Integrated system solutions from ENGEL boost efficiency
Space saving champion
Lighting systems for vehicles are consistently being reinvented in short cycles and, accordingly, their manufacturing processes as well. The growing com-plexity of components makes it essential to further increase efficiency and cost-effectiveness. That is why productivity per floor space plays an increas-ingly important role, as the example of a Tier 1 supplier demonstrates. The Eu-ropean plastics processor uses ENGEL easix multi-axis robots to keep its in-jection moulding cells to a compact size.
The company specialises in the development and manufacturing of exterior lighting systems for passenger cars: lenses, housings, panels and reflectors that leave the factory as fully assembled, ready-to-install front, rear or fog lights. The injection moulding and assembly facilities have recently been expanded, therewith plant extension has not yet been complet-ed.
“The market for automotive lighting systems continues to diversify,” explains the Manager of the facility. “Accordingly, the demands placed on the products we manufacture in injection moulding are constantly increasing.” Various developments have contributed to this trend. For example, more use is being made of innovative technologies such as anti-fog coating, the integration of new functions such as bending light requires ever more electronics, and thirdly, automotive manufacturers are increasingly using lighting as a differentiating design element. The processor uses the entire spectrum to develop individual solutions together with its customers. From halogen, Xenon and LED to the laser light.
Narrower by one and a half meters
In order to ensure that increasing production and assembly costs are not reflected in the effi-ciency balance sheet or even in unit costs, the company continually adapts its manufacturing strategy and consistently invests in process optimization. Process integration and automation are two key factors to top competitiveness. “Fully automated two- and three-component in-jection moulding processes are our standard today,” says the manager. In this way it is pos-sible to reduce the number of work steps and increase efficiency, despite the increasing complexity of the products. The only drawback: The space requirement of the production cells expands with increasing integration and automation. Since productivity per floor space is also included in overall efficiency, this poses new challenges for the mechanical engineer-ing partner ENGEL. “High reproducibility, short cycles and reliable service are not enough to be successful in the automotive industry”, underlines the manager. “We must constantly look for new technologies that require less space. ENGEL supports us optimally in all these aspects.”
“We really have made adjustments everywhere to make things even more compact,” reports Reinhard Holzner, project manager at ENGEL’s Schwertberg headquarters in Austria, on the recent cooperation. In order to design a new production cell for the manufacturing of head-light lenses for a current SUV model, he and his team worked closely with the customer’s production managers. The result is now setting a precedent for the further expansion of the plant. This is mainly due to the very compact integration of the easix multi-axis robot. The automation requires only two metres of movement area. This saves an entire metre and a half compared to the previous solution with a linear robot.
Precise handling of sensitive parts
The headlight lenses consist of two different types of polycarbonate which are simultaneous-ly processed in a two-component rotary table mould on a duo 1100 injection moulding ma-chine with a clamping force of 11,000 kN. In the first step, crystal-clear PC is processed, fol-lowed by black PC in the second step.
The task of the easix robot is to remove the finished components and place them on the con-veyor belt. This is encapsulated as a clean room, because the hardcoating process immedi-ately follows the injection moulding process. The robot also handles the removal of sprues for some headlight models.
The duo belongs to the predominant machine type in the plant, not least because of its com-pact design. With their dual-platen clamping unit, the large-scale ENGEL machines are built particularly short. The low-friction platen guidance on the carriage ensures optimum platen parallelism and high mould protection. For multi-component injection moulding, several injec-tion units can be arranged side by side or on top of each other to save space.
Even with a pneumatic unit, the arm of the easix robot fits comfortably under the bars of the duo machines and can operate safely when the mould is open. “This is a critical factor for highly sensitive optical parts,” explains the plant manager. “The mould has several core pulls and sliders. Therefore, the robot must be able to move extremely precisely in a confined space.”
The fact that the robot is also sufficient in terms of space outside of the machine is due to the freely definable prohibited areas and the safe monitoring of the robot workspaces. “With the safety gates we can move very close to the robot,” explains Holzner. “Since we supply the injection moulding machine and the robot as an integrated system solution from a single source, we project from the outset including the disturbance range. It’s the only way to make sure we don’t waste any space at all.”
Uniform operating logic for more convenience and safety
To date, the European plastics processor has already equipped several injection moulding machines with a multi-axis robot, and the trend is clearly upward. Ten years ago, a first Kuka multi-axis robot for injection moulding was put into operation, which proved to be a very complex task at that time because the robot control system was completely new territory for the machine operators. In order to simplify the use of multi-axis robots in injection moulding, ENGEL joined forces with two industrial robot manufacturers – including Kuka – and inte-grated the complete robot control unit into the control unit of the ENGEL injection moulding machines. In the ENGEL easix version, the multi-axis robot and the injection moulding ma-chine now have the same operating logic and the entire production cell can be controlled via the control panel of the injection moulding machine. The role models for this were the viper linear robots from ENGEL’s own production, whose control unit was designed from the outset as a subsystem of the machine control unit. “Whoever can operate the injection moulding machine can also operate the robot, regardless of whether it is a linear or multi-axis robot,” explains Holzner. “The control unit does not differentiate between controlling a linear or a rotary process. The additional movement instructions for the multi-axis robot integrate seam-lessly with the graphical user interface.”
“We now only have one control logic for the injection moulding machines, the viper and the easix robots. We now only need one technician for maintenance,” confirms the manager add-ing another advantage of control integration: The lower risk of errors, since machine and robot use a common database.
“We really have made adjustments everywhere to make the production cell even more com-pact,” reports Reinhard Holzner, project manager at ENGEL AUSTRIA in Schwertberg.