Large Volume, Multi-material High Speed Sintering Machine
Lead Research Organisation:
University of Sheffield
Department Name: Mechanical Engineering
Abstract
Additive Manufacturing (aka industrial 3D Printing) technologies have been widely recognised as extremely important for the reshaping, re-shoring and sustainable growth of UK manufacturing. The lack of process speed has been cited as the greatest inhibitor to growth of Additive Manufacturing, identifying a need for speed improvement by 4-10X over today's technologies.
High Speed Sintering (http://www.lboro.ac.uk/enterprise/hss/) is an Additive Manufacturing process invented under EPSRC funded research with granted patents globally. High Speed Sintering (HSS) has the potential to be the world's first Additive Manufacturing process that is capable of producing robust polymer parts at a production rate quicker than 1 second per part and at a cost that is comparable with today's high volume manufacturing processes such as injection moulding. Additionally, HSS has the potential to create multi-material parts in a scalable manner. In this project we propose to create the world's first HSS machine capable of high part throughput and multi-materials and thus open up the possibility for a vast range of hitherto impossible research of international significance to be undertaken.
HSS works by first taking a 3D computer aided design model of a part to be made and slicing this into thin layers, each layer being represented by a 2D bitmap image file. A computer file containing all the bitmap images that comprise each layer of the part to be made is sent to an HSS machine. The machine starts by depositing a thin layer of fine polymer powder onto a flat platform and then printing the bitmap image of the bottom layer of the part to be made onto the powder using a special ink designed to absorb infra-red energy. Next, a lamp emits infra-red energy across the surface of the powder/ink and the ink absorbs the energy becoming hot enough to melt and fuse together the polymer powder directly beneath it - areas that have not been printed do not heat enough to melt the powder. The machine then deposits a further layer of powder over the first layer and prints the 2D shape of the next layer of the part being made and again applies infra-red energy over the bed surface. This melts particles under the ink in the second layer to each other but also melts these particles to those that were melted in the previous layer, starting to build up a 3D part. The process is repeated many times to create a part that is embedded in a "cake" of un-melted powder. The un-melted powder is then removed to reveal the part.
HSS has been proven to work on a small scale using single materials. The aim of this project is to create a large machine with a bed area of 1m x 1m that is capable of creating many parts simultaneously. Our models predict that a 1m x 1m x 1m bed will enable a production rate of small components <1 second per part, representing a speed improvement over 10X compared to today's comparable state of the art machines. The machine we will make will also allow us to print further materials additional to the ink that absorbs infra-red energy - for example we will be able to print conductive inks so that we can create parts with embedded electronic circuitry and devices such as capacitors.
There will be significant technical challenges to create the machine especially in terms of powder deposition and thermal control; our additional ambition to create multi-material parts will present substantial challenges in terms of inkjet printing and thermal control of dissimilar materials. We will address these challenges by first conducting a range of experiments into aspects such as method of powder deposition and approaches to printing dissimilar inks to inform our design decisions. We will create the machine by employing a team of engineers with a strong track record for producing manufacturing research equipment led by the lead inventor of the HSS process.
High Speed Sintering (http://www.lboro.ac.uk/enterprise/hss/) is an Additive Manufacturing process invented under EPSRC funded research with granted patents globally. High Speed Sintering (HSS) has the potential to be the world's first Additive Manufacturing process that is capable of producing robust polymer parts at a production rate quicker than 1 second per part and at a cost that is comparable with today's high volume manufacturing processes such as injection moulding. Additionally, HSS has the potential to create multi-material parts in a scalable manner. In this project we propose to create the world's first HSS machine capable of high part throughput and multi-materials and thus open up the possibility for a vast range of hitherto impossible research of international significance to be undertaken.
HSS works by first taking a 3D computer aided design model of a part to be made and slicing this into thin layers, each layer being represented by a 2D bitmap image file. A computer file containing all the bitmap images that comprise each layer of the part to be made is sent to an HSS machine. The machine starts by depositing a thin layer of fine polymer powder onto a flat platform and then printing the bitmap image of the bottom layer of the part to be made onto the powder using a special ink designed to absorb infra-red energy. Next, a lamp emits infra-red energy across the surface of the powder/ink and the ink absorbs the energy becoming hot enough to melt and fuse together the polymer powder directly beneath it - areas that have not been printed do not heat enough to melt the powder. The machine then deposits a further layer of powder over the first layer and prints the 2D shape of the next layer of the part being made and again applies infra-red energy over the bed surface. This melts particles under the ink in the second layer to each other but also melts these particles to those that were melted in the previous layer, starting to build up a 3D part. The process is repeated many times to create a part that is embedded in a "cake" of un-melted powder. The un-melted powder is then removed to reveal the part.
HSS has been proven to work on a small scale using single materials. The aim of this project is to create a large machine with a bed area of 1m x 1m that is capable of creating many parts simultaneously. Our models predict that a 1m x 1m x 1m bed will enable a production rate of small components <1 second per part, representing a speed improvement over 10X compared to today's comparable state of the art machines. The machine we will make will also allow us to print further materials additional to the ink that absorbs infra-red energy - for example we will be able to print conductive inks so that we can create parts with embedded electronic circuitry and devices such as capacitors.
There will be significant technical challenges to create the machine especially in terms of powder deposition and thermal control; our additional ambition to create multi-material parts will present substantial challenges in terms of inkjet printing and thermal control of dissimilar materials. We will address these challenges by first conducting a range of experiments into aspects such as method of powder deposition and approaches to printing dissimilar inks to inform our design decisions. We will create the machine by employing a team of engineers with a strong track record for producing manufacturing research equipment led by the lead inventor of the HSS process.
Planned Impact
The potential impacts form this project are profound. Additive Manufacturing has been identified as extremely important for the future of manufacturing globally but especially in developed economies such as the UK. However, a recent Technology Strategy Board (TSB) report - 'Shaping our National Competency in AM' - identifies the lack of process speed as the greatest inhibitor to growth of Additive Manufacturing, identifying a need for speed improvement by 4-10X over today's technologies. We propose to create an Additive Manufacturing machine that could create parts at a rate 50X faster than any comparable machine available today, competing on process rate and cost for the first time with high volume manufacturing processes such as injection moulding. Our machine will also allow the creation of parts with embedded functional materials. If we succeed we should expect substantial re-shaping of many sectors in manufacturing with products of increasing value and very high volumes being produced across the globe, including the UK. We should also expect this project to catalyse further new areas for research to ensure that UK manufacturing research remains a global leader.
Organisations
| Description | The overarching aim of this project was the design and manufacture of a large-volume, multi-material, High Speed Sintering (HSS) system, which has been achieved. Throughout this process we have been able to optimise many aspects of its functionality. We are currently in the process of fully characterising the system's manufacturing performance, and expect to publish the results of this within the next few months. Further understanding of the intricacies of thermal transfer and absorption across this larger build area has also been key. During the process of building this system, we have been able to undertake preliminary work on an existing, small-scale, HSS system, to begin to understand the potential for enhanced sensing and optimisation to scale up to the large system. This should enable us to make more rapid progress when we come to test these ideas on the large system. |
| Exploitation Route | Once we've completed characterisation of the system 'as is', it will be used for further research (both scientific and industrial) into the HSS process and the complexities of scaling up for large volume manufacture. Our EPSRC Future Manufacturing Hub in Manufacture using Advanced Powder Processes (Sheffield lead) will also feature the system as one of its Grand Challenges. voxeljet have recently commercialised a HSS system, and will benefit from evidence that scale-up is possible and the understanding obtained regarding challenges and sensing. Other HSS licensees who have chosen not to be named publicly will also benefit from the same. By enabling scale-up to speeds comparable with Injection Moulding, likely end-user beneficiaries will include Fast Moving Consumer Goods companies (e.g. Unilever, who have an existing history of working with Sheffield on High Speed Sintering projects), as well as automotive, where the production of geometrically complex parts in larger sizes than currently possible using powder-based AM will provide benefits in terms of material wastage, and optimisation of light-weight parts and components. Whilst a more difficult technical challenge, the additional ability to include functional materials (e.g. conductive tracks) into components will be of interest in many areas, and in particular for aerospace applications. |
| Sectors | Aerospace, Defence and Marine,Electronics,Energy,Manufacturing, including Industrial Biotechology,Transport |