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Effect of Wood-based Material Type on Drilled Hole Diameter
This study examines the influence of furniture board material type on real drilled hole dimensions. Five samples were fabricated from two medium-density fibreboards (MDF), two particleboards, and plywood. Fifteen holes were drilled in the side surface of each sample using a 12 mm drill bit, a rotational speed of 3000 rpm, and a feed rate of 0.67 mm/rev. For each hole, the diameter of the cylindrical plug gauge was identified to determine whether it could be inserted freely, partially, or not at all. The results showed that in each case the effective hole diameter was smaller than the nominal drill diameter. The smallest plug gauge diameters were observed in plywood (a plug gauge with a diameter exceeding 98.8% of the drill bit diameter could not be freely inserted). Particleboards exhibited varying usable hole diameters (99.2-99.6%), while MDF showed the largest diameters of freely insertable plug gauge (99.6%). The observed differences between the plug gauge diameter and the nominal drill bit diameter can be attributed to variations in material structure. Adhesive layers in plywood and structural changes induced by drilling in particleboard likely contribute to the reduced practical hole diameter. In contrast, MDF's more uniform structure results in minimal deviations. These differences in hole diameter are crucial for the design of self-assembly furniture, as they can impact the fit and assembly process.
Chair Size Design Based on User Height
General principles derived from anatomical studies of human body sizes should be applied to chair designs. Chairs can be designed for a specific user or a particular group of users. Universal chairs for public spaces should be comfortable for the largest possible group of users and should not be adjustable, such as office chairs. However, the fundamental problem is that the anthropometric data available in the literature either come from many years ago and are out of date or do not provide a complete set of all the dimensional parameters of a sitting human body position. This article proposes a way to design chair dimensions solely based on the height range of the intended chair users. For this purpose, based on literature data, the main structural dimensions of the chair were assigned to the appropriate anthropometric body measurements. Furthermore, calculated average body proportions for the adult population overcome the incompleteness, outdated and burdensome access to anthropometric data and link the main chair design dimensions to one easily accessible anthropometric parameter: human height. This is achieved by seven equations describing the dimensional relations between the chair’s essential design dimensions and human height or even a height range. The result of the study is a method of determining the optimal functional dimensions of a chair for a chosen range of sizes of its future users based only on users’ height range. Limitations of the presented method: the calculated body proportions are correct only for people with a standard body proportion characteristic of adults, i.e., they exclude children and adolescents up to 20 years of age, seniors, and people with a body mass index exceeding 30.
Adjustments in production costs linked to the redesign of wooden chairs for the bariatric population
Purpose Current furniture design principles fail to keep pace with the global rise in obesity. This study aims to address this issue by proposing a novel methodology for manufacturing cost estimation of common-use chairs that can accommodate even severely obese individuals. Design/methodology/approach The approach prioritizes universal design principles and user safety while ensuring furniture producers’ economic viability. This study utilizes real-world data to determine the establish appropriate load capacity for common-use chairs. Empirical height and weight data were collected from 7,938 young Slovakian men (aged 18–25) between 2001 and 2023. Additionally, data on Slovakia’s bariatric population, encompassing all genders, were obtained from medical facilities (2020–2024). Findings Considering the 95th percentile weight among bariatric individuals, the authors factored in a 20% design safety margin. This resulted in a target load capacity of 230 kg for all chairs designed for common use – a significant increase from the standard 110 kg capacity. An essential contribution of this study is a method for estimating chair production cost based on its designed load capacity. This method’s calculations reveal that the redesigned chair is estimated to cost 11.6% more than a standard chair. However, considering its ability to cater to broader user needs, this price point remains competitive. Practical implications The research indicates that the standard load capacity of common-use chairs should be substantially increased to accommodate the growing obese population. The study offers a methodology for estimating the cost implications of designing chairs with a higher load capacity, enabling manufacturers to assess the economic feasibility of implementing such changes. Social implications Chairs with higher load capacities improve accessibility for individuals with obesity, promoting their participation in social and professional activities. By accommodating individuals of all sizes, these chairs reduce the risk of falls, injuries and other problems associated with poorly fitting furniture. Originality/value This study links universal design, safety and affordability. The authors used real data from Slovakia to find the right weight limit for these chairs. The study addresses the pressing issue of furniture design failing to keep pace with rising obesity rates. The method helps make chairs that are accessible to everyone. While these chairs cost a bit more, they are affordable considering their expanded user base. The study’s originality lies in its novel methodology and data-driven approach, while its value lies in its potential to address a significant societal issue.
Impact of seat and back angle settings on seating furniture quality: an experimental study
Impact of Seat and Back Angle Settings on Seating Furniture Quality: An Experimental Study. The fundamental measure of the quality of seating furniture is seating comfort. Sitting comfort is described in the literature by the discomfort coefficient D, calculated from the pressure values and distribution measured between the human body and a sitting furniture "body support system". The work aims to experimentally verify the influence of selected anthropometric features on sitting comfort. The research was carried out on 12 people using a piezoelectric sensor mat and a model of adjustable sitting furniture. The study investigated how different seat and backrest inclination variants impact pressure distribution. The test results are the values of the contact pressures and discomfort coefficients D for nine combinations of the backrest and seat inclination related to the anthropometric characteristics of the tested group of people. The results indicate that anthropometric factors, such as body mass index (BMI) and user gender, significantly impact objective seating comfort. These findingswill help optimize the seating furniture dimensions at their design stage
Analysis of the lamella dimensions of the bed slat for the bariatric respondent: A modelling approach
Integration of Multi-Criteria Decision-Making and Dimensional Entropy Minimization in Furniture Design
Multi-criteria decision analysis (MCDA) in furniture design is challenged by increasing product complexity and component proliferation. This study introduces a novel framework that integrates entropy reduction—achieved through dimensional standardization and modularity—as a core factor in the MCDA methodologies. The framework addresses both individual furniture evaluation and product family optimization through systematic complexity reduction. The research employed a two-phase methodology. First, a comparative analysis evaluated two furniture variants (laminated particleboard versus oak wood) using the Weighted Sum Model (WSM) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). The divergent rankings produced by these methods revealed inherent evaluation ambiguities stemming from their distinct mathematical foundations, highlighting the need for additional decision criteria. Building on these findings, the study further examined ten furniture variants, identifying the potential to transform their individual components into universal components, applicable across various furniture variants (or configurations) in a furniture line. The proposed dimensional modifications enhance modularity and interoperability within product lines, simplifying design processes, production, warehousing logistics, product servicing, and liquidation at end of lifetime. The integration of entropy reduction as a quantifiable criterion within MCDA represents a significant methodological advancement. By prioritizing dimensional standardization and modularity, the framework reduces component variety while maintaining design flexibility. This approach offers furniture manufacturers a systematic method for balancing product diversity with operational efficiency, addressing a critical gap in current design evaluation practices.
Anthropo-Mechanical Cradles: A Multidisciplinary Review
Domestic cradles are beds that are movable but non-mobile for babies up to five months of age. The “anthropo-mechanical” cradle simulates the physiological movement of the human body. The article reviews scientific literature discussing the impacts of swinging on infants, provides classifications of all currently used cradles due to how the child moves, and briefly describes modern technologies within cradle automation. This made it possible to calculate and propose safe motion parameters within mechatronic cradles. The main conclusions of the article are as follows: (1) the scientific literature reports the beneficial effects of harmonic movement on a child, (2) motion analyses substantiating the classifications of all cradles into six types (tilting, yawing, hammock, Sarong, swing, and surging cradle; the classification criterion included the nature of the cradle movement in relation to the planes and anatomical axes of the child’s body), (3) modern technologies allowing for the use of movement with thoughtful parameters, thus, safer for a child, (4) movement within the parameters similar to the motion and speed passively performed by the child in the womb while a mother is walking was considered beneficial and safe, and (5) the use of advanced technology allows for the possibility to devise and create an automatic mechatronic cradle with a child-safe motion. Future innovative anthropo-mechanical cradles that follow physiological human motion parameters can be used safely, with a vertical amplitude ranging from −13 to + 15 mm and a frequency of up to 2 Hz.