Nozzle Temperature Research Articles

Refined dimensional accuracy in FDM components via ensemble weight-optimized surrogates and hybrid NSGA-II-TOPSIS optimization

ABSTRACT In this paper, a novel approach was developed to predict the geometrical deviation and density of fused deposition modeling (FDM) parts and to optimize these outcomes by fine-tuning the relevant process variables. The prediction process utilized an ensemble approach, combining the optimized weighted sum of three individual surrogate models. These models correlate the input variables – nozzle temperature (NT), infill fraction (IF), and print speed (PS) – with the output responses of density, internal ovality (IO), and external ovality (EO). According to the results, the ensemble outperformed the individual surrogates, exhibiting enhanced predictive accuracy. Subsequently, non-dominated sorting genetic algorithm II (NSGA-II), a multi-objective optimization technique, was integrated with the technique for order of preference by similarity to ideal solution (TOPSIS), a multi-criteria decision-making method, to optimize the ensemble of surrogates (EoS) and generate a ranked set of Pareto-optimal solutions. The outcomes from the EoS, combined with the NSGA-II-TOPSIS hybrid optimization process, revealed that the most effective optimal control parameters were approximately 195°C for NT, 50% for IF, and a range of 55–66 mm/min for PS. This hybrid approach affirmed the reliability and robustness of the identified processing parameters for the production of top-quality FDM parts with desired dimensional accuracy and density.

Effect of process variables on Ultimaker 2+ 3D FDM printed Tough PLA parts

ABSTRACT Fused Deposition Modeling (FDM) is pivotal in creating functional prototypes and end-use parts, with Tough PLA emerging as a favored material due to its durability. However, fine-tuning printing process variables for Tough PLA on the Ultimaker 2 + 3D printer remains challenging. This study employs Taguchi Grey relational analysis to optimize these process variables. L09 Taguchi’s systematic approach and Taguchi Grey Relational Grade Analysis (TGRGA) investigated Layer Thickness (LT), Infill Density (ID), and Nozzle Temperature (NT) at varying levels for which response variables such as Ultimate Tensile Strength (UTS), Average hardness (AH), and Surface Roughness (Ra) are evaluated. Utilizing Taguchi Grey Relational Grade Analysis (TGRGA), enhancements in ultimate tensile strength from 43.182 N/mm2 to 46.56 N/mm2, average hardness from 64 to 67, and Surface roughness from 8.60 µm to 8.35 µm are achieved. This study contributes to advancing additive manufacturing optimization, offering insights into refining Tough PLA part production on the Ultimaker 2 + 3D printer for bio implants like stent application.

Experimental Study on Cryogenic Compressed Hydrogen Jet Flames

Cryogenic compressed hydrogen (CcH2) technology combines the advantages of high pressure and low temperature to achieve high hydrogen storage density without liquefying the hydrogen, which has broad application prospects. However, the safety concerns related to cryogenic hydrogen need to be carefully addressed beforehand. In the present work, cryogenic hydrogen jet flames are experimentally investigated for various release pressures and initial temperatures. The flame length and thermal radiation flux were measured for horizontally releasing with nozzle diameters of 0.5–2 mm, temperatures ranging from 93 to 298 K, and initial pressures of 2–10 MPa. The results show that the flame length is dependent on the nozzle diameter, stagnation pressure and temperature. At a given pressure, the flame length, size and total radiant power increase with decreasing temperature, which is attributed to the lower jet flow velocity and higher density of low-temperature hydrogen. The normalized flame length Lf/D is correlated with the pressure ratio and temperature ratio. The correlation can be used to predict the flame length at various hydrogen pressures and temperatures. The normalized flame length of the cryogenic hydrogen jet flame is greater than that of the room-temperature hydrogen jet flame. The radiative heat flux of the flame can be predicted by the mass flow rate of the jet flow.

Optimization Parameters for PLA Through Additive Manufacturing: Taking Mixed Shapes as an Example

In recent years, additive manufacturing has been widely used in industrial, medical, and educational fields. Material extrusion is used in most industries to increase development efficiency and reduce costs. This study used the material extrusion to discuss the print quality of additive manufacturing and optimized the processing parameters based on material properties. Based on the literature, this study summarized the fishbone diagram influencing printing quality. The layer height, nozzle temperature, printing speed, infill pattern, and filling spacing were selected as the control factors of the Taguchi method. An orthogonal array L16 was used for parameter design. The optimal parameters were analyzed using the variance and the response surface method. The results of the study are as follows.

High-throughput in-situ mechanical evaluation and parameter optimization for 3D printing of continuous carbon fiber composites

The mechanical properties of carbon fiber reinforced thermoplastic (CFRTP) molded parts produced by thermal fusion lamination 3D printing vary with printing conditions. This study assesses the influence of the 3D printing parameters on the mechanical properties of resulting CFRTP products through parameter evaluation testing. An in-situ three-point bending test mechanism was developed to enhance the efficiency of these tests, allowing the same 3D printer to handle all processes from printing multiple CFRTP specimens simultaneously to conducting a bending test, reducing manual handling time to about one minute. Using this modified 3D printer, 700 specimens with varying printing conditions were produced, and their flexural strength was measured semi-automatically. Results revealed that the flexural strength of the 3D-printed CFRTP object varied with nozzle temperature, printing pitch, and stacking pitch, but not with printing speed. Machine learning was then employed to predict the maximum flexural strength and determine optimal printing parameters using the collected data as training data.

Assessments and Investigation of Process Parameter Impacts on Surface Roughness, Microstructure, Tensile Strength, and Porosity of 3Dprinted Polyetherether Ketone (PEEK) Materials:

Additive manufacturing (AM) is emerging as a competitive technology with promising applications across various sectors, including biomedical, automotive, construction, and dental implants. This study investigates the influence of key process parameters on the surface roughness, microstructure, tensile strength, and porosity of Polyether Ether Ketone (PEEK), a high-performance thermoplastic used in dental prosthetics. Traditionally, metals and ceramics have been the standard for dental restorations, but advancements in computer-aided design (CAD) and computer-aided manufacturing (CAM) have improved accuracy, particularly for implant-supported prostheses. However, conventional methods like CAD-milling face challenges such as material waste and tool wear. AM techniques, such as fused deposition modeling (FDM), offer a solution by constructing objects layer by layer, minimizing waste. This research explores the effects of nozzle temperature on the mechanical properties of 3D-printed PEEK, emphasizing its role in optimizing performance and minimizing issues like porosity. Key factors like surface roughness and microstructure are highlighted as critical to the biocompatibility and longevity of dental restorations. The study identifies the optimal nozzle temperature range for PEEK 380-440°C, noting that deviations from this range lead to compromised mechanical properties. Overall, the findings provide valuable insights into optimizing the AM process for PEEK in dental applications and suggest that further biological and chemical studies are necessary to fully realize the material's potential in replacing traditional dental restoration materials.

Investigating the influence of bending stiffness and processing parameters on single-leg bending geometries of additively manufactured composites

In less than a decade, additive manufacturing technologies have been developed so successfully that they already produce small and medium-sized lot sizes of prototypes or customised components in the industry. With its new possibilities such as combining materials and technologies, the benefits of different technologies can be merged and broaden future application fields. One way is to print with one technology on a part produced by another. Thus, a thermally bonded part composed of, e.g., selectively sintered and material-extruded components can be created. This combination of technologies was considered in this study to investigate the bonding strength of extrusion-based layers on selectively sintered surfaces and the impact of nozzle temperature, orientation, and thickness of imprinted materials. The extrusion-based layers covered stiff (fibre-reinforced polyamide) and soft (thermoplastic polyurethane) material properties with pre-cracked single-leg bending (SLB) specimens to study their effect on delamination tendencies. This combination of materials and additive manufacturing technologies has not yet been studied for the SLB testing method. The scope of this study is to obtain more information on how relatively hard-hard and hard-soft combinations behave for this special testing method. The results of this testing method were evaluated using two different fracture mechanical approaches to determine the energy release rate. A clear trend towards an improved bonding, thus, higher values, was found for higher nozzle temperatures. Furthermore, a limitation regarding the required bending stiffness of the composites was found. Overall, the single-leg bending testing method enables a relative ranking for material combinations with a certain bending stiffness.

Optimization of Production Parameters for Impact Strength of 3D-Printed Carbon/Glass Fiber-Reinforced Nylon Composite in Critical ZX Printing Orientation.

Additive manufacturing (AM) methods are increasingly being adopted as an alternative for mass production. In particular, Fused Deposition Modeling (FDM) technology is leading the way in this field. However, the adhesion of the layers in products produced using FDM technology is an important issue. These products are particularly vulnerable to forces acting parallel to the layers and especially to impact strength. Most products used in the industry have complex geometries and thin walls. Therefore, solid infill is often required in production, and this production must take place in the ZX orientation. This study aims to optimize the impact strength against loads acting parallel to the layers (ZX orientation) of PA6, one of the most widely used materials in the industry. This orientation is critical in terms of mechanical properties, and the mechanical characteristics are significantly lower compared to other orientations. In this study, filaments containing pure PA6 with 15% short carbon fiber and 30% glass fiber were utilized. Additionally, the printing temperature, layer thickness and heat treatment duration were used as independent variables. An L9 orthogonal array was employed for experimental design and then each experiment was repeated three times to conduct impact strength tests. Characterization, Taguchi optimization, and factor analyses were performed, followed by fracture surface characterization by SEM. As a result, the highest impact strength was achieved with pure PA6 at 8.9 kJ/m2, followed by PA6 GF30 at 8.1 kJ/m2, and the lowest impact strength was obtained with PA6 CF15 at 6.258 kJ/m2. Compared to the literature and manufacturer datasheets, it was concluded that the impact strength values had significantly increased and the chosen experimental factors and their levels, particularly nozzle temperature, were effective.

Effect of Material Extrusion Process Parameters to Enhance Water Vapour Adsorption Capacity of PLA/Wood Composite Printed Parts

This study aims to optimise the water vapour adsorption capacity of polylactic acid (PLA) and wood composite materials for application in dehumidification systems through material extrusion additive manufacturing. By analysing key process parameters, including nozzle diameter, layer height, and temperature, the research evaluates their impact on the porosity and adsorption performance of the composite. Additionally, the influence of different infill densities on moisture absorption is investigated. The results show that increasing wood content significantly enhances water vapour adsorption, with nozzle diameter and layer height identified as the most critical factors. These findings confirm that composite materials, especially those with higher wood content and optimised printing parameters, offer promising solutions for improving dehumidification efficiency. Potential applications include heating, ventilation, and air conditioning systems or environmental control. This work introduces an innovative approach to using composite materials in desiccant-based dehumidification and provides a solid foundation for future research. Further studies could focus on optimising material formulations and scaling this approach for broader industrial applications.

Characterization of PLA/LW-PLA Composite Materials Manufactured by Dual-Nozzle FDM 3D-Printing Processes.

This study investigates the properties of 3D-printed composite structures made from polylactic acid (PLA) and lightweight-polylactic acid (LW-PLA) filaments using dual-nozzle fused-deposition modeling (FDM) 3D printing. Composite structures were modeled by creating three types of cubes: (i) ST4-built with a total of four alternating layers of the two filaments in the z-axis, (ii) ST8-eight alternating layers of the two filaments, and (iii) CH4-a checkered pattern with four alternating divisions along the x, y, and z axes. Each composite structure was analyzed for printing time and weight, morphology, and compressive properties under varying nozzle temperatures and infill densities. Results indicated that higher nozzle temperatures (230 °C and 240 °C) activate foaming, particularly in ST4 and ST8 at 100% infill density. These structures were 103.5% larger on one side than the modeled dimensions and up to 9.25% lighter. The 100% infill density of ST4-Com-PLA/LW-PLA-240 improved toughness by 246.5% due to better pore compression. The ST4 and ST8 cubes exhibited decreased stiffness with increasing temperatures, while CH4 maintained consistent compressive properties across different conditions. This study confirmed that the characteristics of LW-PLA become more pronounced as the material is printed continuously, with ST4 showing the strongest effect, followed by ST8 and CH4. It highlights the importance of adjusting nozzle temperature and infill density to control foaming, density, and mechanical properties. Overall optimal conditions are 230 °C and 50% infill density, which provide a balance of strength and toughness for applications.

Fused Filament Fabrication 3D Printing Parameters Affecting the Translucency of Polylactic Acid Parts.

The effect of 3D printing parameters by Fused Filament Fabrication (FFF) on the translucency of polylactic acid (PLA) parts was investigated. Six different printing parameters were studied: object orientation, layer height, nozzle temperature, fan speed, extrusion multiplier, and printing speed. The commercially available Plasty Mladeč PLA filament and the Original Prusa MK4 3D printer were used for the experiments. The translucency of the printed samples of 50 × 25 × 1 mm dimensions was measured using a luxmeter in an integrating sphere. A total of 32 sample combinations were created. Each sample was printed ten times. The results show that all investigated parameters significantly affect the optical properties of PLA parts. The best measured translucency values were obtained when printing in portrait mode, with a layer height of 0.30 mm, nozzle temperature of 240 °C, fan speed of 100%, 0.75 set extrusion multiplier, and a speed of 40 mm/s. ANOVA was used to statistically evaluate the effect of each parameter on translucency, and statistically significant differences were found between different combinations of parameters (p < 0.05). Scanning Electron Microscope (SEM) analysis provided detailed images of the surface structure of the printed samples, allowing for a better discussion of the microscopic properties affecting the translucency. The best print setting has an efficiency of 88% compared to the default setting of 65%. The ability of visible light to pass through the print (translucency) improved by 23%.

Robust design optimization of Critical Quality Indicators (CQIs) of medical-graded polycaprolactone (PCL) in bioplotting

Polycaprolactone (PCL), either in its pure grade or as a polymeric matrix for bio-composites, plays a key role in the biomedical and bioengineering industries. It is also considered a multifunctional and versatile polymer for bioprinting and bioplotting purposes, especially in tissue engineering. Herein, an undiscovered yet valuable aspect of PCL extrusion-based bioprinting, such as the predictability of Critical Quality Indicators (CQIs), is investigated in depth. With the aid of the robust L25 orthogonal matrix design, the six most generic and device-independent control factors proved their impact on quality metrics such as global porosity, dimensional conformity, and surface roughness, determined with the aid of highly evolved Nondestructive Testing (NDT) and algorithms. To this end, 25 experimental runs were set, and 125 specimens were fabricated using an industrial-scale bio-plotter and medical-graded polycaprolactone. Various infill densities (ID), layer thicknesses (LT), raster deposition angles (RDA), printing speeds (PS), nozzle temperatures (NT), and bed temperatures (BT) were applied. CQIs were determined using optical profilometry and microscopy, and micro-computed tomography. Quadratic predictive equations were compiled and verified using two additional, well-chosen experimental runs. These generally applicable predictive models carry a massive amount of research and industrial merit, as they ensure visibility in bioprinting with PCL.

Optimization and prediction of additively manufactured PLA-PHA biodegradable polymer blend using TOPSIS and GA-ANN

Recent years have seen the proliferation of fused deposition modeling (FDM) as a means of manufacturing biodegradable products, for different applications such as rigid packaging, agricultural and biomedical. Blends of Polyhydroxyalkanoates (PHA) and polylactic acid (PLA) have been investigated to ascertain their prospective applications through FDM. This paper includes three parameters that affect the build process: layer height, nozzle temperature, and flow rate. 3D printed PLA/PHA can be characterized mechanically, and process parameters can be optimized to maximize design functionality. The experimental setup utilized a Taguchi L9 design, and TOSPIS was employed to optimize the output results. Using TOPSIS analysis, 0.2 mm layer thickness, 195 °C nozzle temperature, and 100 % flow rate were found to be the most optimal initiation parameters. The Taguchi analysis was used to analyze the output responses, and it was found that layer height had the greatest influence on mechanical properties, followed by flow rate and nozzle temperature. The percentage elongation at break has been improved significantly by adding PHA i.e., 170 % compared to PLA (5–10 %). This paper presents a framework for in-depth mechanical characterization of PLA-PHA 3D-printed parts, along with methods for optimizing process parameters to achieve optimal performance, as well as tools for modeling output responses using GA-ANN with an accuracy of 95 %.

Research on size optimization of 3D printed parts using Grey-Taguchi method

Abstract Fused deposition modeling (FDM) is one of the earliest developed 3D printing processes, which has the advantages of a clean processing environment, low overall manufacturing costs, and a variety of optional materials. However, it still has the disadvantages of low dimensional accuracy and poor surface quality of the molded workpiece. Therefore, how to solve this annoying problem has become an important research topic in the current industry-university-research fields. In this study, a square container with a bottom area of 48 mm×48 mm, a height of 30 mm, and a thin wall of 6 mm was used as the design object, and four controllable factors were adopted: layer thickness (A), nozzle temperature (B), printing speed (C), and forming path (D), combined with Grey- Taguchi’s experiments and calculations are carried out in order to achieve the purpose of optimizing the inner volume (IV) and inner diagonal length (IDL) of the square container (dual-objective quality characteristics). The experimental results show that within the selected printing parameter range, the optimized process parameter combination is layer thickness of 0.25 mm (A3), nozzle temperature of 190 °C (B1), printing speed of 50 mm/s (C3) and the molding direction of the annular surface (D2). Finally, use the GOM Inspect software (ATOS Q 3D scanner) and vernier caliper (VC) to compare the physical errors. According to the verification results, the errors of IV and IDL of the square container obtained by optimizing process parameters are 0.49% and 1.53%, and 3.76% and 6.33% respectively in GOM Inspect software and vernier caliper measurement. The results of this optimization process not only prove that the GOM Inspect software has a considerable degree of accuracy, but also can be used as a means to improve FDM multi-quality printing process optimization when combined with the Grey-Taguchi method.

3D Printing Conductive Filament for Fuel Cell Bipolar Plates

Fuel cell bipolar plates are commonly manufactured from metals and graphite. Utilizing a polymer material, while still adhering to the standards set by the U.S. Department of Energy for bipolar plate electrical conductivity, could greatly reduce production costs and time. 3D printing bipolar plates could have benefits that include weight reductions as well as ease of testing different flowfield designs. However, very few 3D printing filaments are electrically conductive. In this work, samples were printed with Electrifi conductive filament, a copper-polyester composite material. Samples were printed at various conditions to determine optimal print settings for dimensional accuracy and electrical conductivity. Printing parameters such as nozzle temperature, flow rate, and infill pattern were varied to affect sample density and conductivity. Several combinations of print conditions led to conductivities nearing the US DOE technical target for bipolar plate conductivity. SEM imaging was performed to better understand the structure of the Electrifi filament, and an Energy-dispersive X-ray spectroscopy scan provided details on its elemental composition.

Anomalous Temperature Effect on the Deposition Morphology in Reactive Inkjet Printing

Reactive inkjet (RIJ) printing represents an important approach for printed electronics. Different from the traditional inkjet printing of colloidal inks with nanosized metal particles, RIJ prints the solution of metal organic compound, that is, metal‐organic decomposition (MOD) ink, and reduces it to the pure metal during the post‐treatment to form conductive electrodes. Successful RIJ printing of MOD inks has been demonstrated; however, the fundamental understanding of droplet deposition involved in RIJ printing is lacking. Herein, the effect of substrate temperature and nozzle temperature during inkjet printing of copper MOD ink on the deposition morphology is investigated. It exhibits distinct behaviors in the deposition morphology at elevated temperatures when compared with the ones at room temperature. The different deposition morphology of the copper ink at various temperatures is attributed to the generation of a localized seeding layer which attracts the copper ions to deposit. In addition, the copper MOD ink printing is compared with a silver MOD ink. The different deposition morphology between the copper ink and silver ink is due to the solvent system. Understanding the deposition mechanism for reactive inks provides valuable information and guidance in the fabrication of printed functional devices using particle‐free reactive inks.

Effect of printing temperature on the mechanical properties of 3D printed polyphenylene sulfide (PPS) during simple and repeated impact tests

AbstractFused filament manufacturing (FFF), also known as 3D printing, is one of the most commonly used additive manufacturing techniques for creating high-quality materials. This process demonstrates the intricacies and challenges involved in choosing appropriate manufacturing parameters to achieve the desired outcomes. Among these critical parameters is the nozzle temperature, which can be adjusted to enhance the mechanical properties of the 3D-printed Polyphenylene Sulfide (PPS) parts. The main objective of this study is to investigate the influence of the printing temperature on the mechanical properties and failure characteristics of 3D printed polyphenylene sulfide (PPS) parts during impact testing. To do this, a series of simple and repeated impact tests were carried out on printed PPS samples in the nozzle temperature range (320–350 °C). CHARPY tests were carried out on the samples manufactured with different sequences for the optimal orientation of the filaments. Furthermore, the impact energy absorption capacity and the induced damage as a function of nozzle temperature were evaluated. CHARPY test results showed that samples with stacking sequence (0/0) had the best impact resistance and specific absorbed energy (SEA). This sequence, printed horizontally, was used to test different print temperatures in single and repeated impact tests. Furthermore, the results indicated that samples printed with a nozzle temperature of 340 °C exhibited higher CHARPY impact resistance and specific absorbed energy (SEA), with a percentage difference of 45.57%, 41.95% and 44.21% compared to samples printed with nozzle temperatures of 320 °C, 330 °C and 350 °C respectively. For repeated impact tests, the results also show that samples printed with a nozzle temperature of 340 °C have a higher initial energy absorption rate and a greater number of impacts before complete failure of the sample. This result proves also that the changing of nozzle temperature does not have a significant effect on the induced damage after CHARPY and repeated impact.

Programming the deformation of the temperature driven spiral structure in 4D printing

Abstract Achieving shape programming of 4D printed actuators by varying the manufacturing process parameters. In this study, the effect of different path combinations on structural deformation was investigated. By altering the driving layer, passive layer, and grid angle, the spiral deformation direction of the double-layer structure was precisely controlled. Additionally, a finite element analysis model was established to predict the deformation behavior of PLA-based spiral structures. Furthermore, the influence of printing speed, nozzle temperature, line width, layer height, and plate temperature on the spiral curvature of the structure was examined. The results show that increasing printing speed and plate temperature can improve the spiral behavior of the structure, whereas increasing line width, layer height, and nozzle temperature have opposite effects. A multiple linear regression analysis was conducted on the five printing parameters to predict their influence on the spiral curvature of the structure, and a predictive model for the spiral deformation was developed. The structure was partitioned for design purposes, aiming to achieve diverse deformations of the actuator under the same geometric configuration. A loop-shaped actuator was designed to capture objects. The results showed that the path combination determined the spiral direction of the actuator, while the forming parameters effectively controlled the spiral curvature of the actuator.

In situ foam 3D printed microcellular multifunctional nanocomposites of thermoplastic polyurethane and carbon nanotube

Electrically conductive and mechanically robust thermoplastic polyurethane (TPU)/carbon nanotube (CNT) foams were achieved using a novel in situ foam 3D printing (F-3DP) process. Thermally expandable microspheres (TEMs), as blowing agent, were incorporated into the TPU/CNT filaments and fed to the F-3DP process. Foams with uniform morphologies and repeatable properties were achieved in a wide density range by solely regulating the nozzle temperature and its correlated flow rate. Overall, the degree of foaming increased substantially with an increase in the temperature, providing a density range of 0.96 to 0.17 g/cm3. It was interestingly found that a small amount of CNT (1 wt%) increased the expansion ratio. A further increase of CNT (to 3 and 5 wt%), however, caused a reduction in the expansion ratio. These opposing trends were attributed to the competing effects of CNT on the melt's thermal conductivity and viscosity. Both CNT content and nozzle temperature exhibited significant impacts on the tensile properties and electrical conductivity. This resulted in foams with diverse Young's modulus and strain at break in the range of 3.9–29.5 MPa and 260 to 52 %, respectively. More importantly, the electrical conductivity increased up to several orders of magnitude, as the foam expansion was increased due to temperature rise. This interesting finding was thoroughly discussed in terms of the enhanced inter-bead adhesion, vanishing inter-bead gaps, and realignment of CNTs around the growing TEMs. The results demonstrate a great potential of F-3DP to produce functional foams with controllable density and performance in a wide range.

Experimental study on single-cylinder two-stroke piston expander based on in-cylinder spray heat transfer

Compressed air energy storage stands as a highly promising technology within the realm of energy retention. The piston expander finds applicability in smaller-scale compressed air energy storage systems. In compressed air energy storage systems, the expansion process is critical in energy discharge and significantly impacts overall performance. Isothermal expansion techniques are effective in enhancing the operational efficiency of piston expanders, in contrast to adiabatic expansion methodologies. Previous simulations by our research group show that the isothermal expansion model has a lower power output than the adiabatic expansion model due to its higher exhaust pressure. To further validate the accuracy of the simulation results, an experimental platform was constructed and the uncertainty of the experimental system as well as the measured data was evaluated. This study conducted experimental research using the single-variable method, focusing on different load conditions and spray parameters. The study findings indicate that the exhaust pressure during isothermal expansion consistently exceeds that of adiabatic expansion. The exhaust pressure of isothermal expansion increased by 3.85 % to 14.9 %. Under varying load conditions, the average rotational speed and output power of isothermal expansion were noted to be inferior to those of adiabatic expansion. Despite changes in nozzle diameter or spray temperature when the spray timing is set at 0°-180°, the average rotational speed and output power of isothermal expansion remain lower than that of adiabatic expansion. The average output power of isothermal expansion decreased by 1.29 % to 5.24 %. Nevertheless, if the spray timing is set between 0°-120°, the average output power of the isothermal expansion surpasses the adiabatic expansion with an improvement of 1.84 %.