The dynamic weighing checkweigher characteristics of the weight sorting checkweigher conform to the normal distribution curve, and the same product will have different values measured multiple times. These values will be distributed in the interval of this normal distribution curve. Therefore, the upper and lower limits of the online dynamic checkweigher settings are more.The upper and lower limits required by the user to be rejected are smaller, that is, the upper and lower limits of the rejection required by the customer cannot be used as the upper and lower limits of the checkweigher. If this is done, many unqualified products will enter the qualified range. Specific settings The test data can be obtained through the blind spot test and then set.
(1) Normal setting method
Take the product's nominal weight range plus or minus 3 times the standard deviation as the upper and lower limits. This setting method will have an inaccuracy rate of 0.3%. In addition, a nonconforming product range of 6 times the standard deviation will be included. This setting can allow most qualified products to pass, ensuring the continuity of production, but there may be unqualified products entering the qualified range (need to see the position of the critical point of qualified products).
(2) Meet 100% non-rejection qualified products
Then you need to enlarge the standard deviation of 3 times to the standard deviation of 4-6 times. Although this setting meets the requirement of 100% not rejecting qualified products, more unqualified products will enter the qualified range.
(3) Meet 100% rejection of unqualified products
To meet this requirement, it is necessary to use the heaviest product among the ultra-light unqualified products plus 4-6 times the standard deviation as the lower limit of the qualified product, and use the overweight unqualified product to subtract 4 from the lightest product. The standard deviation of 6 times is regarded as the upper limit of qualified products. If the user's product distribution interval is more concentrated near the average interval, there will be fewer qualified products that are mistakenly rejected, and it can be guaranteed that products in the unqualified interval will be 100% eliminated.
(4) Ideal condition
The following figure shows the interval setting in an ideal state, which is related to the uniformity of the user's product and the application of removing substandard products required by the customer. In this state, it can meet 100% rejection of unqualified products and 100% pass of qualified products.
To sum up, the upper and lower limits of the checkweigher need to be set according to the specific requirements of the customer and the accuracy of the checkweigher.Welcome to contact us at any time,we will give you the most suitable online checkweigher solution！
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