Fault Phenomenon: SANY SR235 rotary drilling rig extremely low efficiency when drilling in cobblestone layers; inspection reveals a large number of drill bit teeth are broken or missing.

Troubleshooting Process:
– Checked teeth: tungsten carbide tips worn or insufficient welding strength.
– Checked tooth holders: holders worn and deformed, causing teeth to loosen.
– Checked drilling parameters: speed/feed pressure mismatched with ground conditions.
– Checked material: tooth material unsuitable for cobblestone layer.

Root Cause: The selected tooth type is not suitable for the high-hardness cobblestone layer, and the tooth holders are worn and deformed due to long-term impact, causing the teeth to loosen and fall off.

Required Parts: Replace with reinforced teeth suitable for cobblestone, repair or replace tooth holders.