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Research Article
Process Planning and Precision Fabrication of an Aluminum Linkage Arm by CNC Milling and Wire EDM
Issue:
Volume 11, Issue 4, August 2026
Pages:
105-114
Received:
13 July 2026
Accepted:
23 July 2026
Published:
10 August 2026
Abstract: Linkage arms containing a keyed bore, forked end, pivot hole, and tapered web require coordinated datum control and machining sequence because setup transfer and local stiffness variation can degrade geometric accuracy. This study develops and experimentally evaluates a requirement-driven process-planning framework for the low-volume manufacture of a precision linkage arm from 6061-T6 aluminum alloy using three-axis computer numerical control (CNC) milling and wire electrical discharge machining (WEDM). The objective is to translate the functional requirements into an auditable chain covering datum selection, allowance distribution, tool choice, setup sequence, machining conditions, and final inspection. A single component was fabricated on a VF-1 vertical machining center. The route comprised primary and secondary face generation, staged roughing and finishing, contour milling, circular interpolation, reaming, reverse-side re-fixturing through previously machined features, chamfering, and final WEDM of the internal keyway. The principal bore was completed before WEDM to reference the keyway to the actual bore axis and retain stiffness during bulk material removal. Inspection showed that the principal bore and pivot-hole diameters and the local section thicknesses conformed to the drawing requirements. The reported parallelism deviation was 0.04 mm, while the hole-axis-to-end-face non-perpendicularity was 0.06 mm. A preliminary screening error budget indicated that primary-datum generation and reverse-side re-fixturing accounted for approximately 55–60% of these deviations, identifying setup transfer as the dominant improvement target. The results demonstrate that accuracy depended on datum continuity, controlled re-fixturing, and correct multi-process sequencing rather than on any single operation. The proposed framework provides a practical and traceable basis for low-volume linkage-component manufacture, although repeated trials, formal uncertainty analysis, surface metrology, and mechanical validation remain necessary before industrial process capability can be established.
Abstract: Linkage arms containing a keyed bore, forked end, pivot hole, and tapered web require coordinated datum control and machining sequence because setup transfer and local stiffness variation can degrade geometric accuracy. This study develops and experimentally evaluates a requirement-driven process-planning framework for the low-volume manufacture of...
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Research Article
Selection of Project Delivery Method for Libyan Residential Building Construction by Means of Expert Opinions and Owner Preferences
Abdulmojeb Ali Almhroog*
Issue:
Volume 11, Issue 4, August 2026
Pages:
115-128
Received:
25 April 2026
Accepted:
22 May 2026
Published:
17 August 2026
DOI:
10.11648/j.eas.20261104.12
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Abstract: This study addresses the challenges facing the rapidly growing Libyan construction industry, which requires sophisticated decision-making approaches to support the selection of optimal project solutions. One of the most critical decisions in construction projects is the selection of the Project Delivery Method (PDM), which significantly influences project performance and implementation efficiency. In Libya, the Design–Bid–Build (DBB) method remains the dominant delivery approach despite persistent issues related to quality, time performance, and coordination. The present study aims to identify the most suitable PDM for residential building construction in Libya by introducing and evaluating alternative delivery methods within the Libyan construction context. The research integrates owner preferences and expert opinions using the Analytical Hierarchy Process (AHP) as a multi-criteria decision-making tool. Four delivery methods—Design–Bid–Build (DBB), Design–Build (DB), Construction Management at Risk (CM@R), and Integrated Project Delivery (IPD)—were evaluated based on four key criteria: scope/quality, time, cost, and risk. Data were collected through interviews with residential project owners and construction contract experts to obtain the information required for selecting the most appropriate delivery method for residential building projects. All pairwise comparison matrices achieved acceptable consistency ratios, confirming the reliability of the evaluation process. The findings indicate that CM@R is the most suitable project delivery method for residential construction projects in Libya, followed by DB, IPD, and DBB. The results reveal a significant gap between the currently dominant practice and the most performance-oriented delivery approach. Furthermore, the study provides a structured decision-support framework that can assist stakeholders and decision makers in improving project delivery method selection within the Libyan construction industry.
Abstract: This study addresses the challenges facing the rapidly growing Libyan construction industry, which requires sophisticated decision-making approaches to support the selection of optimal project solutions. One of the most critical decisions in construction projects is the selection of the Project Delivery Method (PDM), which significantly influences ...
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Research Article
Assessment of Blood Pressure Variation Due to Noise Exposure Among Machine Operators Without
Ear-protection at Workshops
Edwin Francis Aboche*,
Ezekiel Kuara Makama,
Oladele Francis Anjorin,
Nestor Monday Dangu Chagok
Issue:
Volume 11, Issue 4, August 2026
Pages:
129-140
Received:
13 July 2026
Accepted:
28 July 2026
Published:
18 August 2026
DOI:
10.11648/j.eas.20261104.13
Downloads:
Views:
Abstract: Blood pressure variability (BPV) has been linked to cardiovascular diseases, including death and end-organ damage, according to several studies. Industrialization is typically linked to noise pollution, which can have negative health implications. Sounds in industries and workshops are classified as noise pollution when human activity exceeds the recommended threshold. The aim of the study is to determine blood pressure (BP) variation as a result of noise exposure among machine operators without ear protection at workshops, using an automatic arm BP monitor (model RAK269) with an accuracy of BP within ±3 mmHg. The longitudinal method was used for BP measurements of the operators before and after operating the industrial machine for two hours. The results showed that after using the machine, 44 operators between the ages of 20 and 29 had a mean BP elevation of 125.2/82.8 mmHg and a mean variability in their BP of 17.2/8.1 mmHg, which is in the prehypertensive range, with noise exposure level between 107.5 and 115.0 dBA. When exposed to noise pollution levels of 110.2–117.3 dBA, the 64 operators between the ages of 30 and 39 had a mean BP elevation of 129.7/84.8 mmHg and a BP variability of 20.4/9.0 mmHg, both of which are in the prehypertensive range. Furthermore, the 17 operators within the ages of 40 and 49 had a mean BP elevation of 135.5/86.6 mmHg, and their BP variation was recorded at 24.5/9.9 mmHg, which is also in the prehypertensive range when they are exposed to noise pollution that varies from 111.9 to 117.6 dBA. In conclusion, it has been confirmed that using an angle grinder or aluminium cutter without wearing ear protection directly affects the operators' SBP/DBP, raising their risk of developing cardiovascular diseases and other health issues associated with high noise exposure in workshop settings. In order to protect their health, operators must wear ear-protection and routinely monitor their blood pressure and hearing sensitivity, regulatory bodies to mandate the use of earplugs, earmuffs, and other ear protection at workshops.
Abstract: Blood pressure variability (BPV) has been linked to cardiovascular diseases, including death and end-organ damage, according to several studies. Industrialization is typically linked to noise pollution, which can have negative health implications. Sounds in industries and workshops are classified as noise pollution when human activity exceeds the r...
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