The EU has now removed the exemption for using lead in the solder for electrical connection soldering for glazing applications (such as for heated rear screens). As such, any new model seeking type approval after 1 January 2013 will be required to use lead-free solder for such applications. This will result in a significant step towards truly lead-free production car architecture. To find out more, Matthew Beecham talked with executives of Antaya Technologies.

Antaya, a relatively small, family business based in the US, has being supplying GM and Ford in the US with the lead-free solder connections for some time without any issues arising from this global-leading product.  But there has been reluctance among the European divisions and glazing suppliers to adopt it.  One reason cited being that it is more expensive (approximately 1 Euro per application). However, the EU ruling will force the issue into implementation.

As we understand it, Antaya has developed a unique lead-free soldering process.  Could you explain this process?

Antaya has developed a range of lead free alloys which meet the functional requirements of the automotive industry while allowing the European Commission to remove the exemption (for on glass connectors) to the ELV Directive. It is only unique because it is lead free. The primary component of the alloy is indium, a harmless although expensive element.

Indium solders were introduced in 1998 to reduce cracking on laminated windshields.  Higher melting point and less malleable leaded solders caused significant cracking when used on windshield heated grids and windshield antennas.  The introduction of indium solders made these features feasible.

Antaya Technologies researched alternatives to indium for a lead free electrical connection to glass but indium and the soldering process using indium alloys is still the highest performance solution.

Various indium alloys are formulated to meet the varied OEM requirements and optimised for performance and cost.

What are the forces driving innovation in your field?

Innovation is driven by the automakers adding features to their vehicles that give them a competitive advantage.  These are features that involve the electrical connections to glass.  Some recent examples are extended range remote start antennas, electrical contacts between the three panels of glass in a powered sliding pickup truck rear window so a defroster can be added and lead free solder contacts.

European legislation, specifically the ELV Directive is the chief driving force behind the innovation and development of lead free solders. The ELV Directive was passed into law in 2000 and included Annex II which contained a list of “exemptions” permitting the continued use of lead and other heavy metals. In 2009, the European Commission determined that “There were no significant performance differences between the lead-free and the lead solder in the joint test programme”. Thus, the exemption for the “use of lead in solders in electrical glazing applications on glass” will expire on 31 December 2012.

I guess that there are a number of ways in which to integrate an antenna onto a vehicle – you can use fine wires embedded in the glass, you can use conductive coating or you can use print onto the glass in the same way heating grids.  In what ways does each method change the criteria for terminal and connectors design? And does that method differ at all depending on the complexity of the antenna? 

Connectors for fine wire antennas are called flat flexible connectors (FFC) and made from thin copper foil and laminated with thin polyimide for electrical insulation.  FFCs are used for antennas in laminated glass and are inserted between the two glass sheets connecting to the fine wire antenna.  The FFC comes out of the edge of the glass and transitions to a wire or connector for connection to the antenna module.

Conductive coatings and printed silver antenna connectors are typically pre-soldered with lead free solder and soldered to the outer surface of the glass.  Different OEMs have different preferences for pre-soldered connectors from miniature snap connections to pre-soldered terminals crimped to a wire.

Premium vehicles tend to incorporate more laminated glass for theft protection and sound proofing so more flat flexible connectors are use in premium vehicles.

To date, we have seen a lot of information going into cars yet I guess we shall see more of it going out as well not just through the telephone but through the internet, too.  I guess that places greater demands on antennae design. 

Higher frequency antenna applications require coaxial connection to the glass and complex grounding technologies.  Coaxial connection and capacitance and direct grounding antennas have been developed by our antenna engineers and are currently in production with several OEMs for higher frequency applications.

The EU has now removed the exemption for using lead in the solder for electrical connection soldering for glazing applications. In what ways will this affect your business?

There is no difference between processing leaded and lead free solders except that processing lead is extremely hazardous for the workers throughout the supply chain including installers in the assembly plants and even end-users in some cases. The cost of the raw material (indium) is higher and so we will need a little extra working capital. Overwhelmingly, this is a good thing for our business; the costs, risks and liabilities associated with working with hazardous materials are relentlessly negative.

Will the change in the EU regulation make it more expensive for carmakers?

The changeover to lead free alloys using Antaya’s technology will add approximately EUR1 to the cost of a vehicle.

In terms of product performance, how does your lead-free connector compare with lead solder?

The lead free indium based solder actually performs better than the leaded solder when comparing the frequency of micro cracking on tempered glass or the propagation of larger cracks on laminated glass.  This is apparent from its initial use for electrical connections on laminated glass. 

In terms of functionality, the lead free terminals pass all the customary tests used in the automotive glass industry. During the past three years, the industry has attempted to modify the testing standards in an effort to prove that the (more expensive) lead free solders could not be used as a replacement for lead.

The industry has expressed concerns about the performance of the lead free material at elevated temperatures and conducted tests at 100°C (500 hours with ½ kg weight). General Motors has validated the material to the SAE USCAR Standard which includes a 105°C test.

European temperature requirements are higher than North American standards.  In anticipation of the higher temperature standards in Europe indium based solders have been formulated and proven to withstand even the highest temperature standards recently released by the VDA.

More and more European cars are being fitted with laminated side glazing, acoustic windshields, solar-protected glazing, etc.  As far as the lead-free connectors are concerned, are there special considerations regarding the use of alloys for certain glazing applications and temperatures?

The ELV directive does not provide an expiration date for the use of leaded solder “in laminated glass”.  Therefore the use of lead will still be permitted for FFCs soldered to fine wire windshield antenna and fine wire heating elements inside the laminate.   Our focus has been to provide lead free solutions for soldered connections “on glass” for silver printed heating elements, silver printed antennas and antennas made from conductive coating on the outer glass surface.  The use of lead free solder “in laminated glass” is not a significant technical challenge and will be our next focus of development.

As previously stated the temperature requirements of the lead free solder varies across OEM and regions.  Indium based lead free solders have been formulated and proven to meet all published high temperature standards.

In September 2014, Delphi Automotive signed an agreement to acquire Antaya Technologies, enhancing the company's portfolio in the growing automotive electrical connectors business. Antaya provides a broad range of on-glass products including power terminals, antenna assemblies, keyless entry and tyre pressure monitoring, and other custom connector assemblies for automotive electronics.