Setting up Sample Determination

If an inspection lot is created, the Quality Technician must know how many items must be inspected. Listen to Petra to learn how the sample determination works.

In a sampling procedure, the Quality Planner defines two points:

1. How does the system calculate the sample size?
2. How does the system valuate the results after the quality technician has recorded them?

In the following video, Marco shares a business example to illustrate how the sampling procedure works.

A sampling procedure is a separate master data object the Quality Planner defines. If you inspect with task lists, the Quality Planner assigns them at characteristic level of a task list or material specification. If you inspect without reference to task lists, you enter a sampling procedure in the inspection type in the material master (→ Quality Management view of the material master).

The following image shows which data the Quality Planner maintains when creating a sampling procedure:

1. The sampling procedures technical key is FIX-5-1. You can define an arbitrary name, however it is recommended to use a mnemonic key describing the sampling procedure.
2. A sampling type defines how the sample is determined. As indicated in the example, the sampling type is fixed, meaning that the Quality Technician must extract 5 units to be inspected. Note that the number is defined on a different screen.
3. The valuation mode defines the rules for acceptance and rejections. In this example, the valuation mode is Inspection by Nonconforming Units. The Quality Technician records the number of nonconforming units during result recording. In our example, the Quality Planner defined 1 as the highest number of nonconforming units, meaning that, out of the five inspected units, up to one unit can be defect to still accept the sample. If two or more units are defective, the system rejects the sample.
4. The Quality Planner defines whether or not the sampling procedure can be used in combination with inspection points (→ calibration inspections in plant maintenance, samples in physical sample management, or free inspection points) . Note that, due to technical restrictions in the SAP S/4HANA system, you cannot use the same sampling procedure with and without inspection points.
5. Finally, the system indicates whether the procedure has already been used in an inspection plan and whether their usage is blocked.

In our example, we defined the sample type fixed and the valuation mode Inspection by Nonconforming Units. Other values are possible, too. Depending on the defined sampling type or the valuation mode, the Quality Planner can or must make further entries, for example: Sample size, sample percentage, reference to a sampling scheme, acceptance number, and so on.

The following sample types can be defined in the SAP S/4HANA system:

• Fixed sample: The quality planner defines a fixed quantity to be inspected.
• 100 % inspection: The quality planner defines that 100 % must be inspected. This is a special variant of the percentage sample.
• With reference to a sampling scheme: The system dynamically calculates the inspected quantity. However, the quality planner defined the sample size as a function of the lot size in a table in another QM master data object (→ Sampling Scheme and Sampling Plan).
• Sample percentage: The quality planner defines a percentage quantity to be inspected and the system dynamically calculates the inspected quantity as a function of the lot size.

The following valuation modes are available in the SAP S/4HANA system:

• Attributive inspection of nonconforming units / defects

  The quality planner defines the maximum number of nonconforming units / defects that are still allowed to accept the sample (→ acceptance number). This valuation mode applies to quantitative and qualitative characteristics. For example, the Planner defines that even with two defective units / two defects in the entire sample, the characteristic is still accepted.

• Valuation according to characteristic attribute code

  The quality planner defines a list of allowed and forbidden values. Depending on what the quality technician selects during result recording, the characteristic is either accepted or rejected. Note that this valuation mode only applies to qualitative characteristics. For example, the technician selects the packaging material from a list. While paper and wood wool is accepted, plastic foil is permitted due to environmental reasons.

• Manual valuation

  After recording the results, the Quality Technician manually selects whether to accept or reject a characteristic.

• Mean value within tolerance

  The quality technician records multiple single results and the system calculates the average value. If the average value lies within the accepted value range, the system accepts the characteristic. Note that this valuation mode only applies to quantitative characteristics. For example, the acceptable value range is 45 .. 55 cm. If the average length is inside the value range, the characteristic is accepted, otherwise, it is rejected.

  Note

  Note that the system only checks the average value: Assume that the acceptable value range is 45 .. 55 cm. One item has a length of 40 cm and another has the length of 60 cm. Although both are outside the accepted value range, the average value lies within the accepted range. In this case, the system would accept the characteristic. If you want it to be automatically rejected, use attributive inspection of nonconforming units instead.

If you require additional sample types and valuation modes, the application consultant can define additional entries in SAP Customizing and link them to function modules developed by an ABAP Developer.

In the sampling scheme, the Quality Planner can define different sampling tables with sampling plans. In the individual sampling tables, they define corresponding sampling plans for each lot size interval, for example, n or n-c/d, n-k. The Quality Planner assigns the sampling scheme to the corresponding sampling procedure.

In addition to the lot size and the sample size, you may also have to enter other values in the sampling plans depending on the valuation parameter. Enter the acceptance number (c1) and the rejection number (d1) in the sampling table for attributive inspections. Note that in the single sample for an automatic valuation, the following should be valid: d1 = c1 + 1.

The following image shows a simple example of a sampling table:

On the left, a table with lot size ranges and sample sizes is displayed.

• Example 1: Assume the lot size is 900 pc, then the Quality Technician must inspect 25 pc since the lot size is bigger than 100, but smaller than 1000 pc.
• Example 2: If the unit of measurement for the inspection lot does not consist of single units (for example, the unit of measurement liter or kg), then the lot size is determined by dividing the lot quantity by the sample quantity. The lot size determined in example 2 is 4000. As a result, the sample size of 50 is used. In the example, this can be used for a lot size greater than 1 000 or smaller than or equal to 10 000.

  If the maximum possible lot size is exceeded, the sample size for the maximum possible lot size is used.