Significance and Use
The spiral flow of a thermosetting molding compound is a measure of the combined characteristics of fusion under pressure, melt viscosity, and gelation rate under specific conditions.
This test method is useful as a quality control test and as an acceptance criterion.
This test method, by itself, is not a valid means for comparing the moldability of similar or different molding compounds because it cannot duplicate actual conditions prevalent in different types of production molds.
This test method is presently intended for use at a transfer pressure of 6.9 MPa (1000 psi) and a mold temperature of 423 ± 3 K (150 ± 3°C (302 ± 5°F)).
1.1 This test method covers a procedure for measuring the spiral flow of thermosetting molding compounds (soft or very soft) designed for molding pressures under 6.9 MPa (1000 psi). It is especially suited for those compounds used for encapsulation or other low pressure molding techniques. It involves the use of a standard spiral flow mold in a transfer molding press under specified conditions of applied temperature and pressure with a controlled charge mass.
1.2 The values stated in SI units are to be regarded as standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Note 1—There is no known ISO equivalent to this test method.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
D883 Terminology Relating to Plastics
D958 Practice for Determining Temperatures of Standard ASTM Molds for Test Specimens of Plastics
E105 Practice for Probability Sampling of Materials
spiral flow; thermosets; Flow and flow rate--thermoplastics; Spiral flow; Thermosetting plastics;
ICS Number Code 83.140.99 (Other rubber and plastic products)
ASTM International is a member of CrossRef.
Citing ASTM Standards
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