Why Often Appear Shrinkage in Casting Surface? How to prevent?

1. casting surface

Your cast iron metal pans are shipped with pinholes, causing your customers to have a string of complaints. What happened? How could you have prevented this from happening?

Production in a foundry is a complex multi-step process. The skill level of each process varies greatly. Operator skills, quality management and equipment all affect the final quality of the casting.

The causes of shrinkage in casting surface are as follows.

  1. Molding wax injection locations poorly designed, thick wall parts not feeding.
  2. Casting wall thickness difference is too big, thick, thin in cooling rate.
  3. Mold material overheating, molding temperature is too high, cause a large mold material shrinkage rate, solidification time growth.
  4. Injection pressure and holding time is not enough, did not get full filling and feeding pattern material.
  5. Type pressure cavity brush oil too much, or in cold water after cooling molding, the residual water in the cavity not wipe clean.
  6. Mold material at low temperature, the shrinkage of large stone makes much more content of wax pattern itself.

To prevent casting Surface shrinkage depression are as follows.

  1. Inject molding wax is open in the thick wall; Too thick mold will place into a hollow form, or in easy to produce “shrinkage in” thick most place “false core” (false core is embedded in advance within thick ranks as one of the most pressing type with the same pattern material making good core, pressure injection molding material after let it stay at most a middle thick, and pouring of people paste fusion pattern material (together).
  2. Reduce the pressure of work and betting the pattern material (temperature, can according to the summer and winter temperature is different, adjust the pressure injection speed.
  3. Pressed parting agent should be thin and uniform coating, can not form accumulation. Pressed on with cold water after cooling cavity should be residual water wipe clean. Adding an appropriate amount of stearic acid
  4. Mold of material

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