Automobile Assembly Research Articles

A HYBRID MODEL FOR MIX-BANK BUFFER CONTENT DETERMINATION IN AUTOMOBILE INDUSTRY

In mixed-model automobile assembly lines, paint defective vehicles are the main reason for unintentional sequence alteration that stirs up the production sequence so that resequencing is required. This study aims to decide optimal spare vehicles that are held in the mix-bank buffer to be replaced instead of defective vehicles in order to regain the production sequence. We develop a hybrid solution methodology in which optimal spare vehicle content is determined by genetic algorithm (GA) and the releasing order of the vehicles to final assembly (FA) are decided by stochastic mixed integer programming (MIP) model. In addition to discussing the efficiency of the hybrid model, the following insights were gained: 1) not only FA but also paint shop constraints should be considered in production sequence determination when mix-bank buffer is efficiently used; 2) the decrease in defect rate improves sequence restoration linearly; 3) effect of an additional lane on SSAR increase is diminishing. [Received: 22 December 2018; Accepted: 28 October 2019]

A hybrid model for mix-bank buffer content determination in automobile industry

In mixed-model automobile assembly lines, paint defective vehicles are the main reason for unintentional sequence alteration that stirs up the production sequence so that resequencing is required. This study aims to decide optimal spare vehicles that are held in the mix-bank buffer to be replaced instead of defective vehicles in order to regain the production sequence. We develop a hybrid solution methodology in which optimal spare vehicle content is determined by genetic algorithm (GA) and the releasing order of the vehicles to final assembly (FA) are decided by stochastic mixed integer programming (MIP) model. In addition to discussing the efficiency of the hybrid model, the following insights were gained: 1) not only FA but also paint shop constraints should be considered in production sequence determination when mix-bank buffer is efficiently used; 2) the decrease in defect rate improves sequence restoration linearly; 3) effect of an additional lane on SSAR increase is diminishing. [Received: 22 December 2018; Accepted: 28 October 2019]

Digital Lean Manufacturing - Collaborative University-Industry Education in Systems Design for Lean Transformation

There are several examples of successful lean practice in manufacturing and service to reduce cost, achieve quality and increase competitiveness; however, some companies still fail to adopt lean practice. The lean practice is not only about implementing lean tools, but also developing people and transforming company culture. Facing a declining manufacturing competitiveness, Thailand needs lean manufacturing and lean automation to regain competitiveness. This paper presents Digital Lean Manufacturing, a one-semester course based on project-based learning (PBL) designed by university and industry under SIIT-DENSO collaboration. It focuses on adopting Japanese-style lean manufacturing culture and digital engineering to empower students with high-tech T-shaped skills. Using exercises in Lego car assembly, the course develops both cognitive and non-cognitive skills in lean manufacturing.

자동차 조립작업의 작업부하 및 연령에 따른 작업능력 차이 조사

자동차 조립작업의 작업부하 및 연령에 따른 작업능력 차이 조사

Process Design and System Layout for an Automobile Manufacturing and Assembly Plant

The Automobile is the most complex product, and the development of a vehicle will take years of Research and Development (R&D) starting from designing, analyzing the product structure from sub-levels, building prototypes, testing the prototypes, finalizing the vehicle to manufacture. It is also essential to find the correct suppliers to manufacture the components, parts for the vehicle, assembly of all these to the vehicle, and go through examination and analysis of various stages of the processes in building the vehicle, and it is a herculean task. With the increase in competitiveness in the Automobile industry, the Original Equipment Manufacturers (OEM’s) want to reduce their investments in manufacturing, keeping core competencies of R&D within the industry, and outsourcing remaining functionaries to Tire companies. The main goal of this paper is to illustrate the step by a step manufacturing process that is needed to produce an Automobile. And explaining each step that takes the Automobile from sheet metal to complete product, this helps to understand the process chain, logistical and distribution network that an Automobile follows throughout its Product Life Cycle (PLC).

Violências contra trabalhadores adoecidos e instrumentos de gestão

Trata-se de estudo realizado por demanda de um sindicato de trabalhadores metalúrgicos à Fundacentro, objetivando analisar as situações de violências vividas por trabalhadores adoecidos pelo trabalho em uma montadora de automóveis. Foram realizadas entrevistas com sindicalistas, visita à montadora, entrevistas individuais e coletivas com trabalhadores, validação dos dados. À luz da discussão sobre violências relacionadas ao trabalho e intensificação do trabalho, analisou-se sua relação com instrumentos de gestão. Com base na compreensão de gestão de Gaulejac e na perspectiva das evoluções conceituais sobre violência no trabalho, expressada por Soboll, entre outros, confirmaram-se práticas de exclusão e isolamento de trabalhadores adoecidos, humilhações e descaracterização das doenças relacionadas ao trabalho, deslegitimando e colocando os adoecidos sob suspeita. Instrumentos de gestão e elementos da cultura organizacional eram utilizados nestas práticas violentas caracterizando um modo de agir sistêmico que contribui para a cronificação de doenças e a geração de incapacidade, além de prejudicarem ações preventivas, tanto da própria empresa, como do Estado, pela ocultação de riscos e danos. Demandas dessa natureza são frequentes, evidenciando que a violência contra adoecidos pelo trabalho e o ocultamento de doenças do trabalho constituem sério problema social com impacto dramático nas vidas de trabalhadores e no sistema de saúde pública.

Automotive painting process: Minimizing energy consumption by using adjusted convective heat transfer coefficients

The process of drying/curing automobile painting is characterized as one of the main stages in automobile assembly. To guarantee the final painting quality, optimal operating conditions (mainly the temperature profile in the painting chamber) must be satisfied, and they are empirically defined in most cases. The availability of a mathematical model in transient regime enables the prediction of the drying/curing process behavior and consequences of possible operational changes on the final quality of the paint. However, obstacles continue to exist with respect to the implementation of the aforementioned types of models given the large number of parameters and complexity involved in their determination among which convection heat transfer coefficients are notable. Thus, the study presents a methodology to adjust the mathematical model of a paint-curing oven via determining convection heat transfer coefficients based on industrial data. The adjusted model was used to predict new operational scenarios for the most commonly used oven in automobile painting processes, namely the Elpo oven. The results indicate that the proposed methodology can be applied as a tool to develop operational optimization strategies that result in decreasing rework and energy costs without compromising painting quality.

Studies of Application of LED-Based Lighting Devices in a Car Assembly Shop

The article describes the problem of replacement of active fluorescent lamp lighting installations of an assembly line of a car assembly plant with LED LDs including a comparison of the gained lighting and economic indicators. Therefore, several LED-based LDs by different manufacturers were selected. Based on LI computer modelling using DIALux Evo, an optimal option in terms of light engineering and economy was found. Lighting characteristics of the active LI and areas of the assembly line with the application of LED-based LDs were determined experimentally. The results of the study allow assessing relevant changing of visual performance of shop workers and to compare the pay-off periods of LED and fluorescent lamps-based lighting devices.

Genetically elevated levels of metals and subclinical atherosclerosis in an adult population from Spain

TPS 636: Metals and health 2, Johan Friso Foyer, Floor 1, August 28, 2019, 3:00 PM - 4:30 PM Background/Aim: While the evidence supporting a causal association of metals with clinical cardiovascular disease is substantial, fewer studies have evaluated subclinical atherosclerosis. We tested the association of non-essential metals with subclinical atherosclerosis by using genetic polymorphisms in candidate genes as a proxy of unconfounded metal exposure. Methods: Urine Antimonium (Sb), Barium (Ba), Cadmium (Cd), Chromium (Cr), Titanium (Ti), Tungsten (W), Uranium (U) and Vanadium (V), and urine Arsenic (As) speciation, were measured by ICPMS and HPLC-ICPMS, respectively, in 1815 workers from a car assembly factory in Figueruelas (Spain) participating in the Aragon Workers’ Health Study. Atherosclerosis presence (yes/no) was measured in carotid and femoral arteries with ultrasounds, and in coronary arteries with NMR. For statistically significant metals in traditional logistic models, we evaluated the association of genetically controlled biomarker levels with atherosclerosis presence using 2-stage least squares Mendelian Randomization methods. Results: The geometric mean of Sb, sum of inorganic As (∑iAs), Ba, Cd, Cr, Ti, W, U and V was 0.22, 8.1, 1.88, 0.43, 1.06, 213.05, 0.23, 0.03, and 0.5 μg/g, respectively. In multi-adjusted models (including arsenobetaine adjustment for ∑iAs), the odds ratio (95% CI) for atherosclerosis presence in any of the evaluated vascular territories were, 1.21 (1.00-1.46) for ∑iAs, 1.60 (1.17-2.19) for Cd and 1.26 (1.05-1.52) for Ti. These associations were driven by ∑iAs and Cd in carotid, Cd and Ti in femoral and Ti in coronary territories. For ∑iAs the associations of genetically-elevated concentrations (3 ∑iAs-associated SNPs) were statistically significant and directionally consistent compared to the observational associations. For Cd the corresponding associations (2 Cd-associated SNPs) were only consistent in femoral atherosclerosis models. Conclusions: Replication of findings is needed. Our results, however, support a role of As and Cd as cardiovascular risk factors. Reinforced exposure reduction interventions may decrease cardiovascular disease.

Influence of electrode force on metallurgical studies and mechanical properties of resistance spot welded dual phase (DP800) steel joints

Abstract The DP steels are attractive to automotive sectors due to the improved fuel efficiency, occupant’s safety and reducing the car body weight. The resistance spot welding (RSW) most appropriate eco-friendly process for sheet metal and white body car assemblies over fusion welding. The present research work analysis the impact of electrode force on mechanical and metallurgical characteristics of dual phase steel. In this investigation similar joint of DP 800 joints (lap shear and cross shear) specimen fabricated and tensile shear test was evaluated using a universal testing machine. Micro and macrostructure were evaluated optical microscope. The hardness was taken along the weld nugget using Vickers microhardness tester machine. The electrode force was varied at five levels (3.75 MPa to 4.75 MPa). The tensile shear strength is found to be increased with an increase in electrode force up to a certain limit and then it decreases. The microhardness survey revealed that peak hardness in the nugget zone and the hardness is lower in the HAZ. The softening of HAZ is mainly attributed to inter-critical heating during welding, which leads to weld failure.

The reduction of production lead time using holonic manufacturing: experiment and analysis

PurposeIn modern industrial processes, the need of reducing lead time is imperious. This goal is pursued by “Holonic” structures, which are systems based on a network of collaboration. The purpose of this paper is to appraise the possible benefits, in terms of production duration, of such organizations compared to non-holonic arrangements. In addition, this analysis represents virtual teams, which are a significant and strategic attribute of holonic manufacturing systems.Design/methodology/approachThe experiment performed in this paper is a simulation of an automobile assembly process under both a holonic and a non-holonic structure to observe lead times and the distinctive characteristics of each organization. Other targets of this research are to monitor the advantages that either strategy may offer in terms of efficiency and to examine a possible model of how virtual teams can be used in holonic networks.FindingsThe findings are unexpected. An initial expectation might lead to the belief that, given the better coordination and communication of holonic networks, lead times would be diminished. This experiment, utilizing virtual teams of university students, indicated otherwise.Research limitations/implicationsIt should be noticed, however, that future experiments in real manufacturing assembly processes are recommended to complement the findings of this study.Originality/valueThe management of lead times is indeed a complex task that includes a diversity of variables. Holonic structures should balance several factors that might play a role in lead times and ultimately in the success of a project. An original experiment with the participation of many universities in different countries is presented in this study. The exposure of global characteristics of modern manufacturing structures constitutes the main value of this research.

The implication of the stochastic gross-profit-per-day objective on the cargo ship profitability, capacity, and speed

Purpose This paper aims to study the implication of the stochastic gross-profit-per-day objective on the ship profitability and the ship capacity and speed. Design/methodology/approach The paper has used the mathematical model and the solution methodology given by El Noshokaty, 2013, 2014, 2017a, 2017b, and SOS, 2019. Findings The paper finds that if the ship owner follows the rate concept and the cargo demand forecast, he can improve the profitability of his company and be able to select the proper capacities and speeds for the ships used. Research limitations/implications The findings are not only useful for the shipping or other cargo transport companies but also for businesses like gas reservoir development, car assembly lines in the industry, cooperative farming and crop harvesting in agriculture, port cargo handling in trade and road paving in construction. Originality/value The contribution of this paper lies in notifying the ship owners of the possible profitability improvement and the consequences of building ships of larger capacities and slower speeds.

RFID-based material delivery method for mixed-model automobile assembly

In order to deal with the increasingly intensive market competition and make rapid response to customers, the automobile manufacturing enterprises in China begin to explore new methods of material supply to meet the management requirements of precision and efficient production. For this purpose, an RFID-based material delivery method for mixed-model automobile assembly is proposed in this paper. The assembly line material classification and its distribution pattern are analyzed, and the production progress data acquisition scheme with RFID is designed. Based on the periodic inventory monitoring strategy, a buffer inventory demand model and an optimized delivery plan are formed to provide accurate material feeding service for the assembly line. In addition, an RFID-based material distribution prototype software for automobile mixed-model assembly line is developed and applied. This software has realized the RFID information collection, buffer material requirements management, as well as the logistics distribution and replenishment plan. It provides a feasible method and solution for automobile enterprises.

A rolling horizon simulation approach for managing demand with lead time variability

This paper proposes a rolling horizon (RH) approach to deal with management problems under dynamic demand in planning horizons with variable lead times using system dynamics (SD) simulation. Thus, the nature of dynamic RH solutions entails no inconveniences to contemplate planning horizons with unpredictable demands. This is mainly because information is periodically updated and replanning is done in time. Therefore, inventory and logistic costs may be lower. For the first time, an RH is applied for demand management with variable lead times along with SD simulation models, which allowed the use of lot-sizing techniques to be evaluated (Wagner-Whitin and Silver-Meal). The basic scenario is based on a real-world example from an automotive single-level SC composed of a first-tier supplier and a car assembler that contemplates uncertain demands while planning the RH and 216 subscenarios by modifying constant and variable lead times, holding costs and order costs, combined with lot-sizing techniques. Twenty-eight more replications comprising 504 new subscenarios with variable lead times are generated to represent a relative variation coefficient of the initial demand. We conclude that our RH simulation approach, along with lot-sizing techniques, can generate more sustainable planning results in total costs, fill rates and bullwhip effect terms.

Abstract 1434: The Costimulatory Signal Domains 4-1BB and CD3ζ Do Not Improve the Function of CD16A Chimeric Antigen Receptor Transduced NK Cells

Abstract Chimeric Antigen Receptors (CAR)-T cells are genetically modified to express an extracellular binding domain, transmembrane domain and intracellular signaling domain. The extracellular binding domain is usually derived from antibodies; however, it can be replaced with other ligand-receptor binding systems, such as with an Fc receptor. CD16A has been tested in second-generation 4-1BB-CD3ζ CAR T cells and NK cell lines (NK-92) and enhances tumor killing; however, it is not clear whether these cells provide superior tumor killing compared to cells modified to express CD16A alone. In this study, we designed three CAR constructs containing the extracellular binding domain of high affinity mutant CD16A (CD16A-V158) and intracellular signal through 4-1 BB-CD3ζ that differed in leader sequences and transmembrane domains. CAR1 contained the CD16A leader and CD16A transmembrane domain; CAR2 had the CD16A leader and CD8α transmembrane domain; CAR3 contained the CD8α leader and CD8α transmembrane domain. When transduced into Jurkat cells via lentivirus, CD16A V158 and all three CARs showed stable high surface expression of CD16A (> 70%). In contrast, NK-92 cells were only successfully transduced to express CD16 by CD16A V158 (29.8%), CAR2 (42.3%), and CAR3 (42.5%) with no expression of CD16A by CAR1. Transduced cells were sorted by FACs based on CD16A expression. All sorted cells showed >90% stable expression of the constructs for up to 42 days post sorting. We observed a much higher CD16 MFI in cells transduced with CAR2 and CAR3 compared with CD16A V158. Western blotting with anti-CD3ζ identified the full assembly of CARs. We then tested the function of the transduced cells by a Rituximab binding assay. Although there was no difference in binding to Rituximab at 0.01 and 0.1 mg/mL; CAR2 and CAR3 showed better binding at the 1 and 10 mg/mL. In a 4-hour coculture toxicity assay with 721.221 LCLs, CD16A V158 and CAR3 increased the target lysis by two-fold while CAR2 only showed a 50% increase. When cocultured with 721.221 HLA-E+ LCLs, a 721.221 subclone more resistant to killing by NK-92 cells, we observed similar tumor killing with CD16A V158 and CAR3 (killing doubled) in contrast to CAR2(killing increased by only 50%). We next tested against the B-cell line Raji and found that there was only a mild increase of target lysis with transduced NK-92 cells; however, the CD16A V158 and CAR3 still showed higher toxicity (around a 40% increase). In summary, CAR2 and CAR3 expressed a higher CD16 MFI in NK cells and demonstrated better binding to Rituximab at1 and 10 mg/mL compared to CD16A V158; however, CAR3 and CD16A V158 had similar killing of target cells that was higher than was observed with CAR2. Our data indicate that NK cells transduced to have a CAR structure combining CD16A with 4-1BB-CD3ζ have augmented ADCC, although this augmentation is not superior to NK cells that are simply transduced to express CD16A alone. Citation Format: Long Chen, Vicky Li, David Allan, Robert Reger, Elena Cherkasova, Stephanie Pierre, Stefan Barisic, David Granadier, Emily Levy, Giacomo Waller, Susan Doh, Mala Chakraborty, Kate Stringaris, Richard Childs. The Costimulatory Signal Domains 4-1BB and CD3ζ Do Not Improve the Function of CD16A Chimeric Antigen Receptor Transduced NK Cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1434.

Fatigue crack detection in rotating steel shafts using noncontact ultrasonic modulation measurements

In this study, a noncontact fatigue crack detection technique for rotating steel shafts is developed using air-coupled transducers (ACTs). Two ACTs are used for ultrasonic wave generation at two distinctive frequencies, and a third ACT is used for sensing. The proposed technique is based on the premise that nonlinear ultrasonic modulation appears at the sum and difference of two input frequencies in the presence of any crack due to crack opening and closing. First, the spectral correlation (SC) between ultrasonic modulation components at the sum and difference of two input frequencies is computed. Next, an outlier analysis is performed on spectral correlations obtained from different input frequency combinations for automated crack diagnosis. To the best of the authors’ knowledge, this is the first study in which a sub-millimeter fatigue crack is detected in a rotating steel shaft using noncontact transducers. In this study, real fatigue cracks on half-scale and full-scale steel shafts used in automobile assembly lines are produced through cyclic loading tests, and the performance of the proposed technique is experimentally validated using ultrasonic response data obtained from the half-scale and full-scale steel shaft specimens. The formation of fatigue cracks is confirmed using fluorescent magnetic particle inspection (MPI), fluorescent penetrant inspection (FPI), and metallographic analysis.

Implementation of RFID Middleware Based on Client-Multiserver Architecture for Traceability of Autoparts

The implementation of RFID systems allows automation of information flow along the production chains. This is a desirable condition for increasing efficiency, productivity and management, and it simplifies other activities such as traceability records along these supply and production chains, especially in the automobile assembly supply chain as in the case of Renault-SOFASA-Colombia, where the traceability of automotive parts is realized manually by means of mobile terminals, which is time consuming and laborious, with low automotive parts rate and high error rate. In this work, a RFID solution for the traceability of automotive parts in real time in Renault-SOFASA-Colombia is implemented, where a middleware under client-multiserver architecture for Siemens readers is developed. The terminal, where the middleware is located, behaves like a client and links to several RFID readers which behave like servers, forming a star type network topology. This architecture allows a cost reduction in the implementation and operation of RFID solutions by reducing hardware acquisition and energy consumption, being an alternative that can compete with the solution provided by a manufacturer as Siemens without neglecting the robustness and the proper functioning of the system. Moreover, the proposed solution concentrates all the maintenance efforts of the system at a single point, which is due to the fact that a terminal attends all RFID portals. The tests performed, where the transport carts with the automotive parts and their respective RFID tags are passed through the RFID portals of the assembly plant, are in agreement with the results reported by the developed middleware.

Deep Learning Approach of Energy Estimation Model of Remote Laser Welding

Due to concerns about energy use in production systems, energy-efficient processes have received much interest from the automotive industry recently. Remote laser welding is an innovative assembly process, but has a critical issue with the energy consumption. Robot companies provide only the average energy use in the technical specification, but process parameters such as robot movement, laser use, and welding path also affect the energy use. Existing literature focuses on measuring energy in standardized conditions in which the welding process is most frequently operated or on modularizing unified blocks in which energy can be estimated using simple calculations. In this paper, the authors propose an integrated approach considering both process variation and machine specification and multiple methods’ comparison. A deep learning approach is used for building the neural network integrated with the effects of process parameters and machine specification. The training dataset used is experimental data measured from a remote laser welding robot producing a car back door assembly. The proposed estimation model is compared with a linear regression approach and shows higher accuracy than other methods.

Design of the Intelligent Manufacturing Demonstration System based on IoT in the Context of Industry 4.0

With the concept of German Industry 4.0, the Chinese manufacturing industry is in a critical period of restructuring and upgrading. With the gradual change of Chinese manufacturing industry from the mass and mass to the niche, personalized stage, the traditional rigid production system couldn’t make enough. This paper designed an Industry 4.0 intelligent manufacturing demonstration system based on Internet of Things. The system is based on the background of the model car assembly, which simulates the whole process of the delivery of the consumer from the single to the manufacturer. The vertical seamless integration of network production system is realized by getting through the information communication interface on the device layers between ERP and MES. The system adopts modular manufacturing mode, via WIA-FA and Software defined Control System technology, adjusting the production process dynamically, to achieve the function of scale production of customized products and the predictive maintenance of equipment etc. This system may reduce equipment downtime and improve equipment utilization, which solves the lower flexibility of the traditional rigid production system responding to the changing demands of design the production. It fully embodies the concept of Industry 4.0 in the smart factory.

Scheduling just-in-time part replenishment of the automobile assembly line with unrelated parallel machines

With increasing product customization, just-in-time part replenishment has become a significant scheduling problem in the automobile assembly system. This paper investigates a new unrelated parallel machine scheduling problem of an assembly line, where machines are employed to deliver material boxes from an in-house warehouse to workstations. The schedule is to appropriately specify the assignment and sequence of material boxes on each machine for minimizing line-side inventories under no stock-out constraints. By taking advantages of domain properties, an exact algorithm is developed to cope up with small-scale instances. In terms of real-world scale instances, a hybrid teaching–learning-based optimization metaheuristic is established by integrating teaching–learning-based optimization with a beam search technique. Experimental results indicate that the scheduling algorithms are effective and efficient in solving the proposed unrelated parallel machine scheduling.