ANALYTICAL AND EXPERIMENTAL STUDY ON PDC DRILL BITS QUALITY
Under geological extreme conditions, polycrystalline diamond compact bits (PDC) are a relevant choice because of their interesting drilling performances. In this way, the quality of innovating PDC bits materials has to be determined with accuracy by measuring cutting efficiency and wear rate, both related to the overall mechanical properties. A lathe-type test device was used to proceed to the first experiments. During these tests, cutters have been worn over an abrasion length greater than 15 km, with a mean normal load range from 3000 to 5000 N, a cutting speed about 1:8 m/ s and a penetration depth close to 2 mm. Analyses are based on models establishing coupled relations between cutting and friction stresses related to the drag bits excavation mechanism. In this work, models are implemented in order to evaluate cutting efficiency and to estimate the life time of the diamond insert. A variety of cutters was characterized by wear rates ranged from 9.4•10^(-15) to 1.1•10^(-13) mm^3/(Nm) (Archard’s model) and cutting efficiencies at 10 km evaluated between 31 and 55%. From here, an original approach is developed to describe the overall cutter quality by defining a ratio between efficiency and wear. The reference samples during preliminary tests clearly revealed various mechanical behaviors due to changes in the material composition and distinct manufacturing production methods. These changes are detected at several levels: coatings, grain sizes, surface roughness, etc.
The current state of PDC bit technology
Part 1 of 3: Development and application of polycrystalline diamond compact bits have overcome complex challenges from the difficulty of reliably mounting PDC cutters in bit bodies to accelerated thermal wear.
Trends in kiln drives
The heart of the cement plant is the rotary kiln, and continuous quality production of cement clinker depends on the continuous accurate performance of the rotary kiln drive.