Defect prevention

Increasing the wet tensile strength of the molding material mixture through

  • A higher binder content (bentonite)
  • The use of better bentonites with a larger specific surface
  • The use of optimally activated bentonites
  • Excellent cooling of the mold material
  • A high releasing effect in the core box
  • Aiming at a better (optimum) preparation of the mold material
  • Selection of a courser sand grain size with a sand grain that is as round as possible

Reducing occurring compression stress through

  • Quick and even mold filling
  • Avoidance of mold materials that are too moist
  • The use of mold material additions that buffer the expansion of silica by means of softening or burning (e.g. neutral or basic swelling binders for steel casting)
  • Partial or, if necessary, full replacement of the silica sand with refractory sands with a lower expansion, for example zircon sand or chromite sand.