When the customer gives specifications, when the factory trial-produces the product or the R&D personnel design the product, formulas are often used to calculate the yield rate. When there are many product characteristics or factory machine monitoring parameters, it is not only time-consuming and laborious to confirm defective products, but also the specification every time. The adjustment will involve the modification of the formula. As long as there is a related project, it will take a lot of effort to do the pre-work repeatedly. Therefore, this topic focuses on the calculation of yield rate and the setting of related specifications, including how to make appropriate modifications for subsequent specifications.
how in JMP Setting Yield Specifications ?
First of all, when it comes to yield rate, the first thing you must have is the specification. At the beginning of this article, we will introduce how to set the specification. JMP The specification setting can be set for a single parameter or multiple parameters. After setting, it can be added as column property , let me explain to you two situations below:
Case 1. Single parameter setting specification
As shown in Figure 1 and Figure 2, right-click on any parameter column and select Spec Limits under Column Properties to add specifications and display them on the graph.
picture 1
figure 2
Case 2: Multi-parameter setting specification
exist Analyze>Quality and Process>Manage Spec Limits Down ( picture 3) , you can specify multiple parameters at one time and add Column Properties (Save to Column Properties) , you can also save the specification as a data sheet for future reading ( picture 4) , in addition to manual input, you can also copy the upper limit or lower limit of multiple parameters in sequence and paste them.
picture 3
Figure 4
How to Calculate Yield ? Easily set up the non-performing rate summary table
The second part is to explain to you how to calculate the yield rate, use Analyze>Distribution , if the specification has been set, in Nonconformance Down ( picture 5) It can automatically display the defect rate and the expected value of the estimated defect rate. However, in general, how to aggregate the results of the defect rate of many parameters is also a problem often encountered by users. Here JMP provides a useful little trick in Nonconformance Right-click on the table, select Make Combined Data Table( picture 6) , you can directly generate a summary table of defective rates ( picture 7)
picture 5
Figure 6
Figure 7
If you encounter appearance judgment Pass/Fail Nominal data type ( picture 8) How to calculate the bad rate? Here is another JMP Function, Analyze>Tabulate( picture 9) , drag the relevant variable to the relevant column, and match the red drop-down menu Make Into Data Table( picture 10) , generate bad rate and good rate statistical table ( picture 11)
Figure 8
Figure 9
Figure 10
Figure 11
Judging the impact of adjusting specifications on the defect rate
No. 3 part to talk about According to the distribution of existing data, adjust the specification boundary or understand the impact of specification adjustment on the defect rate , the first step is to confirm the data distribution. If it is a continuous variable, click the red drop-down menu under the parameter Continuous Fit , then choose Fit All ,let JMP Automatically fit the best-fit distribution ( picture 12) , if the data belongs to the normal distribution, you can choose Interactive Capability Plot( picture 13) Dynamically adjust the upper and lower limits to understand the change of expected defect rate under normal distribution ( picture 14) ,
Figure 12
Figure 13
picture 14
In addition, in the drop-down menu of Fit Normal Distribution, you can choose Process Capability ( picture 15) , you can input the probability value of the upper and lower cut-off points according to the data distribution or calculate the specification according to the standard deviation ( picture 16) , it should be noted that some distributions cannot be used here, such as Cauchy, Student t Or a discrete probability distribution.
Figure 15
Figure 16-1 Calculation of specifications from quantile probabilities
(Figure 16-2) Calculate specifications based on multiples of standard deviation
After the specifications are calculated, the relevant process capability, histogram and defective rate data will be displayed (Figure 17), and the adjusted specifications can be stored as Column Property (Figure 18)
Figure 17
Figure 18
The above is the operation process of establishing the specification and adjusting the specification to confirm the defect rate. Users mostly use the specification setting function in the first half, and then want to further adjust the specification according to the collected samples and their distribution. At the same time, users understand less about the change of the defect rate. , through this article to explain, so that users in need can control and design products more time-saving and efficient. welcome try out JMP30 sky , to help you quickly complete your daily analysis work.
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