A contribution to environmental protection: Endress+Hauser assembles electronic components lead-free. The company has voluntarily implemented a directive of the European Union. The know-how gained over the years helped to upgrade production.

Endress+Hauser is leaving the 'Lead Age' behind. The company has banished the toxic heavy metal from all its electronic components - voluntarily implementing a new directive of the European Union. This means a saving of one and a half tons of lead every year. Klaus Endress, CEO of the worldwide group, is pleased to announce, "We are facing up to our responsibilities as a company and reducing the burden on the environment”.

Lead is particularly dangerous because the human body enriches this harmful sub-stance. Even small doses can therefore lead to lead poisoning in the course of time: the heavy metal disrupts the process of the formation of blood, high concentrations damage the nervous system and, in severe cases, result in death. Nowadays a significant source of lead pollution in the environment is the incorrect disposal of electronic devices. These contain the heavy metal as a component of the solder. Acid rain can wash out the lead - so that it finally seeps into the ground water.

The RoHS guideline (Restriction of Certain Hazardous Substances) addresses this issue. Since July it has forbidden the use of certain hazardous substances and forced the electronics industry to find lead-free alternatives for the most important method of connection, soldering. As a manufacturer of measuring equipment, Endress+Hauser is exempt from these requirements. "But we want to meet the requirements of the RoHS guideline voluntarily - for the sake of the environment and our health,” states Klaus Endress.

Endress+Hauser is voluntarily converting to environmentally-friendly engineering;  a project team made up of colleagues from all four production centers of the Endress+Hauser Group have been preparing the conversion for two years. This called for investments amounting to millions. "Lead-free soldering is by no means easy”, stressed Dietmar Birgel, Process Engineer from the Maulburg plant. "There is no lead-free alloy that has the same properties as solder containing lead;  with regard to its melting point, processing options and cost.”

The biggest challenge for lead-free soldering compared with lead alloys is the higher processing temperature. "As the temperature, must not be too high that it damages the component; there is a really narrow 'temperature window' for the soldering process”, explains Dr. Ulrich Kaiser, in charge of the project at group level.

Technically, Endress+Hauser has over ten years' experience of lead-free alloys: in the early 1990s the company group was one of the pioneers of the new technology. A search for heat-resistant alloys led the developers to lead-free soldering. It was first used in a version of the successful Liquiphant level limit switch, designed for use in higher ambient temperatures.

Before this stage could be reached there were many challenges to be overcome - such as the 'whisker' formation, the development of fine, needle-shaped crystals, which could cause short-circuits. Working together with the Technical University of Munich and the Swiss system makers Kirsten Soldering AG, Endress+Hauser developed a suit-able silver solder, the appropriate soldering paste and a soldering unit to meet the special requirements. "A lot of know-how went into all of these developments,” explains Dietmar Birgel. Over two million lead-free components have since been manufactured by Endress+Hauser - without one single complaint.

Nevertheless, the introduction of lead-free engineering across the wide range was anything but easy. "We had to adapt numerous processes, major alterations were needed to tools and machines,” reported Erich Müller, Project Leader at Endress+Hauser Flowtec in Reinach. Acquiring electronic components was a particular challenge: "Thousands of different components had to meet the new specifications. Changing the supply conditions was very complicated. In some cases our suppliers even had to construct new parts.” Even logistics and IT processes had to be adapted.