3D Printed Rockets: Utilising 3D Printers to Develop and Manufacture Rocket Components
WHAT IS 3D PRINTING?
3D printing, also known as additive manufacturing, is the process by which a 3D solid object is formed originating from the creation of a digital file. The 3D object is formed through an additive method whereby a multitude of successive layers of material are laid down until an object takes form.
3D printing is the direct parallel to subtractive manufacturing whereby objects are cut out of a mass of material with the likes of a milling machine. 3D printed rockets and other objects created using additive manufacturing methods are initiated through the generation of a digital design which can be achieved either from the ground up using available software or alternatively, they can be downloaded from a 3D library.
Once a printable file has been generated or obtained, the file is then prepared for a 3D printer – this process is otherwise known as ‘slicing’. The term ‘slicing’ refers to the process of dividing a 3D object into a mass of different layers, which can be achieved using specific software. The ‘sliced’ file is then fed onto a 3D printer through an external hard drive or by utilising a Wi-Fi connection. The printer will then begin printing the object layer-by-layer. Click here to watch Skyrora’s 3D printer in action.
3D PRINTING IN INDUSTRY TODAY
The popularity of 3D printing is ever increasing, whereby organisations yet to eliminate the use of subtractive manufacturing methods are part of an ever-shrinking minority. In its early stages, additive manufacturing was predominantly suitable for one-off manufacturing and prototyping only. Today however, 3D printers are seen as a major production technology.
3D printers have proven to be harnessed successfully for a myriad of applications, to a point where additive manufacturing is used in most industries today. Some examples of objects generated through the additive manufacturing process include dental products, prosthetics, furniture pieces, manufacturing tools, etc.
WHAT CAN YOU MAKE WITH A 3D PRINTER?
Some specific examples of industries who use 3D printing to manufacture various components and products include the following: automotive; aviation; construction; consumer products such as footwear, eyewear, and jewellery; healthcare; and education.
THE ADVANTAGES OF 3D PRINTING
In comparison to traditional manufacturing methods, additive manufacturing offers an abundance of benefits in relation to time, cost, and design, among others. 3D printing allows the design of a solid object to be more complex than subtractive manufacturing methods. Such traditional methods of production restrict the design of an object which no longer apply to additive manufacturing.
3D printers have the ability to manufacture parts and components within a matter of hours, thus accelerating the time it takes to produce a prototype. Rapid prototyping allows for each stage of development to be complete in much less time than alternative manufacturing methods. Using additive manufacturing to produce prototype parts allows design modifications to be complete at a much more economical rate due to the high-speed rate at which the parts are produced.
Utilising a 3D printer requires minimal storage space as there is no need to print products in bulk unless specifically required, thus saving time and costs. 3D design files are stored on a virtual library before being printed as a 3D object from either a computer aided design (CAD) file and can therefore be located and printed as and when needed. Individual files can be edited if a design modification is required in both a time and cost-effective manner. This means that costs invested in tools or wasted on out-of-date or unused inventory are eradicated almost entirely with additive manufacturing.
The most common product utilised for 3D printing is plastic, although certain metals can also be used to produce 3D printed parts. The of use of plastic however offers alternative advantages than to metal as it is a lighter and more inexpensive material. In industries such as automotive and aerospace, the use of plastic to manufacture parts is advantageous specifically in relation to the deliverance of greater fuel efficiency. Parts can also be manufactured from tailored materials to provide specific properties to an object such as water repellence, greater strength, and heat resistance.
Depending on an object’s design complexity, a 3D printed part can be produced at a much faster rate compared to machined or moulded objects. Products can be designed in a CAD file in a short amount of time and can be ready to print just as quickly.
In contrast to subtractive manufacturing methods, the process of 3D printing only requires the exact materials that will be used to create the product. This enables resources to be saved while simultaneously reducing the expenditure on materials.
Due to its status as a single step method of manufacture, 3D printing is both time and cost-effective in the sense that only a single machine is used for the production process. 3D printers can also be unmanned during the printing process and therefore a paid operator is not required. Even the direct costs of the 3D printer itself can be avoided by outsourcing the work to a 3D printing service company.
The accessibility of 3D printing has been made easy through local service providers outsourcing manufacturing facilities to carry out additive manufacturing services. This offers a cost reduction in reference to transport in comparison to alternative manufacturing methods produced in countries abroad such as China.
THE DISADVANTAGES OF 3D PRINTING
As is the same with any manufacturing process, there are also certain disadvantages to consider in relation to additive manufacturing. There is a select limit on the materials that can be utilised by a 3D printer to manufacture solid objects as not all metals and plastics can be temperature controlled to the extent that would allow it to be used as part of the additive manufacturing process. Furthermore, a large multitude of printable materials available cannot be recycled nor are they food safe.
3D printers are often equipped with smaller printing chambers, thus restricting the size of the object in manufacture. Larger objects need to be broken down into even smaller parts and printed separately to then be joined together at a later date post-production. This has the potential to increase the amount of time the production process will take as well as the costs incurred as a result such as the costs of the manual labour required to join the different parts together.
Although the larger parts as mentioned above require post-processing due to their size, most 3D printed parts require cleaning up after manufacture to remove support material from the build of the object and to smooth the surface in attempt to achieve the required finish. This can involve processes such as sanding, air or heat drying, water jetting, a chemical soak and rinse, and others. The methods involved as part of the post-processing are dependent on factors such as the size of the object in manufacture, the intended applications of the object, as well as the type of 3D printing technology used to produce the object. While additive manufacturing has the ability to enable rapid production of parts, this may be slowed depending on the extent of post-processing required.
Compared to subtractive manufacturing methods that often utilise manufacture techniques such as injection moulding, 3D printing is a static cost whereby scaling up to produce larger volumes of an object for mass production does not justify a reduction in the cost per unit as it would with injection moulding for example.
Due to the nature of the structure of objects created as a result of 3D printing, under certain orientations of stresses the different layers of the object have the potential to delaminate. This is a particular area of concern with regard to objects produced via fused deposition modelling (FDM) methods.
Additive manufacturing and 3D technology also has the potential to generate a reduction in the need for human labour, seeing as a majority of the production process is fully automated and completed by printers.
Certain types of 3D printers have lower printing tolerances, which has the potential to lead to design inaccuracies, with the final product differing from the original design. Such inaccuracies can be altered during the post-processing stage, though this may delay the time of production and therefore increase the cost of production.
Copyright and quality control may become more difficult to control as the use of 3D printing becomes increasingly popular and accessible. The production of fake and counterfeit objects is easily facilitated through additive manufacturing methods, whereby it is near-impossible to differentiate between an original and its replica.
ENVIRONMENTAL BENEFITS OF 3D PRINTING
3D printed objects are considered to have many benefits over other objects manufactured by processes considered to be the industry standard. Due to the fact that there is very little material waste produced as a result of additive manufacturing methods, excess drilling, cutting, and milling is therefore not a requirement. Minimal refinement and assembly additionally results in a reduction of storage before sale and distribution.
Currently in everyday 3D printing there are two types of plastics that are predominantly utilised. The first is known as acrylonitrile butadiene styrene, better known as ABS. The second is polylactic acid, or PLA. Both of these plastics are referred to as ‘thermoplastics’ due to their ability to melt and be moulded under certain temperatures.
PLA is corn-based and is categorised as a renewable form of thermoplastic material, producing significantly fewer toxic emissions during the printing stage than alternative plastics. This material even minimises the amount of waste produced when used as a filament for additive manufacturing.
There are additional methods that can be applied to additive manufacturing processes in order to minimise the environmental impact it causes. One of these methods is to use smarter materials and filaments, and another is to use less energy. This can be achieved by either changing the part orientation while printing, printing objects with hollow parts, or printing more than one part at a time on the printer bed.
Hollow objects being created under additive manufacturing methods require less materials and are therefore able to be printed faster. Complex objects occasionally require support materials, though even so, a hollow object will still utilise faster printing times and produce fewer overall emissions. Printing taller objects on their side is an additional way of speeding up the printing process in order to reduce or completely eradicate the need for support materials. The bioplastic known as PLA also uses less energy to produce objects and less energy to print with.
3D printed products tend to last for a longer period of time than objects produced using traditional manufacturing methods, therefore resulting in less general waste. An increased and more widespread use of 3D printing would see a higher level of manufacturing returned to local communities, thus reducing the need for transportation and therefore the environmental impact. Further information regarding the environmental implications of additive manufacturing can be found here.
SKYRORA’S USE OF 3D PRINTING: 3D PRINTED ROCKETS PARTS
Over two thirds of commercial and industrial waste is generated by the commercial sector in the UK. In 2016 alone, the UK commercial and industrial sectors generated 41.1 million tonnes of waste.
Skyrora utilises 3D printing to manufacture an array of infrastructural materials and rocket components. Currently used majoritively for custom items and prototype creations, additive manufacturing consistently utilises fewer quantities of material than conventional manufacturing processes, as the procedures of 3D printing enable the user to fuse, sinter, melt, and bind only the precise volume of material necessary in the production of a specific part.
This method of manufacture has the added ability to produce parts from anywhere, thus reducing the need for transportation of items and lowering the emissions relative to such transportation as a result.
Furthermore, rocket parts produced using a 3D printer have the potential to weigh up to 50% lighter than products manufactured using traditional methods. This is due to the fact that additive manufacturing produces a structural integrity unachievable through alternative production processes. Attributable to the reduction in weight of parts, less energy is therefore required to transport said parts.
A liquid bi-propellant rocket engine became Skyrora’s first 3D-printed component part. It became a huge milestone for the company since the technology allowed fast assembly — only 2-3 months — and precision welding. The ground-breaking, 3-tonne thrust engine was manufactured at the Scottish production facility and, as of now, remains one of the largest rocket engines ever produced in the UK.
The technology behind 3D printing of rocket component parts is based on additive manufacturing techniques and complex materials, such as Inconel. The actual production method is called ‘powder bed fusion,’ meaning that a laser melts and fuses metal powder together. Skyrora chose to 3D-print its rocket component parts because this technology significantly simplifies the manufacturing process and decreases part count. All of this combined drastically reduces the cost of manufacturing. Learn more about the development of the engine here.
Skyrora’s rocket engines have all been manufactured via 3D printing methods. Skyrora’s 3D printed rocket engines in the design suite thus far have all undergone successful testing and have been used to facilitate several rocket launches including the launch of Skylark Micro from Iceland. Read more about the launch here.
REFERENCES
1. TWI. (2021). What are the advantages and disadvantages of 3D printing?. Available: https://www.twi-global.com/technical-knowledge/faqs/what-is-3d-printing/pros-and-cons. Last accessed 22.07.2021
2. Zortrax. (2017). Is 3D Printing Beneficial for the Environment?. Available: https://zortrax.com/blog/3d-printing-beneficial-environment/. Last accessed 22.07.2021.
3. Flynt, J. (2017). The Environmental Impact of 3D Printing. Available: https://3dinsider.com/environmental-impact-3d-printing/. Last accessed 22.07.2021.
