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Comparison: Coarse TD

Man in safety glasses looking at analysis screen

Eight samples of ISO Coarse Test Dust manufactured by Powder Technology Inc. and six samples of AC Coarse manufactured by AC Spark Plug division of General Motors Corp. were analyzed for comparison.

ISO Coarse Test Dust samples (formerly SAE Coarse) analyzed are those used previously to determine particle size limits shown in ISO 12103-1 Test Dust Standard. ISO Coarse samples ID numbers 4420A, 4491E, 4445B, 4446C, 4452C, 4465B, 4491C and 4499C were analyzed. Graph E indicates cumulative volume spread of ISO Coarse Test Dust samples analyzed.

ISO 12103-1, A4 Coarse Test Dust

(Microtrac X-100 Cumulative Volume)

AC Spark Plug Coarse Test Dust samples analyzed were selected randomly and included batch numbers 1418, 1474, 1484, 2071, 2507, and 2787. Graph F indicates cumulative volume spread of AC Coarse samples analyzed.

AC Coarse Test Dust

(Microtrac X-100 Cumulative Volume)

ISO Coarse Test Dust sample analysis data was averaged, as was AC Spark Plug Coarse data. Graph G compares cumulative volume averages of ISO Coarse and AC Spark Plug Coarse. Graph H compares differential volume averages of ISO Coarse and AC Spark Plug Coarse Test Dusts.

Comparison of Averages, Coarse Test Dust

(Microtrac X-100 Cumulative Volume)

Comparison of Course Test Dust Differential Data

Review of Graphs E and F indicate less batch-to-batch variation in ISO Coarse samples as compared to AC Spark Plug Coarse samples. Graphs G and H indicate AC Spark Plug Coarse contains higher particle content below 2.75 micron and above 74 micron than ISO Coarse Test Dust. Inversely, ISO Coarse indicates higher particle content between 2.75 micron and 74 micron. The median particle size by volume of AC Spark Plug Coarse is 34.5 micron, whereas ISO Coarse median volume is 29.6 micron. Generally speaking, AC Spark Plug Coarse is slightly coarser than ISO Coarse Test Dust. Product testing performance differences could be expected if ISO Coarse and AC Spark Plug Coarse were used as part of the same test program.