Hot Edge Detection (HED) allows for the collection of information on the shape change that takes place during forging in real time. Integrating HED will provide a reliable and automatic geometry measurement, which provides a better understanding of the microstructural evolution that takes place during forging.

Despite being one of the oldest manufacturing methods, there is still much to be understood about the complexity of the forging process. However, the forging of metals has certainly come a long way since it first came to prominence in the 13th century and has evolved beyond recognition in the last 800 years.

As technology develops, so too does our ability to forge an ever-expanding range of high-integrity parts. To this day, forging remains a crucial process within the manufacturing supply chain. For sectors such as oil and gas, rail, nuclear and aerospace, where strength, durability and safety are the top priorities, it is the manufacturing method of choice.

But forging has historically been resistant to Industry 4.0, or the fourth industrial revolution, and it has failed to keep up with other manufacturing processes. Slow adoption has resulted in an ancient process existing in a modern world, where most of the industrial forging equipment offers limited data-collection capabilities, with restricted or no data storage. This means we must rely heavily on skilled operators and tacit knowledge.

Compared to its sleeker counterparts, such as machining and metrology, the forging industry lacks a transformative data-driven approach and the vast efficiency benefits that come with it.

The lag in data is not due to the lack of interest in the process but more a reflection of the harsh environmental conditions associated with forging, which makes it generally less amenable to the adoption of Industry 4.0. If we can get beyond this and use data to truly understand a material’s behavior as it goes through the forging process, we can adjust our methods to produce better results. Quality improvements can be met by digitizing key process parameters, resulting in cost and energy reductions, less material waste and higher-integrity parts.

Adding Data to a Historic Process in a Matter of Seconds

Together, the National Manufacturing Institute Scotland (NMIS) Digital Factory and Advanced Forming Research Centre are looking at innovative ways to embed digitalization into the core of the forging process. Operators can only access a certain level of data within the forging supply chain, and this information isn’t live. It’s no small task, but this “black art” process will be truly revolutionized once we can access forging data in real time, allowing us to finally understand what really goes on within the press and how it affects the forged part.

At the first step of digital transformation, we installed a PLC-based data-acquisition system called Data Hub, which allows integration of multiple systems and data streams. This enabled the non-invasive direct data acquisition from the legacy 500-ton hydraulic press, demonstrating that digitalization does not always require costly hardware upgrades and that even legacy machines are capable of communicating with external systems.

Within the same Data Hub, we also integrated data from the furnace and some external sensors to better understand the forging process. Systems integration is important for future analysis because it enables full control of the data streams. More importantly, all data streams become synchronized, which means there is a single time stamp across all systems.

Fig. 1. Demonstration of live dashboards during forging

Comprehensive Machine Vision

The second step of digital transformation is focused on a forged part itself. We have been working on a comprehensive machine-vision solution, which is integrated within the same Data Hub. This machine-vision solution was called Hot Edge Detection (HED). It can detect the size of a billet during the forging process.

Since improving connectivity is key to achieving high-speed image acquisition and data transmission, a GigE Vision-enabled camera was integrated into the system for live shape detection, measurements and analysis. The developed algorithm provides the profile and size of a hot-forged part in 10-30 milliseconds.

Fig. 2. Shape detection response time: 18 ms (left) and 24 ms (right)

Human-Machine Interface (HMI)

A useful display format for operator support is also crucial for live process monitoring and control. A real-time Human-Machine Interface (HMI) was developed, enabling the user to interact with the machine-vision system as the forging takes place. Essentially, the HMI allows the user to set a region of interest to aid the HED if necessary.

In addition, the camera exposure can be changed swiftly to compensate for the chilling effects during manufacturing. For added flexibility, the profile of the component can be extracted in a file format that allows post-processing analysis.

As part of that research, we are using HED to gain surface evaluation of a billet during forging to determine the shape and microstructure of a part, which provides a window into the thermomechanical transformation during the process like never before.

Fig. 3. HMI window for live operator support

 Fig. 4. Initial shape (blue), mid-stage deformation (green) and final-stage deformation (red)

More about Hot Edge Detection (HED)

HED is an automatic process that allows for the collection of information on the shape change that takes place during forging. The conversion of a cast ingot into a billet requires many forging blows combined with reheating steps, which makes it very difficult to understand the exact changes in structure that take place during the process.

In many cases, verifying the final size and shape of a forged component still involves some form of manual checking – a tried and tested approach that lacks a mathematical and data-driven method of validation. Likewise, the process requires extreme heat, which means manufacturers must validate the process from a distance. However, HED is changing that and turning the reliance on skills and knowledge into a numerical system based on data, allowing for validation in a safe environment.

HED uses an innovative system of cameras, which can identify wavelength radiation emitted by hot objects in milliseconds and therefore pinpoint the edges of a given object safely and remotely. Crucially, once the edges of an object have been detected, the system can feed this information into a computer, which then measures the geometry evolution of hot-forged parts during the forging process.

The cast ingots used in forging are typically expensive, and the process itself is energy-intensive and provides minimal margins for error. Yet an inability to retrieve data in real time means we can’t alter the process and errors can occur, resulting in significant delays, energy waste and increased costs.

Through HED we can execute the forging process and then examine the billet in real time, allowing us to review the shape change and alter our approach while the process is still underway.

Using a safe, reliable and automatic system to measure hot-forged parts can also allow experts to develop a better understanding of the manufacturing process and the material response. By integrating this monitoring system into the industrial process, manufacturers can learn how to implement and develop a more accurate modeling system that will make the forging process more efficient in the future.

Forging for the Future

Integrating HED will provide a reliable and automatic geometry measurement, which presents a huge opportunity for better understanding the microstructural evolution that takes place during forging. We can then better predict the final properties of a given object. Think of the benefits that could be developed by means of this system – not least the ability to automatically collect data for future implementation.

The digital elements of the forging process will develop over time and so too will our understanding of the manufacturing method. The integration of Industry 4.0 within a traditional method of manufacture does not come without challenges. It unlocks a unique offering for the forging industry on a global scale, however, and HED is part of that journey into a better understanding.

Clearly, we will rely on the forging process for years to come. To ensure that this established manufacturing method is up to the challenge of excelling in the future, it is crucial that we act now and transform it into a process that can keep up with the demands of a digital world.

 The AFRC forging workshop featuring the Schuler 500-ton, dual-action, server-driven multi-forge and 2,100-ton direct-drive screw press.

About NMIS

NMIS is a group of industry-led manufacturing research-and-development facilities where industry, academia and the public sector work together on groundbreaking manufacturing research to transform productivity levels, make companies more competitive and boost the skills of our current and future workforce.

It is operated by the University of Strathclyde and supported by Scottish government, Scottish Enterprise, Highlands and Islands Enterprise, High Value Manufacturing Catapult, Skills Development Scotland, Scottish Funding Council and Renfrewshire Council.

The new NMIS facility, along with the NMIS specialist technology centers (Lightweight Manufacturing Centre and Strathclyde’s Advanced Forming Research Centre) and the High Value Manufacturing Catapult center in Scotland are key facilities in the Advanced Manufacturing Innovation District Scotland being developed by Renfrewshire Council in partnership with Scottish government and Scottish Enterprise.

NMIS will:

• Increase productivity by reducing barriers to innovation
• Stimulate investment and increase manufacturing competitiveness
• Catalyze job creation and strengthen supply-chain links
• Inspire and attract talent and equip current and future workforces with the skills they and businesses need
• Provide leadership, build collaborations and enhance capabilities to influence adaptation and exploit manufacturing opportunities to boost Scotland’s transition a net-zero-emissions economy by 2045
• Work with manufacturing businesses of all sizes and multiple sectors, providing benefits across the whole of Scotland

For more information: Lead author Alaster McDonach (left) is Senior Manufacturing Engineer at the University of Strathclyde’s Advanced Forming Research Centre (AFRC), a center within the National Manufacturing Institute Scotland (NMIS) Group. Co-author Anastasia Khatuntseva (center) is Digital Connectivity Theme Lead in the NMIS Digital Factory. Co-author Constantinos Vassiades (right) is a PhD student sponsored by core members of the AFRC.

Contact Hayley Blackwood at Hayley.blackwood@bigpartnership.co.uk or nmis@bigpartnership.co.uk for additional information. To find out more about HED and how we are embedding Industry 4.0 into the forging process, visit www.nmis.scot, and contact the team at NMIS to get involved.