Poor lower core (core deviation, core dropping, sand squeezing and core breaking)
A. Mask is not adjusted well, positioning and deviation.
B. The interference of core nail is unreasonable.
C. The positioning surface of sand core is too small.
D. Disa equipment adjustment is unreasonable or faulty.
E. The sand core does not fit well with the outer mold.
Plan improvement measures:
A. The riser and flow path shall not be set on the positioning surface of the sand core as far as possible during the design and manufacture of the scheme, so as to avoid the core deviation or sand squeezing.
B. The copper skin is pasted on the sand extruding part or the model at the part is enlarged, and the drape joint is enlarged, so that the sand core can be placed smoothly.
C. Ask the fitter to readjust the mask to confirm the positioning and the interference of the core pin.
D. Check whether mask is cracked, leaking or deformed.