Modular car windows can improve the quality, aerodynamics, and performance compared to conventional window systems. Matthew Beecham reviews the applications and prospects.

Modular windows are glass panels encapsulated with a plastic moulding. These modules require only a few operations before being assembled to the car body. In contrast, conventional window systems consist of a frame and window glass, which is installed at the car assembly plant. Typical applications of modular windows include rear and liftgate windows, quarter windows, aperture windows, sunroofs, fixed vent windows and windscreens.

Saint-Gobain Sekurit is a major supplier of modular windows. Davide Dardanello, marketing director, Saint-Gobain Sekurit International sees modular construction playing a more important role in the 12-month car. He said: “In a modular approach we can distinguish two things: first, the modular product offers OEMs direct benefits in terms of design (integrated antennae), style (extrusion) and easy integration.

"The second range of modular products is pre-assembly: pre-assembly is another service offered by Saint-Gobain Sekurit for incorporating components and functions on a glass pane. A great diversity of components can be pre-assembled on glass either manually or via automated equipment, such as rear-view mirror base, [and] rain sensor. Modular glazing is a complete glazing system supplied to the car manufacturers. These systems or modules are almost ready-to-mount and require only a few operations before being assembled in the car body. Using modules requires less space in the carmakers’ factories and helps improving their productivity by reducing the glazing assembly time and labour costs.”

A spokesman for BMW said: “Whether you use modular windows or not depends on design requirements and cost factors. Freedom in design is not the main argument in support of a modular window, since the parts and sections open to such modular design are very limited in geometric terms. Typical areas are the seals on the windscreen and the rear window allowing a more harmonious and smoother transi­tion from the window to the body of the car, as well as the side window frames, in some cases including the fastening elements for easier fitting and removal.”

As far as the outlook for modular windows is concerned, Glasstech Inc believes that modular windows are being increasingly sourced by North American OEMs.  John Baxter, senior vice president, sales and marketing, Glasstech Inc, said: “[Modular] glazing is already in considerable use in the North American automotive market and is likely to increase due to simplification of the final assembly process.”  As far as tomorrow’s modular glazing is concerned, Baxter believes that as a result of advances in moulding and bending techniques, the plastic frame is likely to become more slender giving a greater impression of continuous glass surfaces.

Saint-Gobain Sekurit believes that modular glazing is still very important for the automotive industry.  Dardanello added: “About 20% of the glass parts are encapsulated and the market is far from saturation; our direct extrusion on glass remains an interesting technology to frame windshields. Also, assembly of other parts onto glass is also successful, from a very basic pre-assembly of a location pin to a very sophisticated one, as an opening back window can be. The reason for this success is because OEMs want to use their internal resources to assemble cars and not to produce a car’s sub-components any more.”

In terms of manufacturers’ predictions for modular windows in terms of fitment to cars in Europe, Japan and North America over the next few years, Dardanello concluded: “Our predictions are that modular glazing will continue to be massively used in the automotive industry in America, Europe and Asia. We also see more complex modules, such as opening tail-gates, increasingly used.”

Windscreen edging

For some time, there has been a push for an overall smooth, aerodynamic style to the vehicle. Glassmakers have responded by designing smooth curved windows and flush seals. In particular, the use of single-sided window attachment systems such as encapsulation together with the hardware mounted on one side of the glass has grown in response to this need. Such systems reduce drag and noise, improve fuel economy and provide good aesthetic appeal. However, these single-sided mounting systems have created a number of challenges to window suppliers. For example, with both the seal and hardware on one side it is often necessary to have a wider frit area along the periphery of the glass together with a wider body flange.

Most of the flush mounting systems have been for fixed side and rear windows. For windscreens, the preference used to be for a moulding around its periphery. However, manufacturers report a lot of bare edging thereby eliminating the mouldings and giving the windscreen a clean look. That seems to be the trend in a lot of places, especially along the top of the windscreen and occasionally along the A pillars. PPG Industries sees this trend in the low- to mid-range segments.
John Brandmeier, global product marketing manager, PPG Industries, told us: “In the higher segments, OEMs want chrome trim or something with differentiated styling from the lower segments. So you will continue to see use of mouldings and brite trim on - higher-end vehicles.”  In terms of tomorrow’s systems, Brandmeier added: “We are exploring some avenues.  As we are in a very cost sensitive environment, we are looking for the right mix of solutions.  Encapsulation is a costly process. Many OEMs are looking for alternatives that provide the styling or assembly benefits of encapsulation or mouldings.  Those are opportunities for us to add value”

Jay Pyper, North American automotive market development director for Solutia Automotive agreed, adding: “We are seeing a trend to expose windshields where there is no encapsulate and even no moulding strip around the windshield. That is very significant. I think it started with VW in Europe. But you are now seeing a lot of OEMs go to that with the top edge of the windscreen with an exposed edge. The main advantages of that are aesthetics, assembly and ergonomics.”

Matthew Beecham