Why some black spot left on Aluminum diecasting parts

There are some reason:

1.     Maybe the aluminum material not purity enough, it have more black Oxide silica.

2.     Mold release agent spray too much or it contain too much Metal organic.

3.     Black Plunger lubricants left and splash on diecasting parts.

Solution:

1.     Change the raw material aluminum ingot.

2.     Use less mold release agent or increase mix water ratio,;change the mold release agent;

Pro-long the gas blow time after spray release agent.

3.     Use high purity white plunger lubricants, no black or graphite include.

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