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Starting point / Task definition |
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| Reinhardt-Technik, a major supplier of dispensing and mixing equipment, wanted to automate a process for preparing car headlights for bonding. To achieve this, a system was developed employing two six-axis KUKA robots. This robotic team comprises one KR 6, which uses a plasma treatment to improve the adhesive properties of the plastic headlight housing, and one KR 30 which subsequently applies the adhesive. | |
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Implementation / Solution |
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 | | Adhesive bonding of complete car headlight casings |
An operator places the headlight housings on workpiece carriers, which are transported on a conveyor into the cell. Before the first station is reached, the controller monitors whether a headlight is present, and if so, whether it is the left or right headlight. The computer transfers this information to the KR 6. The robot applies the plasma treatment by using a torch nozzle to spray ionized air into the groove of the plastic component, thus increasing the surface tension of the material, and enabling the adhesive to bond better.
While the workpiece carrier is moving the short distance between the plasma station and the bonding station, the KR 30 receives a message about the type of headlight and whether it has been sprayed with plasma. If it has not, it is moved through the bonding station without further treatment. Otherwise, the KR 30 applies a highly viscous, non free-flowing two-part silicone adhesive. Filling of the groove, which is slanted in most places, could only be carried out by a jointed-arm robot with six axes. While moving about the component, the robot has to hold the nozzle of its mixing and application unit perpendicular to the bottom of the groove at all times. Otherwise, the required bead geometry would not be possible, since the downward motion of the nozzle would ruin the bead.
Reinhardt-Technik installed the dispensing module for the adhesive on axis 4 of the KR 30, and the mixing unit on axis 6. This ensures reproducible traversing velocity and a short supply line for the adhesive, both of decisive importance for precise dispensing. After all, if too little adhesive is applied, the headlight in question will not be seal-tight, and too much adhesive would also cause the unit to be rejected. After the adhesive has been applied, the workpiece carrier moves out of the cell and to an unloading position, where an employee fits the polycarbonate lens onto the plastic component and removes the now-finished headlight. | |
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System components / Scope of supply |
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- One KUKA KR 6 robot
- One KUKA KR 30 robot
- Two PC-based KR C1 robot controllers, including control panel with user-friendly Windows interface
- Plasma nozzle
- Adhesive nozzle
- Dispensing module
- Mixing unit
- Workpiece carrier
- Conveyor system for the workpiece carriers
- Safeguards
- Programming
- Bus system connecting the system controller and robot controller
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Results / Success |
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- Short conversion time
One benefit of the system is its short conversion time in the case of a change of model. This can be done merely by exchanging the workpiece carriers and selecting the corresponding program.
- High repeatability and flexibility
Excellent characteristics with regard to repeatability and flexibility are important for the efficiency of the robotic cell, which in this application achieves an output of up to five headlights per minute. Flexibility is of particular importance here, since a variable standard cell is being used. For example, in other applications it may be more efficient to move the component in relation to the nozzle, or to exchange the tool in order to apply different types of adhesive. | |
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| Further information |
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| Video |
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