scholarly journals Impact of Sycamore Maple Thermal Treatment on a Granulometric Composition of Chips Obtained due to Processing on a CNC Machining Mentre

2019 ◽  
Vol 11 (3) ◽  
pp. 718 ◽  
Author(s):  
Richard Kminiak ◽  
Ladislav Dzurenda
Keyword(s):  
Thermal Treatment ◽  
Granulometric Composition ◽  
Negative Impact ◽  
Cnc Machining ◽  
Numerical Control ◽  
Three Dimensions ◽  
Dust Particles ◽  
Feed Speed ◽  
Mode Iii ◽  
Granulometric Analysis

This article deals with a granulometric composition of chips from the milling process of native and thermal treatment maple cuttings on a 5-axial Computer numerical control (CNC) machining center SCM Tech Z5. The aim of this article was to determine the changes in the granulometric composition of chips due to the thermal treatment of wood and to assess the potential risk of the creation of harmful dust fractions. Cuttings were milled with a shank cutter with exchangeable razor blades at feed speed vf = 1 ÷ 5 m·min−1 and material removal e = 3 mm. The thermal treatment in order to modify the color of the maple wood was done with water vapour at temperatures of tI = 112.5 ± 2.5 °C for a period of τ = 5.5 h (Mode I), tII = 127.5 ± 2.5 °C for a period of τ = 6.5 h (Mode II), and tIII = 137.5 ± 2.5 °C for a period of τ = 7.5 h (Mode III). The granulometric composition of the chips was detected by sifting. A granulometric analysis of the chips provided that more than 2/3 of the produced chips are a coarse fraction consisting of flat chips with dimensions over 1 mm. Dust fractions smaller than 500 μm form isometric grains, i.e., chips having approximately the same size in all three dimensions. Inhalable dust particles, smaller than 125 μm, do not exceed a 2.5% share. The granulometric analysis of chips shows that the thermal treatment of maple wood does not create respirable fractions, and therefore, the thermal treatment of the wood does not have a negative impact on the living and working environments.

scholarly journals Multi-Stage Prediction of Feed System Time Series

2021 ◽  
Author(s):  
Lihua Shen ◽  
Biling Wang ◽  
Hongjun Liu
Keyword(s):  
Time Series ◽  
Prediction Models ◽  
Tracking Error ◽  
Cnc Machining ◽  
Numerical Control ◽  
Machining Accuracy ◽  
Feed Speed ◽  
Feed System ◽  
Multi Stage ◽  
Robust Prediction

In order to reduce the tracking error of the computer numerical control (CNC) feed system and improve the CNC machining accuracy, a novel prediction model is proposed based on fuzzy C-means robust variational echo state network. Firstly, the feed speed time series is clustered, and then reconstructed for different categories. The multi-stage robust prediction models are established to realize the multi-state robust prediction of the CNC machining feed velocity to reduce the tracking error of the feed system. Finally, the reference and actual time series with different feed speed are used to verify the established models. The results show that the proposed method can reduce the tracking error and realize the effective prediction of the time series of the feed system.

Adaptive spiral tool path generation for computer numerical control machining using point cloud

2021 ◽  
pp. 095440622199007
Author(s):  
Mandeep Dhanda ◽  
Aman Kukreja ◽  
SS Pande
Keyword(s):  
Tool Path ◽  
Cnc Machining ◽  
Numerical Control ◽  
Numerical Control Machining ◽  
Form Errors ◽  
Spiral Tool Path ◽  
Novel Method ◽  
Mesh Grid ◽  
Cloud Of Points ◽  
Cam Software

This paper reports a novel method to generate adaptive spiral tool path for the CNC machining of complex sculptured surface represented in the form of cloud of points without the need for surface fitting. The algorithm initially uses uniform 2 D circular mesh-grid to compute the cutter location (CL) points by applying the tool inverse offset method (IOM). These CL points are refined adaptively till the surface form errors converge below the prescribed tolerance limits in both circumferential and radial directions. They are further refined to eliminate the redundancy in machining and generate optimum region wise tool path to minimize the tool lifts. The NC part programs generated by our algorithm were widely tested for different case studies using the commercial CNC simulator as well as by the actual machining trial. Finally, a comparative study was done between our developed system and the commercial CAM software. The results showed that our system is more efficient and robust in terms of the obtained surface quality, productivity, and memory requirement.

scholarly journals Evaluation of Marblewood Dust’s (Marmaroxylon racemosum) Effect on Ignition Risk

2021 ◽  
Vol 11 (15) ◽  
pp. 6874
Author(s):  
Miroslava Vandličkova ◽  
Iveta Markova ◽  
Katarina Holla ◽  
Stanislava Gašpercová
Keyword(s):  
Particle Size ◽  
Dust Particles ◽  
Wood Dust ◽  
Sieve Analysis ◽  
Granulometric Analysis ◽  
Analysis Measurement ◽  
Risk Research ◽  
Minimum Ignition Temperature ◽  
The Impact

The paper deals with the selected characteristics, such as moisture, average bulk density, and fraction size, of tropical marblewood dust (Marmaroxylon racemosum) that influence its ignition risk. Research was focused on sieve analysis, granulometric analysis, measurement of moisture level in the dust, and determination of the minimum ignition temperatures of airborne tropical dust and dust layers. Samples were prepared using a Makita 9556CR 1400W grinder and K36 sandpaper for the purpose of selecting the percentages of the various fractions (<63, 63, 71, 100, 200, 315, 500 μm). The samples were sized on an automatic vibratory sieve machine Retsch AS 200. More than 65% of the particles were determined to be under 100 μm. The focus was on microfractions of tropical wood dust (particles with a diameter of ≤100 µm) and on the impact assessment of particle size (particle size <100 µm) on the minimum ignition temperatures of airborne tropical dust and dust layers. The minimum ignition temperature of airborne marblewood dust decreased with the particle size to the level of 400 °C (particle size 63 μm).

scholarly journals Radiológiai osztályon dolgozó szakdolgozók kiégési szintje Magyarországon

2019 ◽  
Vol 160 (27) ◽  
pp. 1070-1077 ◽  
Author(s):  
Dávid Sipos ◽  
Veronika Varga ◽  
Attila András Pandur ◽  
András Kedves ◽  
Melinda Petőné Csima ◽  
...  
Keyword(s):  
Healthcare System ◽  
Emotional Exhaustion ◽  
Negative Impact ◽  
Maslach Burnout Inventory ◽  
Three Dimensions ◽  
Radiology Department ◽  
Online Questionnaire ◽  
Descriptive Data ◽  
Cross Sectional ◽  
Work Related

Abstract: Introduction: Burnout can have a wide negative impact on the quality and the effectiveness of the health care system. The aim of our research was to assess the burnout level of the radiology department workers in Hungary. Method: Our quantitative, cross-sectional, descriptive data collection lasted from June to September 2018 using an online questionnaire. Simple, non-random sampling was carried out among radiology department workers in Hungary. In addition to our self-made questionnaire which included socio-demographic and work-related questions, an internationally validated Maslach Burnout Inventory questionnaire was sent out. Results: After data cleaning, a total number of 404 (n = 404) respondents were included in the statistical analysis. The majority of the respondents works in county hospital, the average year spent in the healthcare system was 18.3 (SD 13,7). The sample’s values at the depersonalization and emotional exhaustion dimension were slightly elevated in contrast to the average values. Educational level, age and years spent in the healthcare system had a significant influence on all the three dimensions of burnout (p≤0.05). The group of workers being 31–35 years old and the group of those who spent 16–20 years in the healthcare system are considered to be the most compromised groups in all the three dimensions of burnout. Respondents with master degree had significantly lower emotional exhaustion values than their colleagues. Conclusion: The increased value of the depersonalization and the emotional exhaustion can be an indicator for employers. Our results are similar like described in the international literature. Orv Hetil. 2019; 160(27): 1070–1077.

Adaptive neuro-fuzzy fusion of multi-sensor data for monitoring of CNC machining

Sensor Review ◽  
2017 ◽  
Vol 37 (1) ◽  
pp. 78-81 ◽  
Author(s):  
Srdjan Jovic ◽  
Obrad Anicic ◽  
Milivoje Jovanovic
Keyword(s):  
Selection Process ◽  
Spindle Speed ◽  
Cnc Machining ◽  
Numerical Control ◽  
Periodic Component ◽  
Sensor Data ◽  
Depth Of Cut ◽  
Inference System ◽  
Content Type ◽  
Neuro Fuzzy

Purpose Acoustic emission (AE) could be used for prevention and detection of tool errors in Computer Numerical Control (CNC) machining. The purpose of this study is to analyze the AE form of CNC machining operations. Design/methodology/approach Experimental measurements were performed with three sensors on the CNC lathe to collect the data of the CNC machining. Adaptive neuro-fuzzy inference system (ANFIS) was applied for the fusion from the sensors’ signals to determine the strength of the signal periodic component among the sensors. Findings There were three inputs, namely, spindle speed, feed rate and depth of cut. ANFIS was also used to determine the inputs’ influence on the prediction of strength of the signal periodic component. Variable selection process was used to select the most dominant factors which affect the prediction of strength of the signal periodic component. Originality/value Results were shown that the spindle speed has the most dominant effect on the strength of the signal periodic component.

scholarly journals Performance of Village Unit Co-Operatives in Yogyakarta Special Region: A Data Envelopment Analysis Approach

2017 ◽  
Vol 1 (2) ◽  
pp. 067
Author(s):  
Abi Pratiwa Siregar ◽  
Jamhari Jamhari ◽  
Lestari Rahayu Waluyati
Keyword(s):  
Data Envelopment Analysis ◽  
Technical Efficiency ◽  
Best Practice ◽  
Negative Impact ◽  
Positive Impact ◽  
Three Dimensions ◽  
Scale Efficiency ◽  
Data Envelopment ◽  
Rice Milling ◽  
Special Region

This study assessed the performance of 32 village unit co-operatives (KUD) in Yogyakarta Special Region during 2011 to 2012. The efficiency level of the KUD were evaluated by employing the data envelopment analysis and multiple regression analysis using panel data to determine the factors affecting efficiency level. Efficiency analysis was decomposed into three dimensions to explore possible sources of inefficiency. According to Marwa and Aziakpono (2016), the first dimension was technical efficiency, which explored the overall effectiveness of transforming the productive inputs into desired outputs compared to the data-driven frontier of best practice. The second dimension was pure technical efficiency, which captured managerial efficiency in the intermediation process. The third dimension was scale efficiency, which explored whether KUD were operating in an optimal scale of operation or not. The results found that the average scores are 64%, 92%, and 68% for technical, pure technical, and scale efficiency respectively in 2011, while in 2012 the average scores are 57%, 94%, and 60% for technical, pure technical, and scale efficiency. Factors having significantly positive impact on several measures of efficiency are incentive and dummy variables (agriculture inputs and hand tractor). Accounts receivable only has positive relationship to pure technical efficiency. On the other hand, rice milling unit and electricity services have negative impact with several measures of efficiency.

Rethinking reverse logistics: role of additive manufacturing technology in metal remanufacturing

2019 ◽  
Vol 31 (1) ◽  
pp. 124-144 ◽  
Author(s):  
Danielle Strong ◽  
Michael Kay ◽  
Thomas Wakefield ◽  
Issariya Sirichakwal ◽  
Brett Conner ◽  
...  
Keyword(s):  
Supply Chain ◽  
Additive Manufacturing ◽  
Facility Location ◽  
Reverse Logistics ◽  
Small And Medium Enterprises ◽  
Real Data ◽  
Cnc Machining ◽  
Numerical Control ◽  
Content Type ◽  
The Usa

Purpose Although the adoption of metal additive manufacturing (AM) for production has continuously grown, in-house access to production grade metal AM systems for small and medium enterprises (SMEs) is a major challenge due to costs of acquiring metal AM systems, specifically powder bed fusion AM. On the other hand, AM technology in directed energy deposition (DED) has been evolving in both: processing capabilities and adaptable configuration for integration within existing traditional machines that are available in most SME manufacturing facilities, e.g. computer numerical control (CNC) machining centers. Integrating DED with conventional processes such as machining and grinding into Hybrid AM is well suited for remanufacturing of metal parts. The paper aims to discuss these issues. Design/methodology/approach Classical facility location models are employed to understand the effects of SMEs adopting DED systems to offer remanufacturing services. This study identifies strategically located counties in the USA to advance hybrid AM for reverse logistics using North American Industry Classification System (NAICS) data on geographical data, demand, fixed and transportation costs. A case study is also implemented to explore its implications on remanufacturing of high-value parts on the reverse logistics supply chain using an aerospace part and NAICS data on aircraft maintenance, repair and overhaul facilities. Findings The results identify the candidate counties, their allocations, allocated demand and total costs. Offering AM remanufacturing services to traditional manufacturers decreases costs for SMEs in the supply chain by minimizing expensive new part replacement. The hubs also benefit from hybrid AM to repair their own parts and tools. Originality/value This research provides a unique analysis on reverse logistics through hybrid AM focused on remanufacturing rather than manufacturing. Facility location using real data is used to obtain results and offers insights into integrating AM for often overlooked aspect of remanufacturing. The study shows that SMEs can participate in the evolving AM economy through remanufacturing services using significantly lower investment costs.

scholarly journals Design of an Axial Turbine for Highly Downsized Internal Combustion Engines

2020 ◽  
Vol 10 (17) ◽  
pp. 5935
Author(s):  
Lorenzo Baietta ◽  
Mamdouh Alshammari ◽  
Apostolos Pesyridis ◽  
Dhrumil Gohil
Keyword(s):  
Internal Combustion Engines ◽  
High Volume ◽  
Cnc Machining ◽  
Numerical Control ◽  
Driving Experience ◽  
Aspect Ratios ◽  
Efficient Reduction ◽  
High Volume Production ◽  
Axial Turbines ◽  
Efficient Power

This paper describes and discusses the development of an axial turbocharger turbine concept as a potential substitute to commercial radial turbines for high-volume production. As turbo-lag is one of the main issues related to the inertia of the rotating parts in a turbocharger, leading to less responsive and drive-cycle efficient power units, the use of axial turbines, with their inherently lower inertia than radial types for the same application, enables the efficient reduction of the spool-up time of the system, to the benefit of the driving experience and emissions. However, axial turbines for this application usually show complicated blades and level of twist, leading to efficient but expensive designs compared to their radial counterparts. Based on this challenge, the idea of comparing prismatic (generally less efficient, but cheaper) and twisted 3D-bladed axial turbines showed that for lower blade aspect ratios, the efficiency is of the same order. For these reasons, many turbines with a range of different sizes were designed with both layouts (3D and prismatic blades) and compared. Further, the use of 3D optical scanning, as well as dyno-calibrated 1D engine models enabled the gathering of invaluable data to design the proposed solution and compare it to the Original Equipment Manufacturer (OEM) version. Thanks to these processes, the comparison between the proposed design and the OEM one was not limited to the performance, and also included the manufacturing costs, which were calculated via Computer Aided Manufacturing (CAM) programs, with the limitation of using only Computer Numerical Control (CNC) machining for production. To conclude, the work showed a notable performance superiority of the proposed turbine in respect to the OEM one, despite a slightly higher estimated production cost.

scholarly journals Effect of Thermal Treatment of Birch Wood by Saturated Water Vapor on Granulometric Composition of Chips from Sawing and Milling Processes from the Point of View of Its Processing to Composites

2020 ◽  
Vol 10 (21) ◽  
pp. 7545 ◽  
Author(s):  
Richard Kminiak ◽  
Kazimierz A. Orlowski ◽  
Ladislav Dzurenda ◽  
Daniel Chuchala ◽  
Adrián Banski
Keyword(s):  
Composite Materials ◽  
Milling Process ◽  
Point Of View ◽  
Cnc Machining ◽  
Three Dimensions ◽  
Raw Material ◽  
Saturated Steam ◽  
Birch Wood ◽  
Environmental Criteria ◽  
The Impact

The goal of this work is to investigate the impact of thermal modification of birch wood with saturated steam on the particle size distribution of the sawing and milling process. Birch wood (Betula pendula Roth) is an excellent source to produce plywood boards. Wastes from mechanical processing of birch wood are suitable to produce composite materials. Granulometric analyses of chips from sawing processes on the PRW 15M frame saw, as well as on the 5-axis CNC machining centre SCM TECH Z5 and the 5-axis CNC machining centre AX320 Pinnacle, proved that more than 95% of chips are chips of coarse and medium coarse chip fractions with dimensions above 0.125 mm. Depending on the shape, coarse and medium-thick chips belong to the group of fiber chips, the length of which is several times greater than the width and thickness. Fine fractions with dimensions smaller than 125 μm are isometric chips that are approximately the same size in all three dimensions. Thoracic dust fractions below 30 μm were not measured. The performed analyses showed that the heat treatment of birch wood with saturated steam did not affect the grain size of chips formed in sawing and milling processes on CNC machining centre and can be used as a raw material for the production of composite materials. Fabric filters are suitable for separating chips extracted from frame saws, PRW-15M or machining centre. Environmental criteria for the separation of chips from transport air in textile filters are met by filters with a fabric classified in class G4.

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