Mold testing

Fig. 3 -29 Injection molded test specimens that include weld lines.

Injection blow molding that employs injection molded test-tube shaped preforms or parisons... 

Spiral Mold Test. Processing stabilities were also determined by the spiral mold test (5). The resins were injection molded in a 3-ounce reciprocating screw injection molder at 25°F. (14°C.) intervals from 425° (219°C.) to 600°F. (316°C.) using a 55-inch spiral mold under the following conditions mold temperature, 80°F. injection pressure, 16,000... 

Figure 8. Spiral mold test. Spiral lengths at designated molding temperatures...

Figure 9. Spiral mold test. Melt flows of the injection molded spirals at 230°C.

Figure 12.2 Stress-strain curves of HIPS at various test temperatures. Strain rate = 2mm/min, determined on injection-molded test specimens...

Injection molded test specimens. SMMA = Nova NAS 21 styrene-methyl methacrylate copolymer. 

New grades of SMMA are being developed that have shown tremendous potential for blends in SBC. These new grades result in very high impact in the blends with higher loadings of SMMA. Notched Izod impact values of almost 5 ft-lb/in have been reported for injection molded test specimens containing 50 % SMMA [22]. 

Injection molded test specimens. SAN = Monsanto 31-1000 styrene-acrylonitrile copolymer. 

Injection molded test specimens. PP = Marlex polypropylene homopolymer (nominal 5 melt flow). 

A magnetic filler in the form of fiber was added to HDPE and injection molded test products were made. Anisotropic composites were manufactured to induce flow orientation of the fibers. The increased orientation contributed to the generation of a higher permeabihty magnet. The orientation can be affected by changing the die diameter. 

In addition to testing methods and product specifications, ASTM Committee D-20 on Plastics has also prepared definitions of terms and recommended practices for molding test specimens and constructing testing equipment, conditioning and weathering procedures, and related standards. These are published in the ASTM books of standards (4-7). There is also a federal standard for laboratory atmospheric conditions for testing (34). 

Molding. Test specimens were either compression molded in a hydraulic press at 245°C or injection molded at 275°C using a 2-ounce Ankerwerk, Model 75. 

ASTM D 3895 Standard Test Methodfor Oxidative Induction Time of Polyolefins by Differential Scanning Calorimetry Note of the author This procedure cannot be used for filled composite materials regarding Sampling section, particularly for those employing rather large filler particles. Instead of compression-molded test samples into sheet format prior to analysis to yield consistent sample morphology and weight and cut specimen disks (6.4-mm diameter) from the sheet to have a... 

Shahani and associates (37) studied the effects of the antifungal antibiotic Natamycin (Pimaricin) on the growth of several mycotoxigenic molds (Table VII). They found that at 1.0 ppm, Natamycin inhibited mycelial growth from 16.0 to 23.6% depending on the mold tested. Ochratoxin production was inhibited 93.2%, penicillic acid 70.6% and patulin 97.8% at the same concentration. 

ASTM D5224-93 Practice for Compression Molding Test Specimens... 

ASTM D5224-93, Practice for compression molding test specimens of thermosetting molding compounds, American Society for Testing Materials Publication, Philadelphia, 1992. 

The results of tests on molded test pieces and finished products can in many cases be influenced by the way the material has been processed. This in turn is influenced by the materials processability. Indeed there are very many cases of product failure resulting from processability changes, while misunderstandings and lack of information can also result in reduced output rates, high scrap rates, and general production inefficiencies. 

Measurement of shrinkage as a material property is covered by ASTM D955-89. In this test (which also covers transfer and compression molding), the shrinkage is derived from measurement of molded test pieces and the mold cavity dimensions. The moldings used are a bar 127 x 12.7 x 3.2mm and a disc 102mmdia x 3.2mm thick. 

In BS 2782, Method 132B [175], the blistering propensity of thermosets is examined by heating a suitable molded test piece in a liquid bath at a rate of 120 C/hr. At a temperature some lOX below the expected blister temperature, a test piece is removed and visually examined for blisters. The process is repeated on separate test pieces at every 5 increment in temperature until the examined test piece shows signs of blistering. 

ISO 293 Compression molding test specimens of thermoplastic materials... 

This decay rate is nearly equivalent to that exhibited by one g of radium in equilibrium with its disintegration products. A miUicurie (mCi) is 0.001 curie, curie point See magnetized curie point, curing See autoclave nitrogen atmosphere cure extruder wire and cable process, dry cure inhibitor prepreg volatile content reinforced plastic resin transfer molding test, Barcol hardness test, scorch Mooney thermoset plastic vulcanization welding, induction. 

In conceptual form, it has been tooled and molded, tested for tube installation effort and initially tested against the flap assembly baffle for IL performance. Figure... 

Considering the above requirements, we decided that four test methods would be evaluated Polyethylene Compound Test, Mix Mold Test, Precompound and Mold Test, and Concen-trate-Extrude and Mold Test. 

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