As core equipment for mining exploitation, slope stabilization, infrastructure rock drilling and water conservancy projects, pneumatic down-the-hole (DTH) drilling rigs are widely adopted in geotechnical construction projects worldwide for their flexible operation, high drilling efficiency and strong adaptability to complex rock formations. Long-term intensive outdoor operation, coupled with dusty, humid and harsh working conditions, inevitably causes equipment wear. Timely troubleshooting and routine standardized maintenance can effectively avoid construction downtime losses and greatly prolong the service life of the whole machine. Drawing on years of experience in drilling machinery R&D, manufacturing and overseas after-sales service, Hubei Xingda sorts out the common faults, troubleshooting solutions and standardized maintenance specifications for XDQ series pneumatic DTH drilling rigs for global construction clients.

Ⅰ. Common Construction Faults, Causes & Countermeasures

1. Slow Drilling Speed & Declined Drilling Efficiency

Causes

• Worn internal parts and aging valve slices of the impactor lead to weakened impact force;
• Worn or broken carbide teeth on the drill bit reduce rock breaking capacity;
• Insufficient air supply pressure from the air compressor or air leakage along pipelines fails to reach rated working pressure;
• Excessive rock cuttings accumulated inside the borehole increase drilling resistance. Solutions Disassemble and inspect the impactor, replace aged seals and worn components; recondition or replace brand-new DTH drill bits; inspect air hoses and joints for damage and air leakage, calibrate the output pressure of the air compressor; remove rock debris regularly during drilling to ensure smooth air exhaust.

2. Severe Vibration & Abnormal Mechanical Noise

Causes

• Worn or stripped threads of drill pipes result in loose connections;
• Unstable tripod support or tilted legs due to ground subsidence;
• Excessive clearance caused by worn bearings and pistons inside the machine;
• Impurities entering the air circuit trigger collision and abrasion of internal components. Solutions Check threads of all drill pipes, apply special thread grease for tight connection; re-level and fix the rig tripod firmly; disassemble and replace worn bearings and pistons; install oil-water separators at the air source inlet to filter moisture and dust impurities.

3. Air Leakage & Poor Air Supply

Causes Long-term high-temperature aging of sealing rings, loose pipeline joints and cracked hoses will cause compressed air leakage, leading to insufficient power. Solutions Inspect all sealing rings and joints regularly, replace aged accessories promptly; swap cracked hoses immediately; conduct air tightness tests before daily startup.

4. Impactor Fails to Strike & Break Rock

Causes Internal rusting, dust blockage of valve groups, insufficient air pressure or jammed internal components of the impactor. Solutions Disassemble and clean rock dust, water stains and rust inside the impactor; check air supply pressure; inject special pneumatic lubricating oil to unclog jammed parts; replace severely rusted components.

ǁ. Phased Standard Daily Maintenance Specifications

(1) Daily Pre & Post-operation Basic Maintenance (Mandatory)

• Before startup: Check tripod stability, intact drill pipe threads and air hose condition; drain accumulated water and oil from the air compressor oil-water separator; inject a small amount of dedicated pneumatic oil into the air inlet.
• After work: Blow off dust and rock residues on the rig and impactor; drain all water inside the impactor to prevent overnight rusting; coat drill pipes and bits with anti-rust grease before storage.

(2) Weekly In-depth Maintenance

• Disassemble the impactor, clean internal valve slices, pistons and cylinders, replace worn seals;
• Tighten all machine bolts and pipeline joints thoroughly; inspect the tripod for structural deformation;
• Maintain the air compressor system and clean filter elements to guarantee clean and dry air supply.

(3) Monthly Comprehensive Overhaul

• Fully disassemble the rig to inspect wear of bearings, rotation mechanism and lifting cylinder, replace overworn parts;
• Calibrate the verticality and lifting sensitivity of the drilling rig;
• Take inventory of spare drill bits, drill pipes, seals and impactor components to ensure adequate supply of construction consumables.

Ⅲ. One-stop Maintenance Service from Hubei Xingda

With years of expertise in R&D and production of pneumatic DTH drilling rigs, Hubei Xingda supplies complete original drilling tools and accessories alongside full-series XDQ DTH rigs. We deliver one-stop services including remote fault diagnosis, on-site maintenance guidance for overseas construction sites and equipment operation training. Tailored maintenance plans are designed for hot, rainy and dusty working environments in Southeast Asia, Africa and other regions, helping clients cut equipment failure rates and operation costs, and ensure steady progress of mining and infrastructure projects. Standard maintenance lays the foundation for stable equipment operation. Moving forward, Hubei Xingda will keep releasing professional equipment operation & maintenance knowledge. With reliable product quality and comprehensive after-sales support, we strive to facilitate global geotechnical engineering construction.