Defect characteristics, causes and prevention of casting draft


During the molding operation, there is sand sticking on the formwork, and the mold cavity has such phenomena as pulling crack, falling sand, floating sand, etc.


A. Insufficient preheating of formwork

B. Uneven spraying of release solution

C. Molding sand is too dry

D. Draft angle too small or too little sand

E. Poor exhaust and sand shooting

F. The finish of the model or flow path is not enough, and there is reverse draft

G. There are foreign matters or damaged accessories on the back of the formwork, and disa is not vertical when assembling

H. Disa parallelism deviation, resulting in the shape plate is not vertical

Rust on formwork:

Plan improvement measures:

A. Repair the R angle, carefully polish the plan to improve the finish

B. Check the accessories and replace the damaged ones in time

C. If necessary, increase the draft angle. If the draft of the flow path is not good, fill the draft angle with soil or use 2A aluminum flow path

D. Increase the number of air holes (mesh) to avoid poor draft caused by sand shooting

E. Polishing the bad part of draft with air milling cutter

F. Stick rubber head in through hole

G. Copper sleeve is recommended for holes with small diameter and large depth

H. Best solution design