Stäubli six-axis robots benefit plastic molder

News from Staubli Corporation


Designing, manufacturing and installing cost effective automation systems requires a detailed knowledge and appreciation of the capabilities of robotics, control software and integration protocol, to ensure that the system delivers the expected benefits, is easy to use and reliable in performance. While many companies have this type of expertise 'in house', frequently the demands are outside the capabilities of small and medium sized companies. This is when System Integrators, specialists in all aspects of automation, are able to bring the benefits of these advanced solutions to a wider range of applications. System Integrators work alongside automation equipment manufacturers to develop solutions tailored to each specific application. A good example is the co-operation between Forward and Thompson, based in York, UK and Stäubli Unimation, the manufacturer of precision robots, to develop automation systems built around Stäubli’s RX range of six axis robots. Martin Askham, F+T's Managing Director comments, "Only a few years ago six-axis robots were considered as too expensive for use in many applications, they were also quite complex to program. Now they represent good value for money providing payback periods to operators often of less than one year. The developments made by manufacturers like Stäubli, to the control software means that programming is now very much easier and can frequently be interfaced directly with other PC software." One recent application, designed, manufactured and integrated by F+T, illustrates the benefits achievable by the adoption of six axis robots; this is at Strata Products Limited, Pinxton, and Notts. UK. Strata specialize in the manufacture of plastic storage boxes and F+T had previously supplied automation solutions featuring special purpose machines incorporating 3axis pick & place mechanisms. An installation of this type had been integrated on the manufacturing line for a range of large plastic storage boxes that required handles as well as wheels and other fittings and assemblies to be fixed into position. The handles and wheels were being fitted to the plastic storage box by hand, requiring two operatives per shift working on a three-shift basis, positioned alongside the injection-molding machine. The operators were also finding it difficult to keep pace with the production rate of the machine. F+T saw the opportunity to incorporate these finishing and assembly activities into the demolding cycle of the machine. This would enable the six operatives to be employed on more useful work elsewhere and significantly reduce overall manufacturing cost. A typical 3 axis pick & place robot would not have the flexibility and range of movement to accommodate these additional operations, a six-axis robot was required. A multiple task solution based around a Stäubli RX six-axis robot was proposed by F+T. Stäubli RX robots feature high speed and acceleration and are capable of following complex trajectories even at high speeds. Joint speed ranges up to 1125degrees per second. The high degree of accuracy and repeatability make the RX ideal for the performance of detailed, meticulous tasks. At the heart of each RX robot is the patented, unique, JCS gearbox providing zero backlash and consistent performance. The range includes models with load capacities from 1.5kg to 60kg with a reach at the wrist from 665mm to 2135mm. The movement in six axes provides an extremely large work envelope. User-friendly software permits easy programming as well as re-programming to bring the added degree of flexibility often of benefit in automated systems. At Strata, the RX 130 robot first extracts the box from the injection moulding machine, rotates and places it in the handle assembly machine. While the box is gripped securely, it press fits the handles, wheels and any other fittings and assemblies into position, checks functionality and finally places the finished box onto the exit station. The new automation system has dramatically increased productivity rates, by up to 50%, on some boxes, enabling specific moulding machines to be dedicated to producing various ranges of box. The streamlining of production has allowed operators and tooling engineers to be used in other factory areas where they are more cost effective. Consequently, both production and overhead cost for each box produced has been significantly reduced. The programmed robot based test for functionality of the assembly cell guarantees that all box assemblies meet full specification eliminating the need for visual inspection, another major cost saver. Payback on the new robot based system is measured in months rather than years giving an excellent return on investment. The ability of the RX robot assembly cell to accommodate process and product variables was also important in this application where box dimensions and assemblies locations vary. Design modifications could also readily be programmed into the sequencing of the robot providing a level of flexibility not achievable with dedicated overhead pick & place units. Strata were so impressed by the performance of the six-axis robot that similar installations are now being considered for other production lines. The advantages achieved so far have already opened up the real possibility of replacing more and more of the overhead pick & place units that have traditionally been regarded as standard in the plastics industry. The much more versatile RX robot assembly cell can readily perform many additional assembly functions in the same assembly cell and timeframe. Functions such as label application, part verification and marking, box measurements (such as temperature, weight and material shorts) and packaging are already being looked at, as is the final palletizing of finished parts. About Stäubli Robotics Stäubli Corporation is an international privately held group, founded over 100 years ago in Switzerland, employing over 3,500 worldwide. Robot production is centered south of Geneva in the French Alps, with facilities across Europe, North and South America and the Far and Middle East. In 1980, Stäubli Group made the strategic decision to diversify into robotics, beginning with the affiliation of US Company Unimation (a pioneer in industrial robotics). It launched the large SCARA RS robot range in 1987, acquired Unimation in 1988 and launched its RX range of robots in 1992. Today with the addition of the new RS series due to a recent acquisition of the Bosch Rexroth SCARA robot line, the newly developed TX series, and RX heavy payload robots, Stäubli has the broadest robot line on the market. Thousands of Stäubli robots have now been installed worldwide and the company currently boasts 32 sales and service subsidiaries in 24 countries and agents in over 50 countries. For additional information contact: David ARCENEAUX Business Development & Marketing Manager Stäubli Robotics Visit for more information on the company and products.

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