This article distinguishes **PDC cutter chipping** and **insert loss**, two frequently mixed-up bit failures. Statistics from a 15-year bit repair expert show chipping accounts for 55% of scrapping causes and insert loss for 25%. Their failure locations, root causes and fixes differ greatly: chipping means the PDC cutter itself fractures, mainly caused by parameter overload, abrupt formation hardness change or internal cutter defects; insert loss refers to complete cutter fallout at the cutter-pocket weld, stemming from poor welding, excessive assembly clearance, water-induced weld cracking and tripping collision. Four common construction pitfalls include over WOB for faster footage, unchanged rotary speed across strata, insufficient cooling water pressure and rough tripping operations. Five strict operational rules are recommended: graded WOB and rotary speed by formation and cutter size, controlled tripping speed, regular parameter logging and pre-delivery bit inspection. After adopting these rules, one job site tripled average bit footage and cut drilling costs significantly. In most cases, chipping and insert loss come from non-standard operation rather than bit quality issues; following standardized parameters can double bit service life.

This article analyzes four major reasons for frequent breakage of rock drill rods: 1. **Raw‑material defects**: Poor‑quality steel contains impurities and air bubbles. These hidden internal flaws develop into cracks under impact and torsion, leading to premature fracture. 2. **Violent drilling operation**: Forcing against hard rock, empty firing, and operating with bent drill rods subject the

This article addresses a common field issue: PDC bits fail quickly after replacing tricone bits, which is usually blamed on bit quality. In most cases, however, damage results from applying tricone‑based operating habits to PDC bits. Tricone bits work with high weight‑on‑bit for impact‑crushing rock, while PDC bits cut rock by shearing and are sensitive to excessive WOB. When operated within pr