Grzegorz Lajca: “It was almost a rule that the average glazing area of every new model of a given brand was bigger than that of its predecessor.”

Grzegorz Lajca: “It was almost a rule that the average glazing area of every new model of a given brand was bigger than that of its predecessor.”

Glazing continues to play an important part in vehicle design, providing a combination of aesthetic, functional and structural properties.  As a result, automakers are increasingly looking for their glazing suppliers to play a key role in the vehicle development process. Continuing just-auto's series of interviews with leading players in the vehicle glazing market, Matthew Beecham talked with NordGlass Group's CEO, Grzegorz Lajca. NordGlass develops and manufactures windscreens for the automotive sector, railway, shipping and construction industry.  

While windscreens have become more raked, could you comment on the trends in windscreen curvature and what you have seen there?

The cross-curvature of windscreens is growing continuously. Fifteen years ago a windscreen with relative cross-curvature of 1.5% (i.e. the ratio between cross curvature, as measured on the symmetry axis and the height of the windscreen) was considered being heavily bent. Today's windscreens' relative curvature can reach 3.5% and even more, while 1.0 - 1.5% is considered to be a normal value.

Could you also comment on the extent to which the sheer size of windscreens is increasing and how that has affected your business operations?

Generally, the average developed area of glass parts in cars, especially windscreens, has been growing over the past ten to fifteen years. It was almost a rule that the average glazing area of every new model of a given brand was bigger than that of its predecessor. The difference in windscreen developed area size as compared between models from the beginning and the end of the said 15 years' time span may reach as much as 50%. Recently, this trend slowed down to some degree but in many cases can still be observed.

Moreover, some car manufacturers, apart from models with "standard" glazing (already relatively large), started to offer models with extra-large windscreens (so called cielo windscreens), reaching far behind the driver's head. These trends force auto glazing manufacturers to update the existing production equipment, in order to be able to process bigger glass sizes.

Additionally, growing glass sizes generally require constant improvement of production and quality standards, especially those affecting optical quality. To a various degree they also affect the handling, storage, transport, packing and fitting operations, respectively.

The more antennas you can put discretely into the windscreen, the better styling. What are the other factors driving the glass-mounted antennae in vehicles?

Styling is an important factor. Others may be noise reduction and contributing to the compactness of a vehicle. Also, having antenna incorporated in the windscreen removes the need for motorised antenna systems, thus allowing for a simpler, more robust design of a vehicle, without negatively affecting the function.

There are so many services used in cars nowadays, such as radio, TV, cell phone, navigation, emergency calling and tolling.  What are the design implications for integrated antennas?

The actual design of an antenna does not depend heavily on its function. Basically, there are two systems in use. The first is a silver overprint on the surface of glass, similar to the one that is used for defrosting/demisting the rear window in a vehicle. The second solution is a thin copper wire embedded inside the glass laminate. Both of these systems have been around for years, serving as radio antennas, and they are successfully utilised nowadays with new functions added.

Given the rearview mirror incorporates a variety of driver assistance systems, are there special considerations for the rearview mirror hook or adhesives used to support and attach it to the windscreen, respectively?

Whenever a complex driver assistance system is present on the windscreen, it is usually more than one supporting element carrying it. Typically, there is one bracket carrying the rearview mirror, and one or more others, carrying the sensor(s) elements, a camera etc., respectively. The whole system with multiple brackets is hidden under a plastic cover from the inside of the vehicle side and behind an obscuration print from the outside. Therefore, it may seem that all of them are attached to the mirror, but that is not the case. As a consequence, the overall load applied to each individual bracket is not excessively higher as compared with loads applied to a "bare" rearview mirror supporting elements.

To what extent do the sensors and cameras attached the windscreen have to be re-calibrated when replacing a windscreen?

There is no rule. It has to be noted that the systems vary largely both in function and in design. Usually, the equipment works without problems after the windscreen has been replaced. In some cases however, a recalibration may be necessary. It refers especially (but not exclusively) to situations, where a windscreen is installed whose construction is different than that of the original one (e.g. green solar instead of clear).

In terms of heatable windscreens, there are two solutions to clear windows of mist and ice from a windscreen, that is forced air heating and electrical resistance heating.  While forced air has been around for decades, to what extent are windscreens using electrical resistance heating?

While the performance of electrical resistance heating is far superior to that of forced air systems, the market share of the former is limited to very few car makes only. One has to remember however, that air demisting/defrosting system is merely a by-function of the forced air circulation system that is present in a car anyway, and whose primary function is ventilation and heating of the cabin. On the other hand, the resistance heating function is an add-on that requires a special design of the windscreen (increasing its cost significantly) as well as additional power reserve in the electrical system of a vehicle.

To what extent are heated windscreens being fitted in the European market? How does that compare to the US market?  What are the reasons for the differences in fitment?

In Europe heated windscreens are covering 5-10% of the market, but there are big differences in distribution between countries. There is significant difference arising from car models sold in Europe and US. Some of the car manufacturers use heated windscreen as a standard solution. In some cases it is used depending on country - i.e. you don't find it in cars sold in Spain or Italy whereas it is standard in UK. Generally speaking, this solution is less popular in the US.

To what extent are carmakers adopting one-sided mouldings which provide the flush look while hiding the gap between the edge of the glass and the pinchweld?

The remainder of this interview is available on just-auto's QUBE research service

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