How can manufacturers develop sophisticated customisable products at scale, such as printing electronics onto large curved glass surfaces, that are affordable both for the manufacturer and for the consumer?
Technologies for late-stage customisation are being researched through collaborative projects between the Institute for Manufacturing at the University of Cambridge and multinational glass manufacturer NSG Pilkington.
Sarah Wightman talks with the research teams to find out more.
Customisation is no longer the exclusive domain of the wealthiest companies. The demand from mass markets, both business and consumer, is for increased ability to personalise products, and innovative manufacturers are seeking ways to deliver this customisation in higher volumes at lower unit cost in order to gain competitive advantage.
Late stage customisation of curved glass can include additive electronics and sensors.
Emerging technologies, including advanced inkjet printing, have the potential to support ‘mass customisation’ by enabling product features to be added to order at a late stage in the manufacturing process.
Researchers at the Institute for Manufacturing (IfM) are collaborating with glass manufacturer NSG Pilkington to investigate how the capabilities offered by inkjet can be scaled up for customisation that is affordable both for the manufacturer and the customer.
Dr Ronan Daly, Head of the Fluids in Advanced Manufacturing research group at the IfM, explains; “We have been working with NSG to research and test technologies for printing customised embedded electronics, sensors and other features onto curved glass surfaces at scale.
“This is a technically challenging process, but a potentially exciting one: rather than embedding the electronics onto the glass earlier in production, the use of inkjet printing technology will allow late-stage customisation to order.”
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Customising curved glass
Large curved glass components are used in many different types of product. In certain applications, such as automotive glass products (mainly windscreen, windows and mirrors) – production involves a range of multiple-layer processing steps before the glass is formed into curved shapes.
The current manufacturing of float glass and advanced coatings is only efficient with continuous production and can make customisation difficult and costly if it happens early in the production process.
However, NSG Pilkington’s R&D team has identified that inkjet printing can enable customisation at a later stage in the process.
A range of product features (including embedded sensors and security features) can be added using inkjet, through advanced functional material deposition directly to product surfaces.
“A particular challenge is to identify new techniques for printing directly onto larger curved surfaces,” Dr Ronan Daly added.
“Existing technologies for achieving this have limitations: these include continuous inkjet printing (CIJ) which is used for printing barcodes and best-before dates to items like small bottles, but this can be limited in terms of achievable colour and precision over larger surfaces.
“There has been increasing interest in using Drop on demand (DoD) printing in printing to complex shapes, but this will face severe challenges in terms of precision and predictable drop placement when working on non-flat surfaces.”
One of the other technical issues with printing on to large or complex surfaces is that the printhead itself needs to be moved across the product. This is different from the existing solutions where the product is the moving element, using automation to enable simple, smaller curved surfaces to move past the inkjet printhead.
Dr Cristina Rodriguez Rivero, a researcher in the inkjet team at the IfM, is working to address these challenges. Her research is focused on droplet and jet behaviour, inkjet visualisation techniques, aerodynamic effects and complex fluid behaviour in the micro- and milli-scales.
“To develop an improved understanding of printing direct-to-shape,” she explained, “we are working with NSG Pilkington to map the detailed surface textures and chemistries that will need to be coated. We can then examine with ultra-high-speed imaging the surface impact and drying dynamics of advanced functional material inks.
“There is a strong link between misplacement of ink droplets and the surrounding airflows. We are working to understand this better, in order to improve the ability to deliver sensors, responsive surfaces and electrical pathways to non-flat surfaces.
“To do this, we apply advanced visualisation techniques to study droplets and airflows in commercial and in-house equipment to analyse the effect of a variety of printing parameters.”
“By developing virtual simulation of product printing, we can determine the influence of factors that can affect the precision of the process, including angle of approach, rate of printhead rotation and required distances. Pilot trials are planned for testing different product requirements,” Dr Rivero added.
Scaling-up customisation
It is one thing to establish new techniques in the lab, and quite another to scale them up for a manufacturing environment and for higher volume production. Techniques developed in the lab need to be tested in a production environment, and then further refined in the lab again.
The collaboration between NSG Pilkington and the IfM is enabling the necessary early research to guide long-term development of inkjet printing techniques to create active devices and conductive tracks on advanced curved glass products.
“We focus on the need to understand the challenges of scaling up, so our collaboration with manufacturers including NSG Pilkington provides a way to test and analyse lab-based results in a production environment,” Dr Daly explained.
“Issues such as the impact of airflows on inkjet accuracy need to be understood both in the lab and in the factory for development of technologies which are both cutting-edge and robust. We anticipate that establishing and refining production techniques using advanced inkjet printing to be reliable in a factory environment will enable manufacturers to unlock affordable customisation in higher volume.”
In addition to advanced inkjet technologies, researchers at the IfM are also investigating laser techniques for printing integrated electronics onto glass. This has potentially valuable applications in a range of sectors including automotive, solar energy and display technologies.
PhD researcher James Macdonald has been working on laser induced reverse transfer (LIRT) for this purpose – a direct-write method to produce patterned deposits including conductive tracks on glass.
The process involves passing a laser through a transparent layer (glass) to a target layer of material (such as metal) which is vaporised by the laser. This ejects a plume of the target material, which is transferred to the underside of the glass.
The use of digital manufacturing techniques allows for customisable, cost-effective fabrication with low input resource requirements.
Conventional techniques for depositing thin layers of metal onto glass involve mask fabrication, but the cost constraints of this method require a high volume of units to be produced using each mask, with masks being expensive and slow to change.
LIRT, in contrast, can enable digital patterns to be changed much more quickly and easily, allowing more variation or customisation for a lower unit volume without prohibitive cost.
This project, led by the Institute for Manufacturing, is supported by NSG Pilkington, EPSRC, and the Worshipful Company of Engineers.
The Fluids in Advanced Manufacturing research group at the Institute for Manufacturing tackles the complex fluid flow and functional material challenges and delivers the science to enable scaleup to real manufacturing.
For more information, visit: www.ifm.eng.cam.ac.uk/research/fiam/
Nurturing innovation
NSG Pilkington has a dedicated R&D facility at its European Technical Centre in Lathom, Lancashire, where technicians have the freedom to test new ideas and look ahead to the next big trends that will shape the future of glass.
Known as the Pilkington Innovation Incubator, the facility is a base where NSG Pilkington’s staff can collaborate with any partner – from new tech start-ups, to larger businesses in other industries, to universities – in the pursuit of technological breakthroughs.
Dr Su Varma, Incubation Portfolio Manager R&D, has been at the forefront of building and growing the Innovation Incubator at Lathom.
“The incubator is designed to look further into the future, at what the medium and long-term needs of the company may be in terms of technologies, and how these could give rise to new value-added products that take us into new markets,” he said.
“It’s about asking ‘Where are the opportunities in the future?’ Clearly, they tend to be outside of our normal glass world, which is why we link up with start-ups and other companies and universities including Cambridge to find those early-stage innovations that we should be thinking about.
“Our collaboration with Ronan Daly’s centre at the Institute for Manufacturing, University of Cambridge, has directly helped us to explore cutting edge applications of inkjet technologies.
“Once we have set up a project through the incubator, we will work to short timescales whereby we run the project for three months before inviting commercial colleagues to review it. If the commercial team believes there is a new, viable product in the offing, we will move it from the incubator into our normal, rigorous product development processes. We then fill the funnel mouth of the incubator with other new things and carry on.”
