The assembly process is one of the final and very important stages in the furniture production cycle, which has a direct impact on the cost price, quality of the finished product, order fulfillment times and, ultimately, customer satisfaction. Suboptimal organization of assembly operations can lead to increased labor costs, defects, slowdown in the production flow and increased risks of industrial injuries. The relevance of a detailed consideration of assembly organization methods is due to the growing complexity of furniture designs, the trend towards customization, the widespread use of furniture supplied unassembled (RTA – ready-to-assemble), as well as the general need to improve the efficiency and competitiveness of enterprises in modern market conditions. The purpose of this article is to analyze and summarize scientific and practical approaches to the correct organization of the furniture assembly process, based on expert knowledge in the field of production and design.
Design for Assembly (DFA)
The efficiency of the assembly process is largely determined at the design stage of the product. The Design for Assembly (DFA) concept is aimed at simplifying the design of a product in order to make it easier, faster, and cheaper to assemble while maintaining functionality and quality [1]. The main principles of DFA include: minimizing the total number of parts; standardizing components, especially fasteners; using symmetrical parts or clearly indicating the correct orientation; designing parts in such a way that they are easy to pick up, move, and install; ensuring easy access for tools and the assembler’s hands; avoiding the need for complex or precise adjustments during the assembly process.
Implementing DFA requires close collaboration between design and manufacturing teams early in product development to enable early identification and resolution of potential assembly challenges [1].
Planning and organizing the assembly process
The design stage is followed by detailed planning of the assembly process itself. This includes determining the optimal sequence of assembly operations, developing process charts and instructions. For flow production, an essential element is balancing the assembly line – distributing operations between workstations in such a way as to minimize downtime and ensure a uniform flow of products [3]. In other forms of organization (for example, cellular assembly), the emphasis is on the efficient arrangement of individual workstations.
An important aspect of process organization is the management of material flows and ensuring the timely delivery of necessary components and fittings to assembly areas. The use of methods such as kitting or point-of-use storage helps reduce the time it takes assemblers to find and move parts. Clear and understandable work instructions, preferably using visual aids (diagrams, photographs, 3D models), describing each step of the operation and quality standards are of great importance [5].
Optimization of work stations and assembly methods
The efficiency and safety of assembly directly depend on the organization of the workplace and the methods used. Ergonomic design of assembly stations is aimed at creating comfortable and safe working conditions, minimizing physical stress and the risk of developing occupational diseases [4]. This is achieved by providing sufficient lighting, adjustable height of work surfaces, optimal placement of tools, materials and devices within the reach of the assembler, as well as the use of equipment that reduces effort and prevents uncomfortable postures.
To improve labor productivity, Motion and Time Study methods are used, allowing you to analyze the operations performed, identify irrational and redundant movements and develop standardized, most effective work techniques [2]. The correct selection of manual and mechanized tools, the use of specialized assembly devices (conductors, templates, clamps) also significantly speed up the process and increase the accuracy of assembly. Tools and equipment must be regularly checked and maintained.
Quality control and continuous improvement
Ensuring proper assembly quality requires the implementation of a control system at various stages of the process. Control operations can be performed both by the assemblers themselves (self-control) and by specialized personnel (quality control inspectors). It is important to check not only the finished product, but also to conduct intermediate control after performing critical operations (for example, installing load-bearing elements, assembling critical mechanisms) to prevent the spread of defects along the chain [3]. Final control usually includes checking the completeness, correctness of assembly, appearance, as well as functional testing (checking the operation of doors, drawers, transformation mechanisms). Detected defects or assembly errors should be carefully analyzed to identify their root causes. This information is used to adjust the technological process, improve instructions, additionally train personnel, or make changes to the product design (feedback to the DFA stage). The implementation of continuous improvement principles (for example, Kaizen), encouraging employee initiatives to optimize their work contribute to the constant improvement of the efficiency and quality of assembly operations [5].
As we can see, organizing the furniture assembly process is a complex task, the solution of which requires a systematic approach covering the stages from design to finished product inspection. Implementation of design-for-assembly (DFA) principles [1], careful planning of the sequence of operations and material flows [3], ergonomic organization of workplaces [4], standardization of effective working methods [2] and construction of a reliable quality control system [5] are the components of a successful organization of assembly production. The result of this approach is an increase in labor productivity, a decrease in the cost of production due to a decrease in labor costs and defects, ensuring a consistently high quality of finished products and creating safe working conditions for personnel. Furniture manufacturers and designers should consider the assembly process not as an isolated stage, but as an integral part of the product life cycle, requiring attention and optimization along with other stages. Continuous improvement of assembly operations based on data analysis and feedback helps to increase the overall competitiveness of the enterprise.
References
Boothroyd, G. Product Design for Manufacture and Assembly / G. Boothroyd, P. Dewhurst, W. A. Knight. – 3rd ed. – Boca Raton, FL : CRC Press, 2011. – 768 p.
Meyers, F. E. Motion and Time Study for Lean Manufacturing / F. E. Meyers, J. R. Stewart. – 4th ed. – Upper Saddle River, NJ : Pearson Prentice Hall, 2016. – 432 p.
Heizer, J. Operations Management: Sustainability and Supply Chain Management / J. Heizer, B. Render, C. Munson. – 13th ed. – Boston : Pearson, 2019. – 864 p.
Bridger, R. S. Introduction to Human Factors and Ergonomics / R. S. Bridger. – 4th ed. – Boca Raton, FL : CRC Press, 2018. – 818 p.
Liker, J. K. The Toyota Way: 14 Management Principles from the World’s Greatest Manufacturer / J. K. Liker. – New York : McGraw-Hill Education, 2004. – 330 p.