From mechanically guided soldering to autonomous and a reproducible soldering process
Customer demands and optimized applications by companies have contributed to raise soldering to a new level of quality in recent years. Key factors in this development were not only technical advancements, but also the methodology.
New customer demands lead to new challenges for equipment manufacturers. In addition to this, manufacturers improve process steps through their own research, resulting in optimized production for their customers. If the two are combined methodically, a company orientation follows, which is strongly focused towards the market and research and has proven itself in the dynamic electronics manufacturing market. EUTECT GmbH works on the improvement of process modules based on Design of Experiments (DoE). This is a systematic approach for planning and statistical evaluation of experiments and test sequences. The aim is to learn as much as possible about the relationships between influencing variables and results at a reasonable time and effort. Based on customer requests, but also due to the in-house development of soldering modules, a wide variety of test series are carried out to determine how individual process parameters can be improved. These experiments provide continuous improvement of the soldering process.
The continuous improvement process (CIP) and the DoE method are used as tools for quality and process optimization. This ensures and guarantees process robustness, process cleanliness and reproducibility beyond the 24x7 capability.
"The chicken-and-egg principle plays a strong role in this process.“
Customer inquiries and the continued development of soldering processes often inspire each other. Customer projects are often only successful if the customer prototype product to be soldered and the process evaluation or development can be set up in parallel. In this way, the planned total cost of ownership (TCO) can be secured at the time of the standard operation procedure (SOP), since the process was developed close to the series product. Thus, many further improvements lead to customer inquiries, which in turn lead to an optimization of the soldering processes. "When we take a closer look at these developments, we move in a cycle as a company," says Fehrenbach.
Fig. 1: Non-wettable solder nozzles for a better solder flow (Fig.: EUTECT GmbH)
One of these soldering modules is the IW1 mini wave. It has been available since the beginning of the 1990s. At that time, the solder within the module was mechanically pumped by an electric motor. Coatings and non-wettable solder nozzles (Fig. 1) were later developed for optimized solder flow. Nitrogen feeds, ground contact pins for checking the wave height and an optical control followed until the turn of the millennium.
Fig. 2: Induction pump for better solder transport (Fig.: EUTECT GmbH)
From 2004 onwards, the solder was conveyed electromagnetically (Fig. 2). A self-learning heating algorithm was developed to ensure the fastest possible, alloy-independent heating. A laser solder wave height control automatically adjusts the solder wave height. Followed by further developments with the lead-free specification and later with the complete digitalization of the process.
The desire for traceability led to production data being stored and accessed for quality control. This has naturally led to some adjustments in the software. A series of software tools and flexible interfaces were developed to simplify the recording and output of data for the user. These further developments of defined, reproducible processes are still ongoing today. Particularly with regard to the high temperature capability of ≥ 450°C as well as with regard to service life and spare parts efficiency, the IW1 mini wave module has been continuously enhanced, making it the simplest functioning product on the market in terms of service and maintenance operability. All in all, this example shows which developments are possible with an integrated "closed loop approach".
