Up with the sun

Illustration | Bosch Rexroth AG / design hoch drei GmbH & Co. KG
Marginal Column

March 2012

 

Fighting cost pressure with automation solutions: for greater availability and simpler setup in the solar industry.

 
 

Around the world, cost pressures are mounting in the solar industry. During the huge growth phase of past years, the manufacturers built enormous production capacities. Now, for example, reduced feed-in tariffs in several European countries are cutting into demand. How can these companies remain competitive under these conditions? In addition to the costs of raw materials and labor, the efficiency of the equipment used plays an especially decisive role. To date, only the efficiency and quality of the machines were considered the most important standard. But unproductive downtimes for retooling, fault clearance, repair and maintenance reduce the efficiency of the machine just as much as a high reject rate.

So the focus is now shifting to Overall Equipment Efficiency (OEE) a metric which also takes availability into account. Manufacturers in the solar industry can increase this metric by standardizing on the component and control levels – to both shorten repair times and make installed plant equipment easier to modernize. Standardization lets maintenance staff concentrate on fewer components when trouble­shooting – and also shrinks the spare parts inventory. As a manufacturer of all drive and control technologies, Rexroth offers automation solutions that boost OEE.

Minimizing maintenance

For instance: the Arnold-Group, which offers a broad spectrum of silicon block processing from a single source, depends on Rexroth linear technology. The benefits are two-fold. Minimum­consumption lubrication has been optimized to extend mainte­nance intervals. Also, the lubrication ports on all sides of the ball rail guides and the central lubrication ports for the linear systems reduce maintenance work. The maintenance-free TS 2pv transfer system lets module man­ufacturers reduce downtimes to an absolute minimum. And TS 2pv also saves energy, as the conveyors only run when a solar module is placed on them. The system automatically switches off when idle.

Standardized drives, transparent data flow

Manz AG, one of the leading technology suppliers for photo­voltaic production systems, depends on the sercos open auto­mation bus, thus pushing standardization in the area of data transfer. Numerous drive, control and peripheral manufactur­ers support this Ethernet-based real-time communication protocol with their products. This enables a transparent flow of data from the drive to the process control system – and seamless integration of pneumatics and I/Os.

Standardization also offers huge advantages for manufacturers of solar cell coating equipment. Companies in this industry are increasingly using a uniform drive technology with Multi-Ethernet interface. The IndraDrive Cs servo drive is one device that uses this interface. Thanks to its power range of from 100 watts to 3.5 kilowatts and its high positioning accuracy, it is ideal for the requirements of photovoltaic automation.

Additionally, this drive lets machine manufacturers respond flexibly to customer requirements. The customer’s preferred communication interface can be implemented with just a single hardware component, as it supports the Ethernet-based protocols sercos, PROFINET IO, Ethernet/ IP and EtherCAT. The drive’s integrated Safety on Board functionality also increases the availability of the entire system. The Productivity Agent is a software tool available for the servo drives that continually evaluates drive data without any additional sensors, for early detection of wear indications. This integrated condition monitoring enables scheduled replacement of components without machine outages, thus increasing both the availability and the service life of the machine.

Universal control solutions

Finally, standardization at the level of the control hardware makes for shorter setup times and faster fault remediation across the entire spectrum of the solar industry. For example, the drive- and controller-based IndraControl system speaks all major “languages”: regardless of whether the customer uses PLCs, Motion, Motion-Logic, CNC or robotics, the software, not the hardware, determines the functionality. Additional functional modules based on PLCopen and pre-defined functionalities also replace time-consuming programming with simple parameter setup. Using standardized automation, solar-industry manufacturers achieve reduced manufacturing costs across the entire value-creation chain – from wafer fabrication to cell and module production.