A Study on the Application of TRIZ in Wooden Stool Design and Manufacturing

This study, based on TRIZ theory, explored the design and manufacturing process of wooden low stools. The results showed that the systematic approach and innovative tools provided by TRIZ theory effectively resolved various contradictions encountered in the design of wooden low stools, thereby enhancing the product's performance, aesthetics, functionality, and competitiveness. Through the appropriate application of TRIZ, product design and manufacturing were optimized, providing a reference for promoting the upgrading and transformation of the entire wooden furniture industry. This study offered TRIZ theory as a thought process for product design research and provided a reference for the wood industry and woodworking workshops.

Wooden furniture has always held a significant position in the global market, particularly under the consumption trend of pursuing natural and environmentally friendly products. Wooden furniture has been widely favored. However, with the increasing market demand, how to ensure product quality while enhancing design innovation has become a major challenge for wooden furniture manufacturers. Wooden low stools, as a typical form of wooden furniture, not only serve practical purposes in home life but also carry certain aesthetic and cultural values. In the process of designing and manufacturing wooden low stools, designers and engineers need to balance multiple factors such as material selection, structural strength, manufacturing techniques, and aesthetics, which often involve many technical contradictions and difficulties.

Although wooden low stools are widely applied in home design, traditional design and manufacturing methods often face technical challenges and innovation bottlenecks when meeting modern demands. For example, how to maintain the aesthetics and durability of the product while pursuing structural strength and material light weighting? How to effectively utilize available resources and materials to reduce waste during the manufacturing process? These issues often involve multiple design and manufacturing contradictions, and relying solely on traditional methods makes it difficult to achieve optimal solutions. Research on factors influencing the purchase intention of wooden chairs (including low stools) has shown that consumers rate small wooden furniture highly in terms of usage, design, material, and environmental factors [1]. However, research on using Taiwanese wood for small furniture remains insufficient.

In the field of wooden furniture design, past research has mainly focused on material properties, manufacturing techniques, and design aesthetics. For example, many scholars have explored the physical and mechanical properties of various types of wood and analyzed their application potential in furniture design. At the same time, some studies have emphasized improvements in manufacturing processes, particularly in the application of CNC machining and digital manufacturing technologies, which have demonstrated significant advantages in improving production efficiency and precision [2]. Additionally, research on the aesthetics of furniture design has continued to expand, especially concerning the application of ergonomics and its impact on user comfort [3].

TRIZ (Theory of Inventive Problem Solving) was proposed by Russian scholar Genrich Altshuller in 1946. The primary goal of TRIZ is to assist innovation and solve technical problems by analyzing a vast number of patents and inventions, summarizing the laws and methods of innovative thinking. The core concepts of TRIZ include contradiction analysis, inventive principles, ideal final result, laws of evolution, and the contradiction matrix. Contradiction analysis is the foundation of TRIZ, helping identify and analyze contradictions within a system to find solutions. The inventive principles offer 40 general strategies to overcome technical contradictions, the laws of evolution describe the trends in system development over time, and the contradiction matrix serves as a tool for identifying and solving technical contradictions [4,5].

TRIZ has been widely applied across various fields, including product design and innovation, process improvement, problem-solving, education and training, and knowledge management. In product design, TRIZ helps designers identify and solve technical contradictions, promoting innovation. In process improvement, TRIZ enhances efficiency, reduces waste, and lowers production costs. For problem-solving, TRIZ provides a systematic approach to tackle business challenges and technical difficulties. In education and training, TRIZ cultivates innovative thinking and problem-solving abilities, while in knowledge management, it drives knowledge innovation. In summary, TRIZ serves as a powerful innovation tool, systematically solving problems, improving efficiency, and promoting technical and business progress [6,7].

The main function of TRIZ is to inspire creative thinking, thereby correctly formulating and solving complex problems in design, ultimately accelerating the entire design process [8]. TRIZ, through contradiction matrix analysis, addresses problems and applies principles of innovative solutions to provide feasible solutions. In life cycle studies, where contradictions frequently arise due to multiple choices, the application of TRIZ is particularly appropriate [9]. The uniqueness of TRIZ lies in its philosophy of solving inventive problems and providing the possibility of using a widely-available knowledge base. TRIZ’s systematic approach emphasizes its detailed nature [10]. Furthermore, TRIZ is a multifunctional innovation tool that can be combined with various process improvement tools [11]. By integrating TRIZ strategic tools, adopting complexity planning guidelines, designers are assisted in effectively managing and reducing product complexity during the conceptual design stage while predicting system evolution trends to enhance complexity management efficiency throughout the product life cycle [12].

However, the application of systematic innovation methods in the design and manufacturing of wooden small furniture, especially TRIZ methodology, remains relatively underexplored in existing literature. Although TRIZ has been widely applied in many fields of industrial design and technological innovation [13,14], its potential application in the design and manufacturing of wooden furniture, particularly wooden low stools, has not been fully explored.

Against this backdrop, TRIZ (Theory of Inventive Problem Solving), as a systematic innovation method, offers new approaches to solving problems. By identifying and resolving technical contradictions in design, TRIZ helps overcome the limitations of traditional design thinking, thus enhancing product innovation and market competitiveness. Therefore, this study applied the TRIZ methodology to the design and manufacturing process of wooden low stools, aiming to explore how this theory can resolve technical challenges in design, optimize manufacturing processes, and ultimately improve the overall quality and functionality of wooden low stools, providing a reference for problem-solving.

Research materials

This study selected three types of wood native to Taiwan as the primary materials for manufacturing the low stools, including Taiwania (Taiwania cryptomerioides), Bead tree (Melia azedarach), and Calocedrus (Calocedrus formosana). Each of these woods possessed unique physical and aesthetic characteristics, making them suitable for furniture production with varying functions and design requirements. Taiwania, widely used for its lightweight and rot-resistant properties, was particularly suited for furniture designs that required portability and ease of handling. Bead tree, known for its high hardness and strong insect resistance, was used for structural components, providing excellent support and durability. Calocedrus, with its pleasant fragrance and superior workability, was often chosen for high-end furniture; its fine grain and smooth surface also added to the aesthetic appeal of the wooden low stools.

In the material selection process, the sustainability and environmental friendliness of these woods were fully considered. Taiwania, Bead tree, and Calocedrus, all locally grown in Taiwan, helped reduce the carbon footprint and supported the sustainable development of Taiwan’s forestry. Moreover, this study paid special attention to the workability of the materials and their ability to adapt to different manufacturing processes. The low density of Taiwania made it easy to cut and shape, while the high hardness of Bead tree required more advanced machining techniques and tools. Calocedrus’ excellent workability made it suitable for fine carving and surface finishing.

The selection process also took into account the woods' performance under different environmental conditions. Taiwania demonstrated good stability in humid environments, while Bead tree maintained its structural integrity in both dry and humid conditions. Calocedrus, known for its durability and weather resistance, was suitable for furniture intended for long-term use. By comprehensively evaluating the physical properties, environmental adaptability, and aesthetic qualities of the woods, this study chose these three materials to meet the functional, durable, and aesthetic requirements of the wooden low stools.

Design indicators

In this study, the selection of design indicators was based on a comprehensive consideration of the functionality, aesthetics, user experience, and manufacturing feasibility of the wooden low stools. A total of 10 key design indicators were established to ensure that the final product achieved optimal results in all aspects. These indicators were:

1. Strength and stability, ensuring that the wooden low stool could withstand the pressure of daily use and maintained stability during use
2. Portability, with the design taking into account the weight of the stool, making it easy to move
3. Comfort, focusing on the design and material selection of the seat to enhance user comfort
4. Aesthetics, ensuring that the appearance of the stool met modern aesthetic standards
5. Material utilization, aiming to maximize the use of wood and minimize waste
6. Durability, selecting durable materials and structural designs to extend the product's lifespan
7. Production cost, considering cost-effectiveness in the manufacturing process
8. Environmental friendliness, choosing environmentally friendly materials and production processes
9. Modular design, exploring how the stool could be designed with a modular structure that was easy to assemble and disassemble
10. Processing difficulty, considering the technical challenges in the manufacturing process and simplifying the steps where possible. These design indicators provided clear direction and specific goals for the design and manufacturing process of the wooden low stools.

Manufacturing process

During the manufacturing process of the wooden low stools, the selected wood was first cut and shaped to ensure that each component met the design specifications. Based on the design requirements, CNC digital processing technology was used for precise cutting, particularly for the stool seat, which featured complex curves. This technology significantly improved machining accuracy while reducing human error. Next, the components underwent an initial sanding process to remove rough edges and smooth the surfaces. Following this, the stool legs and seat were assembled using precise joining techniques such as mortise-and-tenon joints or screws, ensuring stability and durability at every connection point. After the assembly was completed, the entire stool was thoroughly sanded to achieve a flawless surface. Finally, depending on the design requirements, surface treatments such as painting or waxing were applied, which not only enhanced the stool's aesthetics but also improved the wood’s weather resistance and durability. The entire manufacturing process followed the design indicators closely, ensuring that the final product met the expected standards in terms of strength, stability, and aesthetics. The design and physical images of the low stools made from Taiwania, Bead tree, and Calocedrus are shown in figures 1,2.

Figure 1: Three-view design drawing of wooden low stools (W: width, D: depth, H: height, Unit: mm).

Figure 2: The finished wooden low stool.

Methodological framework

In this study, TRIZ (Theory of Inventive Problem Solving) was adopted as the core methodology for analyzing the design and manufacturing processes of the wooden low stools. TRIZ provided a systematic set of tools and techniques to identify and resolve potential technical contradictions during the design and manufacturing stages and to explore innovative solutions. The research framework included 11 analysis items, as shown in table 1.

First, the analysis began with Contradiction Analysis, addressing technical contradictions encountered in the design and manufacturing processes, such as the conflict between stability and portability. The TRIZ Contradiction Matrix was used to identify suitable solutions. Next, the 40 Inventive Principles of TRIZ were applied to explore how innovation could be achieved in the design. For instance, the Segmentation Principle was employed to reduce structural weight. The Law of System Evolution analyzed the evolution trends of wooden furniture with technological advancements and guided innovations in both design and manufacturing processes.

In the Function Analysis, the functions of each stool component were evaluated for their importance, identifying potential areas for improvement to enhance the overall practicality and efficiency of the design. Ideal Final Result analysis sought pathways to achieve an ideal state in the design and manufacturing process, ensuring that required functions were fulfilled without adding complexity or cost. Resource Analysis conducted a comprehensive examination of available resources to maximize the use of existing materials, equipment, and energy, reducing production costs and minimizing waste.

Additionally, problems were analyzed from the perspective of System Operation to ensure optimization at every stage of the design and manufacturing processes. The application of Standard Solutions helped to achieve the best outcomes within the known framework. By using the Contradiction Matrix, innovative solutions were systematically identified to address design contradictions, balancing various performance attributes. Reference to Evolutionary Trends helped predict future design directions and allowed for proactive technical planning. Finally, Function and Attribute-Oriented Search focused on specific functions or attributes of the low stool, conducting cross-industry technical searches to incorporate innovative methods from other fields to improve product performance.

Research process

In this study, the TRIZ methodology was used as the core framework to systematically explore the design and manufacturing process of the wooden low stools. The research first selected and analyzed the properties of materials such as Taiwania, Bead tree, and Calocedrus formosana, determining their applicability in the production of wooden low stools. Then, 10 design indicators were established, including structural strength, stability, comfort, sustainability, and ease of processing, which served as guiding principles for both the design and manufacturing stages. During the manufacturing phase, a combination of traditional and modern techniques was employed, utilizing CNC machines and manual craftsmanship for cutting, sanding, and assembling the wood, while effectively using the leftover wood materials.

On this basis, TRIZ analysis methods were applied to conduct in-depth exploration of 11 items, including contradiction analysis, inventive principles, the law of system evolution, and function analysis. These analyses systematically addressed technical problems encountered in the design and manufacturing processes. Through in-depth analysis of these 11 items, various optimization pathways for the design, material selection, and manufacturing of the wooden low stools were identified, and practical recommendations for improvements were proposed, providing a reference for problem-solving approaches.

Through the application of TRIZ theory, this study addressed various contradictions in the design and manufacturing processes of wooden low stools and proposed several innovative solutions (Table 2). The research found that for the contradiction between "lightweight and stability," solutions such as segmented structures and the use of composite materials were effective. Regarding the contradiction between "material strength and weight," material changes and CNC processing technology enabled the achievement of both lightweight and high strength. Additionally, for contradictions such as "curved shapes and processing difficulty," "leg stability and design complexity," and "screw joints and wooden dowel structures," solutions including local quality, dynamics, and integration were proposed. The results showed that TRIZ theory effectively assisted designers in systematically analyzing and resolving various contradictions in the design and manufacturing processes, thereby enhancing the performance and competitiveness of the product. The effectiveness of these solutions needs further verification. Future research should consider a broader range of user needs and test the performance of different designs in real-world environments.

Through the 40 Inventive Principles of TRIZ, this study thoroughly explored various contradictions encountered in the design and manufacturing processes of wooden low stools and proposed a series of innovative solutions (Table 3). The research found that principles such as "Segmentation," "Extraction," and "Local Quality" effectively addressed issues like lightweight design, structural strength, and processing difficulty. Moreover, applying principles like "Asymmetry," "Combination," and "Universality" enhanced the aesthetic appeal, functionality, and economic viability of the stools. Principles such as "Nested," "Anti-Gravity," and "Pre-Action" improved storage, usability, and maintenance. Further, principles like biomimicry, flexible shells, dynamics, self-service, pre-set pads, and pneumatic or hydraulic systems significantly improved comfort, safety, and durability. The results indicated that TRIZ theory provided a rich theoretical foundation and practical tools for innovative design, helping designers break through traditional thinking and develop more competitive products. The application of these principles should be tailored to specific design needs, considering feasibility and cost-effectiveness in actual production. Future research could further update and supplement TRIZ principles to address challenges posed by emerging materials and manufacturing technologies.

Through the analysis of TRIZ technology evolution principles, this study identified significant technological advancements in the design and manufacturing history of wooden low stools (Table 4). The research showed that from traditional simple shapes and manual production, there has been a gradual development to modern complex curves, multifunctional designs, and automated production. TRIZ principles such as "Dynamics," "Material Transformation," "Automation," "Structural Transformation," and "Multifunctionality" played crucial roles in driving technological progress in wooden low stools. For instance, introducing adjustable design elements and modular structures enhanced adaptability and flexibility; while adopting composite materials and automated production technology increased performance and efficiency. These technological advancements not only met diverse demands for furniture functionality and aesthetics but also drove the continuous development of the wooden furniture industry. The application of these technologies requires a comprehensive consideration of market demand and consumer acceptance, particularly in balancing technological costs with market prices. Future research could explore the environmental impact of these technological advancements and evaluate their role in sustainable development.

Through TRIZ functional analysis, this study systematically explored the functional requirements of wooden low stools and proposed several innovative design solutions (Table 5). The research showed that TRIZ effectively assisted designers in considering all functional elements of the product from user needs and suggested targeted improvements. For instance, ergonomic design enhanced comfort; the use of new composite materials increased durability and environmental friendliness; and multifunctional designs met diverse user needs. TRIZ functional analysis provided a new perspective for designing wooden low stools, helping to develop products that are more aligned with user needs and competitive in the market. The results of the functional analysis should be combined with market trends and consumer preferences to ensure product success. Future designs should pay more attention to sustainability and the demands of the circular economy to increase the environmental benefits of the product.

Through the application of TRIZ Ideal Final Result analysis, this study explored the design objectives for wooden low stools in depth (Table 6). The ideal wooden low stool should combine structural stability, aesthetic appeal, comfort, durability, and cost-effectiveness. Specifically, in terms of design, it should pursue a simple structure and optimized materials to achieve minimal material consumption and maximum strength. In manufacturing, automation should be achieved to improve efficiency and ensure product consistency. In terms of functionality, the stool should offer multifunctionality to meet diverse user needs. Additionally, the ideal wooden low stool should also possess environmental and sustainability features to align with modern societal demands. Although these ideal solutions provide a clear design direction, practical application may face technical limitations and cost challenges. Future research should further assess the feasibility of ideal solutions in actual manufacturing processes and explore ways to achieve these design goals without increasing costs.

Through TRIZ resource analysis, we systematically reviewed various resources involved in the design and manufacturing process of wooden low stools (Table 7). The study found that, under existing resource conditions, local wood, existing equipment, skilled workers, and established market channels could be effectively utilized to improve the design and production efficiency of wooden low stools. Simultaneously, some areas could be optimized, such as using waste, off-cuts, and introducing new composite materials to achieve better resource utilization and environmental benefits; employing digital design and automation production to enhance product precision and consistency while reducing production costs; and training employees and incorporating external resources to boost the team’s innovation and problem-solving capabilities. TRIZ resource analysis helped us gain a comprehensive understanding of the strengths and weaknesses of existing resources, providing a systematic optimization plan for the design and manufacturing of wooden low stools. Through reasonable resource allocation and innovative solutions, continuous improvement in the design and production of wooden low stools could be achieved to meet market demands for high-quality, personalized, and environmentally friendly products. Resource allocation should consider global resource supply uncertainties and environmental protection needs. Future research could explore how to maximize resource utilization efficiency through innovative design and technological advances in the face of limited resources. Additionally, resource analysis results should be combined with market demands and economic feasibility to ensure the sustainability of design and manufacturing solutions.

Through TRIZ system operation analysis, we systematically optimized the entire process of designing, manufacturing, and using wooden low stools (Table 8). The study found that during the design phase, introducing modular design and digital tools could effectively shorten design cycles and improve design quality; during manufacturing, automation production technology and standardized operating procedures could significantly enhance production efficiency and reduce production costs; and during usage, designing ergonomic structures and selecting easy-to-maintain materials could improve product comfort and lifespan. TRIZ system operation analysis provided a systematic methodology, helping us integrate resources and optimization plans from a global perspective, ultimately achieving optimal design and manufacturing results for wooden low stools. The effectiveness of implementing system operation analysis results depends on the coordination and cooperation between various stages. Future research should further explore how to optimize interactions and cooperation between stages and make dynamic adjustments to design and manufacturing processes based on market feedback. With changes in technology and the market, the system operation analysis method needs continuous updating and supplementation.

Through TRIZ standard solutions analysis, we comprehensively optimized the design and manufacturing processes of wooden low stools (Table 9). The study found that by establishing a series of standards for design, materials, structures, processing, assembly, quality inspection, functional testing, packaging, usage, and maintenance, the design quality and production efficiency of wooden low stools could be effectively improved. TRIZ standard solutions provided a systematic solution for the design and manufacturing of wooden low stools. By establishing a series of standards, product quality and consistency could be ensured while improving production efficiency. The development and application of these standards need to be continuously validated and adjusted in actual production processes. Given the natural heterogeneity of wood, standardized processes might require testing and fine-tuning across different material batches. Balancing standardization with flexibility will be an ongoing challenge in optimizing design and manufacturing processes.

Through TRIZ contradiction matrix analysis, we systematically explored the various contradictions present in the design of wooden low stools and proposed innovative solutions (Table 10). For example, for the contradiction of "lightness vs. stability," we achieved lightweight stools without compromising stability by splitting the stool surface and legs and adopting asymmetric designs. The TRIZ contradiction matrix provided a systematic approach to effectively identifying and resolving various contradictions in the design process of wooden low stools, leading to optimized designs. By applying TRIZ inventive principles, we developed wooden low stools with higher performance and better user satisfaction. In practice, different design contradictions may affect each other. Designers need to consider other possible influencing factors while solving individual contradictions. The application of the TRIZ contradiction matrix should be dynamic and iterative, adjusting as the product design progresses.

Through TRIZ evolution trend analysis, it was clear that the design and manufacturing of wooden low stools were undergoing a transition from traditional craftsmanship to modern technology (Table 11). Material selection has shifted from single wood to composite materials and from traditional processing to CNC processing, enhancing product performance and diversity. In structural design, the shift from fixed structures to modular and adjustable structures has made products more flexible to meet different user needs. In functional design, the transition from single to multifunctional designs has increased the added value of products. Additionally, in the production process, the shift from manual labor to automated production has improved production efficiency and product quality. The evolution trend of wooden low stools is moving towards greater personalization, intelligence, and environmental sustainability. In the future, we can foresee that wooden low stools will no longer be just simple seating but will become multifunctional, customizable home products. Designers must closely follow market trends and consumer preferences to ensure that the product evolution direction aligns with market demands. Despite technological advancements providing more possibilities for product design, cost and production efficiency still need to be considered.

Through TRIZ functionality and attribute-oriented search, we conducted in-depth analysis of various aspects of wooden low stools (Table 12). The analysis showed that by deeply understanding material properties, the most suitable wood could be selected to enhance product performance; analyzing structural functions could lead to designing more stable and comfortable stools; researching surface treatment techniques could improve product appearance and durability; optimizing processing techniques could increase production efficiency and product quality; choosing connection methods could enhance product stability and ease of assembly; analyzing cost-effectiveness could achieve high-value products; considering environmental impact could design more eco-friendly products; and analyzing sustainability could extend product lifespan. TRIZ functionality and attribute-oriented search provided a systematic method to analyze wooden low stool design from multiple perspectives and find the best solutions. This method could lead to developing higher performance, more user-oriented, and more sustainable wooden low stool products. In practical applications, functionality and attribute-oriented analysis may face challenges, especially when handling materials with complex attributes. Designers need to continuously accumulate material performance data and make dynamic adjustments. Additionally, with rapidly changing market demands, designers should remain flexible and adjust design solutions promptly.

This study explored various contradictions in the design and manufacturing process of wooden low stools through TRIZ theory and proposed a series of innovative solutions. The research results showed that TRIZ theory had a significant effect on enhancing the performance and competitiveness of wooden low stools. By analyzing contradictions such as "lightweight versus stability," "material strength versus weight," and "curved shapes versus processing difficulty," the study introduced innovative methods including segmented structures, the use of composite materials, material changes, and CNC machining techniques. These methods effectively addressed major contradictions in the design process and improved the functionality and cost-effectiveness of the product. Additionally, tools such as TRIZ's 40 Inventive Principles, Ideal Final Result analysis, and System Operation analysis provided rich design ideas that supported improvements in comfort, functionality, and durability.

Future research should focus on further validating the implementation effects of the proposed solutions and consider a broader range of user needs and real-world performance. Particularly, studies should explore how to achieve optimal cost-effectiveness and sustainability while maintaining product performance, with a focus on cost control, resource utilization, and environmental impact. Moreover, as technology and market conditions change, methods and standards in the design and manufacturing process need to be continuously updated and adjusted. Future research should closely monitor market trends and consumer demands to ensure that the design of wooden low stools meets current market requirements and leads future development directions.

This study was financially supported by the Science and Technology Project of the Taiwan Forestry Research Institute, and we are gratefully acknowledged.

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