At is solar module factory in Frankfurt, Conergy has merged together three production stages – from wafer production to cell, then module assembly – enabling gentler transportation of the very sensitive wafers and cells. This has been achieved by Förster & Krause installing a fully automatic, factory transport system.
The very valuable, extremely thin blanks are, due to the material properties, sensitive to damage and breakage, therefore handling and transportation from process to process must be performed with appropriate care. So, a production area of 35,000m2 handles up to 60 million cells, which are assembled into 1.2 million modules per year. Around 1000m of conveyor belt connect the process stations.
More than 80 vertical conveyors connect the machines with the conveyor belts, which travel at a height of 2.70m for empty boxes and at a height of 3.30m for full boxes. Two 12m high vertical conveyors connect the system between the building storeys, passing through two fire-protection collars.
At each junction within the material handling system, which includes approximately 100 belt changers, are Leuze’s PRK 3B retro-reflective photoelectric sensors. If, due to space reasons, no reflector can be mounted, HRTR 3B diffuse reflection light scanners ensure reliable detection of the wafer boxes. In addition to their compact construction, both products offer excellent background suppression, a benefit in bright sunlit rooms.
In addition to position detection on the conveyor belts and space monitoring at the transfer interfaces and turning stations, optical data transceivers from Leuze are also used. They are used to communicate between the high-bay storage devices of the small-parts stores and the store management system. Optical data transmission with infrared laser light to and from the moving high-bay storage devices occurs free of both contact and wear. The DDLS 200 optical data transceivers are likewise characterised by low interference susceptibility to noise from light sources.
Optical data transceivers consist of a device pair and communicate bi-directionally, with each device functioning as a combined transmitter and receiver unit. Network data is transmitted over a distance of up to 500m and benefits from being highly resistant to electrical interference as well as being contact-free and therefore wear-free.
Any linked system designed for fully automatic operation must have a means for manual intervention, to allow employees to manually load or remove products, even if only for removing samples for quality control purposes. Therefore, on some of the process systems, the short conveyor belts at the transfer heads to the vertical conveyors open on one side and are equipped with SOLID-2E safety light curtains from Leuze.