Implementation of Parameterized Work Piece Deviations and Measurement Uncertainties into Performant Meta-models for an Improved Tolerance Specification

Abstract

Geometrical work piece deviations are unavoidable and directly affect the function and quality of technological products. Tolerance management is regarded as a crucial subtask of the development of technological products, because it ensures the function as well as a sufficient product quality while maintaining reasonable production costs. That means, that geometric tolerances as an essential part of the product description greatly affect the functional capability, manufacturability, mountability, verifiability and the costs of the final product. The research group FOR 2271 was founded to enable the computer-aided specification of tolerances, which meet the requirements of production, assembly, verification and function by close cooperation between the departments responsible for product design, assembly and metrology. The aim of this contribution is to determine the manufacturing process scatter as well as the measurement uncertainty and establish ways and means to include that information into efficient meta-models, ultimately enabling improved and accurate tolerance analyses.

Determination of the single point precision associated with tactile gear measurements in scanning mode

“…This sys-tem (version 1) supports uncertainty estimation for measurements using single point probing (Wäldele and Schwenke, 2002). Additionally, dynamic effects during the scan can worsen the achieved precision (Pereira and Hocken, 2007;Jinwen and Yanling, 2011;Keck et al, 2016). It is possible that the scan control system reaches some limitations, considering the more than 20 years of operating time of the CMM.…”

Determination of the single point uncertainty of customized polymer gear wheels using structured-light scanning with various polygonization settings

“…39 mm) were produced by injection moulding using a polyoxymethylene (POM) of the type Hostaform C9021 by Celanese Services Germany GmbH, Kelsterbach. POM is often used in gear applications due to its self-lubricating properties and resulting good dry running capabilities and low friction and wear (Piorkowska and Rutledge, 2013). The semi-crystalline structure of the material leads to a processdependent microstructure.…”

“…One consequence of higher crystallinity is increased shrinkage and therefore deviations from desired geometric dimensions. Mechanical properties, like yield strength (Darras and Séguéla, 1993), break elongation, stiffness and impact strength (Piorkowska and Rutledge, 2013), are also often increased with a finer and highly crystalline microstructure. In pin-on-disk tests materials with a finer, highly crystalline morphology showed improved tribological properties, especially reduced wear rates (Künkel, 2005).…”

P2.18 Characterization of the single point precision of steel gear wheel measurements using tactile coordinate measurement machines in scanning mode

“…Additionally, this sampling exhibits superior run time properties compared to the existing ray-tracing solution. The determination of the single point uncertainty makes it then possible to pass information about the measurement uncertainty to complex extended tolerance analysis methods and therefore consider the uncertainty inherently associated with any measurement [11]. Fig.…”