Cirp Annals-Manufacturing Technology最新文献

The complexity in the collaboration between humans and robots in smart manufacturing remains a significant challenge. This paper introduces an LLM-based manufacturing execution system enhancing Human-Robot Collaboration (HRC) in smart manufacturing. By leveraging Large Language Models (LLMs), the system provides a natural language interface for operators, integrates with Digital Twins for real-time data, and employs behavior-based control for robots. This integration facilitates intuitive interactions and rapid system programming, addressing communication complexities in HRC. The effectiveness of this approach is validated through two HRC assembly case studies, demonstrating significant improvements in collaboration and efficiency.

Due to complex interrelations between the characteristics of the machine tool, spindle, tool wear and the stability of milling processes, the design of stable machining operations is challenging. Concept drift resulting from, e.g., tool wear and different dynamic behaviours often require fundamental experimental investigations on each machining centre. This paper presents a methodology for modelling process characteristics with respect to resource constraints by transferring insights from extensive experiments conducted on a reference machine to other machine tools in a process-informed manner. This methodology was exemplarily applied to predict wear-dependent process stabilities with a significantly reduced number of required cutting tests.

Shape memory polymer (SMP) parts printed with a fused deposition modeling process are increasingly considered for diverse industrial applications. However, gaps in the current understanding of how the process informs shape memory behaviors limit their applicability. This work studies how the coupled process thermomechanics, obtained at different process parameter settings such as of extrusion temperatures, influences shape memory behaviors. The results show that the process can precisely adjust the glass transition temperature within 42–50 °C and strains within 2.9–14.3% range without compromising mechanical strength. This allows imparting of multiple shape memory properties into printed SMP parts to realize complex shape-morphing behaviors.

In turning thin-walled parts, machining errors and deviations from the aspired workpiece shape occur due to influences of the workpiece clamping and elastic deformations of the workpiece caused by clamping forces. This paper introduces a newly designed sensor integrated chuck jaw for turning applications, which allows for an on-line monitoring of the actual clamping forces and an in-process prediction of shape deviations of the machined parts. The design and characteristics of the sensory jaw are described and its monitoring capability is validated in turning experiments. Correlations of sensor data with workpiece shape deviations and models for error prediction are analyzed.

During machining, tools and workpieces are exposed to high thermomechanical loads. Consequently, it is known that oxidation wear is determined by the choice of tool and workpiece combination. However, machining in an oxygen-free atmosphere, is not known. For this purpose, a method was developed to investigate the influence of oxygen in an XHV-adequate atmosphere. The investigations show a significant influence of the oxygen content on the mechanical loads and the surface integrity of the workpiece when machining Ti-6Al-4 V with uncoated cemented carbide. Machining in an oxygen-free atmosphere resulted in significantly less tool wear, which increased the tool life by 170%.

Finishing of structured surfaces is a challenging task in the manufacturing of functional surfaces. This is due to the aim of reducing the overlaying surface roughness while preserving the general surface structure. Therefore, there is the need for tailored tool concepts concerning the abrasive finishing. In this case, diamond-coated foams are used for the application of finishing surfaces, structured by high-feed milling. The quantitative evaluation by means of area-based roughness parameters and the qualitative observation of the changes in the surface profiles emphasise the capability to smoothen the surface without affecting the functional structure.

Additive manufacturing facilitates the materialization of complex designs, e.g. bio-inspired non-assembly joints. Despite the advantages of this type of joints, such as single-step manufacturing, their performance under operational conditions remains poorly understood. This paper explores the design, fabrication and wear performance of a hinge-type joint inspired by the camel elbow. The joint was fabricated by metal additive manufacturing and its wear behaviour was numerically and experimentally evaluated. The results show that the bio-inspired design performs better than a cylindrical one in terms of wear distribution. This work helps to better understand the wear performance of non-assembled bio-inspired joints.

Human-Robot Collaboration (HRC) has emerged as a pivot in contemporary human-centric smart manufacturing scenarios. However, the fulfilment of HRC tasks in unstructured scenes brings many challenges to be overcome. In this work, mixed reality head-mounted display is modelled as an effective data collection, communication, and state representation interface/tool for HRC task settings. By integrating vision-language cues with large language model, a vision-language-guided HRC task planning approach is firstly proposed. Then, a deep reinforcement learning-enabled mobile manipulator motion control policy is generated to fulfil HRC task primitives. Its feasibility is demonstrated in several HRC unstructured manufacturing tasks with comparative results.

Multiple international organizations and many governments around the world have declared climate emergency. There is a pressing need to minimize the environmental impacts of human activities including manufacturing processes. Machining by mechanical cutting is a fundamental manufacturing process and minimizing and eliminating its environmental impacts is vital. In this keynote paper, sustainability in the context of machining is identified. The resources used in machining have been categorized and the social and environmental impacts and potential methods to reduce them have been identified. The findings are critically discussed and the gaps and challenges for future research direction are highlighted.

Though roll bonding is used to manufacture clad sheets in industries, the bonding criterion of layers has not been fully understood. This paper proposes that same speeds and accelerations are necessary conditions for bonding. Al/Cu/Al stacked sheets were cold rolled and changes in layer speeds and bonding status were investigated. Cu layer entered the roll bite at higher speed than Al layers. In cases without bonding, Cu layer always moved at higher speed than Al layers. In cases bonding was attained, Al layers accelerated and caught up with the Cu layer, then the three layers moved at same speed for a certain distance, then they were bonded together.

Bonding; Rolling; Surface modification; Composite