Sample Inspection (PPAP) under the microscope: Where do the hidden costs arise?
The costs for the sample inspection are shared by many parties. In most cases, the costs are not calculated in detail.
Sample inspection - or "sampling" as it is referred to in the PPF (Production Process and Product Approval Process according to VDA), also known internationally as PPAP (Production Part Approval Process according to IATF/AIAG) - is a key quality assurance tool in the automotive industry. No component enters series production without successfully passing a sample inspection. Both the OEM manufacturer and the supplier know that the processes are complex, expensive and time-critical.
Why is that?
1. complexity of the supply chain
A modern vehicle includes up to 30,000 individual parts sourced from global supply chains. Each part needs an initial sample inspection, including complete material and process documentation. Coordination between OEM and Tier 1 is already complex, but it becomes exponentially harder with each additional tier.
2. high manual coordination effort
The study by Prof. Dr. Tuczek brings it to light:
Coordination and planning rounds between OEMs and suppliers are costly.
Each Tier 1 must make the same effort again with its subcontractors.
In addition, there is test plan creation, laboratory commissioning, tracking and communication - all largely manual (supplier portals seem like a digital approach here, but mostly it's just about document management with PDFs, Word and Excel files in exchange with Tier 1).
3. laboratory costs and tests
An essential part of sample inspection is material testing. Components are tested in accredited laboratories (e.g. mechanical, chemical or safety-related tests).
Laboratory capacity is scarce and expensive.
Each OEM often requires specific checks or its own formats (e.g. OEM-specific Excel templates).
Deviations lead to re-sample inspection, which not only takes time but also incurs additional costs.
4. time-critical factor series start-up
Sample inspection is directly linked to the start of production (SOP). Delays can jeopardize the entire start-up planning. For this reason, a great deal of resources are often used to meet deadlines. This also drives up costs.
5 Fragmented IT landscape
Today, OEMs, Tier 1 and laboratories usually work with different systems:
PLM systems (e.g. Siemens Teamcenter) for product development,
QMS systems for quality processes,
LIMS systems for laboratory results.
There are numerous media discontinuities in between. Data has to be recorded multiple times and transferred into different formats - an enormous source of costs and errors.
6. estimate: 5,000 € - 9,000 € per component
The study "Potentials of digital sampling" by Prof. Dr. Tuczek puts the total costs of sampling at around €5,000 to €9,000 per process - without fully taking into account the expenses of Tier 2 to Tier n suppliers or laboratories. In practice, the actual total costs are therefore significantly higher.
In addition, suppliers at the lower levels of the supply chain (tier 2 to tier n) include their sampling costs in the negotiated parts price after the start of series production. As a result, Tier 1 suppliers and OEMs ultimately bear the financial burden of the entire process - often without any transparency in the total cost calculation.
7. digitization as a way out
The good news is that digital platforms and multi-business networks such as material.one show that costs can be significantly reduced - for all levels and participants in the supply chain (OEMs, suppliers, laboratories):
Automated processes (e.g. test plan creation, communication, reports, etc. ...)
direct interfaces to laboratories,
digital archiving and feedback into QMS systems,
Central data storage of standards and requirements.
tiered integration into the existing system landscape (PLM, PDM, QMS, etc. ...)
Additional security (TISAX certified)
According to the study, the savings potential is up to 50% of the process costs. This not only saves several thousand euros per component, but also significantly shortens throughput times - a decisive competitive advantage in the automotive industry.
Conclusion
Sample inspection is expensive because it takes place in a highly complex, globally distributed and heavily regulated environment. High manual effort, laboratory costs, re-sampling and IT disruptions quickly add up to five-figure sums per component.
The future lies indigitized sample inspection, which automates processes, integrates data and creates transparency across the entire supply chain. Manufacturers, suppliers and laboratories can thus not only save costs, but also achieve series approval faster and more reliably.
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