四梭圆织机主传动系统改进与设计

2000-2001年,我公司陆续从浙江、常州购进了75台四梭塑料圆织机,组成了我公司塑料编织产品的主要生产群体。这批织机经多年的使用。发现主传动系统所采用的蜗轮减速机构,频繁地出现蜗轮磨损严重的现象,而且油封处漏油的现象也屡屡发生。当我们利用新机构对其进行更替改进后,经十几年的使用检验效果良好。杜绝了漏油现象减少了维修时间和维修费用。同时提高了开机时间,增加了产量,从而取得较好经济效益。本文就改造设计情况予以阐述。     

奥地利LRW4—560型圆织机的维修与改进

本文介绍对LRW-560型圆织机的梭轮、推梭轮、供油滑块、测布器及自动张力调节器等进行适当改进，提高技术经济效益的经验。     

LRW4—560型圆织机纺织袋折迭器的设计与安装

本文介绍LRW4－560型圆织机上设计并安装折迭器生产折选编织袋的经验。     

LRW4-560型圆织机编织袋折迭器的设计与安装

本文介绍LRW4-560型圆织机上设计并安装折迭器生产析选编织袋的经验。     

奥地利LRW4／560型圆织机技改续谈

本文介绍奥地利LRW4／560型圆织机的技术改造经验。     

S-STL-II480型凸轮收卷机改进与设计

2007年,我公司从浙江购进了SJ-2200造纱机,其收卷机在使用过程中,收丝纱锭产品质量达不到要求,纱锭两端起棱,两边高中间低。当我们利用原凸轮对其进行改进设计后,经四年的使用检验效果良好。杜绝了产品质量问题,提高了产品合格率,增加了产量,从而取得较好经济效益。本文就改进设计情况予以阐述。     

刍议数控机床的电气控制改进与设计

随着现代社会的发展,数控机床的应用越来越广泛,考虑到数控设备的成本,直接淘汰会造成巨大的浪费．因此就必须通过对机床关键部分的电气改进求得企业最大经济利益与社会效益的实现。本文从数控机床电气控制系统组成出发,阐述了电气改进的主要步骤及各环节中应予以注意的问题,以期能与同行交流。     

D-optimal experimental design for production models in nonstandard experiments

Robust design is an effective Quality by Design method to reduce product variation by selecting levels of design factors. For a number of situations, a nonstandard design region with linearly limited resources is needed to conduct an experiment. In the literature, little attention has been given to the development of robust design models for the nonstandard design region with a combination of linearly limited resources and a limited number of design points. In this paper, a selection scheme of D-optimal experimental design points is proposed to generate design points using the modified exchange algorithm for the nonstandard design region while specifying linearly limited resources and the limited number of design points. The modified exchange algorithm is able to generate global design points with less time complexity than the improved Fedorov algorithm. In addition, robust design models linking a D-optimal experimental design with quality considerations are proposed in order to obtain optimum settings of design factors for the product. Comparative studies are also presented. Finally, a real-life experimental study shows that the proposed models with the desirability function and the sequential quadratic programming technique achieve greater variance reduction than the traditional counterparts.     

Combination of Lean value-oriented conception and facility layout design for even more significant efficiency improvement and cost reduction

Global market competition and fluctuating customers’ demands require manufacturing enterprises to focus on cost reduction and efficiency improvement to increase competitiveness and sustainability. The purpose of the research was the elaboration of the methodology and procedure of a new combined efficiency improvement method which basically applies Lean methods and also uses the facility layout design (FLD) method simultaneously, integrating the different advantages of these methods, which is even more efficient that applying each of the methods individually. The main significant added-value of the study is the elaboration of a new combined method, which results in even more significant improvement of efficiency and several KPIs, furthermore, cost reduction, which is confirmed by a real case study for the improvement of a manufacturing plant. In the case study, the application of 13 Lean methods and the FLD method (which aims at the minimisation of material workflow, travel distance of materials, material handling cost and space used for assembly) led to the improvement of 10 quantitative and 5 qualitative indicators: productivity; cycle-time; number of workstations and operators; WIP (work-in-process) inventories; space used for assembly; material workflow; travel distance of materials; material handling cost; labour cost; component supply; products’ quality; transparency; standardisation; workplace ergonomics.     

圆弧包络线在罗茨转子型线设计中的应用

罗茨转子是罗茨鼓风机、罗茨压缩机、罗茨流量计和罗茨真空泵等设备中最关键的核心部件。罗茨转子的设计成功与否，对这些设备的性能至关重要。本文使用计算机动画编程的方法，对圆弧包络线的生成和性质进行了研究，并将其应用于罗茨转子型线的设计中。文中还引入了形状系数c和峰顶系数c1，详细给出不同类型的圆弧型线的罗茨真空泵容积利用系数随形状系数c和峰顶系数c1的变化情况。文末给出了一个转子加工的实例。     

Reliability improvement and production decision under Cournot competition

We consider two competing manufacturers who are unreliable and exert effort endogenously to improve their reliability within a dynamic decision framework. The manufacturers first decide the optimal level of effort and then input quantities after observing improvement outcomes. We explore the relationship between optimal input quantity and realised reliability, and find that the balance between two effects – price reduction effect and cost reduction effect – plays an important role. When market potential is low, the cost reduction effect dominates the price reduction effect, resulting in that the optimal input quantity increases in the realised reliability. The opposite situation is true when the market potential is high. By further examining the interaction between competition and reliability improvement, we find that the competition reduces the effort level of reliability improvement and this impact increases in the probability of the improvement success. In terms of expected input quantity, the reliability improvement intensifies competition with lower market potential but weakens competition with higher market potential. While in terms of expected output quantity to the market, the improvement behaviour of each competitor always intensifies competition by reducing the output inefficiency caused by random yield.     

Recyclable mono materials for packaging of fresh chicken fillets: New design for recycling in circular economy

The focus on sustainability and circular economy is leading to a need for development of new food packaging concepts, including recyclable materials that ideally consist of a single material in a monolayer system. This research was focused on the possibility of replacing complex multilayered material [amorphous polyethylene terephthalate/polyethylene (APET/PE)] with simple recyclable mono material [high-density polyethylene (HDPE)] for packaging of chicken fillets in modified atmosphere packaging (CO₂/N₂: 60%/40%). Bacterial growth measured as total viable count (TVC), lactic acid bacteria and Enterobacteriaceae, Brochothrix thermosphacta and Escherichia coli for chicken fillets packed in HDPE mono materials was compared with chicken fillets packed in APET/PE. TVC increased during the storage period (24 days) with high level of TVC count (7 log₁₀ CFU/g) recorded at Days 19–20 of storage in both HDPE and APET/PE material. No significant differences were recorded in off-odour between chicken stored in APET/PE compared with HDPE in CO₂/N₂ atmosphere during the storage period (samples were regarded as acceptable on the 24th day of storage). The drip loss increased in all samples during storage, and no significant differences between samples stored in different materials were recorded. Significant differences in bacterial growth were recorded between samples with different gas volume to product volume (G/P) ratio (Day 17), implying that higher G/P ratio is resulting in lower TVC count. The lowest G/P ratio caused the highest drip loss, whereas addition of CO₂ emitter reduced the drip loss to some extent. This research is very encouraging as it provides new insight into the use of monolayer materials as well as the importance of design for recycling in circular economy.     

Optimum stacking sequence design of laminated composite circular plates with curvilinear fibres by a layer-wise optimization method

The optimum stacking sequence design for the maximum fundamental frequency of symmetrically laminated composite circular plates with curvilinear fibres is investigated for the first time using a layer-wise optimization method. The design variables are two fibre orientation angles per layer. The fibre paths are constructed using the method of shifted paths. The first-order shear deformation plate theory and a curved square p-element are used to calculate the objective function. The blending function method is used to model accurately the geometry of the circular plate. The equations of motion are derived using Lagrange’s method. The numerical results are validated by means of a convergence test and comparison with published values for symmetrically laminated composite circular plates with rectilinear fibres. The material parameters, boundary conditions, number of layers and thickness are shown to influence the optimum solutions to different extents. The results should serve as a benchmark for optimum stacking sequences of symmetrically laminated composite circular plates with curvilinear fibres.     

Development of a sequential optimization procedure for robust design and tolerance design within a bi-objective paradigm

Many practitioners and researchers have implemented robust design and tolerance design as quality improvement and process optimization tools for more than two decades. Robust design is an enhanced process/product design methodology for determining the best settings of control factors while minimizing process bias and variability. Tolerance design is aimed at determining the best tolerance limits for minimizing the total cost incurred by both the customer and manufacturer by balancing quality loss due to variations in product performance and the cost of controlling these variations. Although robust design and tolerance design have received much attention from researchers and practitioners, there is ample room for improvement. First, most researchers consider robust design and tolerance design as separate research fields. Second, most research work is based on a single quality characteristic. The primary goal of this paper is to integrate a sequential robust design–tolerance design optimization procedure within a bi-objective paradigm, which, the authors believe, is the first attempt in the robust design and tolerance design literature. Models are proposed and numerical examples along with sensitivity analysis are performed for verification purposes.