The factory of the future brings to mind abstract concepts like big data, artificial intelligence, digital twins, algorithms and connected machines. It creates for us a vision of speed, communication and flexibility. What is not always addressed is how you turn all these ideas into products you can touch. What tools are equally fast, flexible and free of physical constraints, and can actually machine a workpiece in these highly connected and flexible processes?
This is where the world of photonics comes in – the science of harnessing photons through the cutting edge use of lasers and fibre optics – and it has become a key technology for smart factories. The connection between data and the physical world is a focused beam of light that is weightless and contactless – connected light.
And look at what that light can do. The capabilities of lasers alone range from ablation and material deposition to drilling, cutting, joining, perforating, welding and creating metallurgical changes, as well as roughening, smoothing, hardening and cleaning surfaces.
Machining at the speed of light
One of the biggest advantages of lasers is that they can process whatever material you like, from metals and glass to plastics and even skin. They give you complete freedom. They don’t have tool changes, they don’t break down and they don’t wear out.
They also have a high degree of precision in processes monitored by sensors to produce micro and even nanosystems; and they are ideal for sensitive materials, as heat input can be controlled precisely. In combination with scanners and sensors, control loops are possible that adjust themselves in real time. Smart lasers understand what material they are processing, how the process develops and when it is finished; and they can adapt to changes in the material such as shape, reflectivity, thickness and orientation.
Photonics is the enabler
Photonics is widespread in industries ranging from automotive, aeronautical and mechanical engineering, to plastics, glass and electronics. Lasers can be used to manufacture a strong, lightweight wind turbine blade or the crash-safe chassis of a car. The production of batteries, fuel cells and solar cells requires laser technology. Shipbuilding yards use lasers to cut and weld enormous steel structures for freighters.
Every semiconductor chip today is manufactured using optical lithography; and photonics provides smart factories with optical fibres for high speed, reliable data communication, fibre lasers for production, and sensors for intelligent feedback.
Laser technologies also provide the accuracy and flexibility needed for the production of millions of electric motors, electronic power components and lightweight 3D printed metals and plastics. Laser-welded hairpins are replacing costly windings in electric motors. Laser-cut electrical sheets have advantages over mechanically machined sheets in the production of motors.
Changing the game
The vision of IIoT is to create smart, efficient factories where autonomous machines can recognise their surroundings and communicate with other machines, as well as people. Intelligent production means the machine finds out for itself what to do. This is done by using photonic sensors to combine data connectivity, sensor technology, speed and artificial intelligence.
This is already happening. With reliable in-line quality monitoring, many machines in today’s production lines are now intelligent enough to interface and operate themselves without the need for manual input. They can deliver reports automatically as well as report or shut down any processes after analysing the data collected. For example, a machine can recommend a change in material flow if it identifies an interruption in the production line or a change in average completion times for a process. Sensor systems enable safe human-machine cooperation.
Small batch sizes need flexibility and easily controllable tools. This is a problem in factories that still depend heavily on mechanical processes such as milling, punching, sawing and drilling. But mechanical tools are gradually being phased out. They are being replaced by lasers, which offer a faster, simpler and more flexible way to produce things on demand. These are the trends:
• Manufacturing chains using lasers are on their way in, manufacturing chains using mechanical tools are on their way out
• The actual workpieces are turning into data carriers with the power to communicate
• Individual parts are being made from data sets
• Part shapes can be changed with each different set of data
Smart laser industries
These are some of the industries where lasers are paving the way for IIoT, with the processes provided by cutting edge companies such as Trumpf, Coherent|ROFIN, II-VI HIGHYAG, IPG-Laser and Manz.
Additive manufacturing
Also called 3D printing, this allows fully automated, digitally controlled serial production from one unit. Lasers build up highly complex components layer by layer from metallic or plastic powder – without tools and with previously unimaginable design freedom.
Photonics for a new era of mobility
The automotive industry is driving two future global projects: electromobility and autonomous driving. Based on a survey of more than 320 automotive manufacturers, digital transformation consultancy firm Capgemini reports that smart factories could add up to $160 billion annually to the auto industry alone in productivity gains by 2023.
Lasers play a key role in high voltage battery manufacturing. One third of an electric vehicle’s added value is accounted for by the battery process chain alone – considered to be the very nucleus of electromobility. Lasers are as indispensable here as in in-line process monitoring. The same is true of the complex manufacturing processes needed for the mass production of electric motors, power electronics and lightweight designs.
Imaging specialists such as Keyence, Stemmer and PCO contribute indispensable in-line inspection solutions for battery cell manufacturing. Cell service life and operating safety are often a question of nanometres and micrometres. Sensors measure electrode thickness, monitor the homogeneous distribution of active materials, and control all the rolling, drying, cutting and welding processes, enabling production defects and deviations in tolerances to be immediately rectified.
Photonics also forms the backbone of automated driving, for imaging, sensing, smart displays and media communication networks. Light detection and ranging (Lidar) systems for control and navigation in autonomous vehicles are replacing the sensory perception of human drivers. Optical sensors generate massive volumes of data (in the terabyte range every hour), so the trend is towards intelligent sensor systems that perform their own data analysis before deciding which data to forward to the on-board computers. This high level computing power in confined spaces together with efficient data transmission would not be possible without laser technology and optical inspection.
Printing
The printing process chain is another typical example of IIoT in action. Small print runs and personalised prints mean more frequent order changes, so automated process chains prevail. Printing is done on packaging, glass, metal and ceramics, as well as on individualised print products. Inks are fixed on surfaces with UV or IR heaters or LED technology. Laser and camera systems control the quality.
Codes applied by laser to the products transport the control information to the respective machining centres and robots. These codes allow clear allocation of production parameters to individual products and also make the process transparent. The production status can be tracked and documented. The codes also contain shipping information.
Ultrashort-pulse laser technology
At the cutting edge, ultrashort-pulse laser (USPL) technology, awarded the 2018 Nobel Prize in physics, is rapidly breaking into industrial production. This is set to transform the photonics landscape and revolutionise applications for IIoT. Operating at extremely high peak intensity and ultrashort pulse widths in the femtosecond range (10-15 seconds), USPLs suppress heat diffusion to the surroundings and enable ultra-high precision nanofabrication of a wide range of materials that cannot be achieved with existing microfabrication technologies. Optical fibres will soon distribute the energy from USPL lasers instead of solid-state lasers, paving the way for completely new applications.
In the automotive and railway industries USPL technology meets the demand for miniaturisation, high precision, high quality, applicability to a diversity of materials, smaller lots and cost-effectiveness. For example, ultrafast lasers have been used to produce exhaust gas sensors made of special ceramic layer systems. Panasonic has used picosecond lasers in mass production to produce funnel-shaped ink-jet nozzles. Irradiation by a femtosecond laser in halogen gas produces conical microstructures on a Si surface that can act as an antireflective surface. This technique was commercialised by SiOnyx for the production of photovoltaic Si solar cells and led to a 15% reduction in costs.
In addition, the development of killer apps for semiconductor chips such as printed board drilling by CO2 lasers and photolithography by excimer lasers will establish a firm position for USPL processing in manufacturing.
Adaptive beam shaping
Another approach to smart laser manufacturing is being pursued by research fellow Dr Ben Mills at the Optical Research Centre of the University of Southhampton. He is combining the precision of femtosecond lasers with the high speed control of beam shape, potentially enabling some extraordinary new applications. “We’re ready to unlock a revolution in laser processing for applications ranging from sensing to healthcare,” says Mills of the highly customisable technology. The latest closed loop system self-corrects in real time, for example to work around a speck of dust – perfect for IIot.
The potential for industrial applications is significant – this beam-shaping approach enables processing in almost any material at extremely high precision. The current challenge is to move to 3D manufacturing. “We believe our technology will eventually enable the fabrication of 3D structures from almost any material at a resolution of hundreds of nanometres,” Mills concludes.
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