The Application of 3D printing

Mark Cundle, Head of Technical Marketing at RS Components, takes a look at just a few of the enormous range of applications that could benefit from the latest 3D printing technology, including rapid prototyping, architectural design, medical applications and scientific experimental tooling.

Three-dimensional (3D) printing, also known as additive manufacturing, is revolutionising product development with its ability to create quick-turn-around prototypes, potentially saving weeks or even months in the design cycle. In addition, it is enabling new possibilities in a number of extremely different fields such as design in architecture and the arts, health and medical applications, and scientific research. Whilst a major barrier to adoption in the past has been the cost of 3D printing hardware, this is changing with relatively low-cost printers now becoming available from companies such as RepRapPro and 3D Systems among others, so 3D printing technology is becoming increasingly accessible to individuals and small businesses alike. 3D printing service bureaus, such as Quickparts, also offer access to 3D prints without having to invest in the machines themselves. In addition, the integration of new technology such as the ability to print with different materials is increasing the scope for new applications.

The technology is largely still seen as being too slow and too expensive for manufacturing –certainly in any sort of volume. But not only is the initially high capital start-up cost of 3D printers sharply declining, strong competition in the market has led to decreasing costs of raw materials. In the case of plastic filament for example, an object can be made within an hour or two, at very low cost indeed. Another issue has been the tensile strength of low-end plastic 3D printed parts: According to Adrian Bowyer, director of RepRapPro, the reality is that many ABS and PLA 3D printed objects will not actually be that much weaker – perhaps offering close to two-thirds of the strength of a ‘solid’ injection-moulded part. These 3D printed objects typically have an interior honeycomb structure, which is similar to the I-beam cross-section concept commonly used in construction; this makes 3D printed objects considerably lighter, while retaining more than enough strength for most applications. More advanced 3D printing technologies and materials, such as SLS, (Selective Laser Sintering) offer very impressive tensile strength ratios, usually matching if not beating traditional materials at significantly lower weights. These technologies are being thoroughly researched and are now used by aerospace and automotive manufacturers seeking to deliver much lighter aircraft and automotive parts without any loss of performance and strength. The constraints known in 3D printing are being lessened over time with the further development of the technology, and it is now starting to be used in production, although perhaps in very low volume or highly customised ‘one-off’ applications.

 

Rapid Prototyping

Where 3D printing has really taken off over the past few years, and across a wide assortment of industries, is in the area of rapid prototyping as part of the product design and development process. Although CAD software is no doubt becoming increasingly sophisticated, it does not deliver quite the same experience to a designer as being able to actually hold a prototype of a target product. So, rather than creating early prototypes of new parts or components via a conventional machine tools workshop, the technology is being used to design and test new concepts in companies both large and small, enabling the creation of prototypes in a matter of hours rather than weeks or months. This in turn can enable huge time-to-market benefits as well as delivering a significant increase in design freedom.

In addition, the process offers more than just time and cost savings: rapid prototyping via 3D printing can also mean more innovative and higher quality products. Product developers no longer have to wait for tools or parts to come back from machine workshops; the quick availability of a 3D-printed prototype enables physical testing and further improvements to be made before moving forward with volume production.

An interesting example of 3D printing use for rapid prototyping is the use in the vehicle tyre manufacturing industry. Korean company, Hankook Tire, utilises 3D printing as a key part of its concept design process. The 3D printer delivers a finished mock-up model that perfectly matches the original CAD design within only seven to eight hours whereas previously, mock-ups were handcrafted via an external contractor, which was an expensive option and took considerably longer to produce. Overall, 3D printing has helped the design team at Hankook Tire deliver better communication between departments, while saving on costs and also improving on the security of proprietary design data.

 

Architecture

Another application for 3D printing is in the field of architecture. The building of models can be extremely important in demonstrating and presenting architectural designs. Often architects prefer designs in abstract colourless forms, which makes a low-cost 3D printer ideal for this purpose, although colour mixing will soon be available in the lowest cost printers. Making a traditional architectural model out of balsa wood or other materials is a highly time consuming and painstaking process, so producing a model direct from a 3D-CAD system means the architect can continue on with a design while the previous design is being printed. The technology is already being widely used in architecture and the lowering of cost for machine and materials is only likely to accelerate the take-up of 3D printing.  The progression of 3D printing technology can already been seen moving into the world of theatre- and film-set design, not to mention designs for exhibition stands or shop interiors. It was used in the production of highly detailed physical model of a 30,000-seat civic sports arena in Stockholm, creating a 1.2 x 1.2m model that captured virtually every detail in the architect’s 3D digital model, including 7400 highly detailed seats, each measuring 4mm wide.

 

Health and Medical

Dentistry is an area that is already experiencing the possibilities of the technology. However, an important aspect is the precision and accuracy of the machine. For example, the current RapRapPro machine is not able to make features on objects smaller than a couple of millimetres in size. A tooth is perhaps only 5mm across, so this means working at the limits of the machine. But 3D Systems recently began shipping a new micro-SLA 3D printer, the Projet 1200, with a cost of $4,999, that quickly produces very tiny parts at low cost. This printer can print dental ‘wax ups’ that are used in production of dental crown and partials, as well as jewellery casting patterns and other small components. At the top end of the market, metal and ceramic teeth can be printed directly on much more expensive 3D printers such as Direct Metal Sintering systems. But as development of these technologies increases then it starts to become a possibility for lower cost printers. However, it is not always about making things that are designed to fit permanently in people mouths – dental tools can be made for training purposes or perhaps checking a fit in the field of orthodontics.

There are also other aspects of medicine, in orthopaedics for example, making insoles for shoes as a walking aid perhaps, or the production of precisely customised artificial limbs that perfectly fit the end user. And again at the top end of the medical arena, printers from 3D Systems have been in used in human facial reconstruction applications, for example by the ‘Centre for Applied Reconstructive Technologies in Surgery (CARTIS)’ in South Wales.

 

Research

A key element in research is obtaining specific tools or devices for experimental investigations in scientific or engineering fields. Whether it’s a multi-billion dollar research operation looking into fundamental particles and the nature of the universe or biological research in a small laboratory, the very nature of research dictates these are things never looked at before, and the necessary tools are unlikely to be found off-the-shelf. Traditionally, a scientific or engineering research laboratory would have access to a workshop that could make things using conventional tooling. But in many cases, required objects or devices could easily and quickly be constructed using 3D printers. And because the researchers will typically need only one or two items, a 3D printer is the ideal provider.

But these are just a few areas and markets where 3D printing can make an impact. As the hardware becomes cheaper, in conjunction with the technical know-how to mix materials with different properties and colours in increasingly low-cost printers, then the list of possible applications is only limited by the imagination.

Low-cost 3D printing machines currently available from RS Components include those from RepRapPro such as the low-cost self-replicating Ormerod 3D printing kit, and from 3D Systems including the Cube and CubeX ranges