Applications Note

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www.alliedhightech.com 
Allied High Tech Products, Inc. 
Call for more information: 800.675.1118 
Applications Note
1200 (P-4000) Grit vs. 1200 Fine Grit 
 
 
Descriptions 
 
1200 (P-4000) grit abrasive discs are 
sputter coated. This causes the silicon carbide 
(SiC) particles to be randomized, which 
provides more of a “polishing” action. 
1200 (P-4000) grit is recommended for general removal of deformation from a previous step. 
 
1200 Fine grit abrasive discs are 
electrostatically coated. This causes the SiC 
particles to stand on end, which provides more 
of a “cutting” action. 1200 Fine grit is recommended for soft materials that smear, step grinding for 
failure analysis, or when continued material removal is desired (typically after 600 grit). 
 
Surface Finish Comparison 
 
 
 
Material Removal and Durability 
 
Aluminum rods were encapsulated in green phenolic mounting 
powder, while steel rods were encapsulated in red phenolic 
mounting powder (Figure 2). They were ground separately to a 
600 grit finish using the MetPrep 3™ grinder/polisher with PH-3™ 
power head. 
 
The mounts were then ground using 1200 (P-4000) grit and 
1200 fine grit to compare material removal using the procedure 
outlined in Table 1. Only one abrasive disc was used for each 
test; the disc was not changed in order to determine durability 
for each set of conditions. Material removal was checked every 
minute using a digital indicator measurement system. 
Figure 1: 5X objective, Brightfield. Left: Aluminum rod ground using 1200 (P-4000) grit. 
Right: Aluminum rod ground using 1200 fine grit. 
Figure 2: Aluminum rods (green) and 
steel rods (red) were mounted in 
phenolic. 


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www.alliedhightech.com 
Allied High Tech Products, Inc. 
Call for more information: 800.675.1118 
 
2 
Table 1: MetPrep 3™ with PH-3™ Grinding Parameters 
 
Variable 
Specification 
Platen RPM 
300 
Sample RPM 
150 
Direction 
Comp 
Force (per sample) 
6 lbf 
Time 
1 min 
 
Testing was first performed using three aluminum and steel mounts and then repeated using only one of 
each mount, to compare material removal under different conditions (Figure 3). The data shows that 
1200 fine grit discs remove much more material over the same amount of time than 1200 (P-4000) grit 
discs. The removal rate dropped off after 2-3 minutes, indicating that they should be discarded after that 
timeframe for the best results. 
 
 
 
Figure 3: Graphs showing rates of material removal for the rod samples. 
0
2
4
6
8
10
12
14
1
2
3
4
5
6
Average Material Removal (µm)
Minute
1200 (P‐4000) Grit 
3 Al Samples
1 Al Sample
3 Steel Samples
1 Steel Sample
0
20
40
60
80
100
120
1
2
3
4
5
6
Average Material Removal (µm)
Minute
1200 Fine Grit 
3 Al Samples
1 Al Sample
3 Steel Samples
1 Steel Sample