Research On Feeding Concept Of Casting Tooling For A Disc Braking Caliper

Brake caliper is a core part in the automobile disc braking system.When the automobile brakes,the piston in the cylinder is affected by the hydraulic oil delivered from pipe,which pushes the friction plate to brake against the brake disc,forcing the wheels to stop.The author of this paper,take the nodular cast iron brake caliper of pattern design and process as a research project,with the aid of Magma casting simulation software to simulate the metal filling and solidification process,study the shrinkage porosity distribution and its forming reason,to optimize the filling and feeding system on the pattern,in order to eliminate the shrinkage defects in the casting process and improve internal soundness of the casting.First,based on the structure and material requirement of the casting,determine the chemical composition of molten iron.Secondly,according to the solidification theory of nodular cast iron,analyze the solidification character of brake caliper,including the size(modulus),quantity and location distribution of the hot spot,with the help of simulation software,to guide the casting pattern gating and feeding system design process.The core theory of this paper is taking advantage of feeding system design and other auxiliary process to intervene the solidification sequence and solidification rate of the iron liquid,to make the whole casting solidification process tend to progressive solidification,which would ensure there is no shrinkage porosity in the casting due to the structure design of the part.It studies several design schemes that combine the cooling fin,feeder and heating block in different process parameters,the optimal pattern design scheme with lower tend of internal shrinkage and higher benefit is determined by Magma software simulation to kick off the pattern,subsequent pouring test is implemented to verify the final design and process.Through the research in this paper,the preliminary conclusion of eliminating or reducing shrinkage defects from the direction of pattern process design are as follows: the tapered pressure riser with smaller modulus runner that connected to the riser,compared with the riser neck to solidify earlier,can improve the feeding efficiency.At the same time,the molding sand in the certain narrow area can be heated by setting a heating block or adjusting the parting surface of the casting.Because the specific heat of the molding sand is bigger,the overheated sand mold can keep the internal feeding path open longer,and then to extend the feeding distance of the riser.