What does code grading, code classification or code measurement mean?

How standardized evaluation procedures ensure the reliability of barcodes and 2D Codes

It prints a standardized procedure for the quality assessment of codes such as barcodes or 2D Codes, which are used in numerous industries and application areas. The importance of code grading, also known as code classification and code measurement, lies in its ability to ensure the readability and reliability of these codes - a crucial factor for smooth processes in areas such as retail, logistics and the pharmaceutical industry.

Using a uniform grading system that grades codes on a scale from 4.0 (very good) to 0.0 (fail), code grading enables precise quality control and process optimization.

Classification of the results

Requirements and quality specifications

Typical code quality requirements:

• Retail EAN codes at the checkout: Grade 1.5
• Retail discount stores (Aldi, Lidl, Netto, Norma etc.) EAN codes at the checkout: Grade 3.0
• Transport labels for parcel services: Grade 2.5
• Large codes on outer cartons (>= 0.635mm module size): Grade 0.5 (ITF-14)
• GS1-128 codes on cartons (>= 0.5mm module size): Grade 1.5
• Pharmaceutical industry EU 2016/161, USA DSCSA: Grade 1.5
• Medical devices EU 2017/745, USA FDA UDI: DPM Grade 1.5 or ISO/IEC 15415 Grade 1.5 depending on the product

Determination of quality:

The worst test parameter determines the final result. When multiple measurements are taken per code: The worst test parameter determines the result of each individual measurement. The average of these results per measurement is the final result.

What is verified during a code measurement?

Classification of test parameters, layout & code selection, reflection & contrast, dimensional accuracy & print accuracy

It is important to measure and verify various parameters in the quality assurance of codes and markings. This section provides an overview of the key aspects that have to be taken into account during the inspection of codes. We look at the classification of inspection parameters and the three main categories: Layout and Code Selection, Reflectance and Contrast, and Dimensional Accuracy and Print Precision. Each of these areas contributes significantly to the overall quality and readability of the code.

Classification of test parameters

Classification can help to evaluate each test criterion more efficiently. This facilitates the necessary failure analysis. To further simplify the analysis of the results, the test criteria are divided into three categories. Differences in test methods and standards are not taken into account.

Layout and code selection

Verifies that the correct code type is being used and that the code is the correct size and code content. The code position must be correct and the code must not be damaged (typical: light margin error).

Reflection and contrast

Verify that the code is sufficiently dark, that the substrate (label, carton on which the code is printed) is bright enough (symbol contrast), and that all dark areas are equally dark and all light areas are equally light (modulation).  
If a brown substrate with 45% brightness (Rmax) is used and a satisfactory level is desired, the blackened area should not be brighter than 5% reflectance (Rmin). Typical errors include substrates that are too dark, prints that are too light, spots and/or voids and translucent materials.

Dimensional accuracy and print precision

The future of code grading

Continuous improvement of code quality

Accurate code measurement and classification of these parameters can ensure high code quality. This is crucial for the reliable functioning of barcodes and 2D Codes in various application areas.

Code grading thus contributes significantly to the optimization of processes by enabling a precise assessment of code quality and identifying potential weaknesses. This enables companies to improve their processes and increase the reliability of their coded products and documents.