Editorial for the special issue on manufacturing: tribology, surface engineering and lubricants

Machining is one of the key manufacturing processes, focussed on precision manufacturing and final component production. Key challenges associated with machining include evolving productivity and quality requirements, combined with new and smart materials and green environment regulations imposed in the industry. Tribology is of fundamental importance, allowing an understanding of what happens at the cutting interface [1]. By understanding the fundamental interactions of the cutting tools and workpiece in terms of Tribology, Surface Engineering and Lubrication can greatly impact tool life, advanced material machining, surface finish and machining time. There is a global shift towards ‘Industry 4.0’ and ‘Smart Manufacturing’, which is reshaping methods and technologies for scalable production with the aim of improving productivity by more than 25% [2]. The contributions included in this special issue seek to demonstrate how machining and tribology research play key roles in addressing the modern challenges in manufacturing. The topics covered in this special issue is diverse: they highlight a creative scientific approach across the spectrum of manufacturing as well as demonstrate emerging technology and novel testing methodologies. The special issue begins with the manuscript ‘Braking performance of friction materials: a review of manufacturing process impact and future trends’ which is a review on the variant manufacturing techniques used to modify the tribological behaviour of brake pads. This manuscript provides a thorough review of the current manufacturing methodologies utilised and how they impact the friction behaviour of brake pads. The review also highlights future trends needed to develop green and eco-friendly brake pads to help mitigate the negative manufacturing impact on the environment and on respiratory health conditions. The review highlights the need to employ natural formulations alongside utilising the latest AI technology to monitor and optimise the manufacturing process. Metal cutting fluids are typically used to improve the machinability of materials, to improve the life and function of cutting tools and to improve the machined surface quality. Current research into testing the performance of cutting fluids are often unique in methodology, therefore there is a need for a simplified and cost-effective screening test for use by the industry. In ‘Expanding the applicability of ASTM D3233A Pin & Vee Block method to evaluate lubricant emulsions for cutting applications’ a simple Falex pin and Vee desktop Block machine was modified to allow the ranking on MWFs depending on their performance. They provide a controlled system to replicate the conditions found in larger systems, allowing for cheap testing with high repeatability. Whereas the team in the manuscript ‘Resource efficient performance testing of metalworking fluids utilising Single Point Milling’ utilises a single point milling to realistically replicate machining conditions to screen the performance of cutting fluids. The use of cryogenic and Minimum Quantity Lubricants as metalworking fluids has been gaining interest due to both the reduction in machining costs and environmental advantages incomparison to traditional emulsion coolants. ‘Applying multi-response optimization for sustainable machining of 316 stainless steel with coconut oil assisted minimum quantity lubrication’ explores the use of coconut oil as eco-friendly minimum quantity lubricant for the machining of difficult-to-cut materials. The machining of new materials presents numerous challenges which several manuscripts within this Special Issue address. The manuscript ‘Effect of Nose Radius on the Chip morphology, Coating Integrity and Tool wear during dry turning of Inconel 718’ investigates the optimisation of the nose radius of cutting tools to improve the machinability of Inconel. Whereas ‘Tribological Properties of (Al)10(FeCoNiCu)90 High Entropy Alloy’ focusses on investigating the tribological properties of high entropy alloys which are deemed as an alternative to Nickel alloys such as Inconel. This special issue was born from discussions with the journal’s editorial board, in particular Professor