Configuring Result Recording and Valuation

Objective

After completing this lesson, you will be able to configure result recording and valuation of inspection characteristics

Valuation of an Inspection Characteristic

After the Quality Technician has performed a measurement and recorded the inspection result, the characteristic must be valuated as either accepted or rejected. Depending on your business requirements, SAP S/4HANA offers different valuation methods.

Play the video to learn when to use manual characteristic valuation or valuation by characteristic attribute codes.

The following image shows additional valuation modes that are available in the system:

You can valuate a quantitative characteristic by comparing the mean value with the acceptable tolerance range. For quantitative and qualitative characteristics, the system can compare the number of defects or nonconforming units to the acceptance value and valuate the sample accordingly. For quantitative characteristics with active control charts, automatic valuation according to the control chart action limits are possible. For more information, refer to the following text.

The valuation method Mean value within tolerance range can be used for quantitative characteristics. Here, the system calculates the mean value of single results (→ characteristic with single result recording) or the mean value entered by the Quality Technician (→ characteristic with summarized recording) and compares the mean value to the tolerance values the Quality Planner entered in the characteristic. If the mean value is between the lower and upper limit, the characteristic is accepted; otherwise, it's rejected.

Caution

When using this valuation method, the system really only takes the mean value into account. Assume that you've defined a characteristic Length with a lower limit of 0.9 m and an upper limit of 1.1 m. The Quality Technician measures two samples. The length is 0.5 m and 1.5 m respectively. Since the average value is 1.0 m, the system accepts the characteristic although the two individual samples are clearly out of tolerance.

If you don't want this behavior, use the next valuation method instead.

During an Attributive inspection, the valuation for the inspection characteristic occurs based on the number of nonconforming units or number of defects corresponding to an n-c or n-c-d sampling plan. n is the number of items to be inspected. c is the acceptance number that defines the highest number of nonconforming units or defects that still permits the acceptance of the characteristic. d is the rejection number that defines the lowest number of nonconforming units or defects that leads to the rejection of the characteristic. Usually, d = c + 1.

Note

What is the difference between the number of defects and the number of nonconforming units?

To illustrate this, let's consider the example of checking light bulbs for scratches. If we define a light bulb with at least one scratch as defective, then we would count the number of nonconforming units. This means we would count the total number of light bulbs that have scratches, regardless of whether they have one scratch or multiple scratches.

On the other hand, if we are interested in evaluating the characteristic based on the total amount of scratches, we would count the number of defects. For example, if one light bulb has three individual scratches while two other light bulbs do not have any scratches, we would count the total number of scratches, which in this case would be three.

In the example, the Quality Technician measures 125 units. If they find three defects or defective units, the system accepts the characteristic. Otherwise, it rejects the characteristic.

If the characteristic requires single result recording, the system automatically counts the number of defects or defective units. When performing summarized recording, the Quality Technician must enter that number in the respective field.

When using SPC Valuation, you valuate inspection characteristics based on action limits for a control chart. The system compares, for example, the measured value with the action limits of a control chart. If the characteristic value lies outside, the system valuates the characteristic as rejected.

Note

What is a control chart? A control chart is a graphical tool used by quality technicians to control, analyze, and document the processes involved in production and other quality-relevant areas. Control charts are primarily used in inspections during production to monitor and manage controlled production processes. A process is controlled or under statistical control if the observed process parameters only vary randomly from sample to sample. If a measured value lies outside the action limits of a control chart, it deviates more than the process-inherent random variation from sample to sample. Therefore, the sample might be defective so that the system rejects the characteristic.

For more information on control charts, have a look into the Application Documentation.

Technically, the Quality Planner defines the valuation mode in the sampling procedure which they assign to a characteristic. As a prerequisite, the Application Consultant must have defined a list of valuation modes in customizing (IMG: Quality Management → Basic Data → Sampling, SPC → Define Valuation → Define Valuation Mode).

Note

The technical implementation of the valuation is implemented in the system as function modules. The Application Consultant assigns the function module to a valuation rule. Then, they assign the valuation rule to the valuation mode. The latter is then used by the Quality Planner when they define the sampling procedure.

Although this approach might seem complicated, it offers the potential that customers can define their own valuation logic if the SAP standard is not sufficient. For more information, review the documentation of the IMG node mentioned above.

Unplanned Inspection Characteristics

As briefly mentioned in the previous chapter, the Quality Technician can add additional inspection characteristics during results recording to document, for example, additional findings, perform an ad-hoc inspection of a characteristic that was not pre-planned by the Quality Technician, or add a characteristic, reject it, and document a defect, as shown in the following image.

The image shows an example in which the Quality Technician adds an unplanned characteristic during results recording to document a defect on the characteristic level. For more information, refer to the following text.

In this example, the Quality Technician performs two tests: a functional test and a power consumption test on a purchased lamp. The Technician records the inspection results. The inspection characteristics were originally planned to be inspected by the Quality Planner, but the Technician noticed that the surface of the lamps was damaged when taking them out of the box. To document this issue, the Technician wants to record a defect. There are three options for recording the defect: on the inspection lot, the inspection operation, or the inspection characteristic level. According to the company's standard operating procedures, the defects should be recorded at the characteristic level to obtain the most detailed data. However, the Quality Planner has not defined such a characteristic, so the Technician is unable to document the issue. To solve this problem, the system allows the Technician to add ad-hoc characteristics to the inspection operation. The Technician adds a master inspection characteristic to the current lot, records the results, and rejects the characteristic. To provide additional information and trigger a repair, the Technician records a defect against the ad-hoc characteristic.

From a technical standpoint, the system copies the specifications from the master inspection characteristic to the unplanned inspection characteristic. If the user has authorization to change master inspection characteristics, they can make changes to the copied specifications, such as tolerances and target values. The sampling procedure control indicator in the master inspection characteristic determines whether a sampling procedure is assigned. If the indicator is not set, the system uses the sampling procedure set in Customizing for QM at the plant level. If no sampling procedure is entered in Customizing, a 100% inspection is performed.

Note

The ad-hoc characteristic only applies to the current lot. The system does not add the unplanned characteristic to the inspection plan.

Closing Inspection Characteristics

Closing Inspection Characteristics

The processing of an inspection characteristic is completed with the closing of the inspection characteristic. During closing, the system checks if conditions set in the inspection specifications (material specification, inspection plan, routing, recipe, and so on) for inspection characteristic processing were met. In general, all required inspection characteristics and all processed optional inspection characteristics must have been closed before the Quality Engineer can make the usage decision.

Before a inspection characteristic is "properly" closed, the system checks the following points:

  • Whether the required inspection scope was complied with. For example, the Quality Planner defined a sample size of 10 units with single result recording. Only if the Quality Technician indeed recorded 10 results, they can close the characteristic.

  • Whether the conditional inspection characteristics were processed dependent on the valuation of a controlling inspection characteristic. For example, the Quality Planner defined the power consumption of a device as an optional characteristic that must be measured once the upstream functional test was valuated as accepted.

  • Whether an inspection description was entered for inspection characteristics that require documentation. For example, the Quality Planner defined in the characteristics attribute that the Quality Technician must provide a short text if a characteristic was rejected.

If the Quality Technician is unable to properly close a characteristic, the system provides the option to forcibly close inspection characteristics within results recording. However, this action requires special authorization (→ Q_INSP_FIN). From a business perspective, there may be a need to forcibly close a characteristic if result recording cannot be completed. For example, if the device being checked is accidentally broken and further measurements cannot be carried out.

Hint

Pro tip: You can enhance the checks performed when closing an inspection characteristic in results recording by using an implementation of the Business Add-In (BAdI) BADI_QEEM_CLOSE_CHARACTERISTIC. This BAdI allows you to add additional checks to the closing process.

For example, in a delivered implementation of this BAdI, the system verifies that the user who recorded the results is not the same user who closes the characteristic. This implementation follows the principle of dual control or four-eyes-principle. By implementing this BAdI, you can ensure that there is an extra layer of validation when closing inspection characteristics, promoting accountability and accuracy in the results recording process.

Alternatively, the Quality Planner and the Application Consultant can implement a digital signature strategy that requires two signatures to complete. For more information, refer to the Application Help.

Reopening Inspection Characteristics and Tracking Changes

After closing a characteristic, you cannot change it any more. However, what if the Quality Technician made a mistake they want to correct? Provided that there is no usage decision, the Quality Technician or Quality Planner can reopen a characteristic in results recording. From a business perspective, you must decide whether the system shall keep track of such changes via change documents and when it shall create them. You have two alternatives:

  • Write change documents only if a user reopened a completed characteristic
  • Write change documents every time a user makes a change to a characteristic and saves the change to the database

Irrespective of the selected alternative, the change documents contain data on the changed field, the time the change was made, or the person who made the change. In this way, all changes to an inspection characteristic can be completely monitored. This is especially important if you work in regulated industries, for example medical devices, pharmaceutical industry, and so on.

The first alternative applies if:

  • The control indicator for change documents during results recording is set in the characteristic (→ RR Change Docs).

  • Results recording has been completed (→ status 5) and saved for the inspection characteristic, and the inspection characteristic has been reset for processing (→ status 2).

The second alternative applies if:

  • The control indicator for change documents during results recording is set in the characteristic (→ RR Change Docs).

  • The Application Consultant has activated the immediate creation of change documents in the Customizing activity Maintain Settings at Plant Level (IMG: Quality Management → Basic Settings → Maintain Settings at Plant Level: Tab Results recording:Immediate Creation of Change Docs).

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