Selective Soldering

MEG Mechanik GmbH installs Ersa VERSAFLOW 4/55 with integrated AOI

On the road to a successful future

In the midst of the Thuringian Forest, close to the Rennsteig, there is a real Hidden Champion based in a small side valley of the Schleuse, a tributary of the Werra: MEG Mechanik GmbH develops and manufactures complex charging and power electronics for vehicle technology at its Schleusegrund location. The MEG machine park has now been prepared for further development with a new VERSAFLOW 4/55 with integrated AOI module.

The founding of the company on 1 April 1960 was the starting point for a now very successful mid-sized company with 150 employees. 60 of these work in the electronics division. The product range includes about250 different charger types for forklift trucks, pallet trucks and ride-on cleaning machines, among others.

Renowned manufacturers in the materials handling and cleaning machine industries place their trust in the innovative charging technology from Thuringia. The company’s second pillar is the Mechanical Center, which produces high-quality components from sheet steel, used for the front-end of the high-speed ICE train, for example, or components for lithium-ion batteries in industrial trucks. Both fields complement each other in-house, because the metalworkers develop and produce the housings and sheet metal components required for electronic products.

Component development in charging technology

A great deal has been achieved in charging technology over the years, which of course has an effect on the assemblies to be soldered. These days, chargers are often installed “on board,” in other words in the forklift truck or cleaning machine. Since the design space available is limited, chargers have become smaller and smaller over time.

Hand-in-hand with this development, a change occurred in the printed circuit board equipping of assemblies: THT components have increasingly been replaced by smaller SMD components. Initially, one-sided SMD equipping was sufficient. As miniaturisation and complexity of the assemblies advanced, the limited space on the printed circuit board was soon no longer sufficient. Today, boards with THTs and SMD equipping on both sides offerthe most advanced technology.
“We see significant potential for growth due to the continued electrification of drive technology, and are setting the company’s course accordingly,” says Torsten Friedrich, Plant Manager, Electronics Center at MEG. This is illustrated by the projects the company is involved in.

Until recently, the end-consumers were mainly manufacturers of industrial trucks or ride-on cleaning machines. Now the company is supplying products for passenger car charging systems in the form of wall boxes with an intelligent charging structure for homes. Another driver is the development and production of high-voltage charging technology and voltage converters, for the transport infrastructure required at airports, for example, as well as the electrification of smaller commercial vehicle applications. The focus also is on the development of charging methods that go easy on batteries and extend runtime.

In the electronics business field MEG relies on contract assembly, which is continuously expanded upon. In addition, MEG offers the complete package – from development to series production of the final product, including procurement processes. Customers benefit from the comprehensive know-how of more than 60 years of company history and the enormous flexibility of the mid-sized, Thuringia-based company. “If customers need help quickly, we are able to change the production line from one product to another within 15 minutes,” Torsten Friedrich reports. “Our company structure with extremely short paths makes this possible.”

MEG Mechanik GmbH

  • Company founded: 1. April 1960
  • Number of employees: 150, 2 Standorte
  • Portfolio: High-voltage charging technology, DC/DC converters, AC/DC converters, battery controllers,
    power modules, voltage converters

State-of-the-art production with Ersa VERSAFLOW 4/55

The further optimisation and modernisation of the production processes is critical for future company development. This was made possible by investment in a VERSAFLOW 4/55 selective soldering system. “We have another wave soldering system ETS 330 – also from Ersa – in operation in the THT division. However, the system was reaching its limits due to increased product variety and the current requirements on traceability and soldering quality,” Production Manager Jörg Neumann explains.

Assemblies with tight pin spacing were increasingly leaving the soldering system with solder bridges. The lack of traceability interface also was becoming more of a problem, because customers of MEG Mechanik GmbH are increasingly manufacturing to the high quality standards set out by the automotive industry, where the traceability of individual components is a compulsory requirement for suppliers. In the meantime, this also is applicable in the field of charging technology for non-automatic vehicle construction. MEG Mechanik does not produce large-scale series, rather the day-to-day business is characterised by high product variety with small and medium-sized series of between 200 units to 10,000 or 20,000 units per year. Frequent product changeover and mixed production are a daily occurrence here.

Decisive for the changeover from wave to selective soldering technology were the significant increase in soldering quality, and productivity and retention of the cycle time. The very first soldering tests in the Ersa Applications Center achieved a cycle time of 2:45 minutes, quite close to the two minutes required. Following optimisation of travel paths and optimum distribution of the soldering tasks to the individual soldering pots, the VERSAFLOW 4/55 – equipped at MEG with two VERSAFLEX soldering modules – is now fulfilling this requirement in day-to-day operation without any problems.

Individual solder joint programming with CAD Assistant 4.0

There were usually three or four products waiting for processing at the ETS because more than one product is equipped at the seven equipping stations. In order to minimise downtimes caused by product changeover, a joint soldering program was prepared for the wave soldering process for assemblies with similar requirements, which was then used for soldering the products. The prime concern was to find the best compromise for flux application, wave printing and soldering time.

Thanks to the individual solder joint programming of selective soldering technology, these parameters can be optimized for each assembly and each individual THT solder joint using the program editor CAD Assistant 4.0 with VERSAFLOW 4/55. This is an enormous advantage for the latest MEG product generation, where small components with narrow grids are used. Bridge formation, incomplete or missing passages are no longer a problem – a major step towards zero fault production. The individual solder programs start automatically on the basis of the product codes on the printed circuit board. Setup times between the individual product changeovers are kept to a minimum or no longer required at all. Thus smooth and delay-free mixed operation was achieved with the VERSAFLOW selective soldering system.

Additionally, the expensive soldering masks required for the processing of printed circuit boards equipped on both sides in the wave soldering process are no longer needed with the VERSAFLOW 4/55. They cover the SMD components previously soldered on the underside of the printed circuit board in the reflow furnace so that they cannot come into contact with the soldering wave, and thus be re-melted and flushed from the board. These soldering masks cost between 500 and 600 euros each. The soldering masks must be replaced after 2,000 to 3,000 production cycles. “They are a considerable cost driver if you have various products in the range for which new masks are required two or three times every year,” Jörg Neumann explains.

The conversion to selective soldering technology is another advantage for MEG for the development and production of samples or very small series. Previously, sample series could either be soldered manually or using the ETS 330. However, this does not work without a soldering mask, even for the smallest of series. “We no longer have to think about this at all. On the basis of the CAD data or a simple photo of the printed circuit board, I can write the soldering program for the VERSAFLOW quickly and easily, and then start protection,” a delighted Jörg Neumann reports. “We have become significantly faster and better.”

VERSAEYE module: AOI for traceability

The second main requirement for the new investment was documentation and traceability of soldering quality. Ersa solved this with the VERSAEYE module. This AOI system, also available as a standalone module, is integrated in the soldering system at MEG. In the VERSAEYE there are a total of eight cameras arranged in a circle around the main camera. The main camera takes over the 180° supervisory inspection. Thanks to its telecentric lens, the entire field of view, which is 36 x 36 mm in size, can be examined without distortion in the edge areas.

Thanks to the circular arrangement of the side cameras, a 360° inspection of the meniscus takes place. The inspection image is created by the interplay between software and special lighting. The software forms a colour scheme of blue, white and red on the basis of the reflection. Detection of whether the solder joint is okay is performed don the basis of the colour share, and the inspection result per assembly is saved in a database and thus documented. Faulty or critical assemblies are ejected from the production process.

Torsten Friedrich is confident: “We have made quite a substantial investment here, which will pay for itself over time. We are already seeing considerable improvements in solder quality and productivity.” MEG sees potential for further strong growth in the future. The main driver will be the continued electrification of vehicle construction and in-drive technology. In order to be optimally prepared, further steps towards process optimisation in MEG electronics production have already been taken into account in the VERSAFLOW 4/55 – already planned is the connection of the system to the equipping stations by means of conveyor belt and return loop. The VERSAFLOW is currently still working in 1-shift operation, with 2-shift operation to follow shortly. If capacity for a third shift should also be required, the VERSAFLOW 4/55 can be expanded with a third soldering module. The necessary connections and preliminary work have already been completed. If necessary, the machine can be converted within three days and continue production. The course is set for a successful future!

Article Author

Mark Birl Area Sales Manager, Ersa GmbH