Friedrichshafen, Germany — A new capacitive vibrating haptic feedback touch steering control solution developed in a "Vibra" project is molded in Sparneck, Germany, and Suzhou, China, by the KH Foliotec GmbH and KH Unikun subsidiaries, respectively, of Helmbrechts, Germany-based Kunststoff Helmbrechts AG, using injection molding machines from Lossburg, Germany-based Arburg GmbH + Co KG.
The new control is applied with differing symbols but the same base molding to Volkswagen's latest Golf GTI and R sport models and the ID.3 battery electric vehicle (BEV) car, which went into production on Jan. 29. KH Foliotec received first orders for the control from its Tier 1 supplier customer in Fall 2020 for use in VW's Dessau and Dresden plants and at SAIC-Volkswagen in Shanghai, China.
KH Sales Director Christoph Ernst says the capacitive steering control is the "first to be produced by in-mold labeling (IML) and the first use of functional foil bonding (FFB) in automotive construction." KH Foliotec Sales Director Thomas Ruff stresses, however, that FFB had previously found application in other areas such as washing machine control panels.
The ID.3/Golf unit is based on a 3D capacitive touch control smart door panel demonstrator for GE-T developed with decorative film specialist Leonhard Kurz Stiftung & Co. KG and displayed as a highlight on the KH booth at K 2019.
Both the K 2019 demonstrator and the ID.3/Golf application involve Kurz FFB functional foil bonding sensor technology, itself based on transparent touch sensor technology from Fürth, Germany-based PolyIC GmbH & Co. KG, using a silver-based metallic grid applied to a PET foil carrier.
Rudersberg, Germany-based Kurz hot stamping machinery subsidiary Baier GmbH + Co. KG Maschinenfabrik developed FFB and launched it at Fakuma 2018.
FFB fully mechanically bonds touch sensors to plastic components outside the core injection molding process: an alternative to in-mold labeling (IML) integration. Ruff says KH Foliotec desisted from a single-stage, one-shot IML process in favor of IML followed by a separate FFB stage, as faulty IML moldings can be jettisoned on their own, without loss of relatively expensive but less precise sensor foils.
Kurz says FFB avoids potential adhesion loss and bubble formation under climate tests when using optically clear adhesive (OCA) or pressure-sensitive adhesive (PSA) to bond sensors to plastic moldings.
A particularly innovative feature of the variably configurable high-gloss polycarbonate foil-based hidden-when-inactive vanishing symbol "black panel" display on the new control is "finger-guiding." Here, a cross-form recessed area in the foil produced by a "Speedform" technique enables drivers to safely feel for desired functions with a finger or thumb without looking at the control.
KH Foliotec has used lacquered and laser-scribed foils on the mechanical switch steering wheel controls on preceding VW shared modular design platform (MQB) models, but sensor switch technology for the new control unit has now cut depth by 12 percent, Ruff said.
With a switch for each of typically 10 different functions, Ernst said, the earlier design required a "huge investment in around 15 single- and some two-component injection molding tools, compared with just three eight-cavity tools with the new design."
A white injection molded "spacer" part under the display provides light diffusion. Located a one-hour drive from Sparneck, KH Czechia in Chodov, Czech Republic, ultrasonically bonds the components together and assembles the final control.