Description
Impregnated bits can penetrate a broad range of formations from the softest to the hardest rocks. They are manufactured with very small, high quality synthetic diamonds mixed evenly through a tungsten carbide matrix. During drilling the matrix wears away evenly resulting in continuous exposure of new, sharp diamond points throughout the life of the bit.
All impregnated bits have T.C. and diamond gauge protection. The optimum diamond size, concentration and matrix composition varies according to the hardness and abrasiveness of the rock formations to be drilled.
Depth of impregnation (D.I.)
Manufactured in two standard matrix depths – 3 mm and 6 mm D.I. – other depths can be supplied to order. The deep matrix is most cost-effective when drilling medium to hard non-abrasive formations. The shallow matrix is more suited to highly abrasive or fractured formations where large wear of the bit diam¬eter is anticipated and a deep matrix cannot be fully utilized.
Face profiles and waterways
Thin kerf bits (<10mm face thickness) are usually manufactured with a flat profile, and thicker kerf bits (>10 mm) with a W profile. The number and depth of waterways is optimized for the formation to be drilled. Secondary waterways or face dis-charge ports may be incorporated for certain applications.
Six standard matrix types are available as follows:-
| Matrix Type | Formation Type |
|---|---|
| GG-2 | A very hard matrix for drilling very abrasive or fractured softer formations. Used on powerful drills with high torque and thrust |
| GG-4 | General purpose bit with good abrasion resistance for medium-hard and abrasive formations. Suitable for most drills |
| GG-6 | For hard, moderately abrasive formations |
| GG-8 | For hard, uniform, non-abrasive formations |
| GG-9 | Free-cutting bit for hard to very hard formations of medium abrasively |
| GG-10 | Softest matrix for ultra-hard non-abrasive formations. Needs high speed, low thrust |
See “Core bit selector” for further information on matrix type and see Data Tables for full range of bit sizes and types.