Graining

Section 1 List

Description

Defect Type

Negative

Appearance

Mottled, rough appearance at the surface, sometimes in patches.

Size

varies

Typical Location

Large flat featureless surfaces

Aliases

Orange peel

Method for defect determination

Visual inspection with tangential lighting (at a low angle to the surface to create shadows of small protrusions)

Mechanism

Irregular surface condition is cause dependent

Corrections

Equipment Out of calibration

See Best Practices Section

Equipment Low wax temperature

Increase wax temperature.

Equipment Low injection pressure

Increase injection pressure in reasonable increments

Equipment Wax flow insufficient

Increase flow rate.

Equipment Filler separation

Use proper conditioning parameters including appropriate agitation in melting tank and in tank. Ensure wax has not separated in injection hose/nozzle by purging. Consult wax supplier for conditioning and melting procedure

Pattern Die Cold die

Reduce cooling water. Preheat die before injection.

Pattern Die Poor surface finish in die

Polish die cavity.

Pattern Die Excess mold release

Reduce amount of mold release