State-of-the-art electrified conveyors contribute to production levels and offer a safer working environment
Self-propelled electrified carriers, monorail systems and skillet lines with lifting platforms are state-of-the-art solutions in today’s automotive manufacturing process. Electrification with conductor rail systems has been in common practice for several years, continuously adapting to real-world technical needs. Furthermore, the application requirements have changed significantly as productivity has increased. Conveyor speed, numbers of carriers and operation times are each helping to improve productivity. Modern standards and regulations are improving the work environment, and electrical safety aspects became a major subject in recent years, as well as modern power electronics and drive controls.
Based on decades of experience with electrification in a variety of automotive industry applications, Conductix-Wampfler has improved its reliable and durable conductor rail systems to meet these business expectations. The Conductix-Wampfler conductor rail system SingleFlexLine 0811 is well known for its robustness in electrified monorail systems (EMS) for bodyshops and assembly lines. Installed in automotive plants worldwide it is also the solution of choice for skillet lines.
What is behind the outstanding performance of this conductor rails system? The backbone is the robust design of the copper rail itself, with a thickness of 1mm. This is a unique stand-alone feature of the SingleFlexLine 0811 system giving it the strength for a durable lifetime. A cross-section of 25mm2 stands for a reliable electrical performance on long conveyor flights. Safety aspects are incorporated in the design of the conductor rail.
Right from the beginning it was a finger-proof design based on IEC/UL/NEMA. Today’s safety requirements include polarity protection for phase and protective earth (PE) collector shoes – a derailing of PE collector shoes into a phase rail is prevented by the geometry of the collector shoes and the design of the insulation covers. This is an important safety improvement and became a standard solution for the big players in the automotive industry. Fire prevention in electrical systems is a top priority and self-evident. All insulation covers and plastic components of the conductor rail system fulfil the flammability standard UL94 V-0 / V-1: burning will stop within 10-30 seconds after ignition.
New shoesIncreasing production performance with higher conveying speed, many more carriers and three-shift production have a countable impact on the lifetime of the conductor rails. Rail and collector-shoe wearing became an issue. At the same time, new standards and regulations for carbon-shoe materials required new solutions – the Restriction of Hazardous Substances Directive was the key control. Changing technology from copper graphite shoes to pure graphite carbon shoes is the answer for high-performance installations. Pure graphite is a lubricant and in comparison with copper graphite carbon shoes there is hardly any wear in the copper rails and about 50% longer lifetime of the pure graphite carbon shoe.
Even after more than 12 million tested operation cycles, conveyor systems don’t show any wear in the copper conductor rails running pure graphite shoes – an impressive improvement of the conductor rail performance that minimises maintenance costs and keeps to existing standards for the work environment.
Uneven wear of carbon shoes and worn-out copper rails are issues of the past. Lighter, pure graphite shoes, combined with cable routing templates are state-of-the-art designs. It is well known in the automotive industry that the SingleFlexLine 0811 system can cope with higher mechanical tolerances than other conductor rail systems. For many applications in harsh environments an important key factor.
Its robustness has made the conductor rail system SingleFlexLine 0811 a first choice product for skillet line electrifications. Collector shoes on skillet platforms are engaged and disengaged to and from the conductor rails several times during one production cycle. The mechanical stress of the conductor rail components is much higher than EMS applications. At the same time, the mechanical tolerances of skillet systems are higher and access to the conductor rail components is much more limited in a skillet system. That needs a robust and reliable solution.The conductor rail system has proven its performance for skillet lines in many assembly lines. Long-life entrance funnels with stainless steel cladding and quick exchangeable current collector modules are an essential guarantor for a continuous production flow. Current collectors with an extended tolerance range covering the mechanical demands, while multi-pole electrical connectors minimise service time.
Safety first is self-evident – preassembled entrance / testing modules for the electrical safety of a skillet line are part of the product portfolio. Being installed right above the floor, the conductor rails require step protection to withstand carelessness in daily operation.
Conductix-Wampfler conductor rail systems for EMS, as well as for skillet systems, have proven their reliability and performance in assembly lines of premium-class car manufacturers all over the world. Nevertheless, conductor rail systems need regular maintenance. Conductix–Wampfler offers services that cover the entire electrification scope, starting with expertise during the engineering phase, supporting OEMs and end users, providing installation services for new or retrofit electrification systems, carrying out regular inspections of and maintenance for conductor rail systems, and last but not least training for maintenance crews and equipment installers.
Following the market requirements of turnkey projects, Conductix-Wampfler offers the whole solution from planning to realisation – from engineering, detailed system calculation, conceptual solutions to production, shipment, installation and commissioning on the spot.
EMS conveyor electrification at BMWTo fulfil market requirements and customer expectations BMW extended the bodyshop for the 5 and 7 Series in recent years. The welding line of the bodyshop at ground-floor level is connected to buffer lines at various floor levels by an EMS system, allowing a most flexible production. More than 15km of EMS conveyors with 58 lift stations and 128 switches of different types and 520 carriers were installed in the new bodyshop. Together with BMW, the conveyor supplier, ROFA AG, chose the Conductix-Wampfler SingleFelxLine 0811 conductor rail system for the electrification of these conveyors. The decision was made on long-term experience with the excellent performance of the conductor rail system in various BMW plants globally.
Today a total of approximately 35km of EMS conveyors with around 3,500 carriers, running three shifts for six days per week, assure the required production output in this BMW plant. All conveyors are equipped with the robust conductor system SingleFlexLine 0811. State-of-the-art features such as polarity protection for PE rails and pure graphite collector shoes for long-term performance are mandatory for BMW. Based on long-term experience and various field tests under production conditions, BMW led the automotive industry in changing copper graphite collector shoes to pure graphite collector shoes. Today the installed conductor rail system SingleFlexLine 0811 stands for best practice and highest performance in bodyshop applications.
Skillet system retrofitFor decades, skillet lines have been established in automotive assembly lines. One of the early installations from 2001, with 252 skillet platforms, is also located in a BMW production facility. Right from the beginning the skillet system is powered via Conductix-Wampfler conductor rails. In late 2015, Conductix-Wampfler replaced the conductor rail systems of 11 lines on two floor levels, including cross sections and lifting stations. This major maintenance measure assures reliable production for the next decade with state-of-the-art safety requirements and improved lifetime.
The experience with polarity protection and pure graphite collector shoes has been transformed from EMS systems to skillet system applications. A special challenge of this project was the very limited installation space for the conductor rail system – a back-to-back installation of SingleFlexLine 0811 conductor rails made it possible to embed the conductor rails between skillet frames and pit floor. A customised substructure with integrated step-on-protection was key to its success. Pre-assembled entry funnels made it possible to achieve the tied time schedule on site.
Robust entry funnels together with quick change current collector units are the core components for durable, high-performance skillet electrification. Stainless steel guiding ramps on the entry funnels are assuring long lifetimes for the funnels and the collector shoes, as these reinforced funnels can withstand the high mechanical stress.