【正文】 s build the quality in the process.Some says, Our products are very reliable because of severe inspection. Is it correct?It is a great loss to select defective products by severe inspection after producing certain number of defective products. First, we have to make an effort to establish a system not to produce defective products.Moreover, there are some products whose characteristics will not allow to be selected by total inspection, like explosive power of the bomb.Basically, the quality of the products must be assured in each process.We have to assure the quality of products that we produce by total inspection if it allows, but we should realize that the inspection is only to select, but not to build the quality.45 Let39。39。1 There are three steps until we can do something perfectly, To know, To understand and To be able to do. To reach the third step or to be a professional worker, hard training is necessary. So, basically, before working in the workshop, we have to be well trained until we can produce excellent lent products.Now, let39。 will do it.Oral explanation or memory of each people is not always reliable, therefore, we have to standardize them as Operation standard.It is important not to describe them by imagination.We have to try the job actually to find out essential points of the job, and describe them as the operation standard.Quality control in workshop begins from describing the Operation standard.Operation standard should be corrected when ever better methods are found, or circumstances are changed.Let39。s study the causes of possible defects in your job, by actual samp1es or experiments. If we know these concrete causes well, we can avoid unnecessary causes of defects.It is also helpful to study causes of defects in the past, and listen to the lecture of technical engineer about important point of Quality.42Let39。s study control chart, because it is Very helpful when we are accustomed to use it. Chapter 4. Basic steps of Quality assurance41Let39。1stratification39。s study cause of problems. (Causeandeffect diagram)To solve the problem, it is very important to know the real causes, and interrelations among causes.For example, when we have loose brake of the car, there might be many causes. How many causes do you remember? Wornout tire, lack of brake fluid,.. etc.Then, we arrange these causes in a fishbone chart, shown here.Big branches are direct causes to effect the final effect. Medium branches are causes of big branches. Small branches are causes of medium branches.So, every branch is connected in a form of causeeffect, causeeffect...If branches have no causeeffect relationship, the diagram has no meaning, so this Fishbone is not attractive even for cat.A causeandeffect diagram is useful to help us sort out the causes of problems and organize the mutual relationship.35Quality data always have dispersion.We are producing large quantity of products wittyGreat numbers of parts and materials. So, the quality of these products always have some amount of dispersion.Excellent products should have less dispersion of quality, and if not, customers will suffer inconvenience.For example, when the specification says This electric bulb has 2000 hours life. it means only mean value.When 100 bulbs are tested, some bulbs have maximum life more than 2500 hours, and some have minimum life less than 1500 hours.We can show this dispersion as Histogram shown here, and with this histogram, we can know the percentage of defective bulb, when the given standard is minimum 1600and hours. . people lay more stress on dispersion than mean value.Dispersion es from dispersion of materials, operations and machines, etc.Let39。s not talk the fact by literary expression like I think it is about… How to collect data.In order to analyze quality, it is indispensable collect data that represents the fact.Before starting new job, it is necessary to prepare the system to collect data, because initial data is more important to analyze.We have to prepare check sheet to collect data, which is classified into two types as follows:(1) Data recording check sheet To record actual data or number of defective products, or the like classifying them according to each category.(2) Confirmation check sheetIn order to produce excellent products, there are many elements of production like air pressure, or temperature of soldering iron to be checked.After preparing a list of this element, periodically check them, and mark OK or NOT OK on this list.These record are fully informative to know the39。 wrong time? His secretary found the battery worn out, and replaced it. Now, it is all for her to do? Several months later, what will happen? What should we do more?Chapter 3 Fundamental attitude of Quality Control is scientific approach, based on the fact and data.31Let39。 utilizing the latest technology.Vital will:⊙Strong willingness to achieve the target, and positive action.⊙Enthusiasms to get full cooperation of other people.⊙Strong sense of responsibility to fulfill what is decided.Good method:⊙Application of statistical method. ⊙Adequate standardization, systematization of data collection. ⊙Utilization of knowledge and. skill of each individual.Basically, developing vital mind and capability of each person is indispensable.To carry out the program, it is important to confirm whether everybody is fully aware of the final objective.When certain change of circumstances or severe difficulty is found, it39。s think about following points.⊙Does the plan really lead to the success in realizing the target?⊙Can you get full cooperation of all people related to your job?⊙Is the concrete countermeasure considered? ⊙Is the system of record and report of the control well planned to know the results and take action?Now, again, let39。s widely observe the level of your petitor or b