Selective soldering

Impressive sample soldering across the board

Ka-Ro electronics relies on Ersa VERSAFLOW 4/55

The advantages of selective soldering compared with wave soldering are obvious: improved quality, greater process reliability, lower energy and solder consumption, reduced thermal stress for the printed circuit board and greater design options overall thanks to customized settings for every solder joint. The extent to which a selective soldering system complies with customer requirements can be seen during its first use on site – or during sample soldering at the machine manufacturer’s premises. Ersa GmbH offers existing and potential customers the opportunity to come to the perfectly equipped Application Centre in Wertheim am Main – without sending the board to be soldered in advance. Aachen-based Ka-Ro electronics GmbH was considering changing to selective soldering technology, accepted the sample soldering invitation and, at the end of the day, was completely convinced by the VERSAFLOW 4/55.

Ka-Ro electronics GmbH was founded in 1987 as an EMS service provider in the middle of the border triangle between Germany, Holland and Belgium. The portfolio of the Aachen-based EMS service provider has developed greatly over the past 30 years and was expanded by the product range “Computer on Modules” (CoM) in the year 2000. Three cutting-edge manufacturing lines as well as multi-level quality inspections led to a manufacturing capacity of more than 16 million electronics components per month. The range encompasses the complete service – from development through prototype production to series production. During the past business year 2019 more than 2,000 customers were supplied with approx. 350,000 modules through a global dealer network.

CoMs are small embedded computers that are soldered or inserted onto a carrier board. All of the relevant functional units that characterize a computer – such as processor and graphics unit, RAM and program memory as well as various communication interfaces – are located on a Ka-Ro module. Since the modules are compact and energy-saving, they are optimized for mobile applications in the industrial, medical and test equipment fields, but also are used in parking ticket machines or time recording systems. As digitization increases and ever more demanding requirements are being made on ever more powerful, ever smaller embedded computers, the complexity of these systems is rapidly increasing. The two overlapping business divisions lead to synergies within Ka-Ro electronics GmbH, which will secure the overall success of the medium-sized company in the long term.

Economic production with selective technology

In the field of THT production, a wave soldering system had been used, which was to be replaced in 2018 on account of the increased requirements. “Our wave soldering system was perfect for assemblies equipped only with THT,” says Thomas Wahnberger, THT/Test Field Division Manager at Ka-Ro. “Today, with assemblies being equipped on both sides, there is quite simply no way we can do without selective soldering if we wish to continue economic production.”

To be more precise, the use of selective soldering technology was intended to further optimize the already high quality of the products and achieve a correspondingly higher throughput. To achieve these objectives, the fourth generation of the VERSAFLOW series, the VERSAFLOW 4/55, was considered following an initial contact at the productronica trade show in Munich. With this selective soldering system, solder parameters can be entered for every individual component on an assembly, leading to significantly improved soldering quality and a tangible increase in flexibility.

Another special feature of the modular-design machine generation is the second pot that automatically adjusts in the Y-direction, thus adapting to the product panel and making higher throughput possible. Both degree of automation and process reliability can be improved considerably due to the additional use of a VERSACAM. This camera not only provides complete process monitoring, it also serves to control setup and inspect the nozzle properties. The greatest advantage of the VERSAFLOW selective soldering system, however, is its modular design, which results in a multitude of configuration options and tailor-made solutions for the customer.

Sample soldering – getting to know the system under real manufacturing conditions

In order to be able to clarify which of the possible options – such as pre-heaters, further soldering pots or spray fluxers — are necessary for the product on the basis of their own real assemblies, Division Manager Thomas Wahnberger and his team visited Wertheim for sample soldering. Initially, the aim was to record all of the data relevant for the cycle time, since the slowest process determines the cycle time on the selective plants. To achieve an overall reproducible and stable process through the solder trials – the three areas fluxing, pre-heating and soldering – are focused on individually. With the aid of an X-ray machine, the test results can be evaluated quickly and precisely after the trial. This is the basis by which the application engineers decide which changes are necessary to achieve the required result.

Philipp Haar, Ersa Area Sales Manager, explains: “Through sample soldering, we offer our customers the chance to get to know the machine under conditions that are as realistic as possible. The idea is to involve them from the very beginning in the creation process of the soldering program and the setting of parameters for their applications, thus indicating different possibilities. As a result, customers can bring their boards to us without any advance preparation and we work on the setup here together.”

The ideal soldering result thanks to years of experience

According to M. Haar, the transparent process without detailed advance information about the assembly is a unique selling point for Ersa and the reason why contracts are concluded in more than 90 percent of cases. At the same time, this procedure is  a real challenge. After all, the application engineers do not know what soldering tasks they will be asked to solve live with the customer. The key here is years of comprehensive experience and the necessary know-how about the process in order to achieve a perfect soldering result.

For the team from Ka-Ro electronics, the day at the Wertheim Application Centre was the decisive criterion. Haar explained: “We brought a manufacturing order from our EMS field with us, without having exchanged any information at all about it with Ersa in advance. The on-site soldering went excellently and convinced us all.”

Thanks to its modular design, the VERSAFLOW 4/55 in use at Ka-Ro can be expanded at any time for even more flexibility and to deal with an increasing order volume. The company’s satisfaction with Ersa as a system supplier for electronics manufacturing also is illustrated by the fact that Ka-Ro deploys an Ersa HR 600/2 rework system and a solder fume extraction unit in addition to the VERSAFLOW 4/55. Rework systems are increasingly being used in prototype construction, in particular to maintain the value creation of ever more complex electronic assemblies.

“Expert contacts, transparent communication and quality-enhancing results with the new equipment – we were greatly impressed by the Ersa complete package and our customer feedback confirms that we made a good decision with this investment,” Wahnberger concludes. The Ersa team will be ready to help with any future decisions to be made by Ka-Ro electronics – whether these involve modular expansions or completely new systems.

Article Author

Stefan Wurster Area Sales Manager, Ersa GmbH

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