Which Geological Conditions Are Suitable for Flat‑face, Concave‑face, and Convex‑face Drill Bits?

1. Flat‑Face Bits

General‑purpose bits, suitable for most common conditions.

Features:

Simplest and most versatile structure; impact force acts directly on the rock, offering high energy transfer efficiency; moderate cuttings removal capacity; average directional stability.

Applicable formations:

Hard rock and highly abrasive formations.

Not suitable for:

Loose formations (prone to bit sticking) and highly fractured formations (prone to hole deviation).

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2. Concave‑Face Bits

Features:

The concave center creates a guiding effect; excellent cuttings removal (critical); best hole straightness with minimal deviation; impact force is slightly dispersed, but overall efficiency remains high.

Applicable formations:

Medium‑hard rock and projects that demand high hole‑straightness accuracy.

Not suitable for:

Very soft formations (may lack sufficient traction for effective penetration).

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3. Convex‑Face Bits

Features:

The convex center concentrates the contact point, delivering the most focused impact force, which enables fast penetration in soft rock. Cuttings removal is weaker, and hole straightness is relatively poor.

Applicable formations:

Soft rock, loose formations, soil layers, or weathered layers under medium‑to‑low air pressure – for example, clay, weathered rock, and sand layers.

Not suitable for:

Hard rock (prone to severe wear) and applications requiring high‑precision holes (prone to deviation).