The present work aims to show the development and application of a continuous improvement procedure as well as statistical methods and management tools to improve the quality of high-density bags in the Chemical Company of Cienfuegos.
The work explains the application of root cause analysis, process capacity and statistical software, as well as the formulation of improvement and control plans.
Finally the progress of the improvement is measured.
INTRODUCTION
Today's economies are increasingly interdependent; Since the Japanese irruption in the world market, no one can be calm about the throne that at a given moment could be built. The driving force behind this maelstrom has been quality. The improvement of quality must be made possible by the systematic control and constant analysis of the company's activity, an analysis that has to reveal the imbalances in the work, the losses due to defective productions and due to a decrease in the qualitative levels, as well as reveal the causes of production being produced in a way that is not profitable for the organization and does not satisfy customers.
Increasing efficiency and effectiveness in Cuba is a permanent objective to be pursued, both in the production of goods and the provision of services, as well as in consumption, particularly in cases involving foreign exchange expenditures. However, even the results achieved are far from those expected, requiring the improvement of business management, as well as the acquisition of new technologies and resources, among other aspects, to achieve this purpose (Castro Ruz, 1996).
International theory and practice confirm the need to maintain high quality in processes, this condition being little achieved in many cases. Almost always, in the absence of control over them, many become obsolete, stop adding value and being competitive, not adapting to the changes experienced by customer needs (Villa, Eulalia, 2006).
The rapidity of technological evolution, in combination with rising customer expectations, has created global competitive pressures on costs and quality. These pressures have stimulated the exploration of transversal processes, to identify them, understand them and improve their functioning (Juran, 2001).
A considerable number of companies, both globally and nationally, among which machinery construction companies stand out, employ unstructured approaches to improve the quality of their processes. These approaches are taken from the scientific literature on the subject, without stopping to assess, among other aspects, the nature of its processes and the way to manage them, the culture of the organization, the strategic orientation, the prevailing leadership styles and the approaches to manage quality (Evans, 2000; Gómez Dorta, 2001; Juran, 2001; Pons, 1994; Sangüesa, Marta, 2005). Functional objectives conflict with customer needs, which must be served by cross-cutting processes. In addition, the processes generate a variety of waste such as deadlines not met,factory waste, compensation and warranty expenses, among others. They are also not easily modified in response to the ever-changing environment. Consequently, there is a need to improve these processes to better serve the needs of society.
Based on all of the above and the importance of improving quality for the development of Cuban companies, especially in areas as important as the production of goods and services vital to the population, the scientific problem of the investigation as follows:
In general, machinery construction companies do not use properly founded and structured procedures to improve the quality of their processes.
The following hypothesis is raised:
The identification of the root causes that cause non-conformities and other waste, as well as the preventive elimination of said causes, in machinery construction companies, will be possible through the design and application of scientifically argued procedures for the continuous improvement of their processes.
This hypothesis will be validated if it is verified that:
- The proposed methodological instruments are applicable in the selected practical object of study. The application of the procedure allows to identify and eliminate, in a preventive way, the root causes that cause quality problems in the processes. An improvement is evident, in terms of reduction of waste, in selected processes.
This is why the work is proposed as a general objective:
Develop a scientifically based continuous improvement procedure that allows reducing waste rates in production processes and preserving the effects of improvement.
With the following specific objectives:
- Build the theoretical-referential bases of the research, derived from the consultation and analysis of the updated literature on the subject Select a conceptual approach that allows scientifically substantiating the procedure for the improvement of the processes Develop the procedure for the improvement of the manufacturing processes and describe the associated tools. Apply and validate the procedure in selected processes in the mechanical industry.
The methods used in the investigation are: the dialectical, the experimental, the observation, the analysis and the synthesis, as well as the statistical-mathematical methods.
DEVELOPING
1.1 Theoretical conception of the procedure to improve the quality of processes
Improvement means, for the purposes of this work and according to Juran (2001), a process of organized creation of beneficial change to achieve unprecedented levels of performance.
The beneficial change is applicable to two quality classes:
- Product characteristics (Improvement to increase revenue, to increase customer satisfaction). No deficiencies (Increased performance of work processes, reduction of error rates, reduction of failures in operations).
The final results of both cases are called quality improvement. However, the processes used to ensure these results are fundamentally different.
Quality improvement to increase revenue starts with setting new goals, such as new product features, shorter cycle times. Meeting new goals requires several kinds of planning, including quality planning.
In the case of chronic waste, the product goals are already in place, as well as the processes to meet them. However, not all products and services meet these goals. As a consequence, the improvement process to reduce chronic waste is different and consists of: 1) discovering the causes, and 2) applying actions to eliminate the causes.
The latter is the improvement process that will be addressed in this research, in correspondence with its objectives.
The starting point for improvement is recognizing the need. This comes from the recognition of a problem. If no problem is recognized, the need for improvement is also not recognized. Consequently, any improvement procedure must emphasize the recognition of the problem and provide clues for the identification of problems (Imai, 1995).
Once identified, the issues must be resolved. Therefore, the improvement process is also a problem-solving process, which requires the use of various tools to solve the problems. Improvement reaches new levels with each problem that is solved. However, to consolidate the new level, standardization is required (Imai, 1995).
Deming highlighted the importance of constant interaction between research, design, production and sales in conducting business. To achieve better quality that satisfies customers, all four stages must be constantly traversed, with quality as the ultimate criterion. Later, this concept of always turning Deming's wheel for the better, was extended to all phases of administration and it was found that the four stages of the wheel corresponded to specific administrative actions, which are shown in table 1.1.
Table 1.1 Correlation between Deming's wheel and PHVA cycle
Subsequently, the revised version of the PDCA cycle was evolved, in which planning means making plans for improvements in current practices using statistical tools; do means the implementation of the plan; to verify means to see if the desired improvement has occurred; acting means preventing recurrence or institutionalizing improvement as a new practice. The wheel turns and turns incessantly to produce new standards of performance.
The foregoing justifies the use of this revised PDCA management cycle, as a basis for designing improvement procedures that allow managing processes on a day-to-day basis, in correspondence with the needs of strategic alignment, to fully satisfy customers.
The quality improvement procedures are based on the principles described below.
Principles for improving the quality of production Wenzell and Schölling demonstrate that the procedures for quality improvement and error-free performance are based on the following principles:
- Principle of complexity. Quality improvement encompasses all processes, factors, objects, means and workforce that are involved in the reproduction process of the company. This principle shows the dialectical unity of procedures, methods, models and data. Principle of integration. All elements of the reproduction process of the company will be analyzed in terms of their content and time; The analysis of the integration relationships leads to the verification of the existence of a regulatory system that allows the recognition and prevention of failures. Principle of flexibility. The improvement measures lead to the flexibility of the breeding process for the adoption of different alternatives. Principle of continuous development.The improvement process is developed continuously to achieve error-free performance in all areas and processes of the company.Principle of objectivity. The elimination of subjective criteria in the adoption of improvement measures requires the use of models, programs, computers, cutting-edge technologies and other achievements of science and technology. Principle of redundancy. To achieve high quality production, redundant elements are used in the quality improvement process (error detection and prevention) using early warning systems, error-proof mechanisms, joint working methods and forms of organization. for collaboration in the analysis of quality problems and their causes. Principle of uniformity. It presupposes the application of the principles of management,Uniform Quality Improvement Procedures, Methods, Models, and Data Today's Principle. Quality improvement presupposes the application of advances in science and technology in terms of market research, methods of organization and management of production and updated procedures for projection, manufacture, construction of devices and tools, as well as economy of materials. Principle of simultaneity. The improvement of the quality of the production requires the consideration of different alternatives, on economic bases, which include the improvement of the quality of all the processes related to a product, as well as the improvement of a part of the reproduction process for all the products., with a view to selecting the most economical alternative.Principle of worker participation. It presupposes the participation of all workers in the improvement process, requiring the commitment and active participation of the management.
1.2 Preparation and theoretical validation of the procedure for the improvement of the quality of the processes
For the elaboration of the procedure to improve the quality of the processes, the expert method was used. The work of the experts was developed taking into consideration the theoretical foundation raised above.
The determination of the number of experts, twenty-four (24), was carried out through the use of the binomial model shown in Annex 1. This Annex also proposes the route applied for the selection of the aforementioned experts, using a procedure applied by Ronda Pupo (2002), by means of which said selection was made according to the criteria of experience, intuition, knowledge of the updated bibliography, both national and international, as well as the knowledge they have on the subject under study and other aspects directly associated with it.
The Annex itself shows the results of the Brainstorming session (strip of paper) with the selected experts, using the SPSS v.15.0 software system, to determine the elements into which the improvement procedure is organized. quality, as well as the consistency of the judgment issued by them, using Kendall's Coefficient of Concordance and the corresponding non-parametric hypothesis test. The test results indicate that the experts' judgment is consistent (W = 0.919) with a level of significance less than 0.1%, so it can be inferred that the procedure must be made up of the 17 elements contained in the instrument used for its validation, which is shown in Annex 1 itself.
The result of the evaluation of the reliability of the applied instrument is also shown, using Cronbach's Alpha (α) Coefficient, using the SPSS v.15.0 software system. These results show that the Alpha coefficients have an approximate value of 0.6, from which it is inferred that the instrument used is reliable and the conclusions related to the results of the instrument are repeated to a high degree, when applied repeatedly to validate The procedure.
The construct validity of the instrument was verified by using the Principal Component Factor Analysis, a result that appears in Annex 1. The results of the run of the SPPS v.15.0 software system indicate that the Kaiser, Meyer & Olkin Coefficient (KMO) has a value greater than 0.5, which expresses that the extracted factors explain the dispersion between the variables, the Bartlett Sphericity Test shows, with a level of significance lower than 1%, that the variables expressing the Concepts linked to the procedure are related, and the Correlation Matrix of the variables is not an identity matrix. All this allows us to infer that the instrument used for the validation of the procedure measures exactly what it is desired to measure.
The proposed procedure, and validated by the experts, is shown in a synthesized way in table 1.1.
Table 1.1 Procedure for improving the quality of processes
Procedure description
The steps in the procedure are described below. Also, some quality tools are recommended that can be used in each of the steps.
PLANNING STAGE
STEP 1: SELECT THE TOPIC OR PROJECT
Objective: Clearly define the problem to be solved.
Analysis: Project definition, background, activity program.
Secondary steps
Step 1a: Project background and reasons for its selection.
Step 1b: Setting the objective.
Step1c: Preparation of the activity program (external limits of the project).
Tools that may be useful: Pareto Chart, Trend Chart, Project Charter.
STEP 2: UNDERSTAND THE CURRENT SITUATION
Objective: To understand the problem area and the specific problems.
Analysis: Study of the effects of the problem (time, location, type).
Tools that may be useful: Flow Charts, Pareto Chart, Trend Chart, Control Charts, Process Capability, Process Map, and others.
STEP 3: ANALYZE THE CAUSE AND DETERMINE CORRECTIVE ACTION
Objectives: Find out the causes of the problem and determine the corrective action.
Analysis: What are the root causes? What are the corrective actions?
Secondary steps
Step 3a: Preparation of the cause & effect diagram.
Step 3b: Statement of the hypothesis and verification of the most probable cause.
Step 3c: Determination of corrective action.
Tools that may be useful: Check Sheet, Checklist, Cause & Effect Diagrams and Matrices, Failure Modes and Effects Analysis (FMEA) and others.
STAGE OF DOING
STEP 4: PUT CORRECTIVE ACTION INTO PRACTICE
Objective: Put the plan into practice and eliminate the causes of the problem.
Analysis: Training and communication to understand corrective action.
Secondary steps
Step 4a: List of instructions and flow charts for complicated procedures.
Step 4b: Training.
Step 4c: Follow up on the plan.
Step 4d: Record deviations from the plan and collect data on the results.
Tools that may be useful: Check Sheet, Checklist, Process Trend and Capacity Diagram, others.
VERIFY STAGE
STEP 5: VERIFY THE EFFECT OF THE CORRECTIVE ACTION
Objective: Verify the effectiveness of the corrective action.
Analysis: Measurement of technical-economic indicators, goals, etc.
Secondary steps
Step 5a: Comparison of the total result.
Step 5b: Failure to meet results: return to step 4 if due to implementation, or step 3 for further analysis).
Step 5c: Have the results been achieved? Has the goal been met?
Tools that may be useful: Pareto Chart, Trend Chart, Control Charts, Process Capability, Failure Modes and Effects Analysis (FMEA), Histograms, and others.
STAGE OF ACTING
STEP 6: TAKE APPROPRIATE ACTION
Objective: To ensure that the appropriate level of performance is maintained.
Analysis: Document in the operating procedures, the successful corrective / preventive actions.
Secondary steps
Step 6a: Documentation, standardization and control.
Step 6b: Training.
Tools that may be useful: Trend Diagram, Control Charts,
Check Sheet, others.
STEP 7: DECIDE FUTURE PLANS
Objective: Use the experience gained for future projects.
Analysis: Monitoring of the current project, according to priorities and resources; analyze results and characteristics of the Pareto chart and trend curves to decide whether to undertake new projects or not.
1.3 Tools for quality improvement
The proper implementation of the procedure to improve the quality of the processes requires the application of a set of tools that were recommended in their description. Next, a description of some tools will be made, mainly those that are used not only for improvement, but to carry out the management of processes in a comprehensive manner. This list of tools is not and is not intended to be exhaustive. A more detailed description of these and other tools are offered (Ishikawa, 1990; Juran, 2001; Villa, Eulalia and Pons, R.; 2006 and 2006b).
SIPOC diagram
One of the fundamental tools that make it possible to start a process management is the SIPOC diagram.
This tool is used by an improvement team to identify all relevant elements of an organizational process before work begins. Helps define a complex project that may not be well focused. The name of the tool prompts a team to consider the process suppliers (SUPPLIERS), the inputs (INPUTS), the sequence of process operations (PROCESS), the outputs (OUTPUTS), the requirements (REQUIREMENTS) and the customers that receive the process outputs (CUSTOMERS).
The SIPOC tool is particularly useful when it is unclear:
- Who provides inputs to the process? What specifications are put into the inputs? Who are the real customers of the process? What are the customer requirements?
Villa and Pons (2006) offer a detailed description of the steps to follow to build these diagrams.
Cause & Effect Matrix
The Cause and Effect Matrix is very effective in the design and development of new products and services based on the customer. This type of diagram facilitates the identification of relationships that could exist between two or more factors, be these: problems, causes, processes, methods, objectives, or any other set of variables. A frequent application of this diagram is the establishment of relationships between customer requirements and quality characteristics of the product or service, it also allows knowing how to relate the different input and output variables of a process, in correspondence with the importance they have for the customer. This matrix is built from the process map (SIPOC).
The expected results of this tool are:
- A Pareto analysis of the key inputs to evaluate in the Failure Modes and Effects Analysis (FMEA) and in the Control Plans. Capacity study of the key process output variables.
Failure Modes and Effects Analysis (FMEA)
It is a procedure to recognize and evaluate the potential failures of a product / process and their effects. It consists of identifying the actions that could eliminate or reduce the possibility of the potential failure and documenting the process. The FMEA plays a fundamental role in identifying failures before they occur, that is, it enables preventive actions.
A detailed description of the construction steps, objectives, advantages and applications of these diagrams is offered by Villa, Eulalia and Pons, R. (2006).
Brainstorming
Brainstorming is a group technique for generating new and useful ideas, which allows, through simple rules, to increase the probability of innovation and originality. This tool is used in the project identification and definition phases, in the diagnosis of causes and solutions. Brainstorming (also called Brainstorming) is, above all, a proven means of generating many ideas on a topic. It is a means of increasing the creativity of the participants. Typically, resulting idea lists contain more new and innovative ideas than lists obtained by other means. The most common mistakes are using this type of brainstorming as a proxy for data and poor session management,either because of the dominance of a single or a few people in the presentation of ideas or because of the inability of the group not to judge or analyze until the list of ideas is finished. Villa and Pons (2006b) describe the development of this tool.
UTI Technique (Urgency, Trend and Impact)
It is used to define priorities in the preparation of improvement plans. The definition of priorities is the identification of what must be attended first considering the urgency, the trend and the impact of a situation, hence the acronym UTI.
Urgency:
It relates to the time available versus the time required to perform an activity. In order to quantify the variable, it has a scale from 1 to 10 in which it is scored with 1 for the least urgent, increasing the score to 10 for the most urgent. Note that multiple scores may be assigned the same score.
Trend:
Describe the consequences of taking action on a situation. There are situations that remain the same if we don't do something. Others are aggravated by not attending to them. Finally, there are those that are solved just by stopping the time. Those that tend to worsen by not attending them should be considered as the main one, for which a value of 10 will be given; those that resolve over time, 5; and those that remain identical if we do not do something, we rate it 1.
Impact:
It refers to the incidence of the action or activity that is being analyzed in the results of our management in a certain area or the company as a whole. To quantify this variable, it has a scale from 1 to 10 in which the opportunities with the least impact are rated 1, increasing the rating to 10 for those with the greatest impact. Note that you can assign the same score to multiple opportunities.
Control plans
The control plan is a tool focused on maintaining in a planned, precise, stipulated and controlled way any activity or process, whether productive or service, so that it works effectively and failures occur that may affect the results expected by the internal and external clients. The fundamental objective of the control plan is to preserve the performance and results of the process, as its control is guaranteed through the measures proposed.
The control plans are oriented to:
- Meet the most important characteristics for customers Minimize process variability Standardize processes Store written information Describe the actions that are required to be carried out to maintain the process with an efficient performance, in addition to controlling the outputs of the process. Reflect the methods of control and measurement of the process.
Its fundamental benefits are:
- It improves the quality of the process by reducing its variability Reduces defects, focusing and controlling the processes It provides information to correct the processes.
Questionnaire 5Ws and 2Hs
It is used as a guide to develop quality improvement plans. It can also be used in Brainstorming sessions.
Than?
- What is an activity? What is the essence (business) of the activity? What are the outputs? What is the expected final product or service? What are the inputs? What are the indispensable inputs? What are What are the objectives and goals? What are the necessary resources? What data is collected? What are the indicators? What methods and techniques are used? What other processes interface with it? What are the existing problems?
Who?
- Who are the implementers of the activity? Who owns the process? Who are the clients? Who are the providers? Who are responsible for providing support? Who sets the objectives and targets? Who collects, organizes and interprets the data? Who participates and improves the activity? Who is the responsible sector? Who makes the final decisions? Which sectors are directly involved with the problems that occur? Which sectors are directly involved with the problems that occur? occur?
When?
- When is the activity planned? When is the activity carried out? When is the activity endorsed? How often do certain events of the activity occur? When are the resources available? When are the data collected, organized and evaluated? When do meetings happen? When do problems happen?
Where?
- Where is the activity planned? Where is the activity carried out? Where is the activity endorsed? Where do certain special events take place? Where are the data collected, organized and interpreted? Where are problems occurring?
Why?
- Why is this activity considered necessary? What is it for? Can the activity be eliminated? Why are these the operations of the activity? Why do the operations of the activity occur in this order? Why were they defined these objectives and goals? Why are these data collected, organized and interpreted? Why are these methods and techniques used? Why are these indicators used for validation? Why do problems occur?
How?
- How is the activity planned? How is it carried out? How is it evaluated? How is data on the activity collected, organized and interpreted? How is information disseminated? How is customer satisfaction measured? How is the satisfaction of the executor of the activity measured? How are the needs, interests and expectations of the client incorporated into the activity? How is the overall performance of the activity measured? How is the participation of the different people involved in the activity? How is the training of the human resources involved? How do problems occur?
How much?
How many material and human resources are required to improve the activity?
How many financial and other resources?
Multiple voting
This technique consists of a structured series of votes cast by a team and is used to reduce a long list of topics to a more manageable one.
It is used for a quick 'sifting of the list', in addition to having a high degree of group consensus. This technique tends to eliminate personal identification with the ideas expressed.
Topic selection matrix
It is a technique that helps the team to quickly select a topic, on which to begin data collection. If the selected topic in your opinion requires improvement, then the team should proceed.
This matrix allows the team to classify their issues based on the impact they have on the client and their needs for improvement. In this way the team can focus its energies on customer-oriented improvements. The matrix also helps the team to achieve some mastery and clarity in selecting a topic.
Target Graphics:
Classify complex data in the most meaningful way possible for the observer.
How to select the type of graph to use?
Keep in mind that:
- When you want to compare two situations over time, it is easier to read in bar graphs. Percentages are always better seen in a pie chart. Flowcharts illustrate step-by-step processes. PERT charts visualize planning, sequence and control points for complex projects, showing phases as parallel tasks. Line graphs are commonly used to represent collected data as distributed over time. (Machine downtime, waste material, typing errors, productivity, etc.).
Force field analysis
It is used to illustrate the pros and cons of an improvement project or situation, using graphical analysis.
Performing the Analysis:
On a horizontal line that represents the project, upward arrows are drawn indicating all the possible motivating or driving forces, making the size of the arrows proportional to the intensity of the forces they represent. Similarly, all possible restraining forces are plotted downward; Based on the diagram, the team can begin to formulate a strategy that takes these forces into account.
Histograms
It is a special type of bar chart that visually shows the spread (distribution) of a variable's measurement data and its trend. In addition, it is a snapshot of the process capacity and reveals three characteristics of the process:
- Centered: Average of the same values. Distribution: Dispersion of the means. Shape: Type of distribution.
When analyzing a histogram, do not forget that:
- Some processes by their nature will give skewed distributions. Do not expect all distributions to follow a normal curve. One must be suspicious of the accuracy of the data taken if the classes suddenly end at a point, (which may be the specification limit) without a clear decline towards it. When twin peaks appear it can indicate that the data comes from two different sources; for example, two shifts, two machines, etc., and the histogram is the superposition of two distributions with different centers. When empty cells appear, investigate the possible appearance of an assignable (or special) cause of variation in the system.
Matrix analysis
Compare category groups such as operators, vendors, machines, suppliers, and others.
All the elements that are included in a certain category must carry out the same type of activity. Matrix analysis is a two-dimensional Pareto chart.
Stratification
It is used to find the origin of a problem by studying separately each of the components of a set.
Sometimes, when analyzing the different data sources separately, it is observed that the cause or origin of a problem is only in one of them. It is therefore important when analyzing a problem, stratify the data by worker, machine, process, supplier, shift or any other cause of the process.
Stratification is important in data analysis for: charts, control charts, Pareto charts, and histograms.
Control charts
A Control Chart is a line chart specifically used to track the trend or performance of an ongoing process. This is done by observing how the process variation causes the trend line to fluctuate between two statistically calculated limits.
These control limits are statistically derived from samples from a stable process. They should not be confused with specification limits, which are determined from customer requirements.
Control Charts are very useful tools for analyzing and forecasting the performance of a process when determining whether:
- The process is under control and therefore stable. Corrective actions have improved the process.
Dispersion diagram
A scatter diagram is a tool that allows showing the relationship between two variables (both variables must be continuous) on a graph of X and Y coordinate axes.
Is used for:
- Clearly show if there is a relationship, or correlation, between two variables Determine if the correlation is positive - if X increases, Y also Determine if the negative correlation - if X increases, Y decreases Determine No correlation - a variable has no relationship linear with the other.
Action plans (improvement)
OPPORTUNITY FOR IMPROVEMENT ________________________________
GOAL_____________________________________________________
RESPONSIBLE FOR THE GENERAL PLAN ___________________________
WHAT WHO HOW WHY WHERE WHEN WHEN HOW MUCH
Three Generation Report Template
Used to track management.
The elements of the model are as follows:
Priority:
Opportunity for improvement:
Area or service line:
Responsible:
Goal:
Period:
Past
Planned:
Present
Executed:
Results:
Points with problems:
Future
Proposal:
Cause - effect diagrams (Ishikawa)
It is a tool that is used to formulate theories about causes in low complexity processes. This is useful for conducting an organized search for the root causes of quality problems.
When it comes to improving management processes, whose complexity is greater, or
must work with intangible data, it is recommended to use the seven (7)
management tools for quality improvement (Mizuno, 1988)
CONCLUSIONS
- The procedure designed for process improvement constitutes an important methodological contribution to the implementation of the continuous improvement process in the company, as it uses statistical techniques and process management that allow aligning the strategies proposed with day-to-day management (processes), with which it will be feasible to improve your financial health The improvement procedure, designed, allows to adopt a common and universal language for solving problems, which is easily understood by everyone in the organization and can be used to manage other activities of the company, making it possible for the quality improvement to be carried out taking into account all the factors that promote it and, therefore, be profitable.The procedure designed to improve the quality of the processes was theoretically validated, based on the criteria issued by the experts, through the use of Non-Parametric Statistics, Multivariate Statistics and the use of a professional software system. which showed that the instrument used to create the model is reliable and has construct validity.
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