Procurement Glossary
Start of production (SOP): definition, process and importance in Procurement
November 19, 2025
The start of production (SOP) marks the critical transition from development to series production of a product. This process requires precise coordination between Procurement, suppliers and production in order to guarantee quality, costs and delivery times. Find out below what series start-up means, which methods are used and how you can successfully minimize risks.
Key Facts
- SOP stands for "Start of Production" and refers to the start of series production
- Critical phase between prototyping and full production with high coordination effort
- Requires intensive cooperation between Procurement, quality assurance and suppliers
- Typical duration: 3-12 months depending on product complexity and industry
- Success measurable through KPIs such as start-up time, quality rate and cost compliance
Contents
Definition: Series start-up (SOP)
The start of series production includes all activities for the gradual ramp-up of production from pilot series to full production.
Core elements of the series start-up
The SOP process is divided into several successive phases:
- Pilot series production for process validation
- Pilot production with limited quantities
- Gradual increase in production volumes
- Continuous quality and process monitoring
Series start-up vs. prototype procurement
While prototype procurement supplies individual samples for testing, the start of series production focuses on establishing stable production processes. The transition often requires new supplier structures and adapted procurement strategies.
Importance in Procurement
The start of series production is crucial for Procurement , as this is where the course is set for long-term supplier relationships. Series production is only released after all quality and delivery criteria have been successfully validated.
Methods and procedures
Structured methods ensure a controlled and successful start of series production with minimal risks.
Phase model for SOP
A proven procedure follows a multi-stage phase model:
- Phase 1: Pilot series production and process validation
- Phase 2: Pilot run with first series parts
- Phase 3: ramp-up to target volume
- Phase 4: Stabilization and optimization
Supplier integration
The early involvement of suppliers is critical to success. System suppliers often take on the coordination of complex assemblies and reduce the complexity for the OEM.
Quality assurance
Continuous monitoring through defined inspection points and approval processes ensures that only qualified parts are released for series production. Ramp-up management coordinates all areas involved.
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Important KPIs for series start-ups (SOP)
Measurable key figures enable objective evaluation and control of the series start-up process.
Time-related KPIs
Adherence to schedules is critical to the success of a project:
- Time-to-market: Total duration from project start to market launch
- Start-up time: Duration until the target production rate is reached
- Milestone adherence: percentage of intermediate deadlines met
Quality KPIs
Quality indicators reflect process stability. First-pass yield measures the proportion of fault-free parts on the first run, while the complaint rate quantifies customer problems. PPM values (parts per million) precisely document the error rate.
Cost KPIs
Budget compliance and cost efficiency are key success factors. Start-up costs per unit, deviations from the target price and rework costs provide information on the economic performance of the ramp-up process.
Risk factors and controls for series start-ups (SOP)
Series start-up processes involve various risks that can be minimized through systematic management.
Supplier risks
Insufficient supplier capacities or quality problems can jeopardize the entire start-up. Regular feasibility reviews and backup strategies significantly reduce these risks.
Technical risks
Unforeseen technical problems in series production require quick adjustments:
- Process instabilities during scaling
- Material availability and quality
- Tool and system problems
Coordination risks
Complex coordination processes between different areas can lead to delays. Clear responsibilities and regular status meetings are essential. Engineering change notices must be processed in a structured manner.
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Practical example
An automotive supplier is planning the start of series production for a new brake system. After a successful prototype phase, pilot series production starts with 50 parts for process validation. In the pilot phase, 500 parts are produced and intensively tested. Process parameters are optimized and the supply chain is stabilized. The gradual ramp-up takes place over 6 months from 1,000 to 10,000 parts per month. The qualification programme for alternative suppliers is running in parallel to minimize risk.
- Weekly SOP meetings with all stakeholders
- Continuous monitoring of quality KPIs
- Escalation processes in the event of deviations
Current developments and effects
Digitalization and new technologies are fundamentally changing the design of series start-up processes.
Digital transformation
Artificial intelligence and machine learning enable more precise predictions of start-up risks and optimize resource planning. Predictive analytics identifies potential bottlenecks at an early stage and enables proactive countermeasures.
Agile start-up methods
Shorter product lifecycles require more flexible start-up processes. Agile methods with iterative cycles and continuous feedback significantly reduce time-to-market. Parallel engineering between different development phases is becoming the standard.
Sustainability aspects
Environmental criteria are becoming increasingly important during the start of series production. Suppliers are increasingly required to provide sustainability certificates, and outsourcing decisions take CO2 balances and circular economy principles into account.
Conclusion
The start of production (SOP) is a critical phase that determines the long-term success of a product. A systematic approach, close cooperation with suppliers and continuous monitoring are crucial to success. Modern technologies such as AI and predictive analytics offer new opportunities for optimization. For Procurement , this means a central role as coordinator and risk manager throughout the entire ramp-up process.
FAQ
What does SOP mean in the procurement context?
SOP stands for "Start of Production" and refers to the controlled transition from development to series production. Procurement coordinates suppliers, monitors quality standards and ensures that all components are available on time.
How long does a typical series start-up take?
The duration varies between 3-12 months depending on the complexity of the product. Simple components can be ramped up more quickly, while complex systems with many suppliers require longer ramp-up times. Early planning and supplier integration is critical.
What role does Procurement play in the SOP?
Procurement acts as a central coordination point between internal departments and external suppliers. It monitors delivery deadlines, quality requirements and cost developments. It also develops backup strategies and alternative procurement sources for critical components.
How are series start-up risks minimized?
Risks are minimized through systematic supplier evaluation, regular quality audits and continuous monitoring. Backup suppliers, safety stocks and clear escalation processes reduce the risk of failure. Early communication and transparent reporting structures are essential.
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