Hex-Perforated Cap Screw: An Innovative Solution for Enhancing Mechanical Adhesion in Thin Plastic Components

Hex-Perforated Cap Screw: An Innovative Solution for Enhancing Mechanical Adhesion in Thin Plastic Components | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Hex-Perforated Cap Screw: An Innovative Solution for Enhancing Mechanical Adhesion in Thin Plastic Components Hussam A. Bahr This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7696137/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract A hex-perforated cap screw featuring a hexagonal head with integrated perforations has been developed to address common issues related to mounting screws in thin plastic materials (≤ 3 mm thickness). The novel design aims to enhance mechanical adhesion, ease of manufacturing, and durability while minimizing damage typically caused by conventional screw mounting systems. Initial experimental evaluations demonstrated that the proposed screw maintains comparable load-bearing capacity to traditional bases in flexible plastics and exhibits superior performance in recycled, low-flexibility plastics. These findings highlight the potential of the hex-perforated cap screw to serve as a cost-effective, sustainable solution across diverse industrial applications. Mechanical Engineering Innovation Screw Mechanical Adhesion Plastic Hexagonal Cap Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1. Introduction Screws have undergone numerous advancements over the years to enhance their efficiency and expand their applications across a wide range of industries. Innovations such as self-tapping screws for simplified installation [ 1 – 3 ], corrosion-resistant screws for harsh environments [ 4 ], and smart screws equipped with embedded sensors for real-time monitoring [ 5 , 6 ] exemplify the continuous evolution of fastening technologies. Despite these advancements, a persistent challenge remains in applications involving plastic components, particularly those with minimal thickness (≤ 3 mm). A common failure observed in plastic assemblies is the localized damage at the screw mounting base, leading to structural weaknesses, aesthetic deformities, or, in severe cases, complete failure of the component. For example, plastic bases supporting automotive headlights may sustain minor damage during low-impact collisions, rendering the entire assembly unstable without necessitating full replacement. Current conventional solutions, including the use of strong adhesives or reinforcement patches, suffer from several limitations. Adhesives are vulnerable to environmental degradation, and the application of larger or stronger screws can compromise the integrity of the plastic, often causing additional damage. Therefore, there is a pressing need for a simple, cost-effective, and reliable method to reinforce screw mounting in thin plastics. In response to this need, we have developed an innovative hex-perforated cap screw that leverages basic physical principles to enhance mechanical adhesion. The design emphasizes manufacturability, ease of installation, and durability, aiming to extend the functional lifespan of plastic components without compromising their structural integrity or aesthetic quality. In sec. 2 we will discuss the principles and fundamentals of manufacturing, focusing on material selection and engineering techniques that enhance mechanical efficiency. In sec. 3 preliminary test results are summarized. The last section presents a comprehensive summary of the key findings. 2. Principles and Manufacturing Materials The core principle underpinning the proposed hex-perforated cap screw is the enhancement of mechanical adhesion between the screw and plastic substrates. This is achieved by designing perforations within the hexagonal screw head, which allow molten plastic to flow through during installation. Upon cooling and solidification, the plastic forms “mushroom-like” structures within the perforations (see Fig. 1), significantly strengthening the bond and improving overall structural stability. The effectiveness of mechanical adhesion is heavily influenced by the compatibility between the screw material and the plastic substrate. Material compatibility ensures optimal cohesion, distributes applied forces more evenly, and minimizes the risk of corrosion or material degradation over time. Several material options were evaluated to balance cost, manufacturability, and mechanical performance. Iron is an affordable and readily available option, and its resistance to corrosion and durability can be enhanced through coatings or heat treatment. Carbon steel is also effective, offering strength at a low cost, while stainless steel provides excellent durability and corrosion resistance, making it suitable for long-term use [8]. Aluminum alloys offer lightweight and good corrosion resistance, ideal for applications requiring reduced weight [9]. High-performance or recycled plastic can be used as an economical and eco-friendly option, especially for applications that don't require heavy load-bearing [10]. Low-cost composite materials provide an innovative alternative, combining performance and quality at a reasonable cost [11]. These options strike a balance between performance, affordability, and material availability based on specific application needs. For the purposes of this study, galvanized iron was selected for the fabrication of experimental samples. This choice was guided by the material’s availability, cost-effectiveness, and suitability for evaluating the proposed screw’s performance under realistic conditions. To maximize the mechanical adhesion principles described above, a specific geometric configuration for the screw head was developed. The proposed design incorporates a hexagonal cap featuring uniformly distributed perforations, strategically enhancing both mechanical interlocking and torque distribution during fastening operations (see Fig. 2). Here the concept is divided into two parts: the first (upper part of Fig. 2a) is the soldering iron or hot air gun used to fix screws in plastic and smooth the surface for a polished look, carefully adjusting and distributing heat to avoid distortion, which will be addressed in a separate study. The second (lower part of Fig. 2a), which is the core of this paper, revolves around the screws themselves. The hexagonal geometry was selected due to its superior ability to distribute applied forces evenly across the screw head, reducing localized stress and preventing slippage during installation. Moreover, the integration of perforations enables molten plastic to infiltrate and solidify within the screw head, forming strong mechanical bonds that significantly improve the screw’s load-bearing performance and long-term stability. The dimensions of the screw head were carefully optimized through iterative experimental testing. A thickness of 0.7 mm, an outer diameter of 18 mm, and perforations with a diameter of 3 mm were found to deliver the best balance between mechanical efficiency, durability, and manufacturability. Overall, the hex-perforated screw head design successfully combines mechanical robustness with practical manufacturability, providing a highly reliable solution for thin plastic applications. 3. Experimental Results Experimental validation was conducted to assess the mechanical performance and adhesion strength of the developed hex-perforated cap screw compared to conventional cylindrical plastic bases. Three categories of samples were prepared: 1. Sample 1: Standard cylindrical plastic base combined with flexible plastic (3 mm thickness, orange color). 2. Sample 2: Hex-perforated cap screw fixed in flexible plastic (3 mm thickness, orange color). 3. Sample 3: Hex-perforated cap screw fixed in recycled, low-flexibility plastic (2.5 mm thickness, black color). For each category, three replicate tests were performed to ensure consistency and reliability of the results. The screw samples were installed using controlled heating to promote optimal mechanical adhesion without inducing material deformation, as demonstrated in Figures 4 and 5. A gradual load was applied vertically to each sample until failure occurred. The applied force was calculated based on Newton’s second law (F = m × g), where the gravitational acceleration (g) was assumed as 9.8 m/s² [12]. The maximum load sustained before structural failure, as well as the deformation onset point, were recorded for each sample. Representative failure modes are illustrated in Fig. 6. The summarized experimental results are presented in Table 1. Table 1: Detailed comparison of test samples, including deformation start weight, maximum weight before failure, and relevant material characteristics. Standard cylindrical base - Flexible with thickness (3 mm) (Orange color) Sample Number Deformation Start Weight (N) Maximum Weight Before Failure (N) Sample 1.1 490 892 Sample 1.2 519 727 Sample 1.3 470 878 Average 493 832 Hex-perforated Screw - Flexible with thickness (3 mm) (Orange color) Sample Number Deformation Start Weight (N) Maximum Weight Before Failure (N) Sample 2.1 480 725 Sample 2.2 441 686 Sample 2.3 499 695 Average 473 702 Hex-perforated Screw - Recycled with thickness (2.5 mm) (Black color) Sample Number Deformation Start Weight (N) Maximum Weight Before Failure (N) Sample 3.1 Sudden failure 363 Sample 3.2 Sudden failure 352 Sample 3.3 Sudden failure 313 Average - 342 Analysis of the results reveals several important insights: • Flexible Plastic Comparison: The hex-perforated screw demonstrated a slightly lower maximum load capacity (approximately 15% reduction) compared to the standard cylindrical base in flexible plastic. This is attributed to the additional perforations, which while enhancing adhesion, slightly reduce the effective cross-sectional area. Nonetheless, the reduction is marginal and acceptable, given the improved adhesion and potential for repairability offered by the design. • Performance in Recycled Plastic: Notably, the hex-perforated screw maintained considerable structural integrity even in recycled plastics with low flexibility and reduced thickness (2.5 mm), a material typically prone to brittle failure. While sudden failures were observed due to the material’s inherent brittleness, the screws sustained significantly higher loads than typically expected for such materials, highlighting the screw’s versatility. • Deformation Behavior: In flexible plastics, deformation initiated before ultimate failure, indicating a ductile failure mode, whereas in recycled plastics, sudden brittle failure occurred without prior deformation. The mechanical adhesion provided by the hex-perforated design contributed to delaying the onset of catastrophic failure. Beyond its mechanical advantages, the hex-perforated screw design offers notable environmental and economic benefits. By enabling localized repairs rather than necessitating full part replacement, the screw significantly reduces material waste, aligning with sustainable manufacturing practices and supporting the principles of the circular economy. This characteristic positions the design as an attractive option for industries increasingly focused on resource efficiency and cost minimization. Additionally, while the initial focus of this study was directed toward automotive and general plastic applications, the versatility of the design opens possibilities for broader applications. These include fastening lightweight components in consumer electronics, 3D printed modular structures, and household plastic products, where securing thin-walled plastic parts without damaging the material is a critical concern. Furthermore, the observed mechanical performance aligns closely with international standards such as ASTM D638 (tensile properties of plastics) and ISO 604 (compressive strength), suggesting the screw’s potential for wider adoption across industries adhering to stringent quality benchmarks. Future research directions may include optimizing the perforation shapes and distribution patterns (e.g., elliptical, triangular) and exploring alternative screw materials, such as advanced composites, to further enhance the adhesion and structural stability across different applications and environments. Summary and Conclusions This research focused on the development and design of an innovative perforated hexagonal-headed screw to address minor damages in metals without requiring complete replacement. Through a series of initial tests, the screw demonstrated its efficiency in achieving the primary goal of repairing minor damages, thereby reducing costs and material waste. The tests showed that the screw’s efficiency is comparable to that of traditional plastic bases when used with flexible plastic, exhibiting good load-bearing capacity. It alsodisplayed remarkable strength when used with thin, non-flexible plastic. Additionally, the screw proved effective in manufacturing processes, as it can securely fix plastic components during production, enhancing the overall durability of the products. The screw's design provides an optimal balance between ease of fastening and structural durability. These results highlight its potential as a unique engineering innovation, offering more efficient, economical, and sustainable solutions for repair and fastening tasks. Declarations Acknowledgments We extend our sincere gratitude and appreciation to Engineer Hussein Yahya for his valuable support and assistance regarding the engineering drawing. His contributions had a significant impact on the success of our work, and we deeply value his efforts and ongoing collaboration with us. Thank you for your dedication and professionalism! Conflict of Interest The authors declare no competing interests. Funding declaration: this research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. References P. Dietsch and R. Brandner, Self-tapping screws and threaded rods as reinforcement for structural timber elements–A state-of-the-art report. Construction and Building Materials , 97 (2015)78-89. ‏ A. Ringhofer, R. Brandner and G. Schickhofer, Withdrawal resistance of self-tapping screws in unidirectional and orthogonal layered timber products. Materials and Structures , 48 (2015) 1435-1447. ‏ [3] A. Hossain, I. Danzig and T. Tannert, Cross-laminated timber shear connections with double-angled self-tapping screw assemblies. Journal of structural engineering , 142 (11) (2016) 04016099. ‏ J. A. Disegi and L. Eschbach, Stainless steel in bone surgery. Injury , 31(2000) D2-D6. ‏ S. Y. Wu, C. C. Lin, D. Y. Lin, A. L. Chen, C. S. Chuang, W. C. Huang and S. H. Liu, (2017, June). 3D printed" smart screw" with built-in LC sensing circuit for wireless monitoring. In 2017 19th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS) (pp. 926-929). IEEE. ‏ T. Mendel, D. Wohlrab, F. Radetzki and G. O. Hofmann The smart screw: a fancy skill for sacroiliac screw insertion. Journal of Trauma and Acute Care Surgery , 72(4) (2012) 1089-1092. ‏ M. A. Butt, A. Chughtai, J. Ahmad, R. Ahmad, U. Majeed and I. Khan. Theory of adhesion and its practical implications. Journal of faculty of engineering & technology , 2007(2008) 21-45. ‏ G. V. Shlyakhova, S. A. Barannikova, A. V. Bochkareva, , Y. V. Li and L. B. Zuev. Structure of a carbon steel–stainless steel bimetal. Steel in Translation , 48 (2018) 219-223. ‏ J. Hirsch, B. Skrotzki and G. Gottstein, (Eds.). (2008). Aluminium alloys: the physical and mechanical properties (Vol. 1). John Wiley & Sons. ‏ J. Mark. (2004). Physical properties of polymers . Cambridge University Press. ‏ N. S. M. El-Tayeb. Development and characterisation of low-cost polymeric composite materials. Materials & Design , 30(4)(2009) 1151-1160. ‏ D. Halliday, R. Resnick and J. Walker (2013). Fundamentals of physics . John Wiley & Sons. ‏ Additional Declarations The authors declare no competing interests. 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strength.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7696137/v1/7907efd161973dde552225be.png"},{"id":92130824,"identity":"26420a28-3f94-4642-829e-f2936d5b2627","added_by":"auto","created_at":"2025-09-25 03:05:29","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":73212,"visible":true,"origin":"","legend":"\u003cp\u003e(a) illustrates the schematic diagram of the screw head (lower part) and the soldering iron head (upper part), while (b and c) depict the 3D visual representation of the screw and the soldering iron.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7696137/v1/282728d20aa10b7166291a30.png"},{"id":92130828,"identity":"5d62adae-1676-448d-be37-482810befe7b","added_by":"auto","created_at":"2025-09-25 03:05:29","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":119070,"visible":true,"origin":"","legend":"\u003cp\u003eManufactured screw with a perforated hexagonal head, showcasing precision engineering and robust design, suitable for upcoming performance tests.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7696137/v1/b609cd1862a30c8a7088b2a9.png"},{"id":92130835,"identity":"d64f9bf6-e1b5-4718-b015-91541daee3eb","added_by":"auto","created_at":"2025-09-25 03:05:29","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":148243,"visible":true,"origin":"","legend":"\u003cp\u003e(a) displays our Hex-perforated cap screw alongside the standard screw base. (b) shows a cross-sectional view highlighting the absence of deformation on the opposite side of the sample, despite its minimal thickness (3 mm).\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7696137/v1/30b51a3c4eddee3aa6696a73.png"},{"id":92131440,"identity":"182a6a7e-6c84-490c-87bc-bc1649137cd8","added_by":"auto","created_at":"2025-09-25 03:13:29","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":102074,"visible":true,"origin":"","legend":"\u003cp\u003e(a) shows our screw fixed in recycled plastic with very low flexibility. (b) presents a cross-sectional view demonstrating the absence of the deformation on the opposite face, despite the minimal thickness (2.5 mm).\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7696137/v1/bd11fb1a615d647c46e0db86.png"},{"id":92130827,"identity":"c46eb27b-f69d-4bdf-baf5-3ed3af4108a2","added_by":"auto","created_at":"2025-09-25 03:05:29","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":90612,"visible":true,"origin":"","legend":"\u003cp\u003eIllustration of various samples displaying damage sustained, with annotations indicating the maximum weight each sample withstood before failure.\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-7696137/v1/59830eec3e526995ded5f668.png"},{"id":92132385,"identity":"ce3a6333-56b3-4cc5-a867-37e02049217c","added_by":"auto","created_at":"2025-09-25 03:29:29","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1050354,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7696137/v1/27e84096-5e10-413d-8310-699a0a521849.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eHex-Perforated Cap Screw: An Innovative Solution for Enhancing Mechanical Adhesion in Thin Plastic Components\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eScrews have undergone numerous advancements over the years to enhance their efficiency and expand their applications across a wide range of industries. Innovations such as self-tapping screws for simplified installation [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], corrosion-resistant screws for harsh environments [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], and smart screws equipped with embedded sensors for real-time monitoring [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] exemplify the continuous evolution of fastening technologies. Despite these advancements, a persistent challenge remains in applications involving plastic components, particularly those with minimal thickness (\u0026le;\u0026thinsp;3 mm). A common failure observed in plastic assemblies is the localized damage at the screw mounting base, leading to structural weaknesses, aesthetic deformities, or, in severe cases, complete failure of the component. For example, plastic bases supporting automotive headlights may sustain minor damage during low-impact collisions, rendering the entire assembly unstable without necessitating full replacement. Current conventional solutions, including the use of strong adhesives or reinforcement patches, suffer from several limitations. Adhesives are vulnerable to environmental degradation, and the application of larger or stronger screws can compromise the integrity of the plastic, often causing additional damage. Therefore, there is a pressing need for a simple, cost-effective, and reliable method to reinforce screw mounting in thin plastics.\u003c/p\u003e\u003cp\u003eIn response to this need, we have developed an innovative hex-perforated cap screw that leverages basic physical principles to enhance mechanical adhesion. The design emphasizes manufacturability, ease of installation, and durability, aiming to extend the functional lifespan of plastic components without compromising their structural integrity or aesthetic quality.\u003c/p\u003e\u003cp\u003eIn sec. 2 we will discuss the principles and fundamentals of manufacturing, focusing on material selection and engineering techniques that enhance mechanical efficiency. In sec. 3 preliminary test results are summarized. The last section presents a comprehensive summary of the key findings.\u003c/p\u003e"},{"header":"2. Principles and Manufacturing Materials","content":"\u003cp\u003eThe core principle underpinning the proposed hex-perforated cap screw is the enhancement of mechanical adhesion between the screw and plastic substrates. This is achieved by designing perforations within the hexagonal screw head, which allow molten plastic to flow through during installation. Upon cooling and solidification, the plastic forms \u0026ldquo;mushroom-like\u0026rdquo; \u0026nbsp;structures \u0026nbsp;within \u0026nbsp;the perforations (see Fig. 1), significantly strengthening the bond and improving overall structural stability.\u003c/p\u003e\n\u003cp\u003eThe effectiveness of mechanical adhesion is heavily influenced by the compatibility between the screw material and the plastic substrate. Material compatibility ensures optimal cohesion, distributes applied forces more evenly, and minimizes the risk of corrosion or material degradation over time. Several material options were evaluated to balance cost, manufacturability, and mechanical performance. Iron is an affordable and readily available option, and its resistance to corrosion and durability can be enhanced through coatings or heat treatment. Carbon steel is also effective, offering strength at a low cost, while stainless steel provides excellent durability and corrosion resistance, making it suitable for long-term use [8]. Aluminum alloys offer lightweight and good corrosion resistance, ideal for applications requiring reduced weight [9]. High-performance or recycled plastic can be used as an economical and eco-friendly option, especially for applications that don\u0026apos;t require heavy load-bearing [10]. Low-cost composite materials provide an innovative alternative, combining performance and quality at a reasonable cost [11]. These options strike a balance between performance, affordability, and material availability based on specific application needs.\u003c/p\u003e\n\u003cp\u003eFor the purposes of this study, galvanized iron was selected for the fabrication of experimental samples. This choice was guided by the material\u0026rsquo;s availability, cost-effectiveness, and suitability for evaluating the proposed screw\u0026rsquo;s performance under realistic conditions.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTo maximize the mechanical adhesion principles described above, a specific geometric configuration for the screw head was developed. The proposed design incorporates a hexagonal cap featuring uniformly distributed perforations, strategically enhancing both mechanical interlocking and torque distribution during fastening operations (see Fig. 2). Here the concept is divided into two parts: the first (upper part of Fig. 2a) is the soldering iron or hot air gun used to fix screws in plastic and smooth the surface for a polished look, carefully adjusting and distributing heat to avoid distortion, which will be addressed in a separate study. \u0026nbsp;The second (lower part of Fig. 2a), which is the core of this paper, revolves around the screws themselves.\u003c/p\u003e\n\u003cp\u003eThe hexagonal geometry was selected due to its superior ability to distribute applied forces evenly across the screw head, reducing localized stress and preventing slippage during installation. Moreover, the integration of perforations enables molten plastic to infiltrate and solidify within the screw head, forming strong mechanical bonds that significantly improve the screw\u0026rsquo;s load-bearing performance and long-term stability. The dimensions of the screw head were carefully optimized through iterative experimental testing. A thickness of 0.7 mm, an outer diameter of 18 mm, and perforations with a diameter of 3 mm were found to deliver the best balance between mechanical efficiency, durability, and manufacturability. Overall, the hex-perforated screw head design successfully combines mechanical robustness with practical manufacturability, providing a highly reliable solution for thin plastic applications.\u003c/p\u003e"},{"header":"3. Experimental Results","content":"\u003cp\u003eExperimental validation was conducted to assess the mechanical performance and adhesion strength of the developed hex-perforated cap screw compared to conventional cylindrical plastic bases. Three categories of samples were prepared:\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;1. Sample 1: Standard cylindrical plastic base combined with flexible plastic (3 mm thickness, orange color).\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;2. Sample 2: Hex-perforated cap screw fixed in flexible plastic (3 mm thickness, orange color).\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;3. Sample 3: Hex-perforated cap screw fixed in recycled, low-flexibility plastic (2.5 mm thickness, black color).\u003c/p\u003e\n\u003cp\u003eFor each category, three replicate tests were performed to ensure consistency and reliability of the results. The screw samples were installed using controlled heating to promote optimal mechanical adhesion without inducing material deformation, as demonstrated in Figures 4 and 5. A gradual load was applied vertically to each sample until failure occurred. The applied force was calculated based on Newton\u0026rsquo;s second law (F = m \u0026times; g), where the gravitational acceleration (g) was assumed as 9.8 m/s\u0026sup2; [12]. The maximum load sustained before structural failure, as well as the deformation onset point, were recorded for each sample. Representative failure modes are illustrated in Fig. 6. The summarized experimental results are presented in Table 1.\u003c/p\u003e\n\u003cp\u003eTable 1: Detailed comparison of test samples, including deformation start weight, maximum weight before failure, and relevant material characteristics.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"294\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" style=\"width: 294px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStandard cylindrical base - Flexible with thickness (3 mm) (Orange color)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 91px;\"\u003e\n \u003cp\u003eSample Number\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eDeformation Start Weight (N)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp\u003eMaximum Weight Before Failure (N)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 91px;\"\u003e\n \u003cp\u003eSample 1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003e490\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp\u003e892\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 91px;\"\u003e\n \u003cp\u003eSample 1.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003e519\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp\u003e727\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 91px;\"\u003e\n \u003cp\u003eSample 1.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003e470\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp\u003e878\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 91px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAverage\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e493\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e832\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" style=\"width: 294px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eHex-perforated Screw - Flexible with thickness (3 mm) (Orange color)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 91px;\"\u003e\n \u003cp\u003eSample Number\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eDeformation Start Weight (N)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp\u003eMaximum Weight Before Failure (N)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 91px;\"\u003e\n \u003cp\u003eSample 2.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003e480\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp\u003e725\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 91px;\"\u003e\n \u003cp\u003eSample 2.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003e441\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp\u003e686\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 91px;\"\u003e\n \u003cp\u003eSample 2.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003e499\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp\u003e695\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 91px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAverage\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e473\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e702\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" style=\"width: 294px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eHex-perforated Screw - Recycled with thickness (2.5 mm) (Black color)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 91px;\"\u003e\n \u003cp\u003eSample Number\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eDeformation Start Weight (N)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp\u003eMaximum Weight Before Failure (N)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 91px;\"\u003e\n \u003cp\u003eSample 3.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eSudden failure\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp\u003e363\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 91px;\"\u003e\n \u003cp\u003eSample 3.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eSudden failure\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp\u003e352\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 91px;\"\u003e\n \u003cp\u003eSample 3.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003eSudden failure\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp\u003e313\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 91px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAverage\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 100px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e342\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eAnalysis of the results reveals several important insights:\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u0026bull; Flexible Plastic Comparison: The hex-perforated screw demonstrated a slightly lower maximum load capacity (approximately 15% reduction) compared to the standard cylindrical base in flexible plastic. This is attributed to the additional perforations, which while enhancing adhesion, slightly reduce the effective cross-sectional area. Nonetheless, the reduction is marginal and acceptable, given the improved adhesion and potential for repairability offered by the design.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u0026bull; Performance in Recycled Plastic: Notably, the hex-perforated screw maintained considerable structural integrity even in recycled plastics with low flexibility and reduced thickness (2.5 mm), a material typically prone to brittle failure. While sudden failures were observed due to the material\u0026rsquo;s inherent brittleness, the screws sustained significantly higher loads than typically expected for such materials, highlighting the screw\u0026rsquo;s versatility.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u0026bull; Deformation Behavior: In flexible plastics, deformation initiated before ultimate failure, indicating a ductile failure mode, whereas in recycled plastics, sudden brittle failure occurred without prior deformation. The mechanical adhesion provided by the hex-perforated design contributed to delaying the onset of catastrophic failure.\u003c/p\u003e\n\u003cp\u003eBeyond its mechanical advantages, the hex-perforated screw design offers notable environmental and economic benefits. By enabling localized repairs rather than necessitating full part replacement, the screw significantly reduces material waste, aligning with sustainable manufacturing practices and supporting the principles of the circular economy. This characteristic positions the design as an attractive option for industries increasingly focused on resource efficiency and cost minimization.\u003c/p\u003e\n\u003cp\u003eAdditionally, while the initial focus of this study was directed toward automotive and general plastic applications, the versatility of the design opens possibilities for broader applications. These include fastening lightweight components in consumer electronics, 3D printed modular structures, and household plastic products, where securing thin-walled plastic parts without damaging the material is a critical concern. Furthermore, the observed mechanical performance aligns closely with international standards such as ASTM D638 (tensile properties of plastics) and ISO 604 (compressive strength), suggesting the screw\u0026rsquo;s potential for wider adoption across industries adhering to stringent quality benchmarks. Future research directions may include optimizing the perforation shapes and distribution patterns (e.g., elliptical, triangular) and exploring alternative screw materials, such as advanced composites, to further enhance the adhesion and structural stability across different applications and environments.\u003c/p\u003e"},{"header":"Summary and Conclusions ","content":"\u003cp\u003eThis research focused on the development and design of an innovative perforated hexagonal-headed screw to address minor damages in metals without requiring complete replacement. Through a series of initial tests, the screw demonstrated its efficiency in achieving the primary goal of repairing minor damages, thereby reducing costs and material waste. The tests showed that the screw’s efficiency is comparable to that of traditional plastic bases when used with flexible plastic, exhibiting good load-bearing capacity. It alsodisplayed remarkable strength when used with thin, non-flexible plastic. Additionally, the screw proved effective in manufacturing processes, as it can securely fix plastic components during production, enhancing the overall durability of the products. The screw's design provides an optimal balance between ease of fastening and structural durability. These results highlight its potential as a unique engineering innovation, offering more efficient, economical, and sustainable solutions for repair and fastening tasks.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eAcknowledgments\u003c/p\u003e\n\u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;We extend our sincere gratitude and appreciation to Engineer \u003cem\u003eHussein Yahya\u003c/em\u003e for his valuable support and assistance regarding the engineering drawing. His contributions had a significant impact on the success of our work, and we deeply value his efforts and ongoing collaboration with us. Thank you for your dedication and professionalism!\u003c/p\u003e\n\u003cp\u003eConflict of Interest\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003eFunding declaration: this research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eP. Dietsch and R. Brandner, Self-tapping screws and threaded rods as reinforcement for structural timber elements\u0026ndash;A state-of-the-art report. \u003cem\u003eConstruction and Building Materials\u003c/em\u003e, 97\u003cem\u003e\u0026nbsp;\u003c/em\u003e(2015)78-89.\u003cspan dir=\"RTL\"\u003e\u0026rlm;\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eA. Ringhofer, R. Brandner and G. Schickhofer, Withdrawal resistance of self-tapping screws in unidirectional and orthogonal layered timber products. \u003cem\u003eMaterials and Structures\u003c/em\u003e, 48 (2015) 1435-1447.\u003cspan dir=\"RTL\"\u003e\u0026rlm;\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003e[3] A. Hossain, I. Danzig and T. Tannert, Cross-laminated timber shear connections with double-angled self-tapping screw assemblies. \u003cem\u003eJournal of structural engineering\u003c/em\u003e, 142 (11) (2016) 04016099.\u003cspan dir=\"RTL\"\u003e\u0026rlm;\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eJ. A. Disegi and L. Eschbach, Stainless steel in bone surgery. \u003cem\u003eInjury\u003c/em\u003e, 31(2000) D2-D6.\u003cspan dir=\"RTL\"\u003e\u0026rlm;\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eS. Y. Wu, C. C. Lin, D. Y. Lin, A. L. Chen, C. S. Chuang, W. C. Huang and S. H. Liu, (2017, June). 3D printed\u0026quot; smart screw\u0026quot; with built-in LC sensing circuit for wireless monitoring. 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Structure of a carbon steel\u0026ndash;stainless steel bimetal. \u003cem\u003eSteel in Translation\u003c/em\u003e, 48 (2018) 219-223.\u003cspan dir=\"RTL\"\u003e\u0026rlm;\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eJ. Hirsch, B. Skrotzki and G. Gottstein, (Eds.). (2008). \u003cem\u003eAluminium alloys: the physical and mechanical properties\u003c/em\u003e (Vol. 1). John Wiley \u0026amp; Sons.\u003cspan dir=\"RTL\"\u003e\u0026rlm;\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eJ. Mark. (2004). \u003cem\u003ePhysical properties of polymers\u003c/em\u003e. Cambridge University Press.\u003cspan dir=\"RTL\"\u003e\u0026rlm;\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eN. S. M. El-Tayeb. Development and characterisation of low-cost polymeric composite materials. \u003cem\u003eMaterials \u0026amp; Design\u003c/em\u003e, 30(4)(2009) 1151-1160.\u003cspan dir=\"RTL\"\u003e\u0026rlm;\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eD. Halliday, R. Resnick and J. Walker (2013). \u003cem\u003eFundamentals of physics\u003c/em\u003e. John Wiley \u0026amp; Sons.\u003cspan dir=\"RTL\"\u003e\u0026rlm;\u003c/span\u003e\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"ministry of Electricity","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Innovation Screw, Mechanical Adhesion, Plastic, Hexagonal Cap","lastPublishedDoi":"10.21203/rs.3.rs-7696137/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7696137/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eA hex-perforated cap screw featuring a hexagonal head with integrated perforations has been developed to address common issues related to mounting screws in thin plastic materials (\u0026le;\u0026thinsp;3 mm thickness). The novel design aims to enhance mechanical adhesion, ease of manufacturing, and durability while minimizing damage typically caused by conventional screw mounting systems. Initial experimental evaluations demonstrated that the proposed screw maintains comparable load-bearing capacity to traditional bases in flexible plastics and exhibits superior performance in recycled, low-flexibility plastics. These findings highlight the potential of the hex-perforated cap screw to serve as a cost-effective, sustainable solution across diverse industrial applications.\u003c/p\u003e","manuscriptTitle":"Hex-Perforated Cap Screw: An Innovative Solution for Enhancing Mechanical Adhesion in Thin Plastic Components","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-25 03:05:24","doi":"10.21203/rs.3.rs-7696137/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"6ca62e5b-f382-4480-acb5-4d6078599489","owner":[],"postedDate":"September 25th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":55215350,"name":"Mechanical Engineering"}],"tags":[],"updatedAt":"2025-09-25T03:05:24+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-25 03:05:24","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7696137","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7696137","identity":"rs-7696137","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}