Initial Sample Inspection Report (ISIR/EMPB)

The Initial Sample Inspection Report (ISIR)—in German-speaking regions known as the EMPB—is a standardized document in the automotive industry that summarizes all results of the initial sampling of a new or modified part. It includes dimensional measurements, material proofs, functional tests, and process parameters. As Element 13 of the PPAP, it is the central evidence that a component meets all design and quality requirements before mass production begins.

While international markets often follow AIAG PPAP standards, German OEMs primarily operate according to VDA Volume 2 (Quality Assurance for Supplies).

When is an ISIR Required?

An inspection report is mandatory not only for the first-ever launch of a part but also for specific change classes defined by VDA 2 or Customer Specific Requirements (CSR):

• Initial Launch: Every new part entering series production.
• Tooling Changes: New tools, tool overhauls, or relocation to a different machine.
• Material Changes: New raw materials, different sub-suppliers, or modified material specifications.
• Process Changes: Methodological changes affecting dimensions, surfaces, or material properties.
• Relocation: Moving production to a different site or a different production line.
• Restart after Pause: Typically required after 6 to 12 months of inactivity.

Structure of an ISIR according to VDA Volume 2

A complete report is divided into several sections:

1. Cover Sheet & General Info: Part number, revision level, supplier data, and the specific production conditions (tools and machines used) during sampling.
2. Dimensional Inspection: Every single characteristic from the drawing is measured. This includes nominal values, tolerances, actual values, and a pass/fail (OK/NOK) evaluation. VDA recommends at least 5 samples; however, OEMs often require up to 50 for critical parts.
3. Material & Surface Testing: Material certificates, tensile tests, hardness measurements, and coating thickness reports.
4. Functional Testing: Leakage tests, force measurements, durability tests, or electrical parameters.
5. Process Capability Evidence: For critical and safety-related characteristics, capability studies (Cpk, Ppk) must be attached.
6. Special Characteristics: Features classified as critical or safety-related (SC, CC) require separate highlighting and must meet specific capability thresholds (e.g., $C_{pk} \geq 1.67$).

Common Pitfalls in ISIR Practice

Rejections often stem from the same recurring issues:

• Incomplete Characteristic Mapping: Missing features from the latest drawing revision because an outdated list was used.
• Incorrect Measurement Strategies: Failing to use the methods prescribed in the drawing or Control Plan, especially regarding Geometric Dimensioning and Tolerancing (GD&T).
• Insufficient Sample Size: Measuring fewer samples than required by the CSR.
• Low Process Capability: Cpk values falling below the minimum (often $1.33$ or $1.67$) due to unstable processes or tool wear.

The Shift to Digital ISIR

A digital process connects the characteristic list from the CAD drawing directly to the measurement data acquisition:

• Feature Management: No longer manual Excel work; QM systems automatically sync with drawing revisions.
• Direct Data Capture: CMMs (Coordinate Measuring Machines) and optical systems transfer values directly into the system, eliminating transcription errors.
• Automated Evaluation: The system compares actual values against tolerances and flags deviations instantly.
• MES Integration: Production parameters (machine ID, shift, process settings) are pulled directly from the MES into the report, proving the exact conditions under which the samples were made.

FAQ

What is the difference between an ISIR and a PSW?

The ISIR/EMPB is the technical test document containing all measurement results. The PSW (Part Submission Warrant) is the summary cover sheet and the supplier's formal declaration that the entire PPAP (including the ISIR) is complete and compliant. The ISIR is a component of the PPAP; the PSW is the conclusion.

Can an ISIR be submitted with negative results?

Yes, but only with a documented Deviation/Waiver approved by the customer. If a feature is out of tolerance, the supplier must prove that corrective actions are initiated or obtain a formal temporary approval. An ISIR with failures and no waiver will be rejected immediately.

How long must ISIR documents be archived?

At least for the duration of series production plus the years defined by the customer—typically 15 to 25 years for safety-critical components (as vehicles may remain in use for decades).

How many samples are required?

VDA Volume 2 recommends at least 5 samples per cavity or tool. For multi-cavity tools, every cavity must be measured separately. Always check your specific CSR for the exact count.