A defect is more than just bits and bytes - Paper Technology International 2023 - Paper Technology International 2023 - Flipbook - Page 54

A defect is more than just bits and bytes - Paper Technology International 2023

PAPERTECHNOLOGYINTERNATIONAL
A defect is more than just bits and bytes - Paper Technology International 2023

How camera inspection systems have become indispensable for quality control
and efficiency
Christian Eikmeyer, Product Manager Business Unit Paper, ISRA VISION
INTRODUCTION:
In paper and tissue production, web breaks and substrate defects present significant challenges in all types of paper or tissue
machines, converting and layering operations. Reducing breaks and surface defects is an important objective, given the increasing speed
and operating complexities of present production environments.
Therefore, using cameras inside paper machines is nothing
new. For decades, they were used for plain and isolated defect
detection. However, machine vision is no longer isolated but has
evolved to be an ecosystem. As technology evolves, the amount of
information available grows and grows. What sets a good system
apart these days is what the ecosystem around the cameras
does with the huge amount of data they can collect and how you
communicate with other downstream or upstream processes. The
right information to improve operations is what’s important and what
makes machine vision indispensable to papermakers.
ISRA’s systems allow a mill to handle data, correlate data
by using ISRA´s Paper Quality Management System and interface
between ISRA’s systems and the mill’s quality control system.
Another benefit is the potential to make predictive maintenance
based on what data is collected and what can happen next.
It´s all about grading and classification
Everything today is about grading and detecting defects as
soon as possible. ISRA’s inspection system cameras can achieve a
resolution of 0.25 mm on a 2,000-m/min machine. Thus, the systems
can pick up the tiniest of defects not visible to the naked eye.
The degradation of the secondary fiber quality has led to
decreased yield and quality which you can see in the increase in the
number of defects, for example, dirt count
A web inspection system will help determine the quality.
But communicating that information to the producer requires a
good defect classification system. It´s key to define the nature of
the defect: streak, impurities, oil drops. Defects are automatically
classified according to the papermaker’s specifications and,
Figure 1a: The Web Break Monitoring detected a defect that will lead to a web break.
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