Reducing cycle times and investment with the right nozzle
Bietigheim-Bissingen, September 2017 – Dürr's range includes as many as 360 different nozzles for applying sealing and glueing material. And no two nozzles are alike. As insignificant as they may seem to some, their development requires great expertise to make sure the quality does not suffer.
Every customer has certain requirements in terms of how the desired material should be applied. "Hereby the width or thickness of the seam or the surface quality differentiate or whether an edge contour is required", explains Frank Schnur, who is in charge of high-viscosity system development. "Based on those parameters, we then select a nozzle from our standard set which we know will largely fulfill the requirements. After that we think about how the nozzle must be changed to satisfy the customer's demand one hundred percent."
Using experience and simulation
Of course this requires a great deal of process know-how, but also state-of-the-art technology. The next step is for the flow to be simulated in the various nozzle designs using computational fluid dynamics (CFD). "This flow simulation enables us to view the system with the help of a virtual 3D model. Thanks to the simulation, we can make the flow control in the nozzles more energy-efficient", explains Elias-Joshua Nanninga, development engineer and CFD specialist at Dürr. The simulation results in the design of a nozzle geometry, which is then built as a prototype.
With this prototype, Dürr's nozzle specialists use their precision skills to set the correct distance to the sheet metal, the robot's speed and the optimal material temperature. In the past, several prototypes would have to be tested, but today it is a lot quicker. This way the customer achieves the best-quality result much faster. In addition, many nozzles are made in-house at Dürr and can therefore be delivered to the customer quickly and easily.
Sharp lines without any overspray
The combination of know-how and technology is also valued by the customer. For an American manufacturer of electric cars, for example, Dürr has developed the EcoJet SE wide-slot nozzle for the fully automated rocker panel and underbody coating for stone chip protection. The material is applied in sharp lines without the use of any templates. As this produces no overspray, there is no need for the manufacturer to build a paint booth, which in turn means there is no air-treatment equipment required. The only necessity is a safety barrier.
Standing seams all in one go
At the request of several carmakers, the Bietigheim-based nozzle specialists have recently developed the EcoJet ST sealing nozzle for standing seams. Previously, the material was applied first on one side, then on the other side of the seam. The new device can handle this in a single step: when viewed in cross-section, the applied material surrounds the welded sheet metal like a wrench. Apart from sealing the standing seam safely, this also reduces the cycle time.
Plus: the nozzle can also seal normal coarse seams. Therefore, there is no need to change the nozzle, which reduces the cycle time even more.
You can see the EcoJet ST sealing nozzle sealing a standing seam in our short video. Just click on the film symbol on the right side of this website.
Need a little extra?
Even if a higher area output is required, the customer can count on Dürr: to reduce the cycle time for a Chinese carmaker, a solution has been developed where two wide-slot nozzles are combined. This ensures the quality of material application despite the higher speed.