Press

Press  | 05/03/2017

Inductive brazing processes by eldec: Faster, more precise and economical brazing

The brazing processes in industrial production are countless. Particularly in the electro technical industry and automotive industries, this thermal process is widespread. However, the technologies that are used are just as numerous as the applications in this field. For heating the materials, for example, ovens or gas flames are often used – with one important disadvantage: Processes are relatively slow and sluggish.

In view of that, it is not surprising that inductive brazing by eldec is gaining importance: The process is much faster than, let’s say, brazing with an open gas flame, since the induction generates the heat directly inside the workpiece. In order to control this process with pinpoint precision, the eldec induction specialists are developing individually adapted inductors and generators. Many companies in different industries rely on this innovative approach, which also results in lower costs for a variety of brazing tasks. 

The ‘copper bar’ is a simple application example from the electrical engineering industry that illustrates the benefits of inductive brazing. These components are found in many places inside large transformers where they provide power transmission. To avoid the need for elaborate and costly screw connections, the copper bars and profiles are brazed to their connecting elements by means of a brazing process. A manufacturer of industrial power supplies relies on induction processes by eldec: The profiles are held together precisely by a clamp, and are positioned above the eldec inductor. At a brazing temperature of 680 to 720 degrees Celsius, the inserted phosphorus brazing alloy melts, thus creating a permanently solid connection. Flexibility in the production process is ensured by the wide range of available inductors that eldec produces by its manufacturing processes. Depending on shape and size of the tool, a wide range of different copper profiles can be brazed – without changing the energy source. In each case, the generator of the eldec MICO product family will provide, by means of its control technology, the exact amount of energy required. The procedure is very uncomplicated and fast.

Wind power: Short circuit rings brazed by induction

Inductive brazing is similarly ‘lean’ and effective in wind power generator construction. Here the short circuit rings are brazed to the generator. For this purpose, the inductor produced by eldec is placed below the ring, which is then heated to 680 to 720 degrees Celsius. The inserted phosphorus brazing alloy melts, and brazes the short circuit ring together with all the copper bars. The brazing is completed within minutes. “The greatest benefit of the application becomes evident by a look at the brazed joint”, explains Pasquale Di Santi of Technology Sales Generators at eldec. “It exhibits very little oxide formation and is therefore of very high quality. In addition, only small amounts of heat dissipate into the bars during induction brazing. Therefore, distortions in the component are virtually ruled out because the brazing is done in one shot.” In this application example, the power rating of the generator is also of particular importance. A medium-frequency model from the eldec CUSTOM LINE Series with 250 kW power is used in this case. The individually configured generator and the robust technology ensure a stable brazing process.   

Perfection for the heat exchanger

Another interesting example for inductive brazing is found in the production of heat exchangers. At the central component, which is used in many industrial processes, all pipe bends and connection elements have to be brazed with precision, so that reworking can be ruled out. Brazing with phosphorus brazing alloy rings is in most cases the method of choice for this task. However, many users opt to use simple gas burners, heating the materials by flame. This process is difficult to control with regard to the exact brazing temperature. Inconsistent processing quality is the result. In comparison, induction heating is efficient, more reproducible and more reliable. Using eldec technology, the procedure takes less than ten seconds.

Increasingly present in the market

“All in all, we can observe that our brazing process is being more strongly perceived in the market. It is being used for many applications in the electrical engineering, heat exchanger and automotive industries”, confirms Di Santi. “Particularly in serial production, it proves its superiority by its consistent heat input and high-quality results. Compared to heating in a furnace or by flame, it is, of course, also much faster and therefore more economical. At the end of the day, these are the benefits that convince the users.”