Precision dispensing: Automated color application for emblems

Complex surfaces, complex challenges

Applications as a partial coating, whether opaque, transparent or colored, as well as flat or shaped surfaces are complex to apply. During emblem production, the colored lacquers are dosed into the recess of the metal or plastic moulds. The challenge is both the exact dispensing and the optimum viscosity adjustment of the materials to be dispensed. The thickness of the coating is important in order to keep the excess material low or to prevent post-processing. The coating must neither be too viscous nor too liquid, otherwise the lacquer will run too little or too much. The curing time also plays a key role in ensuring that the material is optimally distributed in the recess.  

The automotive industry places particularly high demands on the supplier in terms of quality and design. In addition, interior emblems are often coated with polyurethane for a more pleasant feel after the painting process. Previously, the complete painting process was often carried out by hand, followed by polishing of the component and removal of excess lacquer. This meant a great deal of effort during production, which was very labor-intensive and time-consuming.

Automated job: repeat accuracy

preeflow’s Spanish distributor, Dotest, has developed an automated system with which the coating of emblems can be applied perfectly and with constant process parameters. Two robotic systems, each with two preeflow eco-PEN300 1 component dispensers in combination with the eco-CONTROL EC200-K dispensing controller, ensure repeatable material application, for example with a three-color logo for installation in a steering wheel. The components are pre-mixed and filled into cartridges: lacquer, solvent and hardener (accelerator). The preeflow eco-PEN300 1 component dispenser takes over the task of precise and absolutely repeatable dispensing from the cartridges. In the Dotest application, the precision volume dispenser applies one color after the other in two steps via the desktop robot. A precise application of lacquer is achieved in a very short time – without splashes, protrusions or irregularities. And therefore, without time-consuming post-processing. The shape of the lacquer application can be precisely pre-programmed into the robotic system, so that even curved shapes and larger surfaces pose no problem. The individual composition of the equipment ensures low material cost on the one hand and high product quality on the other. Batches of complexly shaped and multicolored emblems of excellent design can therefore be produced at low cost.

The preeflow eco-PEN300 1 component dispenser

The preeflow eco-PEN300 1 component dispenser itself is a rotating, pressure-tight displacement system. Thanks to the ViscoTec endless piston principle, aqueous to pasty liquids are conveyed perfectly. The dispenser consists of a self-sealing rotor and stator, whereby the controlled rotary motion of the rotor displaces the material. This creates the delivery in the stator, which can take place without transformation of the material nor reverse movement. preeflow’s dispensing pump guarantees a clean, controlled material cut or material separation without dripping. Independent of fluctuations in viscosity, a clean, process-reliable dosage is therefore achieved. Find out more about the preeflow dispensers at www.preeflow.com