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Hayes Lemmerz has made an enormous leap in technology by creating a new “4 in 1” disc rotor that solves brake industry noise, dimension accuracy, thermal diffusivity and “hot spot” rotor problems. By closely adhering to a disciplined system of concurrent planning, product development and production feasibility studies (which included material development and CAE design and dynamometer and vehicle tests), Hayes has solved the brake industry's top four warranty concerns. Development of several propriety manufacturing methods, production system/equipment and quality assurance procedures followed to bring this product from the Development Laboratory to the Production Plants. Hayes' new brake rotor is designed with damped iron composition, 72 curve fin rotor geometry and is then processed using Hayes' patented ULTRA-Q process. The 72 curve fin rotor design, developed through previous Hayes efforts (Ref-1,2,3,4) creates a 100 degrees F cooler running rotor.

Hayes Lemmerz, in a previous paper (Ref-1), has introduced an HQ (Hayes Quiet) rotor design where the noise level was reduced by 50%. In this paper, various methods of joining the brake plates to the fins are investigated. The effect of welding is to create a metal joining path which connects the bell shape of the rotor and consequently, the noise level increases. Glue between the brake plates and fins acts as an excellent noise damping layer, but welding through such a layer introduces porosity. The successful design used in the HQ Rotor is when brake plates and long fins are glued together and in place of short fins flat head screws that are used to hold the brake plates against the fin's surfaces. The result of this joint is a Q-Factor number of 211. Damped iron cast joints exhibits a Q-Factor of 500. Glued joints with screws show a Q-Factor of 211 and this kind of joint does not raise the Q-Factor compared to just glued joints.

Hayes Lemmerz has published in previous papers (Ref-1, 2 & 3), the method to low temperature nitride and polymer coat cast iron rotors to provide increased corrosion life, wear resistance and reduction in brake noise. We have, in this paper, investigated the two key dimensions of the rotor before and after the Nitriding Process. Low temperature (1050 degrees F) nitride finish machined rotors have to be handled in a special support fixture to prevent a change in thickness variation (TV) and lateral runout (LRO). Hayes Lemmerz has developed methods to keep LRO and TV in the print specification after the Nitriding and polymer coat process. The parts are made to extremely tight LRO and TV tolerances so that Nitriding done on such rotors, the dimensions of the rotors do not exceed print specification.