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Eliminate Cold Box Veining Defects with AF7

  • Eliminate Cold Box Veining Defects with AF7


    Eliminate Cold Box Veining Defects with AF7

    Veining defects are one of the major problems associated with cold box core production but it is also associated with other processes such as resin coated sand. Traditional anti-veining processes can have a bearing on resin demand and gas evolution which can have detrimental effects for certain casting types such as water jackets.

    John Winter recognised a need for an improvement and by working closely with our automotive customers our R&D team have produced a new anti-veining compound product with both environmental and performance benefits.

    The inorganic material of John Winter’s AF7 has no resin demand and has the potential to offer significant reduction in gaseous defects.
    AF7 gives castings a high quality surface finish, reduces subsurface gas defects, fettling costs and reduces scrap, as well as reducing the blowing pressures and times allowing an improvement to production performance.

    This new sand additive has also shown its anti-veining characteristics in resin coated sand, eliminating waste and reducing re-work times. Casting type or geography of the local silica sand may dictate resin coated sand as the preferred method of core production. This heat cured process still suffers from expansion defects and AF7 added during the coating of the sand has been proven to offer the same benefits as used in the cold box process.

    AF7 has been developed with the automotive market in mind and along with solving this common expansion defect it has the added benefit of offering dimensional stability during casting. This is of particular interest to the producers of ventilated brake discs, offering a more consistent planar tolerance.