Changeover Time Research Articles

The short- and long-term properties of welded high-temperature-resistant thermoplastics

AbstractHigh-performance plastics, such as polyphenylene sulfide or polyphthalamide, are increasingly being used in highly stressed areas, primarily due to their outstanding thermal and mechanical properties. Due to the increasing demands on plastic components in terms of geometry, functional integration, etc., components produced by primary molding often have to be welded in an additional process step. Furthermore, there are often restrictions with regard to component cleanliness, which is why converting, non-contact welding processes are of great industrial interest. However, as a result of the changeover-step in these processes, the previously plasticized areas cool down. For materials with high melt temperatures this circumstance can lead to inadequate weld seam qualities.The aim of the investigations was therefore to expand the understanding of the process of welding high-temperature-resistant plastics, to identify optimum welding parameters and to determine the mechanical short- and long-term properties of the welds. Furthermore, a comparison was made between the changeover welding processes and single-stage vibration welding in order to clarify the relevance of short changeover times.It could be shown that a significant correlation exists between the changeover time, the melting temperature and the resulting weld strength. Furthermore, the selection of the welding process and thus the type of heat input seems to have an influence on the long-term properties of the welds at high test temperatures.

Setup Time Reduction of an Automotive Parts Assembly Line Using Lean Tools and Quality Tools

The business world is becoming more competitive. Therefore, it is crucial to increase the flexibility of production by decreasing the time used in the processes of preparing the production lines for new items’ production, reducing changeover and setup times. This paper presents a case study where the main goal is to reduce the setup time of welding robots. Single Minute Exchange of Die (SMED) was implemented, using other tools such as the Spaghetti Diagram, ERCS Analysis (Eliminate, Rearrange, Combine, Simplify), Gemba Walk, Standardized Work, Flowcharts, and Pareto Diagram. The setup time decreased by 36% in the welding robots studied, decreasing the motions by 43% during the changeover process and reducing the time from the categories: “transportation”, “main”, “other”, and “waiting”. In addition to SMED implementation, this study offers an integrated study of several Lean tools and Quality tools to achieve the maximum reduction of changeover and setup times.

Integrated lot-sizing and energy supply planning with onsite generation of intermittent renewable energy

This work considers an industrial production site partially powered by a decentralised energy system based on intermittent renewable energy sources. Our objective is to simultaneous plan the industrial production and the energy supply in this site so as to minimise the total cost. A new way of modelling this combinatorial optimisation problem is proposed: it relies on the extension of a multi-product single-resource small-bucket lot-sizing model called the proportional lot-sizing and scheduling problem. This extension involves among others sequence-dependent changeover times overlapping multiple periods and energy-related constraints. Our numerical results show that the resulting mixed-integer linear programming model enables to obtain good-quality production and energy supply plans with a computational effort much smaller than the one required by a previously published large-bucket lot-sizing model.

Impact of a brief distress intolerance intervention on acute stress modulation of response inhibition neurophysiology in cannabis use disorder

BackgroundThe prevalence of cannabis use in the US has increased within the past two decades. Moreover, cannabis use disorder (CUD) is associated with significant disability, but the underlying neural mechanisms of CUD are unclear. Distress intolerance (DI), a psychological risk factor for CUD, may confer risk in part via impaired inhibitory control (IC) capacity during acute stress. DI and cannabis use problems have been associated with altered N2 amplitude, an IC-related event-related potential, in prior cross-sectional studies, but whether altered N2 is a state marker of CUD severity, a pathoplastic factor responsive to intervention and predictive of CUD symptom change over time, or an enduring trait-like vulnerability is unclear. In this secondary analysis, we tested the impact of a DI-targeted intervention on acute stress-related modulation of the N2 and whether pre-intervention N2 predicted CUD symptom change through follow-up. MethodSixty participants were randomly assigned to a DI-targeted or control intervention. Participants completed an IC task before and after a stress induction at pre- and post-intervention lab visits while EEG activity was recorded. ResultsThe DI intervention did not alter the N2 compared to a control intervention. Pre-intervention post-stress IC-related N2 was associated with worse CUD severity but did not predict changeover time. ConclusionFindings are consistent with blunted N2 after acute stress acting as a stable marker of CUD severity rather than a pathoplastic factor predictive of CUD trajectory. Future research should investigate whether stress-related blunting of N2 is a consequence of severe CUD or a pre-existing vulnerability.

A Model to Reduce Machine Changeover Time and Improve Production Efficiency in an Automotive Manufacturing Organisation

One of the key postulates of the modern automotive industry is the increase in production efficiency while minimizing costs. In the opinion of experts from the automotive industry, meeting this condition may be the first stage on the way to preventing waste generation and implementing a circular economy model. The article presents a case study of issues related to the lean manufacturing methodology in terms of the impact of shortening the changeover time of the assembly line on the overall production efficiency. The presented considerations focus on the optimization of the production process using the SMED (Single Minute Exchange of Die) technique of a selected spare part. From the point of view of the Lean Manufacturing concept, the main goal of the SMED technique is to increase the flexibility of responding to changing customer needs by shortening the changeover times and faster responses to changing orders. The article describes the stages of implementing the SMED method and its impact on the increase in the OEE (Overall Equipment Efficiency) index, which allows for the percentage recognition of the degree of machine park utilization, which is one of the key factors for assessing energy efficiency. In addition, the benefits that have been achieved by using this method in terms of time and economy have been presented. The theoretical aspects related to the method used were supplemented with its practical implementation in order to improve the changeovers in a manufacturing company in the automotive industry. Based on the obtained test results, an analysis of the effectiveness of the measures taken to reduce the changeover time was carried out. The use of the SMED methodology contributed to a significant reduction in changeover time—by as much as 291.4 s. The burden on operators was significantly reduced—the total time and number of operations performed by them (both internal and external) was reduced. Operator paths have also been shortened using simple procedures such as changing the layout of the lines and modifying the changeover tool trolleys and tool locking system at the stations. The presented research may be helpful in answering the question whether the implementation of the SMED idea may be the key to effective resource management and, at a later stage, to the implementation of the circular economy model. In addition, the research results can find their practical application among both manufacturers of spare parts and the vehicles themselves, considering introducing process changes on their production lines in order to increase production efficiency and implementing the idea of industrial sustainability.

Reduction of changeover time through SMED with RACI integration in garment factories

Purpose Shorter lead time with low price and quality product demand is pivotal in the garment industry. Pressure on production lead time stresses the importance of reducing style changeover time in manufacturing factories, and this paper aims to contribute to solving the challenge by showing how the single minute exchange of die (SMED) methodology in practice can be adapted to garment factories in developing countries. Design/methodology/approach The paper investigates three cases of SMED implementation integrated with responsible, accountable, consulted, informed (RACI) matrices in garment factories in an action research approach. Both quantitative and qualitative methods are applied. Findings The study shows a reduction of 50% to 64% of changeover time with SMED implementation measured with two key indicators – throughout time and time to reach peak production. Moreover, the implementation depends on the application of the RACI matrix for the distribution of responsibility as well as integration with the basic production flow before and after the application of SMED. Practical implications The study can guide better SMED implementation in garment factories with limited investment by stressing the need to adapt to the specifics of the garment industry, secure the division of responsibility and integrate SMED in the production flow before and after the changeover. Originality/value Limited research on the application of SMED in the garment industry. This paper contributes to understanding the specific conditions for successful implementation in the garment industry in developing countries and addresses additional activities that help secure a sustainable implementation process.

An adaptive product changeover policy for a capacitated two-product supply chain in a non-stationary demand environment

ABSTRACT The present paper investigates the effectiveness, in terms of fill rate, of a new adaptive production control policy for a two-product, two-echelon (i.e. factory and retailer) supply chain subject to a non-stationary customer demand. To model the capacity constraints more realistically, the factory node consists of an unbuffered production line subject to failures, and non-negligible changeover times. To cope with the disruptive events, we propose a new production control strategy named Adaptive Hedging Corridor Policy. A simulation model based on discrete-time difference equations is developed, and a two-step experimental campaign is conducted to compare the proposed control policy with two well-known alternatives proposed in the literature. The analysis of the results demonstrates the effectiveness of the new adaptive strategy in maximising the fill rate of supply chains subject to a non-stationary demand.

EPH137 Group-Based Trajectory Modeling to Identify Patterns of Antipsychotic-Induced Weight Gain Among Children and Adolescents

Antipsychotic-induced weight gain (AIWG) is the most common side effect associated the use of second-generation antipsychotic (SGA) medications among children and adolescents. Group-based trajectory model (GBTM) can graphically display the longitudinal weight change overtime. The objective of this study was to model the development of AIWG among children and adolescents taking SGAs.

Reduction of Manufacturing Lead Time by Value Stream Mapping of a Selected RMG Factory in Bangladesh

Bangladesh is a fast-growing economy powered by the readymade garments (RMG) industry which has promoted the country in the world through the motto ‘Made in Bangladesh’. The RMG industry has become the lifeline of the economy of Bangladesh. However, this industry faces several significant obstacles to its continued, sustainable expansion. The trading climate has become very competitive because of the phase-out of the export quota system. Additionally, with today’s rapid fashion, consumers want items with short lead times and affordable prices. Adopting the lean methodology across the board in the garment business is essential for long-term sustainability in this cutthroat context. Lean manufacturing is a philosophy to deliver the finest goods on time with minimum endeavor and less price. Lean manufacturing aims to cut lead times and remove wastes that don’t impose value on products. The purpose of this research is to identify wastes and to reduce manufacturing lead time by eliminating or reducing the excess tasks that cause higher lead time by implementing lean concepts. But implementing lean philosophy is a difficult task. During the visit to the selected RMG factory, the Short Sleeve T-shirt, one of their products, was selected for conducting this research. All the processes were observed required for the transformation of raw materials into a finished T-shirt. During the observations, the methodology of time study was applied to collect the data. Necessary information was gathered by observing the processes and interacting with the executives. Then, the current state of the value stream mapping was drawn. Wastes, responsible for a longer time, were ranked by taking the help of an 80-20 rules diagram. After this, root cause analysis was performed to find the reasons for the unwanted time consumption. Improvement strategies were introduced to reduce waste. Lean tools like Kanban to reduce WIP, Single Minute Exchange of Die to reduce changeover time, and Total Productive Maintenance to reduce machine breakdown were used to minimize the waste. Based on improvement strategies, The value stream mapping’s future state was illustrated, showing the refinement where total manufacturing lead time was reduced by 61.20%. Finally, this research has suggested some recommendations to the management of the selected RMG factory to minimize waste and increase efficiency and reduce waste in the operations. This research illustrates the usual conditions of the RMG industry of Bangladesh by presenting the current state of the value stream. The Bangladeshi clothing sector must completely embrace lean principles and embark on the direction of sustainable growth.

From Lab to Pilot Scale: Commissioning of an Integrated Device for the Generation of Crystals

AbstractFast time‐to‐market, increased efficiency, and flexibility of production processes are major motivators for the development of integrated, continuous apparatuses with short changeover times. Following this trend, the modular belt crystallizer was developed and characterized in lab scale with the model system sucrose‐water. Based on the promising results, the plant concept was upscaled and commissioned in industrial environment. The results are presented within the scope of this work. Starting from small seed crystals in solution, it was possible to grow, separate, and dry product particles. Further, the conducted experiments demonstrated that it is feasible to transfer the results from laboratory to pilot scale, which in turn enables accelerated process design as well as development.

Drill from Military to Operating Theater and Safe Reuse of Single-Use Items to Combat the Cost of Optical Fibers and Consumables in Endovenous Laser Ablation of Varicose Veins

Introduction: Can the tandem arrangement of operating theater setup to perform a surgical drill similar to military, together with safe reuse of single-use items combat the cost of consumables of endovenous laser ablation (EVLA)? Methods: Operation pathway of EVLA consisted of cleaning and draping of patient (step 1), access to the affected vein and infiltration of tumescent local anesthesia (step 2), endovenous ablation (step 3), ultrasound-guided microfoam sclerotherapy (step 4), and chemical sterilization of consumables (step 5). Dedicated theater lists for EVLA were arranged to treat several patients per session in a prearranged operating theater. When the step 5 is completed on the first patient, the step 1 on the next patient was performed using sterilized optical fiber (OF) as a cycle while minimizing patient changeover time. Number of patients treated with each session of OF and time taken for step 1 to step 4 was recorded and analyzed. Results: A total of 140 patients treated using eight OFs during December 2019 to December 2022. Average number of patients treated with a single OF and during a single session of fiber is 17.5 (9–23) and 4.2 (3–7), respectively. Average time taken for step 1 was 7.83 min, step 2 was 7.95 min, step 3 was 1.57 min, and step 4 was 6.36 min. All the procedures were performed using four chemically re-sterilized guidewires and introducer sheaths. Conclusion: Tandem arrangement of operating theater to perform EVLA procedure similar to military drill can optimize the utilization of OFs and consumables.

Cost of improved test and treat strategies in Indonesia.

To estimate and compare the cost of improved test and treat strategies in Indonesia under HIV Awal (Early) Testing and Treatment Indonesia (HATI) implementation trial in community-based and hospital-based clinics. The cost and outcome [i.e. CD4 + cell count] and viral load (VL) at the beginning of interventions and their change overtime) analysis of Simplifying ART Initiation (SAI), Community-based Organization and community-based ART Service (CBO), Motivational Interviewing (MI), Oral Fluid-based Testing (OFT), and Short Message Service (SMS) reminder in community-based and hospital-based clinics in 2018-2019. We estimated the total and unit costs per patient (under HATI implementation trial interventions) per year from societal perspective in various settings, including costs from patients' perspective for SAI and MI. We also analyzed the outcome variables (i.e. CD4 + cell count and VL at the beginning of each intervention, the change in CD4 + cell count and VL over time, and adherence rate). The unit cost per patient per year of SAI and SMS were lower at the community-based clinics, and more patients visited community-based clinics. The cost per patient visit from patient perspective for SAI and MI was mostly lower than 10% of the patients' household monthly expenditure. Average CD4 + cell count was higher and average VL was lower at the start of interventions at the community-based clinics, while average CD4 + cell count and VL changes and adherence rate were similar between the two types of clinics. Community-based clinics hold the potential for scaling up the interventions as it costs less from societal perspective and showed better outcome improvement during the HATI implementation trial.

Multilevel anterior cervical fusion with standalone cage or cage-and-plate after cervical discectomy: Benefits and drawbacks

PurposeMultilevel anterior cervical discectomy and fusion (ACDF), especially two-level ACDF, has been usually performed in the cervical degenerative disease, and the incidence rate of complications is controversial. This study aimed to compare the outcomes of ACDF approach with cage alone and with plate fixation in multilevel discectomy. MethodsPatients who had undergone multilevel ACDF by the Smith-Robinson methods were included from 2018 to 2020. Data were collected using a questionnaire containing demographic characteristics, surgical complications, and outcome. All the patients were followed for 18 months post-surgery. Visual Analogue Scale (VAS), Neck Disability Index (NDI) and Nurick Grading scale were used to measure the pain degree, neck pain effect, and myelopathy grade, respectively. Bone fusion rate, subsidence and instrument failure were checked through radiography. Data were analyzed using SPSS, and the significant level was considered 0.05. Results24 patients were included. There was no significant difference between the mean blood losses in the two groups. The rate of subsidence was much higher in group B after 18 months (60% vs 14.3%). As to the VAS score, NDI, and Nurick scale, trend change overtime was significantly improved in each group, but there was no significant difference between the groups. There was no significant difference between the two groups regarding bony fusion rate. DiscussionACDF with plate leads to a more prolonged surgery with no significant benefits. Stand-alone cage approach could be suggested as the gold standard for anterior cervical discectomy.

Analysis of the Possibility of Introducing the Reduction of Changeover Time of Selected CNC Machines Using the SMED Method

Abstract The paper presents the results of improving the production process using the SMED method. The process improvement was carried out in a company in the construction industry, using a machine park consisting of CNC machines. The study evaluated the current state of changeover times for selected CNC machines and proposed a reduction in changeover times for the machine park analysed. By introducing changes to the changeover process on selected CNC machines, it was possible to minimise the changeover time by more than 20% on all the machines analysed. The proposed reorganisation of the CNC operators’ workstations resulted in a time reduction of approximately 61% for machine 1, 52% for machine 2 and 12% for machine 3. The installation of barcode readers on the profiles, on the other hand, made it possible to load the machining programmes into the CNC machines more quickly and resulted in a reduction in loading time of approximately 88% on average for each of the machines analysed.

Google Search Popularity as a Reflection of Medical Literacy and Interest in Breast Reconstruction

Objective: Reconstructive breast procedures have been on the rise over the past decades, implant-based approaches being more popular than autologous techniques. Google search engine remains one of the most utilized sources for medical knowledge about breast reconstruction among patients. This study aims to discover Google search popularity as a reflection of patient’s interest in breast reconstruction options over time. Methods: This study utilized Google Trends (GT), a powerful online tool that analyzes changes in Google search popularity over time and geographical regions. This study searched for breast reconstruction related terms across the United States from January 2007 to January 2022. Search terms included: “breast reconstruction,” “implant reconstruction,” “breast expanders,” “implant after mastectomy,” “DIEP flap,” and “TRAM flap.” Searches terms in Spanish were also included. The data were collected from the GT platform and search terms were compared using best fit linear trend lines. Results: Google search popularity for breast reconstruction has slightly decreased over time, while searches for DIEP flaps have increased. Searches for implant-based reconstruction options and related terms showed relatively low interest and no change overtime. DIEP flap searches consistently rose over time as TRAM flap searches gradually decreased in popularity over time. Significant number of searches for TRAM flap were only available in New York, Texas, and California, while DIEP flap was popular in 35 states. Conclusion: Amongst autologous breast reconstruction options, DIEP flaps are gaining popularity while TRAM flaps are decreasing in popularity across the United States. Patients are increasingly interested in autologous free flap breast reconstruction options. Corresponding Author: Neej Patel, 411 E 2nd St Apt#112 Flint, MI 48503, [email protected], 7343064487

Increasing Overall Equipment Effectiveness (OEE) by Changeover Time Reduction: A Pharmaceutical Case Carried through DMAIC Cycle

Increasing Overall Equipment Effectiveness (OEE) by Changeover Time Reduction: A Pharmaceutical Case Carried through DMAIC Cycle

Toward Industry 4.0 in Surface Mount Technology: Smart Manufacturing in Stencil Printing Operations

As the foremost point of contact in surface mount technology (SMT) operations, the stencil/solder paste printer (SPP) is a major contributor to assembly defects in the printed circuit board (PCB) fabrication process. Initial printing defects lead to reductions in throughput, quality and reliability of the entire downstream system. Because of the high variation in SMT processes, a predictive, real-time machine learning (ML) algorithm to optimize printer settings based on the estimation of printing volumes is a promising solution to improving production performance and process capability. Building upon existing literature, this research discusses the implementation of a lab-trained ML model to predict optimal printing parameters and reduce changeover time within SPP processes through the training and testing of large solder paste inspection (SPI) datasets. To sustain growing market demand for smart electronics manufacturing (SEM), successful development and validation of a dynamic prediction system for optimizing printing parameters provides significant potential for improvements in first pass yield rates and system throughput.

Improvement of auger equipment for processing of vegetable oil crops

The design of an oil press with a combined screw and an adjustable gap between the curb plates for two-stage pressing of oily raw materials is presented. The location of the elliptical links that provide the rotation of the curb plates and the curb plates with maximum and minimum gaps is shown. The proposed design will improve the quality of the oil, reduce material costs and equipment changeover time. Keywords: oil press, process, pressing, oily raw materials, curb chamber, curb plate. klesha78@list.ru, bolgovainessa@yandex.ru, kopylov-maks@yandex.ru, tea_86@mail.ru

Structural and functional properties of spinal dorsal horn neurons after peripheral nerve injury change overtime via astrocyte activation

Chronic pain remains challenging to treat, despite numerous reports of its pathogenesis, including neuronal plasticity in the spinal dorsal horn (SDH). We hypothesized that understanding plasticity only at a specific time point after peripheral nerve injury (PNI) is insufficient to solve chronic pain. Here, we analyzed the temporal changes in synaptic transmission and astrocyte-neuron interactions in SDH after PNI. We found that synaptic transmission in the SDH after PNI changed in a time-dependent manner, which was accompanied by astrocyte proliferation and loss of inhibitory and excitatory neurons. Furthermore, neuronal loss was accompanied by necroptosis. Short-term inhibition of astrocytes after PNI suppressed these physiological and morphological changes and long-term pain-related behaviors. These results are the first to demonstrate that the inhibition of astrocyte proliferation after PNI contributes to the long-term regulation of plasticity and of necroptosis development in the SDH.

An exact algorithm for scheduling tandem quay crane operations in container terminals

This study investigates the scheduling problem of the tandem quay crane (TQC), which is a new type of loading/unloading device used at container terminals. The TQC can execute either a single-lift or tandem-lift at a time. Considering the changeover time between the above two operational modes of the TQC and the weight limitation for executing a tandem-lift, a novel integer linear programming model is established to minimize the time needed for unloading the containers from the containership, and valid inequalities are introduced to enhance the model. Then, an exact algorithm based on logic-based Benders decomposition is applied to solve the problem. The proposed approach decomposes the problem into a mode-assignment master problem and an operation-sequencing slave problem. Logic-based cuts are proposed to ensure the convergence of the algorithm, and several enhancement measures are developed to accelerate the convergence speed. The computational results indicate that the model is superior to the previous model proposed in the literature, and the proposed inequalities are effective. Moreover, the exact algorithm was verified to be efficient for solving realistically sized instances within an acceptable time.