Borealis is a collaborative project funded under the European Union’s Horizon 2020 research and innovation programme whose general objective is to exploit a decade of advanced R&D results in mechatronics and laser processing to demonstrate a novel machine that will produce, at unprecedented throughput and efficiency, with closed loop controlled and certified quality (zero faulty parts delivered), large and complex (in geometry, functionality, composition) products. The machine integrates an innovative solution performing multi-material Additive Manufacturing (AM) deposition and ablation. It exploits the process of Direct Energy Deposition (DED) for metal deposition, where focused thermal energy coming from a laser source is used to fuse metal powders blown through a nozzle thanks to an assisting gas. For the first-time ablation technology will complement the AM fabrication process for metal manufacturing to allow surface finishing and micro texturing that would be otherwise unfeasible in traditional machines. Moreover, Borealis presents an advanced closed loop control methodology for product and process quality monitoring.Borealis presents a redundant machine architecture with 11 degrees of freedom, 4 on the depo-head, 3 on the machine portal, 2 on the galvo scan head and 2 on the a roto-tilting table, whose design enables the reaching of working cubes ranging from 150x150 mm (15° tilt in two directions) up to 4000x1500x750 mm.The demonstrators use cases of the projects are respectively an ADT main housing (Avio Aero) made in A357, an endo-prosthesis for hand surgery (Sintea Plustek) and an automotive gearbox (DIAD Group ES) made in Titanium Alloy, embracing the aerospace, med-tech and motorsport sectors.
THE DEPOSITION HEAD
Borealis mounts a redundant deposition head, engineered by SUPSI, with 2 cartesian and 2 rotational degrees of freedom. It is equipped with a new concept of nozzle with double chamber which supports an efficient usage of carrier gas and ensures an high deposition efficiency . The design of the head itself has been conceived in order to host the placement of the galvanometric scanner head on the top while ensuring the proper distance from the workpiece.
The resource efficiency is an essential topic in the Borealis machine design as it will enable the ability of the machine to boost the process efficiency while minimizing the amount of powder wasted, thus positively impacting on the final product manufacturing cost.
The Borealis’ laser source is an innovative hybrid source obtained by combining a high-power 3 kW continuous-wave (CW) laser, used for the deposition phase, and a 100 W nanosecond pulsed fiber (PW) laser, used for the ablation phase. This solution, available only in the small demonstrator, has been specifically devised to allow alternating additive and subtractive processes, requiring the development of an optical chain that includes two innovative devices: a system to combine the beams emitted by the two sources into a common path and a 3D scanner head able to operate with both beams.
The 3D galvo-scanner includes 2 axis (x and y) to move the beam in the working area, and a third axis (z-axis) to change the spot size. Another key element of the Borealis machine optical system is the innovative beam combiner, specifically developed by OPI Photonics; this device receives the two CW and PW laser beams in separate inputs and redirects the selected source into the scanner head.
The Borealis machine is equipped with a properly designed vision and sensing system that enables the effective monitoring of the process while the manufacturing is running. The goal of this equipment is to capture additional information about the manufacturing process that can be used to react and update the control action and strategy to improve the performance of the machine and the quality of the manufactured parts.
The vision system supports the monitoring of the laser melting process using a ccd camera integrated on the scanner head for monitoring size and shape of the melting pool, the analysis of the surface and the structure of the workpiece being constructed using a pattern projector and infrared camera for thermal data and the reconstruction of the part in a cloud of points for closed loop control of the process.
A high-speed camera is embedded within the laser head and is dedicated to the monitoring of the melt pool. In order to perform such a monitoring, the camera is equipped with a specific optical system and positioned inside the machine tool head to capture images in-axis with the laser beam. Such a solution enables to monitor the size and shape of the melt pool from the best point of view, without obstacles in the field of view of the device.
Monitoring of the thermal profile and the structure of the metal parts being produced is performed using a set of 2 visual cameras, an infrared (IR) camera and an additional pattern projector for actively illuminating the individual workpieces and implementing in this way the 3D surface using structural light.
The entire vision system is included in a “vision box”, which is placed on the top of the z axis and can be moved towards the workpiece from the top and capture the scene.
The CAD systems describes the design of a product in the form of geometry and tolerances. CAM packages support the definition of tool path strategies, accommodates process plans defined in CAPP and post process this data into a format understandable by the CNC. Once the AM built layout is defined, the CAPP will provide information about the most appropriate process strategies for the part(s) to be manufactured.
A CAM strategy is also employed for controlling the ablation process that will be used to correct minor defects that come about as part of the deposition process. To drive this ablation strategy, information delivered by the machine about the current state of the in-progress build are required. The information collected from the system is expected to be a cloud of points representing some portion of the deposited material.
The Process Control Package is responsible for synchronizing the motion actions with the various peripheral elements like laser, nozzle and shielding gas. It includes also a vision System to analyse the process execution and providing information to the CAx system and a CAD/CAM/CAPP chain to generate the next execution layer strategy or a “recovery action” in case of mismatches.
REFERENCE INDUSTRIAL SECTORS
The global commercial aerospace avionics market is expected to reach $8.3 billion by 2020, with a moderate CAGR of 3.9% during the forecast period (Source: Deloittle Report 2014). Despite the adverse economic conditions that have prevailed, total industry sales grew during the last six years. North America holds the largest share of revenue, followed by Europe. Globally, avionics and engine together account for approximately 39% of the market are expected to support the aerospace and defense industry going forward. Geographical analysis shows that the highest Compounded Annual Growth Rate (CAGR) of 14.2% is anticipated from Asia-Pacific region during the analysis period, 2011-2018. Europe follows Asia-Pacific with a CAGR of 12.9%, while North America forecasts to drive with a growth rate of 11.2%. Aerospace and Defense in developing countries such as China, India and Brazil are projected to immense as a great market place in future prospects.
The global market for dental implants and prostheses is estimated to be worth $9.1 billion by 2018 (source: MarketsandMarkets). This means a 30% increase compared with 2013, when the market was estimated to be worth $6.4 billion. The global market analyzed is segmented by implants, prostheses and geography. The dental implants market is classified by material, namely, Titanium and Zirconium. The prostheses market covers segments such as crowns and bridges, dentures, and abutments. The crowns and bridges segment is analyzed further by material. The total market is further divided into four major geographies, namely, North America, Europe, Asia Pacific, and the rest of the world.
Europe is the world’s largest producer of motor vehicles, having 183 production sites dedicated to assembly and powertrain production and more than 2.3 million people employed directly in the manufacture of motor vehicles and components (source: ACEA). This corresponds to almost 7% of all manufacturing employment in the EU27 (1% of total employment in the enlarged EU). It is estimated (source: ACEA) that the automotive industry supports more than 12 million sector-related jobs in Europe and increasingly, these are highly skilled jobs. This sector also makes a major contribution to EU’s Gross Domestic Product (GDP), and exports far more than it imports. For these reasons the Automotive sector is considered central to Europe’s employment and prosperity. In particular the extensive diffusion of turbocharged engines on the US, Cina and India market will represent an important opportunity of growth for the European automotive industries.
In order to guarantee the achievement of Borealis objectives and to efficiently manage related project complexity, a coherent work plan, over 3 years, had been developed. It was organized in 11 work packages clustered in Project Management, Scientific and Technical, Demonstration and Dissemination and Exploitation activities. Particularly, the RTD activities will map the Borealis solution development lifecycle from the product and technologies design phases to processes and equipment design phases till the data acquisition, control and optimization phases.
- WP1 aims at managing the overall project activities.
- WP2 refers to the study of the next generation of products design and the fusion of manufacturing technologies enabling complex geometries and cutting edge dynamic and structural properties.
- WP3 covers the activity of process design and planning where the actual manufacturing process is developed on the basis of the various available technologies and the products and production requirements.
- WP4 deals with the design and configuration of the laser source and the 3D scanner to be nested into Borealis machine.
- WP5 regards the configuration of the Borealis machine including the lightweight gantry and the PKM, which will host the laser head.
- WP6 addresses the design of the sensing system, including the complex vision infrastructure.
- WP7 outlines the design and development of the first of three step Borealis software infrastructure, i.e. the CAx chain which will lead to determine the process and machine adaptations to be executed to match the part and production quality requirements.
- WP8 pertains to the second of the three step Borealis software infrastructure, i.e. the Control design that is responsible for operatively realizing the adaptations identified in WP7.
- WP9 relates with the Borealis solution integration along with the last step of Borealis software infrastructure that is the overall optimization where all the aspects addressed at local level (e.g. process, machine and powder) are investigated and enhanced under a hierarchical optimization strategy selecting dynamically the energy, productivity and resource efficiency trade-offs and planning the strategies over the time.
- WP10 refers respectively to the development of one physical demonstrator and one lab demonstrator for the medtech, aerospace and automotive industries.
- WP11 ascertains an extensive dissemination and exploitation activities with the aim of boosting Borealis industrial solutions in future industrial practice.