Current Manufacturing Practices Research Articles

Pharmaceutical Formulation Facilities as Sources of Opioids and Other Pharmaceuticals to Wastewater Treatment Plant Effluents

Facilities involved in the manufacture of pharmaceutical products are an under-investigated source of pharmaceuticals to the environment. Between 2004 and 2009, 35 to 38 effluent samples were collected from each of three wastewater treatment plants (WWTPs) in New York and analyzed for seven pharmaceuticals including opioids and muscle relaxants. Two WWTPs (NY2 and NY3) receive substantial flows (>20% of plant flow) from pharmaceutical formulation facilities (PFF) and one (NY1) receives no PFF flow. Samples of effluents from 23 WWTPs across the United States were analyzed once for these pharmaceuticals as part of a national survey. Maximum pharmaceutical effluent concentrations for the national survey and NY1 effluent samples were generally <1 μg/L. Four pharmaceuticals (methadone, oxycodone, butalbital, and metaxalone) in samples of NY3 effluent had median concentrations ranging from 3.4 to >400 μg/L. Maximum concentrations of oxycodone (1700 μg/L) and metaxalone (3800 μg/L) in samples from NY3 effluent exceeded 1000 μg/L. Three pharmaceuticals (butalbital, carisoprodol, and oxycodone) in samples of NY2 effluent had median concentrations ranging from 2 to 11 μg/L. These findings suggest that current manufacturing practices at these PFFs can result in pharmaceuticals concentrations from 10 to 1000 times higher than those typically found in WWTP effluents.

In-line Inspection Impact on Cycle Time and Yield

The semiconductor industry constantly drives for high yield and low cycle time (CT), while most current manufacturing practices consider them separately. This research investigates and exhibits the relationship between CT and yield as affected by in-line metrology inspections of production lots. Among the various factors that impact the tradeoff between CT and yield, we focus on single operation monitors and investigate their measure rate and scheduling. The research assumes a simplified production cell consisting of three operation steps that represent a typical segment in a production line. We compose and apply dynamic policies for metrology inspections via simulation and analytical methods. The aim is to concurrently reduce the CT accumulated and increase the yield achieved due to inspections. Ten inspection policies are compared under nine different operation scenarios. The results of most of the policies present a concave curve of yield versus CT. The curve illustrates that growing inspection rate increases both yield and CT until the yield reaches a maximum and then starts to decline. The cause for the yield decline is longer delay in corrective feedback to an out-of-control production tool due to longer waiting time for inspection. A cost-benefit CT-yield objective function is defined and demonstrates that the newly composed dynamic inspection policies are superior to the commonly used fixed measure rate policy. Future research could relax part of the simplified production cell assumptions in order to consider more realistic model structure and scenarios.

Numerical comparison of thermoacoustic couples with modified stack plate edges

It has been demonstrated that the bulk of time-averaged heat transfer between the oscillating fluid and a thermoacoustic couple is concentrated towards the edges of the stack plate. Previous numerical studies which have considered thermoacoustic couples of finite thickness have used a rectangular form for the plate edge. In practice however, current manufacturing practices allow for a variety of stack edges which may improve the efficiency of heat transfer and/or reduce entropic losses. In this numerical study, the performance of a thermoacoustic couple is investigated at selected drive ratios and using a variety of stack plate edge profiles. Results indicate that stack profiles with enlarged and blunter shapes improve the rate of heat transfer at low drive ratios but retard the rate of heat transfer at higher drive ratios due to increased residence time of the fluid in contact with the stack plate. The improvement in COP through minimisation of acoustic streaming on the inside face of the stack, and increased effective cooling power by greater retention of stack thickness at the plate extremities, leads to recommendation of the Rounded edge shape profile for thermoacoustic stack plates in practical devices.

A comparative study of manufacturing practices and performance variables

The reported study was conducted to compare and contrast current manufacturing practices between two countries, Australia and Malaysia, and identify the practices that significantly influence their manufacturing performances. The results are based on data collected from surveys using a standard questionnaire in both countries. Evidence indicates that product quality and reliability is the main competitive factor for manufacturers. Maintaining a supplier rating system and regularly updating it with field failure and warranty data and making use of product data management are found to be effective manufacturing practices. In terms of the investigated manufacturing performance, Australian manufacturers are marginally ahead of their Malaysian counterparts. However, Malaysian manufacturers came out ahead on most dimensions of advanced quality and manufacturing practices, particularly in the adoption of product data management, effective supply chains and relationships with suppliers and customers.

An ant colony optimization algorithm for scheduling virtual cellular manufacturing systems

This paper presents a methodology to solve the manufacturing cell creation and the production scheduling problems for designing virtual cellular manufacturing systems (VCMSs). The objective is to minimize the total materials and components travelling distance incurred. The methodology consists of (i) a mathematical model that describes the characteristics of a VCMS and includes constraints such as delivery due dates of products, maximum capacities of resources, critical tools limitation, and (ii) an ant colony optimization (ACO) algorithm for manufacturing cell formation and production scheduling. Since the proposed ACO algorithm does not indicate a feasible schedule explicitly, two simple heuristics are developed to assign workstations to the operations of the jobs, and to construct the final schedule. To demonstrate the effectiveness of the proposed methodology, both the ACO algorithm and the genetic algorithm are applied to design manufacturing cells for a company in China producing internal combustion engine components. Comparison of the results obtained with the results supplied by the company on the existing manufacturing system show that both the ACO algorithm and the genetic algorithm together with the virtual cellular manufacturing concept perform better than the current manufacturing practice in terms of average workstation utilization, product completion time and system throughput. Also, the results of a set of randomly generated numerical experiments show that the proposed ACO algorithm generates excellent final solutions in a much shorter computation time when compared with the genetic algorithm. Therefore, the mathematical model and the ACO algorithm proposed in this paper form a simple, but effective and efficient methodology to solve the manufacturing cell creation and production scheduling problems for designing VCMSs.

Manufacturing best practices of the electric and electronic firms in Malaysia

A study was conducted to evaluate the manufacturing practices in the electronic and electrical firms of Malaysia based on the criteria identified from literature on a broad‐based manufacturing practice known as world‐class. Based on the replies to a structured questionnaire developed for this study, the current manufacturing practices indicate the status of these firms in their journey towards world‐class manufacturing practices. The result of this study showed that the implementation of “world class” or “best practices” among the respondents is satisfactory especially in the areas of management commitment, internal and external customer service policies and plans, and supplier relationship and development programs. There are some areas of improvement, such as cost of quality, supplier quality, increase operational flexibility and the use of group technology and flexible layout that should be taken into consideration.

Characteristics of the microstructures of alumina-based refractory materials treated with CO 2 and diode lasers

Alumina-based refractory materials are known to possess good chemical attack resistance at high temperatures; thus, they are often used as linings for furnaces and incinerators. However, there are still several components in such commercial alumina refractory materials which limit their corrosion/erosion resistance, e.g., material inhomogeneity (existence of aggregates) and porosity. These promote corrosion attack and allow corrosive agents to penetrate and can possibly increase erosion damage. These properties, although recognised, are very difficult to overcome by current refractory manufacturing practice. Laser surface treatment is one novel method that has potential for eliminating porosity and producing a homogeneous surface layer. This paper describes microstructural and morphological characteristics of CO 2 and diode laser-treated 60% and 85% alumina refractory materials using SEM and optical microscopy. The research shows that a denser, uniform surface layer with solidification microstructures and which resists thermal shock, can be produced. The use of a high power diode laser for surface treatment of refractory materials is reported for the first time.

Results of an Industry Survey on Manufacturing Engineering and Manufacturing Engineering Education

AbstractA survey of 47 manufacturing companies in the Pacific Northwest was taken during the development of a new manufacturing engineering curriculum at Seattle University. The survey asked companies to comment on current and future manufacturing practices and on curriculum recommendations for a new manufacturing engineering program. The survey results indicate that manufacturing engineers need training in a broad range of topics including manufacturing processes, economics, resource management and computer networking.

A STEP-based geometrical representation as part of product data model of a plastics part

Product Data Models are fast becoming important tools for CAD/CAM integration towards a CIM environment. A common information repository on product data would enable significant reductions in design-to-manufacture lead times, reduced costs and effort. However, its widespread implementation is restricted due to insufficient knowledge about the methodology and lack of suitable implementation tools. This paper describes a major government-funded research at the Faculty of Mechanical Engineering, Universiti Teknologi Malaysia to assess the most efficient means of implementing the STEP-based Product Data Modeling methodology for the plastic injection molding industry. The research utilizes a proprietary software, ST-Developer, to develop the geometrical description of a particular plastic product based on the STEP standards. The geometrical description will be transferred into a CAD system to assist the design and machining of a suitable mold for the plastic product. Evaluation of the method with the ultimate aim of achieving automated data model transfer operation will be carried out together with the required implementation methods. The paper describes elements of the product data model of the plastic product, the software systems that will be used for the research and the research methodology. Current progress together with lessons gained so far are included in the discussions. Current indications are that the proposed methodology would give a significant contribution towards improving current design and manufacturing practices in the mold and die industry.

The effect of product quality on the integrity of advanced surface engineering treatments applied to high speed steel circular saw blades

Advanced surface engineering technologies have been successfully applied to high speed steel drills and carbide single-point cutting tools, but, as yet, limited benefits have been realized when applying the same technologies to multi-point cutting tools of commercial quality. This paper discusses the factors that have limited the benefits of advanced surface engineering treatments when applied to high speed steel circular saw blades. Common manufacturing defects have been identified on the teeth of the blades. Tests which evaluate the blade performance throughout its useful life and examination by scanning electron microscopy (SEM) have shown that these defects adversely affect the performance and wear resistance of surface engineered blades. Further investigations suggest that significant improvements in coating integrity can be achieved through the careful preparation of the substrate surface and refinement of the cutting edge geometry prior to treatment. For this application, the need for refinement and enhancement of current manufacturing practices is demonstrated if the full benefits of advanced surface engineering are to be realized.

Challenges for predictive process simulation in sub 0.1 μm silicon devices

The promise of process simulation has always been that it could replace costly experiments in the development of new technology. The reality has been far less, primarily because of deficiencies in the physical models underlying such simulations. This situation is changing rapidly however, as better physically based models are developed. This paper describes recent progress in developing physically based process simulators like SUPREM. A number of examples will be shown which will illustrate the growing predictive power of such TCAD tools, even for silicon structures well beyond current manufacturing practice.

Challenges for predictive process simulation in sub 0.1 μm silicon devices

The promise of process simulation has always been that it could replace costly experiments in the development of new technology. The reality has been far less, primarily because of deficiencies in the physical models underlying such simulations. This situation is changing rapidly however, as better physically based models are developed. This paper describes recent progress in developing physically based process simulators like SUPREM. A number of examples will be shown which will illustrate the growing predictive power of such TCAD tools, even for silicon structures well beyond current manufacturing practice.

Current design and manufacturing practices for gas turbine axial compressor blades : Valentini, E.Diesel Gas Turbine Worldwide June 1990 22, (5), 56, 58, 60

Current design and manufacturing practices for gas turbine axial compressor blades : Valentini, E.Diesel Gas Turbine Worldwide June 1990 22, (5), 56, 58, 60

The Microbiology of Raw, Eviscerated Chickens: A Ten Year Comparison

In 1979 a survey of selected chicken eviscerating plants was conducted to determine the levels of coliforms, Escherichia coli, and Salmonellae sp. on eviscerated chickens under current manufacturing practices. A comparison was made of the data from this survey and one conducted in 1969.The 1979 survey found that the chickens did not have a statistically significant reduced incidence of salmonella compared to chickens analyzed in 1969. Also, much of the bacterial contamination on a carcass at the end of the evisceration line was transient and was readily removed by the final spray washer. The addition of chlorine to chiller water did not appear to have an unusually beneficial effect on the microbiological quality of the chickens.In 1969, in the nine plants studied, the incidence of salmonella on chickens at the exit of the chillers was 20.5%. In 1979, in the nine plants studied, the incidence of salmonella on chickens at the exit of the chillers was 11.6%. In 1979 there was about a 45% reduction in the incidence of salmonella in eviscerated chickens in the nine plants studied compared to the incidence of salmonella in eviscerated chickens in 1969.

24—COMPOSITION TOLERANCES IN THE MANUFACTURE OF TWO-COMPONENT TEXTILE FABRICS PART I: FACTORS CONTRIBUTING TO COMPOSITION VARIATION

The variation in the composition of a finished fabric is a summation of several identifiable independent factors. These may be combined by specially derived statistical methods to provide an estimate of likely within-batch and batch-to-batch variations. A detailed analysis of four typical fabrics indicates that, with the levels of variation attainable in good current manufacturing practice, single-sample testing with a statutory composition tolerance of ±3% must lead to a high failure rate, especially with fabrics composed of blended staple-fibre yarns. A small ‘design error’—the difference between the grand mean of a production and the labelled fibre content—produces a notable increase in failure rate.