MACHINE VISION & INSPECTION As Marián Šrámek, managing director at Micro-Epsilon, explains, the development of machine vision has always faced the same challenges: “It is a battle of the required parameters that have not changed over the years: the resolution of measurement versus material coverage, against the line speeds – and at the same time, the long-term stability of the sensor.” Šrámek argues that new computer chips will facilitate improved speeds and resolution, but sensor stability is down to the robustness of the hardware – which must be able to withstand significant temperature changes and 24/7 operation. “Continental needs machine vision hardware that is robust enough to run in a tire production environment,” agrees Steve Howat, Continental’s general manager of technical services for the UK and Ireland. “Moreover,” he continues, “the imaging hardware must be especially adapted to black surfaces as this is crucial for the quality control of black tires.” Black surfaces make optical sensing particularly difficult if the area is not sufficiently illuminated. “ 50 Even the definitions of product defects on the side of customers are very vague” Marián Šrámek, managing director, Micro-Epsilon Left: Micro-Epsilon’s sheet-of-light profilometer measures thickness, width, length and weight all in one go “We’re always looking for lenses with better optical performance,” says Sofia Nilsson, strategic product manager for 3D Vision at Sick. “Our cameras run at very high speeds. With the cameras we have today we can run at 46kHz; we’re planning to double this speed quite soon.” These extremely short exposure times mean the cameras need a lot of light to accurately detect defects against a black surface. To remedy this, Sick is introducing powerful lasers to ensure adequate lighting is provided. However, Nilsson notes, “It’s hard to get a strong enough laser without having a very high laser class, and that presents safety issues.” In the future, Alain Klein, global account manager at Sick, hopes to eradicate the need for lasers in this process. Instead, LED or other types of lighting will be used to illuminate the area cameras need to evaluate. In this sense, www.tiretechnologyinternational.com March 2024