Toward a better visual inspection of products

Abstract

Purpose Visual inspection is used to assess a product’s quantitative characteristics (physical inspection) and/or to assess a product’s qualitative characteristics (sensory inspection). Due to the complexity of the product, inspection tasks are often performed by humans and are therefore prone to errors. It is particularly the case when controllers have to detect aesthetic anomalies, to evaluate them and decide if a product must be rejected or not. The paper details how to improve visual inspection. Design/methodology/approach This paper details how the performance of visual inspection can be measured. It then lists the actions which can be carried out to improve the detection and the evaluation of aesthetic anomalies. Finally, it describes how can be made the knowledge about visual inspection more explicit in order to be shared by controllers. The methods we propose are illustrated with a concrete example detailed throughout the paper. Findings The gage R2E2 we developed can be used to decide which corrective actions to carry out. The four generic descriptors and the list of their attributes we list are usable by a controller to both describe and characterize any aesthetic anomaly on the surface of any product. The paper details then how evaluate an anomaly with a grid or with a neural network when the link between attributes values and the overall intensity of the anomaly is not linear. Finally, a method to formalize the expertise of controllers is described. Practical implications The proposed approach has been applied in companies which are part of an european research program (INTERREG IV). The practices we suggested have significantly reduced the variability of the visual inspection results observed up to now. Originality/value The paper shows how to improve inspection vision of products.

One-Dimensional Pit Experiments and Modeling to Determine Critical Factors for Pit Stability and Repassivation

“…a single activated surface and inert walls. 7,8 Additionally, the precipitation of a salt film 40,[43][44][45][46][47][48] at high anodic potentials in corrosive solution leads to diffusion-limited dissolution -a quasi-steady state condition that permits the study of one-dimensional mass transport. Consequently, the presence of a salt film at the corroding surface was considered necessary as a critical condition for stable pitting.…”

“…Galvele's formulation, originally intended to describe the conditions leading to pit initiation, has also been successfully extended to pit propagation. 4,7,[35][36][37] Experimental assessment of the Galvele pit model is typically performed using the artificial pit or lead-in-pencil electrode, 4,7,[39][40][41][42] which consists of a metal wire embedded in epoxy. The lead-in-pencil electrode is particularly useful because it closely represents Galvele's pit model configuration, i.e.…”

A High-Throughput Artificial Pit Technique to Measure Kinetic Parameters for Pitting Stability

“…18,[36][37][38] For a theoretical one-dimensional pit, Galvele 18 demonstrated that a critical product of the current density and pit depth -(i · x) -must be maintained within the pit to prevent repassivation. This parameter, later termed the pit stability product, 39 quantitatively represents the steady-state condition arising from the competition between the metal dissolution and diffusion fluxes 40,41 which results in the maintenance of a sufficiently aggressive concentration of metal cations at the actively dissolving surface for continued pitting.…”

Geometric Evolution of Flux from a Corroding One-Dimensional Pit and Its Implications on the Evaluation of Kinetic Parameters for Pit Stability

“…6,7 This critical pit stability product (denoted (i·x) crit ) has been employed as the anodic stability parameter to determine the maximum pit size that can be attained on a particular metal surface in a given corrosive environment. [8][9][10][11] Experimental results obtained using the artificial pit or lead-inpencil electrode [12][13][14][15][16][17] can be directly used to quantify 1-D dissolution kinetics because the construction of this electrode results in inert walls surrounding a single active surface 13,14,16 corroding under a precipitated salt film [18][19][20][21][22][23][24] upon the application of high anodic potential in corrosive solution. The presence of the salt film results in diffusionlimited dissolution conditions that permit the study of the corroding system in a quasi-steady state.…”