Adaptive Quality Control in Tolerancing and Production Strategies for the Economic Production of High Precision Products

• Applicant: Professorin Dr.-Ing. Gisela Lanza
• Subject Area: Production Systems, Operations Management, Quality Management and Factory Planning
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 431571877

Motivation Key functions of complex products often can only berealized by precision component use. Thus, producers are confrontedwith high quality requirements, cost pressure and a rising number ofproduct variants. Especially, micro components, which often havetolerances of less than 5 μm, are challenging. Technologicalimmanent process deviations obviate to manufacture components,meeting quality requirements at any time. Often cost-efficientrealization of precision products is a conflict of objectives in thedevelopment, manufacturing and assembly process, savingproduction cost with high throughput under higher deviations on theone hand and preventing high number of scraped units with morenarrow tolerances assuring the products functionality under highercapabili-ties on the other one. Even technological limits of themanufacturing processes are reached, produc-ing cutting-edgeproducts. In general, there are two approaches to cope with thischallenge: an adap-tive allocation of the tolerances by the productdesigner or an adaptive choice of the production strategy by theproduction planner. Both approaches provide fundamental conceptsfor producers in the market competition of producing economic qualityprecision products, which have not been sys-tematically analysed incombination. Approach A new holistic approach of tolerance allocationand adaptive production strategies will be developed, assessingtechnical and economic valuation of the product. The approach bringsthe en-gineering design requirements, product performanceindicators, probabilistic manufacturing and as-sembly deviations andinspection uncertainties together in a common model, where theeffects of adaptive tolerancing and adaptive production strategies ondesign, manufacturing, assembly and product function performancescan be evaluated quantitatively. Adaptive tolerancing serves toallocate optimal characteristic tolerances under holistic technical andeconomic aspects. Adaptive production strategies take use ofindividual real-time assessment in cyber-physical production systems,compensating component deviations with over-fulfilment of anassociated component. Thus, more narrow tolerance margins can berealized, meeting the quality requirements. The development of afunctional product model enables detailed product knowledgeintegration into the aforementioned strategies. Quantitativedependencies on manufacturing deviations affecting the productsfunctional fulfilment are contained to assess the introduced strategieson technical and eco-nomic aspects. Result Proof on the developedmethodology in quality increase and cost-efficiency will be conductedon an exemplarily industrial application. Micro gears for dentalinstruments serve as an exemplarily demonstration, includingnumerous high quality requirements and complex characteristicinteractions. Thus, the transferability and general applicability ofdeveloped methodologies on further use cases is assured.

• DFG Programme: Research Grants
• International Connection: France
• Cooperation Partner: Professor Jean-Yves Dantan, Ph.D.
• Co-Investigator: Dr.-Ing. Benjamin Häfner