2. The surface finish is poor (including sand holes, burr, sand inclusion scarring)Caused a lot of invalid clay molding sand poor tensile strength and toughness of low, poor permeability.Increasing sand brittleness, the sand fragile boxes, sand, formed in the casting sand is easy to fall when defects such as sand holes, burr and slag scarring, then the quality of the castings.3. The adhering sand4. When modelling off sand, the collapse boxDeath of clay without cohesive force, caused a lot of dead clay sand mould sex difference, make the sand fragile boxes, off the sand.5. Stick mold6. Porcelain phenomenon more and more in the sand7. A simple artificial sand screeningMany enterprises adopt double sands, simple artificial screening, plus a host of new sand and more auxiliary materials used for surface sand after mixing, the back sand is regular screening, more problems.
sive defects such as porosity, water is less than, cold-lap formation.