This study proposes a human-in-the-loop framework that integrates operator observations into a large language model (LLM) to control process parameters for defect handling in fused deposition modeling (FDM) 3D printing. Fully autonomous LLM-based control handles ambiguous sensor data poorly and cannot detect abnormal conditions that lie beyond the installed sensors. Operator observations may compensate for these limitations, but their actual impact on LLM decision-making has not been sufficiently validated. We therefore implemented the proposed framework and defined experimental scenarios involving erroneous parameter injection and environmental disturbances. The framework was evaluated in terms of LLM response quality and print quality. The LLM achieved over 80% response quality on the defined evaluation metrics and generated appropriate parameter adjustments, improving print quality by more than 55% on average. Comparative experiments further revealed that, without operator observations, the LLM sometimes failed to recognize defects. These findings demonstrate the effectiveness of human–LLM collaboration and provide a practical foundation for intelligent FDM process control.

Microfluidic chips have become a critical component in advanced applications such as biochemical analysis, medical diagnostics, drug development, and environmental monitoring because of their ability to precisely control fluid flow at the microscale. The functionality of these chips is highly dependent on the precision and dimensional stability of microchannel structures formed on them. While injection molding is an efficient method for a mass production of microfluidic chips, it is required to minimize undesirable deformation due to thermal and mechanical stresses, which can degrade the overall performance. This study investigated global (Macro-scale) and local (Micro-scale) deformation behaviors of injection-molded microfluidic chips. Effects of processing parameters, including mold temperature, melt temperature, filling time, and packing pressure, were investigated. The Taguchi-based design of experiments approach was employed to systematically analyze these effects and to determine optimal conditions to minimize deformation.

The multi-lumen catheter with complex and small cross section is widely used for interventional radiology and minimally invasive surgery. It is manufactured in the polymer extrusion process with many manufacturing parameters. The profile of the extrudate is difficult to predict because it depends on the die shape and many parameters. In this paper, the effects of the manufacturing parameters for multi-lumen catheter extrusion are studied. The commercial software ANSYS Polyflow is used to simulate the polymer flow and predict the profile of the extrudate. The optimized die shape is used to achieve the target profile of the extrudate. The extrudate profiles are investigated with respect to the puller speeds at the end of the extrudate and blowing air pressure of each lumen. Circularity and major diameter are compared for the different manufacturing parameters. The effects of the manufacturing parameters on the profile of the extrudate are examined. The target profile of the extrudate is obtained with optimized manufacturing parameters.

Metal additive manufacturing using electron beam melting (EBM) process applies electron beam for heating, sintering, and melting of powders to fabricate a three-dimensional component. The component may contain residual porosity internally and may be subjected to poor surface finish externally. To improve the quality of the surface finish and densification, re-melting is conducted. The purpose of this paper was to estimate the appropriate process conditions for a plasma electron beam remelting process using heat transfer finite element analyses (FEAs). The impact of the travel speed of table and thickness of the deposited part on temperature distributions were examined. The size of molten pool was estimated from the results of the thermal FEA. From the estimated size of molten pool, the travel speed of table and the hatch spacing between remelting tracks are discussed and selected as the appropriate process conditions for electron beam re-melting process from the perspective of minimum overlapping region of the molten pool.