The history of additive manufacturing and how it has revolutionized the global manufacturing sector
What is additive manufacturing?
Commonly known as ‘3D-printing’, additive manufacturing (AM) has revolutionized the world of manufacturing across a range of industries. Allowing 3D objects to be built, or printed, layer by layer from a computer-aided design (CAD), this process has realized what was once deemed science fiction. Additive manufacturing has seen significant progress in recent years, opening a plethora of possibilities for the future of manufacturing.
Despite being closely associated with modern manufacturing and cutting-edge innovation, additive manufacturing first emerged in 1987 in the form of stereolithography (SL). This is one type of AM which is typically used to create prototypes from polymer resins and is still commonly used today.
Types of additive manufacturing
Traditionally, manufacturers have utilized subtractive methods of processing in the past, such as molds, cutting and drilling. These processes can be considered as wasteful due to the unused excess material that goes into them.
As its name suggests, additive manufacturing provides an alternative cost-efficient process that reduces material waste. This process also comes in many types, each with their own benefits:
- Binder jetting- One of the most common types of AM, this method utilizes powder material and a binder which acts as an adhesive between the layers of powder. This straightforward process makes it generally faster than others but may be unsuitable for structural parts due to the binder material.
- Powder bed fusion (PBF)- Using a laser or electron beam, this process melts and fuses material together. This method works for a wide range of materials, including titanium, aluminium and stainless steel and is ideal for structural parts while being generally slower.
- Electron beam melting- This process uses focused thermal energy to fuse materials together, by melting them as they are deposited. Commonly used for metals including titanium, aluminium, stainless steel or copper in powder or wire form, the material is deposited using a nozzle onto a surface. This technique makes it ideal for repairing or adding to existing objects.
- Material extrusion- Material is heated and expelled through a nozzle where it is then deposited layer by layer. Each layer then naturally fuses to the next due to its molten state, making it capable of continuous operation, while offering good flexibility in terms of design for better precision.
- Sheet lamination- As its name suggests, this method allows the building of 3D objects through stacking and laminating thin sheets of material on top of each other. The final shape is then achieved through laser cutting CNC machining. This cost-effective method is more commonly used for prototyping.
- VAT polymerization- Using a vat of liquid polymer, this process uses precise UV light to harden the resin in the vat to harden the resin into the desired shape of an object. No structural support provided from the material due to the liquid nature of the process, but it allows for high levels of accuracy and detail.
- Material jetting- Similar to a traditional 2D ink printer, material jetting allows material to be jetted onto a surface where it is solidified and then built layer by layer. While this allows for high accuracy, it is limited to only polymer and wax parts.
What products are made using additive manufacturing?
While 3D printing is typically associated with innovative industries on the cutting edge of technology like aerospace and automotives, additive manufacturing is finding its way into a range of industries looking to streamline their production.
The most typical use of additive manufacturing is its use in prototyping and manufacturing. Whereas traditional injection-molded prototyping would normally be quite costly, taking weeks to produce a single mold, 3D-printing greatly reduces this production time. Not only does this significantly save on costs, but also helps in the early stages of prototyping which usually sees multiple iterations when improving on a design, bringing much greater flexibility.
On a more practical side, additive manufacturing is also becoming increasingly useful in construction. 3D printing technology is now fully capable of printing walls, structures and processing cement. In 2016, the Dubai Future Foundation (DFF) manged to design and construct the world’s first fully-functioning 3D printed building in the form of its ‘Office of the Future’. Construction involved using a robotic arm to complete the 17-day printing process before working on the interiors separately. The project was hailed as a ground-breaking initiative to showcase the potential of AM in construction.
With the cost of entry now decreasing, additive manufacturing has managed to make its way into several other industries, including the clothing market where it has been adopted to manufacture trainers in some cases as well as other items of clothing including accessories such as watches, bags, jewellery and even dresses. Some speculate that eventually 3D printing could be used to manufacture biodegradable clothes as a more sustainable means of production.
Consumer accessibility to 3D printing
AM has also managed to gain traction in the consumer market in the last decade, with consumer-grade printers becoming more widely available and easily affordable. Hobbyists are now able to make their 3D designs a reality, while being able to share and sell their designs with others to print for themselves. Small to medium-sized Resin printers are most commonly used amongst consumers to print miscellaneous designs, from figurines, to kitchen ware and phone accessories. Almost any small plastic item can be produced from home using 3D printing technology.
While consumer 3D printing is currently limited to polymer printing for smaller designs, some have speculated the possibility of printing more complex objects out of different materials. By moving away from plastic resin designs, this could mean a revolutionary change for consumers, being able to print more complicated items from design such as clothing or electronic components.
3D printing in education
The shift in manufacturing is also being reflected in the educational setting, where students are now being introduced to CAD allowing them to experience, first hand, the entire design process from conception to the final finished design. As AM becomes integral in more fields, it is imperative that students become familiar with it at an earlier age.
Outside of manufacturing, education has also benefitted from the integration of physical models into other subjects. Being able to print out physical models of molecules, historical artifacts, organs and more for closer examination, teachers can now create a more engaging experience for pupils.
The future of additive manufacturing
The recent pandemic highlighted existing weaknesses in the global supply chain which gave a significant boost to the AM industry. The Association for Supply Chain Management reported that 66% of supply chain professionals experienced some form of regular disruption in the chain during 2020.
Localizing supply chains through digitalized designs and on-site printing helped to offset the overreliance on international trade. A prime example of this was the printing of PPE equipment during the pandemic to offset the shortages for healthcare workers. This trend is expected to grow for the foreseeable future with sustainability becoming an increasing concern for businesses across the globe. As well as reducing energy and transport costs, stricter regulations on supply are also expected to drive more companies towards an eco-friendly means of production.
Recycling AM powder
For improved sustainability and better product quality, recycling AM powder is a crucial step within the 3D printing process. After the completion of a 3D build there is typically virgin powder left over in the powder bed which can be reused in the next process but requires separation from any oversize and contaminants.
To combat this issue, companies like Russell Finex have built automated powder handling solutions to streamline the recycling process. AM Powder handling solutions allow manufacturers to qualify AM powder, screening it before it enters the production process.
The challenges of additive manufacturing
So, what are the barriers preventing the global implementation of AM across all industries? Despite its flexibility there are significant limiting factors such as the range of compatible materials, cost of entry and time.
While 3D printing is ideal for prototyping different types of parts and objects, it makes less sense as an alternative to high volume manufacturing of a single type of object. This leads to poor economies of scale where it would make more financial sense to invest in a single injection mold specialized in producing a single part for better cost and time efficiency. For one-off testing or prototyping, 3D printing is a lot cheaper than creating a new injection mold, but the initial cost is expensive and current technology for specialized manufacturing is more efficient.
The range of materials currently available for 3D printing are also limited to mainly polymers, select metals and concrete. Meanwhile, materials such as stone, wood and cloth cannot be 3D printed as they burn instead of melt under high temperatures making it impossible to extrude or layer on top of each other. This limitation poses issues for some industries more than others, but there are already projects for alternative materials including 3D-printed fabrics.
With the world becoming more digitalized, AM is considered to be the natural evolution of manufacturing to reflect a global digital age where file designs will eventually replace injection molds. By allowing items to be printed locally on demand, additive manufacturing is at a critical point where it has the potential to solve supply chain and energy issues. However, it still has a way to go before it becomes the transformative technology that is adopted universally across all manufacturing fields.