Ersa equips new Tridonic production facility

The Tridonic electronics manufacturing division was faced with particular challenges: The PCBs in common use in Europe today are fitted on both sides with a large number of components, primarily SMDs, and a number of contact plugs. The manufacturing processes are highly automated, with paste printing and reflow soldering in the SMD sector. Depending on their share in the assembly, an automated selective soldering process is used for the THT components, or they are classically soldered by hand. By contrast, Tridonic uses a large number of what are known as “single-sided” PCBs with a high proportion of axial and radial THT components. “Today, this set-up is found mainly in Asia,” explains Stefan Kerber. With single-sided PCBs, all the component connections are on one side, as only one side is copper-clad. These PCBs are significantly cheaper to buy, reducing the material element in the manufacturing costs. However, for existing SMD components, the single-sided setup means that they also pass through the wave soldering system. The challenge here: how to attach the SMD components to the PCB. The solution: Glue them.

Together with Ersa, a manufacturing process was developed four years ago for the plant in Dornbirn, which is now being successfully implemented in Niš. Initially, the PCBs are fitted with the THT components and the connections crimped. The SMD glue is then applied to the PCB but, due to the many glue points required, not in the classic manner by means of a dispensing system. In order to execute the glue application in an acceptable cycle time, Tridonic decided on a VERSAPRINT P1 stencil printer, in place of a doctor blade head with a closed print head containing a cartridge with the SMD glue. The integrated piston applies even pressure to the glue, pushing its print head through the cut-out in the stencil to the desired spot between the SMD terminal pad on the PCB. Cut-outs in the print stencil accommodate the crimped connection wires of the THT components, so that the stencil lies flush on the PCB and glue cannot run into the space between PCB and stencil, possibly soiling terminal pads.

A special feature in the VERSAPRINT P1 is the integrated SPI for inspecting the print result, with software expanded specifically by Ersa for this application. The inspection not only checks the presence of glue between the landing surface, but also that the connection areas for the SMDs are free of glue so that, in the subsequent wave soldering process, they can be coated with solder and form perfect soldering points. Printing and inspection run in parallel in the VERSAPRINT P1. This saves cycle time; faulty modules are identified immediately and excluded from further processing, which is also reflected positively in the manufacturing costs. Following printing, the SMD components are attached to the glue points on the module, so that the component connections lie directly on the landing surface of the PCB. 0204 chips are the smallest components used. The module is then sent into the HOTFLOW 3/20 and the glue hardens in response to the heat in the reflow oven. The SMD components are now firmly attached to the PCB for the subsequent wave soldering process.

The Tridonic requirements were also examined closely for the HOTFLOW 3/20 and the system adapted accordingly by Ersa. The oven’s working width ranges from 45 to max. 580 mm. A central support is available to prevent the modules bending. Under usual circumstances, central supports rest on the PCB. Due to the density of the fittings, a version of this kind could not be realised for the Tridonic modules. Therefore Ersa found a solution in which the central support is provided by the components of the modules. However, depending on the module, the height of the components varies. Therefore the central support in the HOTFLOW oven at Tridonic is variable in height and can be adjusted by up to 20 mm. The next step is the actual soldering process – due to the high lot sizes, this is carried out in the wave soldering machine. For the plant in Niš, the machine chosen was the Ersa POWERFLOW.

In Zukunft werden in der Lichtbranche das Internet of Things, Vernetzung, Digitalisierung große Treiber sein. LED-Betriebsgeräte werden zunehmend Interfaces beinhalten, mit denen Sensoren unterschiedlichster Ausprägung integriert werden können, um in übergeordneten Systemen entsprechende Funktionen zu steuern. „Die Produkte, die dazu verwendet werden, müssen intelligenter sein. Die Herausforderung ist, diese Intelligenz in die Produkte zu integrieren, aber auch die entsprechende Software bereitzustellen – ob Software für Handy, Computer oder direkt auf dem Gerät, das ist unsere Aufgabe für die Zukunft“, resümiert Stefan Kerber. Der Bedarf an Elektronik und Produktionsequipment wird also nicht kleiner werden. Aktuell sind drei Produktionslinien mit VERSAPRINT P1 und HOTFLOW 3/20 in Niš installiert und eine POWERFLOW, auf denen Konverter und LED-Module produziert werden.