Tectra Automation, part of the Bosch Rexroth South Africa Group of Companies, successfully designed and fabricated a tailor-made stud press for use in manufacturing components for Ford’s Ford Ranger and Ford Everest vehicle ranges. Commissioned for the project by Auto Industrial, the provider of machining and assembly of various automotive components, the stud press is used to insert the wheel studs into the front and rear hubs for these two vehicle types. With no standard stud press on the market that could meet the customer’s requirements, Tectra Automation was approached to provide the solution.
Beginning with concept in 2015, several design changes to this industry first saw the stud press evolve to a servo-mechanical system before the official order was received in July 2016. The brief was to design and build a press that could insert the wheel studs into the front and rear wheel hubs in the specified vehicle types, both of which are built in South Africa.
The stud press id required to press-in each stud effortlessly using a minimum of 50 kN force and it must also record an accurate data capture of each press in cycle while providing a production rate of 175 000 hubs per annum. In addition, Auto Industrial requested that the press be able to assemble at least two studs at once while controlling the force and distance travelled accurately, and the specifications required tight tolerances after assembly. Furthermore, the press was required to perform an infrequent press-out test as part of the quality assurance process.
To achieve these requirements, Tectra Automation designed and manufactured the stud press frame from the Rexroth range of basic mechanical elements. “The studs are pressed in using two Rexroth EMC100XC actuators driven by Rexroth MSK060C motor through standard 20:1 GTM100 gearboxes,” explains Kevin Lombard, General Manager, Tectra Automation. “A turntable to rotate the hub is driven by an MSK040C motor through a 20:1 GTE80 gearbox and control is provided by a Rexroth CML25.1 PLC. Control for the HMI front-end with onboard PC is enabled by the IndraControl VEP 40.5. Additionally, we used customised load cells to measure the exact force and we designed the program to operate and record the data inhouse.”
Tectra Automation’s ingenuity was brought to the fore as its engineers designed a special motor attachment to enable smaller motors. This was necessary as two of the EMC 100XC electromechanical cylinders had to be placed exactly on the pitch circle diameter of the bolts in order to limit any abnormal shaft loading. “To provide the torque required to generate 50 kN force,” Kevin elaborates, “we used 20:1 double reduction planetary gearboxes attached directly to the motors.” Additional sensors to detect any possibility of a faulty hub passing through were required and Tectra Automation was also responsible for data capturing system related to each press in operation. The data is downloaded on to Auto Industrial’s network for storage purposes.
“A real benefit to Auto Industrial is that by incorporating product monitoring during the press-in phase, the company can guarantee product quality without the need of additional production monitoring steps,” Kevin says. “If at any stage the program determines that the press-in process deviates from the specification, the press will stop and the operator will have to call a supervisor in order to reset the operation. The faulty part is removed and set aside for examination, thus minimising the possibility of faulty parts going through the system.”
The project was completed and commissioned during July and August 2016 at Tectra Automation’s premises where the factory acceptance hubs for testing by Ford are assembled. All work was completed within the specified time and the stud press was delivered and installed in January 2017, with an accompanying 12-month guarantee in place.
“The success of this project, and all projects we do, is based on the extensive range of products we represent within the Bosch Rexroth South Africa Group of Companies. It enables us to design and build fairly complex systems at relatively low costs using in-house expertise related to the individual product ranges,” says Kevin in conclusion.
Tailor-made stud press for use in manufacturing components for Ford’s Ford Ranger and Ford Everest vehicle ranges.