OEM&Lieferant Ausgabe 2/2018 / OEM&Supplier Edition 2/2018

Manufacturing 138 Highly productive assembly of guide sleeves for headrests Competence in plastic By Ralf Högel, Freelancer The assembly of plastic guide sleeves for adjusting headrests in the SUV series of a premium German manufacturer places high demands on automation. In this case, automotive supplier Ros placed its trust in the in-house design of an installation that fulfils the ambitious cycle time targets with bravura, thanks to convincing details and two fast six-axis robots. Ros, a family-owned Franconian company, em- ploys a workforce of about 550 at five locations within the Ros Group. It is a renowned manu- facturer of custom-made plastic parts for the automotive, medical and electrical engineering industries. The company produces about 250 million parts per year and places great empha- sis on an above-average vertical integration level. This also applies to the guide sleeves of the headrests that are manufactured completely by injection moulding process and assembled in Ummerstadt. These guide sleeves differ in es- sential details according to vehicle model and their use in the driver’s, front passenger's or rear seat. The newly commissioned assembly plant had to be capable of handling a total of eight different variants produced by Ros. Two YASKAWA type MOTOMAN MH5LS and MOTOMAN MH12 robots, a rotary indexing table with eight stations, diverse feed systems and multiple sensors form the basis of the highly flexible rotary transfer machine. The adjusting sleeve essentially consists of three plastic parts: a guide sleeve, button with a cross bar, spring and cap. Christopher Lamprecht, production planner at Ros and project manager for this plant, de- scribes the real challenge in the assembly of these individual parts: “Depending on the ver- sion, in order to meet the high level of demand we must achieve an output of several hundred parts per hour. That’s why we chose a concept that guarantees overall availability at the high- est level with a rotary indexing table and two dynamic robots.” The assembly stages in detail The assembly process starts with the feeding of the guide sleeves, which reach the transfer position individually by means of a vibratory bowl in a linear system. Here a camera system identifies the position of the sleeve and trans- mits this data to the YASKAWA robot, which then picks up the part and conveys it to a sec- ond vision system that reads the part number and checks it for plausibility. Then the compact The robot moves with the part to a stationary vision system that reads in the part number. This is where the journey on the rotary indexing table begins: the MOTOMAN MH5LS inserting a guide sleeve at Station 1. Images: © Ralf Högel