Optimization of cut surface quality during CNC Plasma Arc Cutting process

Optimization of cut surface quality during CNC plasma-arc cutting (PAC) of mild steel plates is presented. Using design of experiments (DOE) the optimum process parameters are estimated. The process parameters tested include cutting speed, cutting height and arc voltage. Analysis of means (ANOM) and analysis of variances (ANOVA) were used in order for the effect of each parameter on the surface quality to be assessed

Sustainability assessment for manufacturing operations

Sustainability is becoming more and more important as a decision attribute in the manufacturing environment. However, quantitative metrics for all the aspects of the triple bottom line are difficult to assess. Within the present paper, the sustainability metrics are considered in tandem with other traditional manufacturing metrics such as time, flexibility, and quality and a novel framework is presented that integrates information and requirements from Computer-Aided Technologies (CAx) systems. A novel tool is outlined for considering a number of key performance indicators related to the triple bottom line when deciding the most appropriate process route. The implemented system allows the assessment of alternative process plans considering the market demands and available resources

The impact of process parameters on surface roughness and dimensional accuracy during CO2 laser cutting of PMMA thin sheets

This study investigated the impact of the laser speed and power, and the position and orientation of the samples, on the average surface roughness (Ra) and dimensional accuracy (DA) during CO2 laser cutting of polymethyl methacrylate (PMMA) thin sheets. A mixed five-parameter fractional factorial design was applied, and thirty-six measurements for the Ra and DA were obtained. The experimental results were analysed using ANOM diagrams, ANOVA analysis and interaction plots of all parameters. It was concluded that the laser speed is the critical parameter for both surface roughness and dimensional accuracy, resulting in strong interactions with laser power and positioning parameters. It was also shown that Ra values are affected by the orientation of the specimen and can be minimized when the samples are aligned in the laser travel direction. Finally, it was proved that lower laser speed improves the average roughness but reduces the dimensional accuracy

Multi-response optimization of CuZn39Pb3 brass alloy turning by implementing Grey Wolf algorithm

Machinability of engineering materials is crucial for industrial manufacturing processes since it affects all the essential aspects involved, e.g. work­load, resources, surface integrity and part quality. Two basic ma­chin­ability para­meters are the surface roughness, closely associated with the functional and tribological performance of components, and the cutting forces acting on the tool. Knowledge of the cutting forces is needed for estimation of power re­quirements and for the design of machine tool elements, tool-holders and fix­tures, adequately rigid and free from vibration. This work in­ve­stigates the in­flu­ence of cutting conditions on machinability indicators such as the main cutting force Fc and surface roughness parameters Ra and Rt when longitudinally turning CuZn39Pb3 brass alloy. Full quadratic regression models were de­veloped to correlate the machining conditions with the imparted machinability characteristics. Further on, an advanced artificial grey wolf optimization algorithm was implemented to optimize the aforementioned responses with great success in finding the final optimal values of the turning parameters

Pancreatic adenocarcinoma-associated polymyositis treated with corticosteroids along with cancer specific treatment: case report

<p>Abstract</p> <p>Background</p> <p>Adenocarcinoma of the pancreas only rarely is associated with inflammatory myopathy. In this setting, polymyositis may be treated with glucocorticoids in combination with cancer specific treatment.</p> <p>Case presentation</p> <p>We present the case of a 52-year-old man with stage IIA pancreatic tail adenocarcinoma who underwent surgical treatment and six months into therapy with gemcitabine he developed symmetrical, painful, proximal muscle weakness with peripheral oedema. Re-evaluation with imaging modalities, muscle histology and biochemistry conferred the diagnosis of polymyositis associated with pancreatic cancer progression. The patient was treated with glucocorticoids along with gemcitabine and erlotinib which resulted in complete remission within six months. He remained in good health for a further six months on erlotinib maintenance therapy when a new computer tomography scan showed pancreatic cancer relapse and hence prompted 2^ndline chemotherapy with gemcitabine.</p> <p>Conclusions</p> <p>Polymyositis associated with pancreatic cancer may respond to glucocorticoids along with cancer specific treatment.</p

A generalised approach on kerf geometry prediction during CO2 laser cut of PMMA thin plates using neural networks

This study presents an application of feedforward and backpropagation neural network (FFBP-NN) for predicting the kerf characteristics, i.e. the kerf width in three different distances from the surface (upper, middle and down) and kerf angle during laser cutting of 4 mm PMMA (polymethyl methacrylate) thin plates. Stand-off distance (SoD: 7, 8 and 9 mm), cutting speed (CS: 8, 13 and 18 mm/sec) and laser power (LP: 82.5, 90 and 97.5 W) are the studied parameters for low power CO2 laser cutting. A three-parameter three-level full factorial array has been used, and twenty-seven (33) cuts are performed. Subsequently, the upper, middle and down kerf widths (Wu, Wm and Wd) and the kerf angle (KA) were measured and analysed through ANOM (analysis of means), ANOVA (analysis of variances) and interaction plots. The statistical analysis highlighted that linear modelling is insufficient for the precise prediction of kerf characteristics. An FFBP-NN was developed, trained, validated and generalised for the accurate prediction of the kerf geometry. The FFBP-NN achieved an R-all value of 0.98, in contrast to the ANOVA linear models, which achieved Rsq values of about 0.86. According to the ANOM plots, the parameter values which optimize the KA resulting in positive values close to zero degrees were the 7 mm SoD, 8 mm/s CS and 97.5 W LP

Swarm intelligence algorithms for optimising sliding wear of nanocomposites

This paper presents simulation results obtained by a set of modern algorithms adhering to swarm intelligence for minimising wear rate in the case of A356/Al2O3 nanocomposites produced using a compocasting process. Grey wolf optimisation (GWO) algorithm, moth-flame optimisation (MFO) algorithm, dragonfly algorithm (DA) and whale optimisation algorithm (WOA) were the algorithms under examination. A full quadratic regression equation that predicts wear rate, as the optimisation objective by considering reinforcement content, sliding speed, normal load and reinforcement size as the independent process parameters, was utilised as the objective function. Simulation results obtained by the selected algorithms were quite promising in terms of fast convergence and global optimum result arrival, thus prompting to further investigation of applying swarm intelligence to general problem-solving aspects related to tribology

Quality performance evaluation of thin walled PLA 3D printed parts using the taguchi method and grey relational analysis

This paper investigates the quality performance of FDM 3D printed models with thin walls. The design of experiments method (DOE) was used and nine models of the same size were fabricated in a low-cost 3D printer using polylactic acid (PLA) material. Two limited studied parameters were considered (extraction temperature and wall thickness), each one having three levels. External X and Y dimensions were measured using a micrometer, as well as four surface roughness parameters (Ra, Rz, Rt, Rsm) with a surface tester. Two optimization techniques (the Taguchi approach and Grey relational analysis) were utilized along with statistical analysis to examine how the temperature and wall thickness affect the dimensional accuracy and the surface quality of the parts. The results showed that high extraction temperature and median wall thickness values optimize both dimensional accuracy and surface roughness, while temperature is the most important factor

Current issues in global furniture - Proceedings of the 8th biennial Furniture Research Group Conference. Missenden Abbey. Buckinghamshire New University 20 November 2013

'Current issues in global furniture’ attempted to capture contemporary views of where furniture is currently positioned from a world perspective. The first keynote paper firmly placed kitchen design into the field of furniture products showing that it has a similar stylistic development, but with nuances particular to its form and function. Ecological issues were raised concerning durability and the use of recycled components that perhaps to many is not what is expected within the domestic kitchen. Johnny Grey is no ordinary kitchen designer having designed and built kitchens all over the world within a wide range of budgets. Grey shows innovation in his adoption of green principles and especially in reusing components and materials

Western European Variation in the Organization of Esophageal Cancer Surgical Care

Reasons for structural and outcome differences in esophageal cancer surgery in Western Europe remain unclear. This questionnaire study aimed to identify differences in the organization of esophageal cancer surgical care in Western Europe. A cross-sectional international questionnaire study was conducted among upper gastrointestinal (GI) surgeons from Western Europe. One surgeon per country was selected based on scientific output and active membership in the European Society for Diseases of the Esophagus or (inter)national upper GI committee. The questionnaire consisted of 51 structured questions on the structural organization of esophageal cancer surgery, surgical training, and clinical audit processes. Between October 2021 and October 2022, 16 surgeons from 16 European countries participated in this study. In 5 countries (31%), a volume threshold was present ranging from 10 to 26 annual esophagectomies, in 7 (44%) care was centralized in designated centers, and in 4 (25%) no centralizing regulations were present. The number of centers performing esophageal cancer surgery per country differed from 4 to 400, representing 0.5–4.9 centers per million inhabitants. In 4 countries (25%), esophageal cancer surgery was part of general surgical training and 8 (50%) reported the availability of upper GI surgery fellowships. A national audit for upper GI surgery was present in 8 (50%) countries. If available, all countries use the audit to monitor the quality of care. Substantial differences exist in the organization and centralization of esophageal cancer surgical care in Western Europe. The exchange of experience in the organizational aspects of care could further improve the results of esophageal cancer surgical care in Europe