Pixargus GmbH, Automation by Vision

Pixargus detects defects on textured plastics surfaces

At “K 2010” Pixargus will introduce a new generation of its WebControl system for the detection of surface defects on opaque or translucent materials with or without texture. This system is typically used for inspecting any kind of flat technological webs as used, for example, as interior lining material in vehicles.

The system detects and marks any areas of the product which do not comply with the required quality standards. This minimizes waste and guarantees that only flawless material is processed.
Pixargus has developed the WebControl inspection system specifically for challenging surfaces of opaque or translucent material. When the system is analyzing a surface, a special algorithm identifies the natural surface structure and masks it out. Thus it is possible to detect defects hidden in the regular structure of the material.

The system detects and classifies irregularities in leather structures, defects in the weave of glass-fibre mats, orange-peel effects on dark, opaque foils, dense spots in non-woven fabric and even light streaks on the surface. As soon as the system finds a defect, it triggers an alarm and, as an option, marks the affected area.

A dedicated algorithm detects elongated defects, such as streaks, and enables conclusions to be drawn as to the existence of defective rolls in the production line.

Summarizing the benefits for producers of web material, Dirk Broichhausen, Vice President Sales & Marketing at Pixargus, states: “So far manufacturers of surface inspection systems have concentrated on material with a uniform surface structure, such as metals, foils and paper. Working with completely new algorithms, our systems are capable of reliably detecting surface defects even against most irregular backgrounds. It’s like finding a needle in a haystack. Or, in other words: We start where others stop.”

Pixargus customers use the data provided by the system not only for quality assurance in final inspection but also for optimizing the production process and preventing defects in the first place. For example, the fact that trends in the frequency of surface defects are captured in real time enables countermeasures to be taken without delay. The operator can immediately take corrective action and sort out the defective material.

The dynamically operating system automatically adapts to the surface structure and colour of the material. Unlike competing inspection systems, these systems from Pixargus usually do not require any time-consuming teach-in of the surface structure. It is only necessary to enter the relative amplitude of the texture and the size of the smallest to be detected defect.

By means of a dedicated tool for the management of defect classes and densities, simple detection and classification rules can be formulated. The operator can define by himself which and how many defects are to be tolerated within a specified area.

WebControl is a modular system, available for material widths between 150 and 8,000 mm. For different surface characteristics, Pixargus supplies the system with different camera resolutions ranging between 40 and 150 µm. Opaque product can be inspected on one or both sides. It operates at different material speeds depending on the texture. The maximum speed is 600 m/min.
Pixargus uses its newly developed line lighting systems. These systems create a strong contrast on the material surface due to their extraordinary light bundling capacity. Additionally, they distinguish themselves by a distinctly longer service life than conventional systems.

The system - with all its functions - is operated via a touch screen. The touch screen displays a general view of the material surface and individual defect images. All components are sealed according to IP 64. Through remote access via Ethernet and IP-based communication it is possible to make swift diagnoses of the system and, what is just as important, to change and adapt parameter settings.