What is an initial sample test report (EMPB)?

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To reduce time and costs, it is important to identify and avoid any production errors at an early stage. For this reason, products are only produced in large quantities once series production has been tested and sampled under realistic conditions. If these initial samples meet the quality requirements, they are released for production. This process guarantees that companies only produce goods or products once they meet the required quality standards. This quality inspection is known as the initial sample inspection, the results of which are recorded in the initial sample inspection report.

But what is the initial sample test report (EMPB)? The initial sample test report (EMPB) is an important part of the initial sample test. It documents the results of the sampling process for an "initial sample". 

The initial sample inspection report not only plays an important role within the company. It is also of immense importance in the B2B sector. For example, a supplier can prove that the delivered products meet the customer's quality requirements. 

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Why is an initial sample test report necessary? 

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An initial sample test report is carried out either according to a customer's specifications or according to a company's own quality requirements. The aim is to check whether a product is suitable for series production and can be produced in consistent, constant quality. In order to find answers to these questions, a fixed number of the respective products are examined and the results documented in the initial sample test report. The aim is to reduce and avoid errors even before series production. In the B2B sector, customers and suppliers can also reach basic agreements with an initial sample test report. The test reports often differ significantly in terms of their complexity and scope. Furthermore, an initial sample test report is also binding. This means that if the tested product is produced again, it must correspond to the initial sample, provided no defects were detected. However, this also means that all newly produced goods must be manufactured under the same conditions as the initial sample. This is the only way to guarantee consistent quality. This is because even the smallest changes can lead to production running differently than planned. There can be many reasons for this:

• Incorrect settings on the production machines.
• Incorrectly designed production parameters.
• Defects in the means of production.
• Errors in the measuring equipment.
• Error in the specification of the source material.
• Environmental influences not taken into account.
• Influences not taken into account due to on-site conditions.
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Example scenario to explain the necessity of initial sampling:

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Once a product is ready for series production, a test series is carried out for initial sampling before actual production. This reveals that the initial samples tested deviate from the dimensional specifications and the desired quality. When investigating the causes, it is recognized that, for example, the clamping force of the tools was not high enough or the air was too dry and the processed material therefore experienced a negative change. Only with the initial sample inspection report is it possible for the manufacturing company to carry out a precise analysis of the actual situation and eliminate the causes or errors. 

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What is the reason for an initial sample inspection?

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There can be many reasons for an initial sample inspection. Among others:

• Cooperation with a new supplier/sub-supplier of materials
• A new production part
• Changed product specifications
• New or modified tools
• New or modified manufacturing processes
• New production facilities
• An interruption in production

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What are the economic reasons for an initial sample inspection report?

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The initial sample test report is used to determine whether the planned series production is actually economically viable. The initial sample test report therefore provides a comparison between the target data of a produced item and the average properties from pre-series production.

Only when the planned manufacturing process appears viable and correct in reality is continuous production with consistent quality and increasing profitability likely.

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Is the initial sample test report subject to certain standards and specifications?

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Incidentally, the initial sample test report is not a "German invention". In general, it is common practice in industry. It is laid down in the VDA, Volume 2 - Quality Assurance of Deliveries. Volume 2 of the VDA generally describes the procedures for production process and product approval. This is a core element for customer-specific requirements. 

Other applicable standards in connection with the sampling of an initial sample and the preparation of a test report are 

• All specifications of the QS 9001 and VDA series as well as ISO TS 16949 (as amended).
• Relevant DIN ISO standards.
• Purchasing conditions for production material, spare parts and direct means of production of the products.
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Where does initial sampling come into play?

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Initial sampling is standard, especially in the automotive industry. Standardized guidelines, such as IATF 16949 and PPF/PPAP, ensure a standardized product sampling process in the automotive industry and close cooperation between the customer and the supplier. However, initial sampling is also the order of the day in all other manufacturing companies. Especially when new products are to be launched on the market. 

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Scope of an initial sample inspection report

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In order to be able to make valid statements about a new product, it is not sufficient to sample the first product produced in series production. Only after a statistically reliable quantity is a qualified statement about the usability of the production and the production conditions possible. The quantity of products tested for the initial sample test report is based on the empirical values that have already been gained in connection with the production equipment. These include the wear limits of the processing machines. For example, tolerance deviations in the cavities of injection, casting, press and die-casting molds are quite normal after a corresponding number of cycles. In the same way, carbide milling cutters and indexable inserts also wear at different rates when machining materials of different hardness or softness.

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Scope of testing during initial sampling

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The scope of the initial sample inspection depends on the specifications and tolerances. However, the visual, metric and technical properties of a manufactured product are usually checked during the initial sample inspection.

• Optical properties include burrs, porous material, roughness, dents, scratches and clouding.
• The metric properties are some of the most important aspects of the initial sample inspection. All dimensions and weights are checked here. The products are checked manually, by tactile or optical measurement. Measurements with a computer tomograph are also possible here.
• When testing the technical properties, the load-bearing capacity of a product is examined. Tensile, breaking and bending tests can be carried out for this purpose. As soon as non-destructive tests are required, X-ray and ultrasound tests are used. Another part of technical testing is the examination of the material composition of the starting material. This is achieved using a spectrometer.

In general, the scope of testing is always tailored to the respective product. The respective manufacturers and testing service providers agree this in advance.

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What happens if the initial sample test report is negative?

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Ideally, the initial sample should already meet all quality requirements. However, this is wishful thinking. As a rule, initial sampling is repeated until all quality requirements are met. Each adjustment interval requires a new initial sample test report when test production is restarted. All changes, whether improvements or deteriorations, must be precisely documented in this report so that they can be traced accordingly. The initial sample test report is therefore also valid for legal issues. In this context, the initial sample test report is also subject to a statutory retention period. This is based on Section 257 (1) HGB and Section 147 AO and is 10 years.

What does a complete initial sample test report include?
A complete initial sample test report includes a cover sheet with all data, the actual measurement report with all dimensions and at least one stamped drawing. It can also include an acceptance test certificate for raw material. Furthermore, a complete initial sample test report includes:
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• Dimensional, material and functional test report
• Sample parts (5 pieces, for multiple molds 5 pieces per nest)
• Additional documents (e.g. process flow chart, production control plan)
• Proof of process capability, proof of measuring equipment capability
• Material certificates (material certificate, safety data sheets if applicable)
• All material data and details of the IMDS identification number on the cover sheet.

Depending on the order, either the forms of the valid VDA Volume 2 or the valid AIAG PPAP (Production Part Approval Process) must be used.

Deviations from the permissible tolerances must be noted in the test report. The required accuracy depends on the respective application and/or the specification of the parts. With regard to tolerances, the following applies: the measuring and test equipment uncertainty should not exceed a maximum of 10% of the smallest permissible tolerance of the measuring and test criteria. For example, if the smallest permissible tolerance may only be ±0.3 mm, the minimum accuracy of the measuring and testing equipment is 0.06 mm.

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Information on the cover sheet of the initial sample test report
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• Part designation and part number
• Any safety parts must be noted.
• The index of the component must be noted.
• The weight in kilograms.
• The current ID number
• Reason for the submission and the required submission level
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The actual measurement report

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The number of samples to be measured is noted in the actual measurement report. According to VDA, for example, this is 5 samples. If the test is successful, all items must be assessed as OK. In general, all parts must be measured separately for an initial sample test report. All position tolerances must be documented as position tolerances. 

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The materials report

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The materials report contains, among other things, notes and information on 

• Geometry, dimensional check
• Function test
• Materials testing
• Haptics test
• Acoustic testing
• Odor test
• Appearance check
• Surface inspection
• ESD testing
• Reliability check
• Approval of coating systems
• Other
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Stamped drawings

Product-related, stamped drawings are also part of an initial sample test report. All product features, such as dimensions up to standards or specifications, as well as written product requirements such as the pore definition, surface definition, identification of the casting, etc. must be stamped. The stamping serves as numbering and at the same time allows the results to be clearly assigned.
All features must be clearly marked on the drawing with consecutively numbered item numbers.

What is the difference between an initial sampling including initial sample test report and a follow-up sampling?

A follow-up sampling is a repeated sampling of a product after the resumption of production. This can be the case, for example, after a production interruption lasting several months. Follow-up sampling is sometimes also referred to as reduced initial sampling. However, this is factually incorrect, as a follow-up sampling is never an initial sampling. 

In general, the initial sample inspection report is an important factor for error-free and efficient production in industry and business. The focus is primarily on consistent quality in series production, which can be verified with an initial sample test report.

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