CTS takes a closer look at 3D printing, what’s preventing businesses from adopting the technology and how you can manage material quality.

3D printing, sometimes known as additive manufacturing (AM), is one of the biggest technological innovations of the decade. It is technology that can allow you to build anything from the ground up, so long as you have the appropriate schematic.

Additive manufacturing is set to revolutionise the way we do things. Imagine producing and manufacturing spare parts for equipment in remote locations like on oil rigs and in space? Or even purchasing, downloading and printing a tool for use immediately? The possibilities are endless.

Missed opportunities

More than half of the UK’s workforce lack awareness about the revolutionary benefits of 3D printing, which could hold back the economy in comparison to other, more innovative nations. In a survey conducted by 3D printing specialist King of Servers, 88 per cent of respondents do not have a 3D printer in their workplace, while only six per cent said their workplace had invested in one to date.

Furthermore, 63 per cent went on to state that, to the best of their knowledge, their employer was not planning on purchasing a 3D printer. Simon Thomas, 3D printing specialist at King of Servers says it is concerning that the majority of businesses do not realise what the benefits are of the technology.

“I see every day how 3D printing can transform what is possible for UK businesses in a whole host of private and public sectors, so it is disappointing to know that the vast majority of people across the country are not given the chance to work with this revolutionary technology,” he adds.

Some 57 per cent of respondents said they were either unaware, very unaware or did not know about the benefits of 3D printing in the workplace. In addition, 45 per cent said they did not know to what extent their company could be improved with a 3D printer.

However, the data showed that among the few that did work with a 3D printer, 58 per cent would recommend the technology to another company or peer within their sector.

“The data, as well as anecdotal evidence when working with companies, shows that once a business invests in 3D printing, they find it hard to imagine going without the cost savings, return on investment and creativity that comes with it,” Thomas says. “I believe this lack of adoption could really begin to harm UK companies, setting the UK economy back further than economic rivals like the US.”

According to Sculpteo’s most recent State of 3D Printing report, Americans have more experience than Europeans when it comes to 3D printing (3.13 years compared to 2.82 years), while 3D printing is more integrated in American companies’ strategies (43 per cent versus 34 per cent). In addition, the report stated American firms tend to spend more money on external 3D printing services than their European counterparts.

Barriers to adopting 3D printing

In a briefing paper by Imperial College London, it was suggested that some of the main reasons for the slow uptake for 3D printers include the perceived high cost of 3D printers and materials, design tools that do not adequately exploit the full potential of AM and a lack of suitably trained professionals working with 3D printers. These challenges remain despite public funding for additive manufacturing research in the UK increasing from £8 million to around £55 million in 2016.

“Experts in the UK have been saying for years how 3D printers will revolutionise the businesses that embrace the technology, but in that time there has been more talk than action,” Thomas adds. “While it’s great to see that more money is being invested into research, 3D printing is still seen as something of a taboo in practical terms. ‘It’s a novelty product’ and ‘it’s just a phase’ are things I still hear today and, suffice to say, they are the exact same noises I heard when standard printing came about.

“One of the main barriers to adoption of this technology is perceived cost. However, many people are now surprised to find that 3D printing technology is considerably less expensive than they thought. In addition, the total cost savings and return on investment can be huge. One typical user case is where a global car manufacturer saved on average £600,000 per month with the deployment of low-cost, high quality 3D printers over multiple sites.”

How 3D printing works

3D printing works by turning a whole object into tiny slices, producing an item from the bottom up, piece by piece. These tiny slices glue together to form a solid object. Depending on the type of 3D printer, the heated extruder head moves in three dimensions while the printer lays down the filament, layer by layer. Each layer can be complex, meaning 3D printers can integrate moving parts, such as wheels and hinges, onto the same piece.

“The materials used in additive manufacturing are instrumental in determining the look, feel and quality of the item printed,” Peter Morgan, product specialist from Elementar, explains. “The majority of 3D printers use Polylactic acid (PLA) or Acrylonitrile Butadiene Styrene (ABS) filament. However, metals, wood and even biological matter can be used to produce an object.

“The model of a 3D object is loaded onto a computer in a three-axis grid. The X-axis represents the side-to-side movement of the print-extruder head, the Y-axis represents the front-to-back motion and the Z-axis represents the object’s height.

“The printer software calculates the height of the component and analyses how the extruder and the build platform must move to lay down the filament layers. This process, referred to as slicing, sees the printed object’s height sliced into individual layers for printing. The software then converts the slicing data into a language known as G-code, which is effectively the set of instructions needed by the printer to carry out the task.”

Plastics in 3D printing

The most common type of plastic 3D printing is a process called fused filament fabrication (FFF). A continuous filament of a thermoplastic material is fed through a moving printer extruder head. Molten plastic is then forced out of the print head nozzle to create the item to be printed.

FFF can offer numerous advantages to businesses using 3D printers. “This is because the properties of plastics are extraordinarily diverse, with density playing an instrumental role in the malleability of the material,” Morgan adds. “Polyethylene (PE), for instance, is the most common plastic on earth, and can be manufactured at different densities to serve different purposes. For example, Ultra High Molecular Weight PE (UHMWPE) is used in bulletproof vests and Low-Density PE (LDPE) is used for disposable packaging like shopping bags.”

With the considerations above, plastic, as a material, is extremely flexible in terms of its application and as such, is amongst the best material to use for 3D printing.

When considering using plastic for additive manufacturing applications, it is imperative to ensure that the plastic used is of the highest standard. This is because a lower quality plastic will result in an inferior 3D print. Organisations supplying plastic for use in 3D printers should consider the quality of the raw materials used when providing their customers with the materials for FFF.

Elemental analysis holds the key to determining the quality of plastics on an industrial scale. “Spot checks using elemental analysers, such as inductar cubes, can help to determine the quality of plastic,” Morgan, continues. “Plastic contains additives to change the properties of the polymer, and, as such, may increase nitrogen and sulphur quantities within the hydrocarbon. These elements may give undesirable physical characteristics, resulting in a lower quality print. A simple elemental analysis will identify impurities in the plastic, safeguarding against low quality plastics being distributed.”

Metals in 3D printing

Materials used in metal additive manufacturing are predominantly metal alloy powders that are combined with heat from a laser to fuse them into a solid form. Other additives may also be used, helping to catalyse the formation of the process and alter properties of the finished product.

Powders must be used because it is not possible to accurately ‘spray’ a molten metal. They also offer a range of benefits over current methods of manufacturing metals, such as forging or casting from a metal stock. These techniques limit the potential shapes and structures that can be produced due to the physical restrictions imposed by the moulds used.

“3D printing largely removes these constraints as the structure is built up in layers,” Morgan says. “This enables both the range and the complexity of the items that can be produced to be vastly increased.”

Checking the quality of a finished product

The quality of the powders used in additive manufacturing is incredibly important because these powders will impact on the physical properties of the finished product. For instance, powder plays a crucial role in shaping the product’s tensile strength/brittleness, impact resistance, heat tolerance and resistance to corrosion.

As the process requires the combination of multiple powders, a precise understanding of the chemical composition of the finished product is required. The carbon, sulphur, oxygen, nitrogen and hydrogen composition will impact on the physical properties of the final product. This is because elements that were present at the beginning of the process, may be lost or altered under the heating process.

“For this reason, it is important to be able to analyse the final product to compare the product’s elemental composition,” Morgan explains. “By comparing ‘good’ and ‘bad’ products, it is possible to understand what differences there are in elemental composition between the two.

“Another important point to consider is that the powders used in additive manufacturing can oxidise over time. That being the case, it is vital to gain a firm understanding of how quickly this will likely occur and to discover more about how this oxidisation will affect the finished item.”

How the future of additive manufacturing stacks up remains to be seen. However, the benefits of using powders – especially the removal of physical limitation of products – should mean them playing a hugely important role as the industry evolves and develops. Similarly, improvements in the quality of the powders used will help to increase the number of products that can be made.

“The current barriers to successful additive manufacturing are the physical properties of the alloys formed,” Morgan concludes. “They are brittle, and as such, cannot take the stress of a cast/forged metal item. When the technique is refined, it will be possible to produce 3D printed items cheaply. Right now, this is expensive due to the cost of the moulds that need to be created for the production of the piece. This is common with other items, such as plastics.”

With powders being vital to help revolutionise many industries, the importance of using high quality powders is clear. Additive manufacturing could play a crucial role in production in the years ahead – as such, it is imperative that the materials used are properly tested and analysed. With the right equipment, any fears that a powder is unsafe or unsuitable can be allayed.