PSI - Issue 77

Carolina Francisco et al. / Procedia Structural Integrity 77 (2026) 567–574 C. Francisco et al. / Structural Integrity Procedia 00 (2026) 000–000

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To define an e ff ective monitoring strategy, it is essential to understand the physical function of each component, its potential failure modes and the parameters that best describe its condition Stamboliska et al. (2015). The first step in developing the condition monitoring system was to identify, using manufacturing experience and insights from the literature, the components of the press that are most critical to monitor, those with more impact on the overall condition of the press and on the process quality. From this analysis, five primary components were identified — the tool, slide, frame, slider-crank system, and drive system — along with their main failure causes and the monitoring methods that are commonly used and studied: • Tool In stamping operations, the tool applies high force to shape or cut the metal sheets into specific geometries. Due to repeated contact with the workpiece, the tool gradually degrades, leading to surface damage and reduced process quality. Changes in the applied loads can be correlated with the progression of tool wear. By monitoring these, it is possible to distinguish di ff erent wear stages Niemietz et al. (2022). Furthermore, deviations in force displacement curves can indicate faulty process conditions, so analyzing features extracted from those curves reflecting the condition of the tool allows for adjusting the process, enhancing product quality and reducing defects Kubik et al. (2021). To enable this, load sensors can be integrated within the stamping tools, allowing continuous acquisition of force data and its relation to wear phenomena, thus supporting early detection of tool degradation and proactive process adjustments Hohmann et al. (2017). • Slide The slide holds and drives the tool during stamping, and its motion must remain controlled and precise to ensure process quality. Because the slide guides are in constant dynamic contact with the press gibs, both components undergo wear, which can lead to slide imbalance and reduced precision. Such imbalances generate vibrations that, in turn, can accelerate the wear process. To address this, load and acceleration sensors have been employed to estimate the slide’s center of force and monitor potential imbalance Peinado-Asensi et al. (2021). Since the tool is mounted on the slide and directly interacts with the workpiece, monitoring the slide’s motion and the impacts it transmits o ff ers an indirect but highly representative measure of the process conditions. Acceleration signals collected from both the frame and the slide have been used to identify di ff erent stages of the stamping process C. Zhang et al. (2012). Thus, monitoring the slide through load and acceleration measurements provides a dual perspective, capturing both the mechanical health of the press and the quality of the stamping process. • Frame The frame of a stamping press is a structurally closed load system, designed to carry and balance the forming forces within a continuous load path between the slide (tool punch) and the bed (tool die), ensuring rigidity, alignment, and minimal deflection. Its stability and sti ff ness are crucial: if it deforms excessively, the process becomes inconsistent, leading to defects and accelerated wear C. Zhang et al. (2012). Changes in sti ff ness of a structure, whether local or distributed, lead to changes in the natural frequencies Gomes et al. (2019). Accelerometers were used to study vibration monitoring of a hydraulic press and placed in di ff erent parts of the press, including the frame, slide and other structural elements Jancarczyk et al. (2024). To define the best place to install the sensors, a modal analysis of the press was performed to determine its natural frequencies and corresponding mode shapes, and through that select the location with the highest vibration amplitudes. Time and frequency domain processing of the data showed that the vibration patterns can be used to detect potential mechanical problems and assess the health of structural elements, such as the frame. • Slider-crank system The crankshaft plays a key role in the functioning of the stamping press by converting the rotational motion provided by the servomotor into the linear motion of the slide. Its rotation is supported by the journal bearing, which allows smooth operation with minimal friction. Insu ffi cient lubrication can lead to metal-to-metal contact between the bearing and shaft, accelerating wear and increasing the risk of failure Laubichler et al. (2022). As wear and friction increase, the temperature of the lubricating oil rises, and excessive heat from inadequate lubrication or high loads can ultimately cause bearing failure S. M., Muzakkir et al. (2015). Monitoring the oil