Innovation Exchange Challenge: Measurement of coated glass temperature within the furnace/manufacturing process

Background

Over the past 50 years almost every major advance in glass has come from Pilkington, from the invention of the float process to self-cleaning glass. Pilkington invests around £29 million a year in research and development focused on product development and manufacturing efficiency improvement.

Significant among these advances is the use of Chemical Vapour Deposition (CVD) for large area glass coating. The temperature of the glass substrate is critical to promoting & maintaining the growth of the coating which is typically made up of several individual layers, each contributing to the overall properties of the coating. The coating process takes place in the float bath where the glass is formed into a flat ribbon whilst floating on a bed of molten tin. The ability to accurately measure the glass temperature at different stages of the coating process is essential for effective control of product performance. Understanding and tuning of the glass temperature is also central to the development of new coating materials and new coated products.

Pyrometry is the standard method used to remotely measure glass temperature but difficulties arise due to the transparency of glass. Care must be taken to use an appropriate wavelength; some wavelengths sample only the surface, others measure the bulk, and it is possible to capture radiation from other sources which can influence the results. These challenges are generally manageable for standard glass substrates, but coated glass adds additional complexity.

In the automotive area, Pilkington has pioneered the use of press-bending technology to manufacture advanced, high-value, vehicle glazing. This technology has enabled industry firsts with complex glass shapes, very tight tolerances for glass surfaces, and augmented reality head-up display systems. With press-bending, each glass ply is formed between a male and female tooling to precisely control glass shape. Monitoring and controlling the temperature distribution of the glass before pressing is the critical process parameter; too cold and the glass will break during pressing, too hot and the tooling contact can cause optical distortion. Modern windshields incorporate different coatings in selected areas of the glazing for obscuration and infra-red reflection. At the processing temperatures the emissivity of these materials is not well defined and can change during processing. Fixed wavelength scanning pyrometry system cannot accurately map the temperature of the glass.

The Challenge

The challenge holder has identified two specific applications requiring more accurate & reliable measurement of coated glass temperature than is currently achievable with their single wavelength (5 micron) point & scanning pyrometers.

1. Coating deposition process within the float bath
   During the CVD coating process the emissivity of the glass surface changes as molecules are adsorbed onto the glass surface through a multi-stage, potentially multi-layer, process. The glass temperature is a critical process parameter which cannot be reliably determined using existing technology because the emissivity is unknown. Dual band pyrometers reduce the sensitivity to surface emissivity but have not been successfully implemented on glass substrates during the coating process in the float bath.
2. Shaping of vehicle glazing utilising coated glass in the automotive bending furnace
   When manufacturing coated vehicle glazing products, like windshields, the glass temperature determines the glass shape achievable. However, the glass surface has variable emissivity and transparency due to the presence of coated and printed regions. High speed thermal imaging of glass is required before shaping to ensure good quality and process control.

Proposals including solutions to both applications would be at an advantage.

Further details of the operating conditions, functional and technical requirements for each application are given on the Innovation Exchange site at the link below. All possible solutions that meet the requirements will be considered, although those closest to commercialisation are preferable. It is possible that solutions can be adapted from other sectors such as aluminium casting, steel manufacturing, advanced ceramics, and solar panel manufacturing.

This iX is in the Foundation Industries and supply chain challenges group, therefore, the solution provider will be eligible to apply for £25,000 to develop the proposed solution towards meeting this challenge. The funding will cover a 3-month project, the details of which will need to be developed with Pilkington, but it is envisaged that this would include some practical testing of the solution in an environment representative of the final application following the initial development phase. The European Pilkington Technology Centre (Lathom, Lancashire) has lab facilities which may be used to help develop and evaluate the solution.

Eligibility

This iX is in the Foundation Industries and supply chains challenges group. Due to the nature of this challenge and the funding support available, there are the following eligibility criteria:

• Entrants to this competition must be a UK registered business.
• Entrants can only apply to one of the Foundation Industries and supply chains challenges.

Rewards & Market Opportunity

Successful applicants will be given the opportunity to pitch their solution to Pilkington. The winning applicant, as selected by the company, will then be eligible to apply for £25,000 grant funding to kickstart the development of the proposed solution through a 3-month project with a view to co-developing the concept for high volume manufacture with Pilkington’s UK R&D team. This iX challenge is a conduit to working with a global corporation with the potential to deploy the technology in other locations and application areas of the business.

The benefits package for a successful applicant may also include:

• Support from Innovate UK Business Connect.
• Support in the development of a prototype or pilot.
• Technical support.
• Invitation to attend or present at Innovate UK Business Connect events.
• A potential business collaboration.
• Investor introductions (if investment is required).
• Support if any Innovate or similar competitions are relevant.

For full technical and operational requirements, assessment criteria, and further details, visit the Innovation Exchange site at the link below.