Assessment of Abrasion-Induced Visual Defects in Twin Screw Wet Granulation Using Wall Friction Measurements

Starting point of the presented study were abrasion effects occurring during a twin screw wet granulation (TSG) process of a new chemical entity (NCE) formulation, resulting in gray spots on the final tablets. Several actions and systematic changes of equipment and process parameter settings of TSG process were conducted which reduced the visual defect rate of the tablets, i.e., gray spots on the surface, below the specification limit. To understand the rationale and mechanism behind these improvements, correlations of defect rates and wall friction measurements using a Schulze ring shear tester were evaluated. To check the suitability of the method, a broad range of wall materials as well as powder formulations at various moisture levels were investigated with regard to their wall friction angle. As differences in wall friction angle could be detected, further experiments were conducted using wall material samples made out of different screw materials for TSG. Evaluation of these screw wall material samples gave first hints, which screw materials should be preferred in regard of friction for TSG process. In the finally presented case study, wall friction measurements were performed using the above mentioned NCE formulation with known abrasion issues at TSG processing. The results confirmed that changes which led to a reduced visual defect rate of tablets correlated with a decreased wall friction angle. The results suggest wall friction measurements as a potent tool for equipment selection and establishment of a suitable process window prior to conducting TSG experiments. Graphical abstract

Intertemporal Product Management with Strategic Consumers: The Value of Defective Product Returns

Problem definition: An increased incidence of quality issues, resulting in defective product returns (DPRs), is a concern for firms bringing innovative products to market. Although a firm can recover value from DPRs through refurbishing, consumers are known to act strategically in anticipation of the future availability of refurbished units. We study a firm’s strategy for offering a new product and refurbished DPRs to strategic consumers across time. Academic/practical relevance: Aided by emerging shopping tools, an increasing number of consumers consider buying refurbished versions of products rather than their new counterparts. A novel contribution of our work is the recognition of the refurbishing of DPRs as a possible solution to the time inconsistency problem that arises when a firm offers products to strategic consumers across time. We characterize how the product line decisions and profit of the firm are influenced by the defect rate, the perceived quality of refurbished DPRs, and consumers’ hassle cost of returns. Methodology: We develop a two-period game-theoretic model to characterize the firm offering the new product and refurbished DPRs to strategic consumers across time. Results: The refurbishing of DPRs helps the firm implicitly commit to limiting the quantity of the new product offered in the future, allowing the firm to charge a premium for the new product today. As a result, firm profit may even increase with the defect rate. These results persist across various model extensions. Managerial implications: Whereas the firm’s profit is the highest when there are no defects, opportunities to achieve marginal reductions in defect rates may not be worth the investment and may even be counterproductive. Also, efforts toward enhancing the perceived quality of the refurbished product or decreasing the hassle cost for consumers may better serve the firm than efforts toward marginally improving defect rates.

Electronic Current Transformer Defects Statistical Analysis of Intelligent Substation

In order to master operation status of the electronic current transformer(ECT), application investigation and defects statistical analysis were conducted on ECT of 110(66)kV~1000kV applied in smart substation of the State Grid Corporation of China(SGCC). The defect location, defect cause and defect type of ECT with different principles are analyzed. The results indicate that the defects of ECT are mainly concentrated in the acquisition unit, the defect rate is closely related to the reliability of electronic components, the technical level, production process and quality control of the manufacturer. In view of the typical defect analysis, the corresponding solution measures are put forward to provide reference for the subsequent research and application of ECT.

Application Research of Medical Failure Mode and Effect Analysis in Controlling Packaging Quality Defects

Purpose This study explores the application effects of medical failure mode and the analysis of device packaging quality defects. Methods In this study, a total of 183,642 equipment kits were assembled in our hospital from January to June 2020. Using medical failure mode and effect analysis methods, we retrospectively analyzed and evaluated the device packaging process. Besides, we used a decision tree model to determine the strategies that need to be acted upon and formulate improvement plans. We also selected a total of 1,90,231 assembly equipment packages in our hospital from July to December 2020, implemented the improved plan for packaging quality control, and compared medical failure modes, including the incidence of equipment packaging defects before and after the application of effective analysis. Results Before implementing medical failure mode and effect analysis, 1,83,642 equipment packages were assembled, 98 defects occurred, with a defect rate of 0.053%. However, after implementing medical failure mode and effect analysis to improve the packaging process, 1,90,231 device packages were assembled, 22 defects occurred, and the defect rate was 0.012%. The results showed that the packaging quality defects of the disinfection supply center were significantly reduced (χ2=50.822, P=0.001). Conclusion Using the medical failure mode and effect analysis method to control device packaging defects can effectively reduce the rate of device packaging quality defects, ensuring patient safety.

Optimal Design of the Submerged Entry Nozzle for Thin Slab Continuous Casting Molds

For the purpose of increasing the capacity of an Angang Strip Production (ASP) continuous caster and the surface quality of a medium-thin slab with mold sections of 150 × (1020–1540) mm2, the present work investigated the influences of the submerged entry nozzle (SEN) structure and main operating parameters on the flow characteristic and temperature distribution in the mold by physical and numerical simulations. The results showed that the typical “double-roll” flow and a central jet were formed through the three-port SEN. With the original SEN, the mean wave height exceeded the critical value of 5.0 mm after the casting speed was increased due to the strong upper recirculation flow. By the slight increment of the bottom port area and the side port angle of SEN, the mean wave height was obviously decreased below 4.4 mm due to the depressing of the upper recirculation flow after the casting speed increased. Meanwhile, the temperature distribution was slightly changed by using the optimized SEN. The practical application showed that the breakout rate decreased from 0.349% to 0.107% and the surface defect rate decreased from 0.54% to 0.19% by using the optimized SEN, while throughput reached the new level of 3.96 t/min.

Relationship between FDM 3D Printing Parameters Study: Parameter Optimization for Lower Defects

Technology evolution and wide research attention on 3D printing efficiency and processes have given the prompt need to reach an understanding about each technique’s prowess to deliver superior quality levels whilst showing an economical and process viability to become mainstream. Studies in the field have struggled to predict the singularities that arise during most Fused Deposition Modeling (FDM) practices; therefore, diverse individual description of the parameters have been performed, but a relationship study between them has not yet assessed. The proposed study lays the main defects caused by a selection of printing parameters which might vary layer slicing, then influencing the defect rate. Subsequently, the chosen technique for optimization is presented, with evidence of its application viability that suggests that a quality advance would be gathered with such. The results would help in making the FDM process become a reliable process that could also be used for industry manufacturing besides prototyping purposes.

Maintenance optimization of a production system considering defect prevention and spare parts ordering

An innovative maintenance policy is proposed in this paper. This policy can involve spare parts ordering, production quality, and buffer inventory for an efficient production system. In the system, certain batches are required to be produced, and when each batch is finished, a determination is made whether maintenance is needed. The machine state deteriorates with the number of completed batches, and it can be improved by performing maintenance. Two types of maintenance activity, replacement and imperfect maintenance, can be selectively chosen to minimize cost. The defect rate of each batch is related to the number of completed production batches. An innovative concept, defined as the “virtual number” of completed production batches, is used to establish a link between maintenance and defect rate. Monte Carlo simulation and enumerative search is then used to determine cost-effective spare parts ordering and maintenance policies to minimize the cost for the production cycle. Finally, numerical examples are presented to demonstrate the model and to conduct sensitivity analysis. We find that in situations with a high buffer inventory costs, spare parts should be ordered late. When increasing the buffer inventory cost, more replacements should be performed compared to imperfect maintenance. Also, the buffer inventory cost rate and replacement duration time effect the rate of defective products significantly. These two parameters should be kept small, and controlled, if a very low defect rate is needed.

Optimization of a two-echelon supply chain with random demand and random defect rate under strict carbon cap policy

PurposeThe yield of defective items and emissions of greenhouse gases in supply chains are areas of concern. Organizations try to reduce the yield defective items and emissions. In this paper, a constrained optimization model is developed with consideration of the yield of defective items and strict carbon cap policy simultaneously and then optimized. Further, sensitivity analyses have been carried out to draw different managerial insights. Precisely, we have tried to address the following research questions: (1) how to optimize the cost for a two-echelon supply chain considering yield of defective items and strict carbon cap policy, (2) how the total expected cost and total expected emissions act with changing parameters.Design/methodology/approachThe mathematical modeling approach has been adopted to develop a model and further optimized it with optimization software. Costs and emissions from different areas of a supply chain have been derived and then the total cost and total emissions have been formulated mathematically. One constrained mixed-integer nonlinear programming (MINLP) problem has been formulated and solved considering emissions-related, velocity and production related-constraints. Further, different sensitivity analyses have been derived to draw some managerial insights.FindingsIn this paper, many decision variables have been calculated with a set of basic values of other parameters. It has been found that both cost and emissions can be controlled by controlling different parameters. It has been also found that some parameters have very little or no influence either on cost or emissions. In most cases, originations may exhaust the given limit of carbon cap to optimize their costs.Originality/valueIn spite of my sincere efforts, no paper has been found that has considered the yield of defective items and strict carbon cap policy simultaneously. In this paper, it is assumed that both demand and defect rates are random in nature. The model, presented in this paper may give insights to develop different supply chain models with consideration of both defective items and strict carbon cap policy. Sensitivity analyses, drawn in this paper may give deep insights to managers and carbon regulatory bodies.

STUDIES ON PROCESS IMPROVEMENT IN A BISCUIT MANUFACTURING INDUSTRY USING DMAIC APPROACH

Process improvement studies were carried out in Paramount Nutrition Pvt. Ltd. located in Bidadi, Bengaluru, India. Paramount Nutrition Pvt. Ltd. is a contract manufacturer for M/s Britannia and produces six variants of their biscuits. Our work and analysis is focused on a single-line of manufacturing and packing which produces two of the variants viz Good day butter and Good day cashew & almond biscuits. The present work is started by understanding the working facility at the manufacturing unit; and we, then followed a structured methodology to understand the problems which are present and find out ways of countering these problems. For our study, Define, measure, analyze, improve and control (DMAIC) approach was chosen. During the measure phase, it was seen that, packaging defects account to about 27.3% of the overall defects. After the detailed study, suggestions for improvement were given to reduce the packaging defects in the unit along with the reduction in the manufacturing defects. The process ?-levels for defects in packaging and manufacturing are calculated, followed by providing monthly goals to the manufacturer for reducing the defect rate each month in order to attain a 5? level by the end of 7th month.