The partnership project involved the Polyscope team working closely with automaker Groupe Renault, First Tier automotive roof systems market leading manufacturer Webasto SC (Les Châtelliers-Chateaumur, France), along with specialist toolmaker and moulder AARK-Shapers (La Séguinière, France), according to a press release by Polyscope. Webasto engineered the injection moulded rails to include a high level of functional integration while simultaneously reducing part count and the number of assembly operations, cutting manufacturing time, cost and complexity.
The move from conventional anodised aluminum extruded profiles to thermoplastic composite guide rails provided Renault with customer design improvements: freeing up 13 mm headspace for passengers and increasing the angle of vision through the glass panel (called daylight opening). The Xiran Sgh30eb composite guide rails simplified the construction and installation of the sunroof on the Scenic and Grand Scenic vehicle assembly lines. In total, the project delivered a significant system cost reduction for the installed, improved design, panoramic sunroofs.
The formulation was optimised by Polyscope, firstly, to ensure high bond strength with the polyurethane adhesive used to mount the glass to the module, and the module to the body-in white (BIW) roof structure, and secondly, to ensure that dimensionally stable precision parts with a high shot to shot consistency were injection moulded, which is highly critical for the smooth opening and closing operation of the roller-blind system; the need to use a lubricating grease on the rail guides was also eliminated.
Clever tooling by AARK-Shapers enabled eight acrylonitrile butadiene styrene (SMA-GF) composite parts for the sunroof module to be moulded in a family tool that also features modular blocks. This allows both Scenic (five-seater) and Grand Scenic (seven-seater) guide rails to be moulded in the same tool without using costly tool moving slides or needing additional tools. The asymmetric upper and lower thermoplastic rail sections were injection moulded in two pieces and then joined after demoulding. At Renault’s assembly plant, the redesigned sunroof system arrives from Webasto fully assembled and pretested as a one-piece ready to install unit. The sunroof unit is then robotically bonded to the vehicle roof, cutting out two-to-three assembly steps, thereby increasing productivity. In addition to the initial significant cost reduction for installed sunroofs, as the thermoplastic composite module has fewer parts. Renault also expects to benefit from reduced long-term warranty costs, due to lower parts/million defects and higher quality since 2016.
This was a significant automotive innovation for the industry, being the first time that a thermoplastic composite material has successfully replaced aluminum for this type of sunroof design in a mass produced passenger car. Xiran Sgh30eb is a 15 per cent glass-reinforced copolymer compound of styrene maleic anhydride and SMA-GF.
There is an environmental benefit for Groupe Renault in switching to a thermoplastic composite for the sunroof guide rails. Like aluminum, the SMA/ABS base resin material is fully recyclable, but uses significantly less energy to produce the rails and to recycle them at end of a vehicle’s life.
“We are absolutely delighted and feel very honoured to have won this prestigious JEC Innovation Award. It was a challenging application development for the Polyscope team, but we were fortunate to be working with outstanding, highly technical, design and engineering people in Webasto France and Groupe Renault and the specialist partner companies involved in this project,” said Ferdi Faas, business unit director at Polyscope Polymers.
Polyscope specialises in the research and product development of styrene maleic anhydride (SMA) copolymers, compounds, aqueous solutions and styrene, maleic anhydride and Nphenylmaleimide (SMANPMI) terpolymers. The company is working on a number of innovative projects in other market sectors, as well as automotive, where customers are looking for more precise and lighter weight alternative solutions in a high performance thermoplastic composite material which can also simplify component construction and assembly. (PC)
Fibre2Fashion News Desk – India