The quality of textile products has an increasing importance for the market position of the European textile industry. Accordingly, final product inspection forms an important milestone in the production of high quality garments and technical textiles, but nevertheless is executed on a low technical level, e.g. visually, in the vast majority of enterprises. Modern, fully automatic inspection systems have not found wide application in the mostly SME-sized European textile industry. Drawbacks of these expensive systems are an excessive amount of data which have be recorded and processed on-line and a lack of versatility.
In contrast, pre-project studies by the project partners show that an economic margin of approx. 40 % on either personnel costs in the inspection step or throughput of the inspection step is to be expected, if a suitable, simple and - foremost - low-cost sensing system would be employed to aid fault detection. In this concept classification, judging or, where possible, mending of detected irregularities could be left to experienced personnel, while the sensor system would only be employed to indicate a deviation of the regular textile structure and effect a stop of the textile good.
On this background it is the objective of the project to develop a low-cost sensor system based on fibre optical profilometry for the fast, sensor-assisted-inspection of textile and other textured area goods with an emphasis on the detection of geometric defects.
Based on the definition of the most relevant categories of defects by the involved textile partners, the R&D-performers defined design aspects such fibre-optical layout, construction of 5 cm long multisensor modules and combination of modules to large scale systems on the background of the highest possible detection efficiency, e.g. signal-to-noise ratio.
Although an according prototype employing 3 modules was presented on the international fair for textile machinery, ITMA, by the prime proposing company, early tests under industrial conditions indicated problems mainly due to the rather small and narrow working distance of the optical sensors, which resulted in poor performance in case of textile flutter or mis-adjustments.
Given this situation, the R&D-performers started a complete re-design of the sensor layout with an emphasis on a large and variable working distance and a more rigid mechanical construction. Sensor modules of this, 2nd design showed promising results and have been manufactured for a large scale system. It should also be noted, that the 2nd design has marked advantages with regard to ease of production and versatility.
On the basis of the knowledge of the defect response in the signal trains and the appropriately defined algorithm for defect discrimination, purpose-built electronic processing boards were designed and manufactured and combined with the fibre-optical modules to compact and isolated modules (15 cm long).
While it may be stated from industrial-like experiments, that the fibre-optical system in general is able to detects most defects found in visual inspection, typically problems occur with regard to small holes or hole-like warp breakage and form an important topic for follow-up development. a general problem to be addressed in the project follow-up period, is the optimisation of the evenness of the optical performance of the modules and the individual channels of a given modules, respectively.
No abstract received
Funding SchemeCRS - Cooperative research contracts
71263 Weil Der Stadt
4760 Vila Nova De Famalicao