed implants can be designed to perfectly complement the recipient’s body. Another advantage is that such objects can be printed with complex inner patterns. Trabecular lattice structures allow bone tissue to grow directly into the implant itself through a process called osseointegration. The resulting cranial cap or joint replacement incorporates the patient’s natural tissues and can become part of the patient’s body without being attached by screws or other mechanical fasteners, which can wear away and cause further damage to bones over long-term use.

In other applications, 3D-printed titanium is used for replacement bones and implants. One significant benefit of 3D-printed titanium is its slightly porous structure, with which the body can more readily accept tissue growth faster than it could with a solid-machined titanium part.

Dental Repair

Metal 3D Printing from Renishaw is doing for 3D-printed replacement teeth what other manufacturers did for 3D-printed hearing aids. Many years ago, hearing aids didn't fit very well. They were either painstakingly handmade from casts and molds for each patient or chosen from a selection of generic mass-produced sizes that may or may not fit. Today, around 95 percent of all hearing aids are 3D-printed. Now the dental market is undergoing a similar change. Using some of the world’s most complex metal 3D printers, Renishaw's machines are at the forefront of mass-custom manufacturing for the dental market.

Using incredibly strong cobalt chrome metal powders as fine as powdered sugar, with ceramic coverings, every tooth, bridge, and crown can now be custom made for every client. 3D scanning determines the size and shape of the denture before adding a serial number used for tracking in the manufacturing process. Plates of these teeth are grown and post-processed for multiple patients. (See Figure 18-2.)

Image courtesy of Renishaw

FIGURE 18-2: A closeup of a dental build plate using Renishaw metal additive manufacturing machines.

Self-Deploying Robots

Micro robotic insects (microbots) can be created to fashion integrated components capable of transforming into useful configurations directly out of the 3D printer. Traditional equivalents require subassembly steps before they can be deployed, but the 3D-printed versions can be deployed in a single automated fabrication facility. These small robots are being used to search disaster zones for signs of life. When a robot detects noise or thermal energy, multiple robots work together to triangulate the coordinates to the outside rescue teams.

Printed Drones and Aircraft Parts

3D-printed parts for drones allow almost unlimited customization to accommodate changes in flight and weather conditions and other unpredictable requirements. Doing this fabrication and customization where needed or required (rather than in a factory before the aircraft is shipped out) means that the correct sensing equipment or style of design to suit terrain or weather conditions can be selected for the current situation.

These drones are lighter in weight than their traditionally manufactured equivalents because their strength depends on cleverly designed internal structures rather than a solid block of material. This reduction in weight allows more drones to be fabricated from the same pool of raw materials. Also, each drone can operate for a greater length of time using the same amount of fuel.

Airbus and other manufacturers hope to apply these same efficiencies to full-size aircraft as legislation and approvals for 3D-printed materials allow more complex and safety-critical structural parts to be used. 3D-printed parts for aircraft manufacture are certified for use now. The widest use of 3D-printed parts in today's aircraft tends to be smaller plastic housings and custom fabricated parts that traditionally require costly tooling for a relatively small number of components —the use of many different shaped cable ducts to channel the mass of wires used by aircraft today, for example. Using 3D-printed cable ducts can reduce tooling costs and also increase design flexibility and reduce the cost of assembly wiring. 3D printing allows unprecedented design flexibility so tooling can be eliminated completely, lowering production cost and reducing time-to-market.

Meanwhile, hobbyists are using desktop 3D printers to produce custom drones from materials such as carbon fiber. These materials offer reduced weight and increased strength and enable the creation of designs vastly beyond off-the-shelf drones.

High Performance, Lightweight Engine Cooling

The high-performance Formula 1 motor sports teams around the world have fully embraced the capabilities of 3D-printed metal manufacturing, especially for highly complex shaped parts that would be impossible to machine or cast using any other method. Advanced lightweight engine cooling components allow these sports cars to achieve greater performance during a race season. The custom designs can also be monitored for performance and further developed, printed and tested to quickly optimize every aspect of the material surface area to assist with cooling. Many other parts of a Formula 1 car are also now 3D-printed to exactly match proportions and fit the driver of the vehicle.

Custom Objects Created in Space

Because additive manufacturing techniques such as fused deposition modeling (FDM)/ fused filament fabrication (FFF) don’t rely on gravity for layer construction, they can operate upside-down or in microgravity environments such as the International Space Station. NASA has already sent 3D printers to space, and astronauts have used them to print tools and small replacement parts. This technology will allow future astronauts to travel without having to carry spares of all the tools they may need in their explorations. Apart from the raw materials needed for the 3D-printed parts, it would be advantageous for multiple 3D printers to also produce spare parts for themselves, sustaining the ability to make whatever tools or devices required without the need for a trip back to Earth for repair.

Art on Demand

3D printing systems are being used to faithfully reproduce works of art with far more depth than a flat image or photographic print reproduction. 3D printing of multiple layers at fine resolutions can reproduce brush strokes, indents in paint, and even accurate degradation of damaged parts. This is a great way for museums to share works or allow a copy to be on general display while the real artwork is away or unavailable.

In recent times 3D printing and 3D scanning have been used to re-create sculptures and works of art from destroyed collections around the world. As more cultural history is at risk of damage from war or natural decay, many historians are using 3D scanning and high-resolution image captures to archive a digital copy that a 3D printer could reproduce if required.

Locally Fabricated Items

Markus Kayser’s design for the Solar Sinter and current work at the NASA Jet Propulsion Laboratory — or at EU sites for space technologies — are demonstrating the fabrication of complete objects using nothing more than local solid materials and sunlight. Whether the printed objects are bowls formed of glass fused from sand or structures formed from rocks, these technologies represent some of the purest forms of green engineering: Final products could be ground up and returned to their natural state after use, with no further chemicals or fuels required.

Body Parts

One of the most amazing capabilities of 3D printing is making body parts such as organs with complex inner configurations at the cellular level. 3D printing with materials sourced from the patient’s body eliminates the risk of organ rejection. These structures could one day even enhance our bodies’ bionic capabilities, provide resistance to toxins, and add many desirable capabilities beyond the human body’s natural limits.