The typical industrial enterprise has, to a large degree, been slow in accepting and implementing statistical principles in an overall program designed to improve the efficiency of the enterprise and its included functions. Where statistical principles are used, they are for the most part limited to purely mechanical functions involving specific machinery applications. This thesis proposes that the limited use of statistical principles in purely mechanical applications makes use of only a small portion of the potential benefits available through more effective use of the principles involved in the science called Statistical Quality Control. This thesis proposes that through a systematic training program, beginning with use of control chart techniques in day to day operations, the responsible individuals comprising the four business functions, Specification, Production, Inspection, and Sales, may be made to realize the importance of the statistical term capability~of-process. Once the four functions are familiar with the true meaning of capability-of-process, this thesis proposes that the four functions will be better equipped to operate inter-functionally and intra-functionally in a controlled manner. The obvious advantage in operating within an overall capability-of-process framework lies in the ability of the users of such a system to attain realistic goals whether they be in the form of specifications or otherwise. Also of importance is the ability to know within predictable limits what may be expected from processes. This thesis proposes that processes must be defined in a broad sense to include the human, or, the organizational aspects involved in the enterprise. For illustrative purposes, a typical production foundry-machine shop complex was used for research data supporting the thesis. The research data results from a six year association of the researcher with the example enterprise. / Master of Science

Background: Automation of processes is taking place more and more in the manufacturing industry today. Automation today is used by companies to be more productive/efficient to be competitive. Automating a process not only increases the chance of reduced waste, but it also increases productivity, precise measurements, shorter lead times and increased cost efficiency, and that the company maintains its place in the market. Therefore, it is important for small to medium-sized enterprises (SMEs) to be able to automate the processes, especially since SMEs make up the largest part of the market. Quality control is one of the most important parts of the complex production process. This is because the quality controls ensure the quality of the products for both the company and the customers. If the quality controls are automated, this can lead to an increase in the quality of the products and to them becoming more efficient.  The purpose: The basis of this thesis is to be able to increase the productivity/efficiency and safety of the quality controls, i.e. more specific and accurate measurements that increase the credibility of the quality of the products, through automation/digitalization. This is to reduce human assistance, increase the efficiency of the process and be more cost-effective as the workers can focus on other tasks than the quality controls. The research questions in this study are: What is needed to redesign and streamline the quality control processes? What are the important technologies and process changes needed to automate the quality controls? How can the quality controls be made more efficient with the help of automation?  Method: This study is based on a qualitative & quantitative research approach which is based on a case study at the company Senior Material. Through interviews, observations, participant observations and notes, the empirical data was collected. All data was analyzed to help the study find relevant solutions. Theories were collected through various search tools through a literature study. The literature that was relevant and could advance the study was used, this through data analysis of the literature and elimination of irrelevant literature. An analysis of the market also took place to find relevant solutions.  Conclusions: The study's conclusion presents which steps are important to take to be able to redesign and streamline the quality control processes in the companies. These steps are to first understand the problem, understand what requirements the company has, be very involved in the case, set limitations and goals, find solutions that meet all requirements and finally analyze whether the solutions meet all requirements and are effective. A very important part of automation is to understand why it should be done, this especially for SMEs as they do not have as many resources as large companies. Another important point to consider is not to have too high a level of automation as this can have several consequences. One of the most important technologies to consider in automation is the digitization of data. This is to be able to detect deviations or problems early and be able to remedy them. Digitization is a large part of the solution, therefore it is important for companies to first check whether the problem lies in a lack of automation or digitization The solutions found were to automate the controls for the particle, humidity and temperature measurement and digitize the rest of the controls. With the help of these solutions, Senior saves more than 123 working days of unnecessary work while streamlining quality controls.

No / Purpose - The purpose of this article is to examine a sample of paper-based incident reports concerning drug incidents to assess the utility of a reporting system. Design/methodology/approach - A 50 per cent random sample of drug-related incident reports between 1999 and 2003 (n=1,253) was reviewed. Details of the incident including error type and contributory factors were identified, as was status of the reporter. Content analysis of the free text established whether the data provided could promote medication safety and organisational learning. Findings The paper finds that all definitive drug errors (n=991) allowed an error type to be identified, but 276 (27.8 per cent) did not include the contributory factor(s) involved. Content analysis of the errors demonstrated an inconsistent level of completeness, and circumstances, causation and action taken were not always logically related. Inter-rater reliability scores were varied. There was sometimes a significant focus on the actions of one individual in comparison to other factors. Research limitations/implications - Incident reports can be biased by psychological phenomena, and may not be representative of the parent organisation other than those who report. This study was carried out in a single health care organisation and generalisability may be questioned. Practical implications - How health professionals interpret drug errors and their reporting could be improved. Reporting can be further developed by reference to taxonomies, but their validity should be considered. Incident report analysis can provide an insight into the competence of individual reporters and the organisation's approach to risk management. Originality/value - This paper highlights the various data that can be captured from drug error reports but also their shortfalls which include: superficial content, incoherence; and according to professional group - varied reporting rates and an inclination to target individuals.

The purpose of this research was to investigate how the quality control manager perceived complaints received by textile companies from their business customers. The population included all textile firms that weave fabric for outerwear (apparel). A packet consisting of cover letter, questionnaire (developed by the researcher), and stamped self-addressed envelope was mailed to each quality control manager in the population. Fifty-four usable questionnaires (28 percent) were returned. The Chi-squared test for independence revealed that at the .05 level, no relationship existed between the number of employee-hours spent handling business customer complaints and the establishment of written guidelines for complaint resolution within the quality control department; nor between the office that handled complaints from business customers and end-use consumers, and the office from which quality control received business customer complaints. The Chi-squared test also found that no relationship existed between the ratings for intended end use for fabric that weavers produced and the type of business customers from whom the quality control manager received complaints; and between the time spent handling different types of business customer complaints received by the quality control managers and the source of these complaints. The quality control and sales offices frequently collaborated on complaints to ensure that their business customers received satisfactory resolutions within the established time. The most frequent complaints received were spots/stains/streaks/dye resistant area, or faulty weaving that most likely came from the consumer product manufacturer, converter, or dyer/finisher and consumed almost 50 percent of the time spent handling complaints. / M.S.

Advances in air technology have resulted in increased cartridge performance requirements which are crowding the present "state of the art" design performance. Process control, which would seem mandatory, is not implemented by contractors for several justifiable reasons. Further, because production lots are small and infrequent, and because destructive testing is involved; the problem of confidence level and minimum sample size becomes paramount in acceptance tests. The use of control charts in production acceptance tests by the Government can provide: 1. additional confidence in lot acceptance because additional information is available 2. valuable information feedback to the design engineer and contractor for the resolution of design and production problems 3. partial lot acceptance. Control charting could be readily incorporated into current cartridge production lot acceptance procedures where MIL-STD-IOSD is employed with variables datao Cartridge serialization and production records would be the only additional requirements. / Master of Science

Most control charts monitor only one quality characteristic. There are, however, many manufactured products for which good quality requires meeting specifications in more than one physical characteristic. Typical practice when dealing with multiple quality characteristics is to take a separate sample for each characteristic and then create individual univariate control charts which are independently monitored. This method can result in errors due to not accounting for the effects of correlation. In order to avoid these errors, an alternate approach to multivariate quality control problems is proposed and studied here. The original problem is converted into a univariate problem by using the following transformation: y=Σ a_ix_i i where αi = weighting coefficient for the i^th quality characteristic X_i = represents the i^th quality characteristic This transformation retains sensitivity to changes in the original quality variables. The resulting univariate quality control model takes into account the sampling error probabilities for each of several candidate hypotheses. The probabilities of correctly diagnosing process shifts when an out-of-control state occurs are calculated and tabulated as are the probabilities that the model will signal when an out-of-control state occurs. / Master of Science

In recent years, variable sampling interval (VSI) control charts have been intensively investigated. In contrast to traditional fixed sampling interval (FSI) control charts, VSI charts vary the sampling interval as a function of the data. VSI charts detect many process changes faster than their FSI counterparts. A disadvantage, however, of VSI charts as recently formulated is that the advance prediction of sampling times is impossible for more than the next sample. A control chart is proposed which applies a sequential probability ratio test (SPRT) at fixed sampling intervals, the SPRT chart, to monitor the mean of a process with a normal distribution. A natural modification of the SPRT chart, the SPRT chart with sampling at fired times (SFT), is also proposed in which samples are always taken at pre-specified, equally spaced fixed times, with additional samples taken between these times as indicated by the data. A third control chart is introduced as a generalization of the VSI cumulative sum (CUSUM) chart that uses two sampling intervals, called the universal CUSUM (UC) chart, in order to address the need for a general framework for the study of control charts that are equivalent to a sequence of SPRT’s. The UC chart can also be viewed as a generalization of the SPRT chart. The integral equation approach is adapted for the evaluation of properties of both the unmodified and modified with SFT versions of the SPRT chart, such as average time to signal (ATS), steady state ATS (SSATS), and average number of observations to signal (ANOS). After comparisons are performed within the general framework of the UC chart, the unmodified SPRT chart is found to be more efficient than both the FSI and VSI X charts and the FSI CUSUM chart, though very similar in efficiency to the VSI CUSUM chart. The modified SPRT chart with SFT is found to be more efficient than all five of the other control charts, including its unmodified version and the VSI CUSUM chart. General guidelines are provided for the design of both versions of the SPRT chart. / Ph. D.

The standard Shewhart control chart for monitoring process stability is generalized by selecting a point in time at which the distance between the control limits is reduced. Three cost models are developed to describe the total cost per unit time of monitoring the mean of a process using both the standard and the generalized Shewhart control chart. The cost models are developed under the assumption that the quality characteristic of interest is normally distributed with known and constant variance. In the development of the first model, the negative exponential distribution is employed to model the time to process shift. Then, the uniform distribution and the Weibull distribution are used for the same purpose in the second and the third model, respectively. The motivation for this effort is to increase chart sensitivity to small but anticipated shifts in the process average. Cost models are constructed to allow the optimal choice of change over time and the best values for the initial and adjusted control limit values. The cost models are analyzed to determine the optimal control chart parameters including those associated with both the standard and the generalized control chart. The models are also used to provide a comparison with conventional implementation of the control chart. It is shown that the proposed cost models are efficient and economical. Figures and tables are provided to aid in the design of models for both the standard and the generalized Shewhart control chart. / Ph. D.

Control charts based on cumulative gauging scores rely on gauge scoring systems used for transforming actual observations into integer gauging scores. In some cases, the gauging scores are easy to obtain by using a mechanical device such as in the go-no-go inspection process. Thus, accurate measurements of selected quality characteristics are not necessary. Also, different control purposes can be achieved p by using different scoring systems. Cumulative gauging score charts based on two pairs of gauges are proposed to control the process mean or the standard deviation by either gauging one or several observations. Both random walk and cusum type cumulative gauging score charts are used. For controlling the process mean and standard deviation at the same time, a cusum type and a two-dimensional random walk type procedure are proposed. A gauging scheme can be applied to multivariate quality control by gauging either x² or T² statistics. A simple multivariate control chart which is based on the multivariate sign score vector is also proposed. The exact run length distribution of these cumulative gauging score charts can be obtained by formulating the procedures as Markov chain processes. For some procedures, the average run length (ARL) can be obtained in a closed form expression by solving a system of difference equations with appropriate boundary conditions. Comparisons based on the ARL show that the cumulative gauging score charts can detect small shifts in the quality characteristic more quickly than the Shewhart type X-chart. The efficiency of the cusum type gauging score chart is close to the regular CUSUM chart. The random walk type gauging score chart is more robust than the Shewhart and CUSUM charts to observations which have heavy a tailed distribution or which are serially correlated. For multivariate quality control. A procedure based on gauging the x² statistic has better performance than the x² chart. Also, a new multivariate control chart procedure which is more robust to the misspecification of the correlation than the x² chart is proposed. / Ph. D.

Two prominent monitoring procedures in statistical quality control are the p-chart for the proportion of items defective, and the c-chart, for the number of defects per item. These procedures are reconsidered, and some extensions are examined for monitoring processes with multiple attributes. Some relevant distribution theory is reviewed, and some new results are given. The distributions considered are multivariate versions of the binomial, Poisson, and chi-squared distributions, plus univariate and multivariate generalized Poisson distributions. All of these distributions prove useful in the discussion of attribute control charts. When quality standards are known, p-charts and c-charts are shown to have certain optimal properties. Generalized p-charts, for monitoring multinomial processes, and generalized c-charts are introduced. Their properties are shown to depend upon multivariate chi-squared and generalized Poisson distributions, respectively. Various techniques are considered for monitoring multivariate Bernoulli, Poisson, multinomial, and generalized Poisson processes. Omnibus procedures are given, and some of their asymptotic properties are derived. Also examined are diagnostic procedures based upon both small- and large-sample. / Ph. D.