Developments that can reduce ELV activities should always be welcomed – right? A US-based company claims to have a ready-made lead-free replacement for leaded window connectors, and how OEMs are demanding that more research be done before the product hits the assembly line.

The European Commission’s ELV (End of Vehicle Life) directive, which came into effect in October 2000, was put in place to reduce the amount of waste generated by the scrapping of cars and light commercial vehicles. This directive, which is currently due to expire in January 2013, includes an exemption for the use of leaded connectors used to deliver the power supply to window-mounted electrical equipment, such as antennaes and window defrosters.

Most of these window connectors are attached to the glass using lead-based solder. Lead is a neurotoxin, meaning that extended exposure to even small amounts can damage to the central nervous system; children are particularly susceptible to lead poisoning. Such is the poisoning effect of lead that tetraethyl lead (which improved octane ratings and protected valve seats) has largely been removed from petrol. Even lead wheel balancing weights have been banned in Europe and North America, where they were known to fall off the wheel rim and get crushed by passing vehicles, after which the lead dust was carried through the air and into local water supplies. In fact, beyond lead-acid batteries, window connectors using lead solder are one of the only remaining uses of the material in a modern car.

Antaya is a company based in the United States that supplies pre-soldered and pre-fluxed leaded and lead-free window connectors to the automotive glass industry used to deliver power to window-based electronics. Managing Director, Steven Antaya, offers some company background: “In the late 1980s, heated rear windows went from optional to standard equipment, so the glass industry needed to solder connectors on everything. We developed the presoldered, pre-fluxed connectors for the glass industry, together with the controlled soldering process. We supply about 90% of the market in North America. Our direct customers are in the glass industry, but we do a lot of development work with the OEMs.” He adds that while Antaya connectors have been used in Ford and Chrysler models, GM are the largest user of the parts.

In the mid-1990s, Antaya started development of a leadfree connector solution at the request of the automotive industry. Steven Antaya says that the task was made that much more difficult due to the inherent properties of lead.

“The biggest technical barrier to getting rid of the lead is trying to match the material characteristics that stop the glass from cracking. Lead is a very malleable material. When in contact with the glass, it’s not affected by changes in temperature.”

Essentially, lead is the least-reactive substance in terms of material expansion when exposed to higher temperatures. Attached directly to the window glass, other materials simply expand too much when heated, stressing the base glass product until it cracks. Antaya says that the company experimented with different additives and a range of adhesives in its search for a lead replacement, but nothing worked as well as the original material – until the company started experimenting with a new product, indium, which both had similar properties to lead and was non-toxic.

“Indium is a direct replacement for lead,” says Antaya. “There are other products that work in the same way, but indium works better on certain parts, particularly laminated glass. Laminated windshields are particularly delicate, they are much thinner than rear or side windows and they’re not tempered. From the late ‘90s, the ‘Detroit Three’ all had electrical applications in the windshield. The lead would sometimes crack the windshield, but the indium would not.” According to Antaya, connectors using indium were ideal for such applications as the window-mounted antennaes used by GM, while Ford and Chrysler both offered heated windshield applications designed to clear snow from the base of the windshield. “The lead was cheaper, but we always went back to the indium because of the performance,” he says.

Part resistance

If the European Commission decides not to extend the exemption that has allowed the continued usage of lead in parts such as window connectors, carmakers in Europe will need to source a lead-free alternative with immediate effect.

With this in mind, Steven Antaya says that he is surprised that there has not been a higher adoption rate of lead-free connector solutions. The problems, he says, cover three critical areas: cost, location and testing.

With regards to part cost, Antaya estimates that using the lead-free connector solution would add approximately one euro to the build cost of a single vehicle, the increased price solely down to the base material. “Indium is more expensive than lead. The [price of the] solder goes from $17/lb to $200/lb. What we tried to do was minimize the amount of indium used while maintaining the performance, protecting the glass from damage via the solder. We’ve been able to determine the least amount of indium necessary in order to meet the requirements and achieve the same performance levels.”

Location is also proving to be a barrier. “Where automakers in Europe have been used to working with local suppliers in the local supply chain, Antaya is a US-based company. We have protection on the product, so they would be forced into relying on a North American company for the material. We have offered to license the material to our competitors in order to get away from that ‘one supplier’ scenario, but there’s still considerable resistance.” He further says that the company is planning to open offices in Europe, a move which he hopes will help overcome this problem.

Testing, though, has proven to be a greater problem than both cost and location, despite Antaya being able to deliver extensive product data and usage statistics. “North American companies, carmakers and glass providers, all have a history with indium-based products. They know it works and that it works well. They have warranty data to which they can refer extending over many years to see if there were any problems, but they’re confident with the technology.”

Antaya continues by saying that General Motors has been the most proactive in adopting the lead-free solution; the carmaker now has about 20 new vehicle programmes evaluating the indium-based connectors. To get GM on board, the connectors had to pass the carmaker’s own tests, which they did with room to spare.

Yet although the parts exceeded GM’s in-house quality testing, Antaya claims European OEMs have recently introduced a new set of operational standards that are wholly unreasonable. “When we first came to Europe, we met with the European Commission and members of the glass industry, we tested parts to their standards – and passed. We demonstrated that [indium] was as good, if not better than lead. Then the local industry started to ratchet up their requirements. One of the differences between lead and indium is that the new material has a lower melting point. But all the new criteria were for the highest temperatures in the vehicle. The carmakers were setting temperature requirements at levels that could not possibly happen in the vehicle – these were extreme temperatures in which the material would inevitably fail.

“You can make the material fail. You can make any material fail. You can set conditions where anything will fail. In the conditions where the solder would fail, a lot of other materials would also fail.” Further to the temperature tests, parts are required to undergo a salt spray test, which Antaya says is bizarre as the connector is located inside the vehicle.

“How would the salt spray get inside the vehicle?” he asks. As well as being a part supplier, Antaya says that the company is heavily involved in product development. An integral portion of this involves part customization, which up until now has enabled the company to develop new alloys in order to keep pace with these ever-increasing product standards; which is further compounded by different standards being applied in various markets. It is, says Antaya, “like trying to hit a moving target”.

Better go green

Steven Antaya says that approximately 20% of the vehicles produced in North America feature lead-free connectors, and that this number is increasing each month. That said, he still buys in 100,000lbs (45,000kg) of lead per year in order to produce leaded components. Each of these requires approximately two grams of material, with a single vehicle using up to four separate units.

In addition to the cost of the raw material, he explains that as lead is considered a hazardous substance, personnel at the production facility must be protected. Training includes advice about not handling the connectors as the lead can be easily ingested. Further, the company is audited as to its lead usage, meaning that whether it becomes product or waste, the state of Rhode Island (where Antaya is based) demands that every ounce of material brought into the plant be accounted for, which itself requires a dedicated team at the facility.

“We’re slowly converting over to lead-free,” says Antaya. “We have to have dedicated lines for producing the lead-free product because it can’t be contaminated with lead from the other line. Hopefully that trend will continue and the lead will be phased out.”

With a lead-free alternative readily available, it’s difficult to comprehend why some carmakers are not more eager to make use of the technology. Despite the added cost – and how that would be multiplied out across a company portfolio that could achieve single-unit production figures in the millions - the cost of dealing with the lead solder at ELV must outweigh the initial part-price increase.

“The OEMs are responsible for that vehicle when it gets recycled,” says Steven Antaya. “The OEM is responsible for the vehicle being disposed of properly. If lead is discovered in a landfill and it came from all these rear windows, the OEM is responsible. With the indium, parts can be disposed of normally.”

Further to this, there is the public relations benefit of switching to a ‘green’ alternative. While Europe is known for its environmentally-conscious consumers, the connectors will first appear in less ‘green’ regions. “One of the first carmakers to adopt the lead-free solution was GM, and they have set lead-free as their global policy. This means we’ll be involved with lead-free programmes in China before we’re working on lead-free in Europe.”

Before the January 2013 expiration of the European Commission’s ELV (End of Vehicle Life) directive, a stakeholder review will take place in 2012. This will involve all parties, including Antaya. “We’ll meet with the glass industry, the OEMs, and argue our case before the European Commission,” says Steven Antaya. “Consultants will analyze the arguments and recommend either to extend or uphold the exemption.”

Although he believes that the OEMs will be looking for an extension of the exemption covering leaded connectors, Antaya is expecting that the ELV directive will be upheld.

“We have the only solution for lead-free connectors right now, so we’re hoping to become involved in a number of programmes in Europe very quickly,” says Antaya. Yet beyond this, he is looking for a fundamental change in his own business. “Working with lead is a burden. It’s a part of the supply chain we’d prefer not to deal with.”

More about indium

Without trying to be overly dramatic, lead is a nasty substance. It ranks second only to arsenic in the Toxic Substances and Disease Registry, with the other top-five candidates including mercury, vinyl chloride and polychlorinated biphenyl (PCBs).

On the other hand, indium is considered largely non-toxic. The product is widely used in welding and semiconductor production, but even at high exposures there have been no reports of workers experiencing any adverse side effects.

The first large-scale use of indium was as a coating for bearings in aircraft engines in World War II. The material was later adapted for use as a solder and for use in various electronic items, while most recently indium tin oxides had been used to develop thin-film applications used in production of LCD screen and touchscreen applications.

Named after the indigo line in its atomic spectrum, indium was discovered in 1853 by Ferdinand Reich and Hieronymous Theodor Richter.

The scientists were actually testing zinc ores in search of thallium, and the processing of zinc ore remains the primary source of indium. The Teck Cominco mine in British Columbia, Canada is the main source of indium for lead-free fl ux production at Antaya. Interestingly, before the introduction of the modern technologies now using the product, indium was considered to have no commercial value and was returned to mines unused.

While indium is considered harmless it is slightly radioactive, though the element has a half-life calculated to be longer than the universe has been in existence, meaning that it is very stable. About one-third as abundant as silver in the Earth’s crust, world-wide reserves are estimated to total approximately 6,000 tonnes of economically-viable indium, though according to the Indium Corporation, the largest processor of the element, improved recovery methods and sourcing indium from a wider range of ores will substantially increase this amount.

Point, counterpoint

Published in 2010, a study carried out by the Institute for Applied Ecology (part of the German-based Fraunhofer Institute) on behalf of the European Automobile Manufacturers’ Association (ACEA), evaluated the performance of connectors using both leaded and lead-free solder in create a connector-glass bond. Dependent on the results, a recommendation would be made as to the viability of the lead-free product and over what timeframe it would replace the leaded equivalent.

As one of the stakeholders included in the report, ACEA stated that leaded solder ‘is very good at equalising the thermal expansion differences between the metallic connectors used for these products and the base glass’, while also pointing out that indium was the only known element that could be considered as a replacement material. Yet concerns still existed as to the material’s comparatively low melting point.

Submitted by Antaya, the summation from an earlier test, carried out by GM, stated: “It certainly allows us to conclude that there is no higher fatigue risk with the indium solder than the leaded solder”. In spite of this, Volkswagen and BMW were assigned with carrying out additional tests on the different materials. These included simulated ageing of the products, followed by an infrared inspection, a microcrack inspection and a pull test – simply weights hung off the connector to validate the join (Antaya’s own testing saw the material left on two separate occasions for 500 hours, at 105oC and 100oC, the latter followed by a mechanical shock and vibration test).

Summarising the results of these tests, the ACEA report noted: “Within the range of tested glass samples and connectors, there are no technically definable glass and connectors where the lead-free solder joints would have failed to a degree that would prove that they are not appropriate for this kind of glass or connectors.”

Yet while Antaya viewed the test results as ‘a full success’, the vehicle manufacturers were less enthusiastic, describing the final data as ‘promising’. According to the OEMs, the low melting temperature of the lead-free solder remained a concern, as was the description of the new parts as a ‘dropin’ solution. According to the represented carmakers, testing, validation and incorporation of the new component would take a minimum of four and a half years.

Considering that it takes approximately three years for a new model to progress from the drawing board to production, the claimed timeframe seems unduly excessive. That aside, appreciable doubts still remained about the melting point of the indium-based lead-free material, which would reportedly start to melt at 109oC (leaded solder, 160oC). Humidity could create additional problems.

While humid conditions could reduce maximum cabin temperatures to approximately 80oC (OEMs claimed maximum cabin temperatures of 120oC at an air temperature of 45oC in midday sun), such conditions could create fog on the inner glass surface, requiring activation of the heater grid. This would raise the connector’s temperature by a further 50oC above the surface temperature of the glazing.

In conclusion, the report noted that:
• the lead-free solders performed well in the joint testing programme
• there are remaining concerns on the low melting point of the lead-free alloy
• there are different views on the timing of implementing lead-free soldering with [automotive] glazings.

The report continued: “Given the around 60oC lower melting point of the lead-free alloy, it is at least clear that the safety margin for higher temperatures in terms of temperature distance to the melting point is small and may cause problems.” With this, and further contention as to whether a satisfactory replacement for leaded solder has actually been developed, the report recommend that 40 months (from time of publication) be allotted for development and type-approval of a suitable lead-free alloy.

With this recommended timeframe expiring at the end of 2012, will it mean that Antaya will then be able to launch its lead-free connectors into the market, secure in the fact that the leaded alternative is no longer available? That remains to be seen, although while it is clearly beneficial to remove any lead from automotive production, the replacement must be fully fit for purpose.

Trust in performance

It stands to reason that OEMs must have confidence in any new technology. Should it prove successful, the result will rarely draw consumer accolades, yet problems will draw customer ire and possibly unwanted media attention.

Antaya estimates that the total number of vehicles produced with the lead-free connector was 700,000 units.

That said, the company’s case would have been that much stronger if the vehicles in question were still in production, instead of the GM ‘U’ vehicles (Chevrolet Venture, Pontiac Montana and Oldsmobile Silhouette minivans), which went out of production in 2002 and the Ford Thunderbird, which was withdrawn in 2005. Why was the product not incorporated in later models?

On the other hand, ACEA and the OEMs admit in the report’s conclusion that no proof was put forward to corroborate the claim that interior cabin temperatures could reach 130oC.

Although Antaya clearly wants to open up markets for its patented lead-free solder alloy, and removing lead from consumer products can always be welcomed, the company would appear to have a 90% solution. Should Antaya develop an indium alloy with a melting point only a few degrees, other problems such as type-approval could be worked out over time. Until then, carmakers are obliged to deal with leaded connectors, which must cost more than the additional one euro per vehicle that the lead-free product will entail.