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Original Cerchar abrasiveness index tester (OCAI 70) - ASTM D7625-10

The OCAI-70 accurately determines the rock abrasivity index (CAI) employed for the classification of rock materials in terms of abrasivity. The CAI is a dimensionless unit obtained from measuring the wear on a HRC55 Rockwell Hardness steel stylus tip after it has been used to abrade a specimen with a 70N normal force. This instrument follows the ASTM D7625 method for determining the rock abrasiveness. The apparatus comprises a stationary stylus, a deadweight (70N) placed on top of the stylus. An articulated axis allows the user to place the stylus on the specimen. Then the movement of the axis will produce a reproducible stripe of length 10mm. The movement of the test is made by the operator at a speed of 1mm/second. Options include an indenter visualization system, spare indenters and a sharpening tool. The former encompasses a digital camera with indenter support and inspection software to reveal the wear amount which is then correlated to the abrasiveness index (CAI). The sharpening tool rapidly sharpens a worn stylus for subsequent scratch tests.


Standard : ASTM D7625-10.
Manufacturer : Floxlab
Load:70 N
Maximum specimen height: 150 mm (6 inches)
Maximum specimen diameter: 76 mm (3.0 inches)
Scratch distance precision: 0.01 mm
Steel Stylus: Rockwell Hardness HRC 54/56
Weight: 25 kg
Dimensions (WxLxH): 260x 460 x 375 mm


* ASTM-compliant
* Easy manual handling, original version
* Features precision slide for smooth movement of the rock specimen over the required scratch distance
* Easy adjustment of the daylight for different specimen heights

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