Robot path optimization for laser cladding forming

Author(s):  
Huadong Zheng ◽  
Ming Cong ◽  
Dong Liu ◽  
Hang Dong ◽  
Yi Liu

Purpose The purpose of this paper is to provide an optimization method of robot cladding path, which is helpful to solve the problem of path under-optimization in laser cladding forming (LCF) based on robot. Design/methodology/approach First, the error influence parameters need setting before the cladding path generation, and the model of seeking appropriate error influence parameters is established based on the particle swarm optimization (PSO). Second, to solve the problem of collapse during the LCF process, the reason for collapse is analyzed and a robot cladding path error optimization method based on the layer path interpolation is proposed. Finally, the simulation and experiments are carried out. Findings Under the premise of giving the expected error of stereo lithography (STL) model, the optimal range of the chord height and the angle control can be quickly found by using PSO algorithm. Aiming at the collapse problem in the laser cladding process, a robot cladding path optimization method based on the layer path interpolation is proposed. A four-layer path interpolation simulation and the contrast experiments before and after the path optimization are completed; the results show that the robot cladding path optimization method can solve the problem of the collapse in laser cladding. Practical implications Robot cladding path optimization is one of the key technologies of LCF, and the quality of the robot cladding path is affected by STL model error and the path optimization method. This paper proposed a robot cladding path optimization method for LCF. This method can be used in other additive manufacturing techniques. Originality/value The quality of cladding path is important for LCF; this paper first proposed the optimization method of the robot cladding path for LCF to solve the collapse problem.

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2541 ◽  
Author(s):  
Qiu-Lian Dai ◽  
Can-bin Luo ◽  
Fang-yi You

Laser cladded WC/Fe coatings have the advantages of low cost and high abrasion wear resistance. However, cracks always appear in WC/Fe coatings, which limits their industrial application. In this paper, the co-effects of the re-melting process, heat treatments, and amount of Co element on the cracking susceptibility, microstructures, and mechanical properties of WC/Fe laser cladding coatings were studied. Experimental results show that re-melting process is helpful to improve the surface quality of the coating and to reduce the cracking susceptibility. The hardness of the coating decreases slightly but distributes more uniformly. Cracks in the coating can be inhibited effectively by preheating the substrate to 250 °C and maintaining the temperature during the laser cladding process, as well as applying an annealing treatment at 300 °C for 1 h. Heat treatment also results in a slight decrease in the hardness. Crack initiation cannot be restrained completely by applying the above two methods when laser cladding a big area of coating. On the basis of the above two methods, addition of Co element to the coating can further improve its toughness and decrease the crack susceptibility. Crack-free WC/Fe coating can be manufactured when 8% Co is added, and its wear resistance is much better than that of the hardened medium steel, especially when the wear time is long.


2019 ◽  
Vol 63 (10) ◽  
Author(s):  
Adriana Egui ◽  
M. Carmen Thomas ◽  
Ana Fernández-Villegas ◽  
Elena Pérez-Antón ◽  
Inmaculada Gómez ◽  
...  

ABSTRACT One of the current greatest challenges of Chagas disease is the establishment of biomarkers to assess the efficacy of drugs in a short period of time. In this context, the reactivity of sera from 66 adults with chronic indeterminate Chagas disease (IND) for a set of four Trypanosoma cruzi antigens (KMP11, PFR2, HSP70, and 3973d) was analyzed before and after benznidazole treatment. The results showed that the reactivity against these antigens decreased at 9, 24, and 48 months after treatment. Moreover, the 42.4% and 68.75% of IND patients met the established standard criteria of therapeutic efficacy (STEC) at 24 and 48 months posttreatment, respectively. Meeting the STEC implied that there was a continuous decrease in the reactivity of the patient sera against the four antigens after treatment and that there was a substantial decrease in the reactivity for at least two of the antigens. This important decrease in reactivity may be associated with a drastic reduction in the parasite load, but it is not necessarily associated with a parasitological cure. After treatment, a positive PCR result was only obtained in patients who did not meet the STEC. The percentage of granzyme B+/perforin+ CD8+ T cells was significantly higher in patients who met the STEC than in those who did not meet the STEC (35.2% versus 2.2%; P < 0.05). Furthermore, the patients who met the STEC exhibited an increased quality of the multifunctional response of the antigen-specific CD8+ T cells compared with that in the patients who did not meet the STEC.


2019 ◽  
Vol 41 (1) ◽  
pp. 37-51 ◽  
Author(s):  
Xavier Bartoll ◽  
Raul Ramos

Purpose The purpose of this paper is to analyse the association between the type of contract (temporary vs permanent) and the quality of work and its different dimensions before and after the economic crisis among Spanish employees. Design/methodology/approach Structural equations techniques are used to analyse the association between the type of contract and the work quality and its different dimensions before and after the crisis. Data are drawn from the 2006/2007 and 2009/2010 waves of the Encuesta de Calidad de Vida en el Trabajo. Findings The results show that in the two considered periods there are no differences in quality of work among male involuntary temporary workers and those with permanent contracts. However, there is an adverse widening gap across all dimensions of work quality for women in involuntary temporary employment during the economic crisis. There is also a shift among men and women in involuntary temporary employment from valuing intrinsic job quality dimension in the pre-crisis period to valuing more the work environment dimension during the crisis period. Research limitations/implications The analysis is limited by the continuity of variables across years and the high proportion of missing values in some variables. The obtained results cannot be interpreted in terms of causality. Originality/value This is the first study to consider whether the deterioration in the Spanish labour market during the crisis has affected the relationship between the type of contract and the different dimensions of the quality of work.


2019 ◽  
Vol 31 (2) ◽  
pp. 143-165 ◽  
Author(s):  
Päivi Hökkä ◽  
Katja Vähäsantanen ◽  
Susanna Paloniemi ◽  
Sanna Herranen ◽  
Anneli Eteläpelto

Purpose Although there has been an increase in workplace studies on professional agency, few of these have examined the role of emotions in the enactment of agency at work. To date, professional agency has been mainly conceptualised as a goal-oriented, rational activity aimed at influencing a current state of affairs. Challenged by this, this study aims to elaborate the nature and quality of emotions and how they might be connected to the enactment of professional agency. Design/methodology/approach Data are collected in the context of a leadership coaching programme that aimed to promote the leaders’ professional agency over the course of a year. The participants (11 middle-management leaders working in university and hospital contexts) were interviewed before and after the programme, and the data were analysed using qualitative content analysis. Findings Findings showed that emotions played an important role in the leaders’ enactment of professional agency, as it pertained to their work and to their professional identity. The study suggests that enacting professional agency is by no means a matter of purely rational actions. Practical implications The study suggests that emotional agency can be learned and enhanced through group-based interventions reflecting on and processing one’s own professional roles and work. Originality/value As a theoretical conclusion, the study argues that professional agency should be reconceptualised in such a way as to acknowledge the importance of emotions (one’s own and those of one’s fellow workers) in practising agency within organisational contexts.


Author(s):  
Shafiullah Khan ◽  
Shiyou Yang ◽  
Obaid Ur Rehman

Purpose The aim of this paper is to explore the potential of particle swarm optimization (PSO) algorithm to solve an electromagnetic inverse problem. Design/methodology/approach A modified PSO algorithm is designed. Findings The modified PSO algorithm is a more stable, robust and efficient global optimizer for solving the well-known benchmark optimization problems. The new mutation approach preserves the diversity of the population, whereas the proposed dynamic and adaptive parameters maintain a good balance between the exploration and exploitation searches. The numerically experimental results of two case studies demonstrate the merits of the proposed algorithm. Originality/value Some improvements, such as the design of a new global mutation mechanism and introducing a novel strategy for learning and control parameters, are proposed.


2022 ◽  
Vol 961 (1) ◽  
pp. 012035
Author(s):  
Zaman A. Abdulwahab ◽  
Sami A. Ajeel ◽  
Sami I. Jafar

Abstract Nickle based super alloys such as Inconel 600 are being extensively used to manufacture turbine blades for jet engines since their superior mechanical characteristics at higher working temps. The chemical composition of steam turbine blades show that is steel 52 it has a wide range of Energy, Tanks, Rail, Yellow Goods, Engineering, Bridges, Construction, applications. Laser cladding seems to be a surfacing method that uses lasers to improve the characteristics of a component’s surface and/or renew it. Laser cladding involves absorption of laser light that melts a small area of the substrates against which the substance was being introduced and fuses the coating substance to the substrates, resulting in the formation of a new layer. This research aims to investigate the fatigue and fatigue corrosion behavior of these turbine blades before and after exposure to laser cladding. The cladding process applied with this parameter Pulse energy = 11 joules, Pulse width = 6 Ms., Pulse frequency = 12 Hz, Laser Average Power = 132 W, Laser peak power = 1.83 KW. The results show, after cladding process the microstructure of the specimen is smooth and increase the cyclic of fatigue comparison with specimen without laser cladding process. So, the fatigue resistance is increased.


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Belal Fayez Omar ◽  
Hani Alkayed

Purpose This study aims to examine the extent and quality of corporate social responsibility (CSR) disclosure in Jordan for the time periods of 2005–2006 and 2014–2015, ultimately establishing whether there was a change in the extent and quality of disclosure practices before and after the new regulations for CSR. Furthermore, this study additionally seeks to determine if the regulations are a major factor in changing CSR disclosure practices, or whether there are other factors for such a change. Design/methodology/approach The annual reports of 55 manufacturing companies (11 sub-sectors) on the Amman Stock Exchange for the years 2005–2006 and 2014–2015 were selected, and a CSR checklist was measured via the construction an index covering 36 items in 4 themes: environmental; human resources; community; and products and others. The study measures the quantity of CSR via the number of sentences and the quality of CSR by the weighting approach (on a scale of 0–3); furthermore, the paired sample t-test and Wilcoxon signed rank tests were used to establish whether there was a change in the extent and quality of CSR disclosure practices. Findings The results of the study revealed that there being a significant increase in the extent and quality of CSR for the period 2014–2015 compared to that of 2005–2006, the most optimal performance being in 2015, bragging an average of 61,41 total sentences per annual report and an average quality score of 1.423. Moreover, detailed analysis of CSR extent and quality by theme reveals that the highest percentage of CSR extent and quality was within the environmental theme, with an average score 28.6% of total sentences in 2014 (extent) and 1.743 in 2015 of total sentences (quality). Research limitations/implications The current study has some limitations, which have implications for future studies. First, this study examined the extent and quality of CSR for only two time frames: before and after regulation. However, a longitudinal study would have provided a wider scope of study. Second, the study focussed only on the industrial sector, thus limiting the results to only this area. Indeed, the exploration of the CSR extent and quality for other sectors (e.g. financial and services) would generalise the results further, allowing for the making of comparisons compare among different sectors. Moreover, the study at hand has focussed solely on annual reports, which could lead to subjectivity, thus reducing the reliability of results. Future studies should thus focus on other means of disclosure (e.g. websites; environmental reports). Practical implications The current mandatory requirements would suggest Jordanian regulators have begun specifying CSR disclosure requirements in an easier, more user-friendly and traceable format. Indeed, the increase in CSR extent and quality for the post-regulations period would increase the need to organise mandatory requirements in CSR. For managers, on the other hand, the study provides the CSR as a strategic tool for reflecting the actual environmental activities, comparing it with the society’s expectations. Moreover, when budgets are limited, managers prioritise CSR activities that yield a positive impact on financial performance by allocating the limited resources in a broad manner. Social implications The results additionally highlights the ways in which the Jordanian industrial companies increase their levels within the environmental theme in CSR for the post-regulations. It could be argued that a great number of companies in the past decade have started adopting environmentally friendly practices and strategies to protect the natural environment, such as greenhouses, extracting non-renewable resources and reducing amount of industrial waste. Originality/value To the best of the authors’ knowledge, there is currently no existing study within Jordan exploring the change of CSR over time – specifically in terms of before and after the regulations. In addition, exploring the quality of CSR using a weighted approach (scale out of 3) is not conducted in Jordanian studies before.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Muhammad Arif ◽  
Christohper Gan ◽  
Muhammad Nadeem

Purpose Motivated by the enactment of non-financial reporting regulations by the European Parliament, this paper aims to investigate the impact of European Union (EU) directive 2014/95/EU on the quantity of environmental, social and governance (ESG) disclosures by the S&P Europe 350 index firms. This study also investigates whether the implementation of the non-financial information (NFI) reporting regulations influences the association between ESG disclosures and firms’ earnings risk. Design/methodology/approach To measure the impact of mandatory regulations on the quantity of ESG disclosures, this study estimates the average treatment effects using a propensity weighted sample. Then this study uses the difference-in-differences method to estimate the differences in the association between ESG disclosures and earning risk before and after implementation of the EU directive. Findings The results show a significant positive impact of the EU directive on the quantity of ESG disclosures for the sample European public-interest entities, which indicates that the mandatory NFI reporting requirements could boost the availability of increasingly demanded ESG related information. The enhanced association between the ESG disclosures and firms’ earnings risk during the post-directive period reveals that mandating NFI reporting also increases the quality of ESG disclosures. Originality/value Using the legitimacy and decision-usefulness theories, this study provides novel evidence concerning the impact of the EU directive on the quantity and quality of ESG disclosures.


2019 ◽  
Vol 33 (3) ◽  
pp. 260-266
Author(s):  
Kwanrutai Sampoon ◽  
Nuengruethai Posri ◽  
Boonsri Kittichotpanich

Purpose The purpose of this paper is to test the effectiveness of social dance exercise and social support program to improve quality of life (QOL) for older adults in Thailand. Design/methodology/approach A quasi-experimental pre-test and post-test research design was used. The participants were 102 older adults selected by systematic sampling technique. Participants were assigned using the matched-pair technique by age, physical fitness test by the Time up and Go test into intervention and control groups of 51 subjects each. Intervention was conducted for 12 weeks, three times weekly, to improve physical, psychosocial and spiritual domains leading to enhanced QOL as measured by the World Health Organization Quality of Life (WHOQOL–BREF–THAI) assessment parameter. Data on QOL were collected before and after a 12-week training period. Findings Most adults were between 70 and 79 years old (67 percent). After program completion, before and after mean QOL scores for the intervention group at 60.15 and 95.82, respectively, were statistically significant with p-value<0.05. Post-program QOL shown by the intervention group was significantly higher than the control group (p<0.05). Originality/value Application of social dance exercise and social support program is an alternative to traditional methods to improve QOL and maintain functional capacity for older adults.


2020 ◽  
pp. 46-51
Author(s):  
A. N. Gots ◽  
◽  
A. B. Lyukhter ◽  
D. S. Gusev ◽  
A. V. Zavitkov ◽  
...  

A brief analysis of powders used in the industry for surfacing on the work surfaces of critical parts is given in order to increase their wear resistance. The results of experimental studies on the choice of parameters of gas-powder cladding modes are presented. The cladding process was carried out by a laser robotic complex with a coaxial feed of powder to the surfacing zone. The substrate used steel grade 08H18N10T, which was applied to the melt of wear-resistant powder grade PR-08H17N8S6G. The use of ytterbium fiber laser allowed to reduce the heat supply to the surfaces, which significantly reduced the residual stresses in the workpiece. Variable parameters of the laser cladding process were the output power of laser radiation, processing speed, and powder mass flow rate. During visual inspection, the absence of pores and cracks were used as the estimated indicators of the cladding. The study of macro geometry single clad track was conducted on cross section of the clad. During measurements, the quality of a single clad track was determined by its geometric dimensions: clad height, clad width, contact angle between the tangent to the cladding surface and the substrate plane, as well the depth of the mixing layer of the surfaced and substrate materials. According to the results of experimental studies of the selected optimal mode, providing a cladding track with a clad height above 1 mm; clad width 2.5 mm; the depth of the mixing layer – 0.2 mm; contact angle between the tangent to the clad surface and the substrate more than 50º. This work was financially supported by the Ministry of Science and Higher Education of the Russian Federation. Agreement on the provision of subsidies No. 075-15-2019-1833 dated December 03, 2019. Unique identifier PNI RFMEFI60419Kh0245.


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