In the first chapter, the seven skills of QC are summarized. First, the origin of the seven tools, old and new, were summed up by the Japanese. After the Japanese put forward the old seven pieces and succeeded, they put forward the new seven pieces in 1979. Second, the old seven tools QC old seven skills refer to: checklist, analytic hierarchy process, Plato, causal diagram, scatter diagram, histogram and control chart. Third, the new seven tools The new seven technologies of QC refer to: diagram method, KJ method, system diagram method, matrix diagram method, matrix data analysis method, PDPC method and network diagram method. Relatively speaking, the promotion and application of the new seven technologies in the world is far less than that of the old seven technologies, and it has never become an important aspect of customer audit. Chapter ii hierarchical method. Definition hierarchy method is the most basic concept in all technologies, that is, according to the needs of the purpose, all kinds of data are divided into different categories to facilitate future analysis. Second, the most commonly used classification method is spatial classification: operators: different pulling, moving and assembling machines: different machines, different raw materials and parts: different suppliers, different operating conditions: different temperature, pressure, humidity and workplace products: different products (such as simultaneous production of Ni-Cd and Ni-MH batteries) Time: different batches and other products produced at different times: such as similar products produced by different technological methods. Third, the application of AHP is mainly a systematic concept, that is, if you want to deal with quite complex data, you must know how to systematically and purposefully summarize and count these data. Chapter III List 1. Summary list is the simplest and most commonly used of the seven QC methods. But perhaps it is because of its simplicity that it is ignored, so there are many problems in the process of using the checklist. Let's take a look at the various reports in use now. Are many columns empty? Are there many columns that have been revised with pens? Are there many columns to modify? Second, the definition of simple data, in an easy-to-understand way, made into graphics or tables, marked with inspection marks when necessary, and statistically collated for further analysis or check. Objective To record the frequency of some events. Fourth, the timing is 1. When you have to write down the details of an event; 2. When you want to know the frequency of an event; 3. When you want to collect information. List type 1. List of unqualified items; 2. Process allocation list; 3. List of defect locations; 4. Operation list. Notes on the list of intransitive verbs 1 Try to get hierarchical information; 2. Data should be obtained as simply as possible; Measures should be taken immediately. What kind of data warning, shutdown or report to the superior should be specified in advance. 4. If the inspection items were formulated a long time ago and are no longer applicable, they must be re-studied and revised. 5. In general, "other problem categories" cannot appear in the classification. Chapter IV Plato I. Origin The statistical chart designed by Italian economist Vilfredo. Pareto (Plato) was applied to quality management by Joseph Ju Ran, an American quality control master, when analyzing the distribution of social wealth. Plato can fully embody the law of "a few keys, most secondary", that is to say, Plato is a way to find the main factors and grasp the main contradictions. For example, a few users account for most of the sales, most of the equipment failures are caused by a few failures, and most of the unqualified products are caused by a few people. 2. Definition: According to the collected data, it is classified by bad reasons, bad conditions and bad occurrence places; Calculate the proportion of each item in order of size, plus the graph of cumulative value. According to the cumulative percentage, each item can be divided into three categories: 0~80% is Class A, which is obviously the main problem; 80~90% is Class B, which is a secondary factor; 90~ 100% belongs to class c, which is a general factor. 3. Draw step 1. Collect data; For example, the batch of 063048 positive plate is 20000PCS, 600 pieces are defective deformation, 360 pieces are exposed aluminum, 120 pieces are hard, 60 pieces are dark marks, and 60 pieces are other defects. 2. Make a breakdown table (by reason, personnel, process, defective items, etc.). (a) Sort the classified items in descending order of frequency, and put the "other" items at the end, regardless of their frequency; B. Calculate the cumulative frequency of each item; C calculate the proportion (i.e. frequency) of each project in all projects d calculate the cumulative proportion. (See the next page for the demo table) Demo table (statistical table of defective anode production items, with a total batch of 20000PCS): cumulative quantity proportion% cumulative proportion% deformation 600 600 50% 50% exposed aluminum 360 960 30% 80% lumps1201080/kloc-0. 8+0200 5% 100% 3. Draw a vertical axis of pareto chart: left: frequency scale, maximum number of items right: frequency (ratio) scale, maximum number of items 100%. Note: The total number of pieces and the maximum number of pieces 100% should be kept at the same level. B horizontal axis: item (from left to right) c is represented by a square column on the horizontal axis according to frequency, and the accumulated frequencies are connected into a line. 4. Write down the necessary items, such as drawing title, data acquisition time, draftsman, drawing time, total number of inspected products, total frequency, etc. The demonstration diagram (see next page) clearly shows that the deformation and aluminum exposure in the above diagram are Class A defects, and immediate measures should be taken to improve them. Hard lumps are bad items of Class B; Dark marks and so on belong to class C defects. Class b and class c can be improved later. Four. Matters needing attention in using pareto chart 1. Grasp "several keys" and divide the cumulative proportion into three categories: A, B and C; 2. Used to determine the order of taking measures; 3. By comparing pareto chart before and after taking measures and studying the changes of various sub-projects, the effect of the measures can be identified; 4. pareto chart can be used not only to find the main contradiction of a problem, but also to constantly find the ultimate cause of complex problems; 5. The site should pay attention to the comprehensive application of quality management methods such as Pareto Diagram and Causality Diagram. For example, the causality diagram can be used to further analyze the causes of deformation and aluminum exposure. Chapter V Causality Diagram 1. Overview Causality diagram was first proposed by Japanese quality control master Kaoru Ishikawa, so it is also called Ishikawa diagram, and because of its shape, it is also called fishbone diagram, fishbone diagram and branching diagram. There is also a name called feature factor graph. The occurrence of a quality problem is often not the result of one or several reasons acting alone, but the result of the comprehensive action of many factors. In order to sort out these complex factors and grasp the key factors, it is necessary to use scientific methods, start from the "results" of quality problems, rely on the masses, brainstorm, and gradually deepen from the outside to the inside until the root cause is found. Causality diagram is a QC technique to find the cause according to the result. Second, define a chart to find out the possible cause of the problem. Third, the question type that causality diagram can be used for analysis is 1. It represents the characteristics of product quality: size, strength, life, unqualified rate, waste quantity, purity, transparency and so on. 2. Cost characteristics: price, rate of return, working hours, management expenses, etc. 3. Output characteristics: output, delivery time, planned time, etc. 4. Other characteristics: attendance rate, number of mistakes, number of rationalization suggestions. Drawing steps of causality diagram 1 Determine question 2. Draw thick arrow 3. Factors, that is, reasons, are commonly used: 4M 1E, that is, people (personnel), machines (equipment) and materials (raw materials). It can also be used: after the process sequence is classified, draw middle arrows on both sides of the main arrow, making an angle of 45 with the main arrow. 4. For a kind of factors represented by the middle arrow, we should further draw the related factors on the middle arrow with small arrows, and subdivide them again when necessary until we can take action directly. 5. Check whether there are any omissions in the listed factors. If there are any omissions, please supplement them. 6. Among the factors at the end of each arrow, all the important factors with great influence can be marked with small circles, and other simple factors can be added according to the existing data, and no data can be collected or taken. 7. Record relevant matters, such as participants, cartographers, formulation date, etc. V. Precautions 1. In essence, it is an enumeration method, which should follow the mass line and focus on discussion; 2. It is best to use questions that can be expressed in numbers; 3. The smallest reason should also be specific, so as to take measures; 4. Corresponding to a feature, several causality diagrams can be made. For example, it can be drawn according to 4M 1E, and it can also be made according to the classification of working procedures. You can extract the important reasons and make a new causality diagram. 5. Comprehensive application, such as Pareto diagram and countermeasure table; 6. Make more copies, save them, and add new content continuously in the future. 6. Combination of Causality Diagram and Pareto Diagram 1. To establish Plato, it is necessary to establish the required purpose statistics step by step; 2. The purpose of establishing Plato is to master [an important few projects] that have great influence on the overall situation; 3. Then discuss the elements formed by these projects one by one with causality diagram, and take improvement countermeasures; Seven, another drawing step (picture) 1. Convene relevant personnel to convene experienced personnel related to this topic, preferably 4- 10, and choose one person as the group leader (moderator); 2. Hang a big piece of white paper and prepare 2~3 colored pens; 3. The assembly personnel shall speak on the main factors affecting the problem, and the contents of the speech shall be recorded on the map, and no criticism or questioning shall be allowed in the middle (brainstorming method); 4. The time is about 1 hour, and it will be over after collecting 20 to 30 reasons; As for the collected reasons, which has the greatest influence, everyone takes turns to speak. After consultation, the most influential factors are circled in red; 6. Like 5, if you think it is most important to draw a red circle, you can circle it two or three times; 7. Draw a causal diagram again, and remove the ones that are not circled, and the ones that are circled are preferred. Eight. Demonstration of causality diagram. Introduction to Causality Card Diagram Causality Card Diagram is developed on the basis of Causality Diagram, also known as CEDAC (Causality Diagram and Card) Diagram. Cause-and-effect cartoons are often several meters long and several meters wide, and most of them are posted in a conspicuous position on the production site or technical research site. The general structure of the causal card is as follows: the top right is the problem column, which briefly explains the current situation of the problem as the basis for quality improvement, and the bottom right is the goal (generally expressed by quantitative value), project leader and project implementation cycle of the quality improvement project; In the middle of the right is the curve of quality change with the implementation of this project; On the left, there is a fishbone shape. Color-coded cause analysis cards and measures cards are attached to both sides of the fishbone. There are two big pockets marked with the words "reasons" and "measures" nailed below, which contain two different colors of cards for participants to fill in. Then the cards are classified according to certain rules (for example, 4M 1E) and pasted on the fishbone figure. For example, it can be stipulated that the left side of the fishbone is attached with a cause card, and the right side is attached with a measure card, and the corresponding cause card and measure card are connected with a horizontal line. Chapter 6 scatter plot method 1. Definition scatter chart is a chart used to indicate whether there is correlation between a pair of data. This pair of data may be the relationship between [feature-main cause], [feature-feature] and [main cause-main cause]. The classification of scatter charts is 1. Positive correlation (such as capacity and weight of accessories) 2. Negative correlation (viscosity and temperature of oil) 3. Independent (air pressure and temperature) 4. Weak positive correlation (height and weight) 5. Weak negative correlation (temperature and pace) 3. Drawing program of scatter diagram 1. Collect data (at least 30 groups or more) 3. Prepare graph paper, draw the scales of vertical axis and horizontal axis, and calculate the group distance. Usually the vertical axis represents the result and the horizontal axis represents the cause. The calculation of group distance is obtained by subtracting the minimum value from the maximum value in the data and then dividing by the number of groups to be set. Is it necessary to group? 4. Mark the corresponding numbers of each group on the coordinates; 5. Fill in the data collection location, time, determination method, producer and other items. Fourth, the application of scatter plot When the relationship between two factors is unknown or vague, it is necessary to investigate and confirm the relationship between these two factors, and scatter plot can be used to confirm the relationship between them. It is actually an experimental method. What needs to be emphasized is that when investigating the relationship between these two factors with scatter plot, other factors that have an influence on these two factors should be fixed as much as possible, so that the results obtained through scatter plot can be more accurate. V. Five types of demonstration diagrams of scatter charts (see next page) Chapter VII Histogram Method 1. Definition: a chart used to show the distribution of data such as length, weight, time and hardness. Histogram is a graph that divides the total distance of the collected measured values or data into several equal intervals with the horizontal axis as the unit, and arranges the area of the measured values in each interval with columns, so we also call it histogram. 2. Drawing steps of histogram 1. Collect record data II. Determine the number of groups 3. Find the maximum value L and the minimum value S, and calculate the total distance R = L-S4. Determine the group distance R÷ number of groups = group distance 5. Determine the lower group boundary of the smallest group =S-[ the minimum number of digits of the measured value ×0.5] and the upper group boundary of the smallest group = 6. Determine the center point (upper group boundary+lower group boundary) ÷2= the center point of group 7. Make frequency distribution table 8. Make histogram 9. Fill in frequency, specification, average value, data source, date 3, function of histogram 1. Evaluation or inspection process; 2. Point out the necessity of taking action; 3. Measure the effect of the corrective measures taken; 4. Compare the mechanical properties; 5. Comparative materials; 6. Compare suppliers.