Appearance
A deep hole drilling machine that receives only reactive maintenance — fixing things after they break — operates at 60–70% of its potential uptime. The difference between a machine that runs reliably for years and one that has frequent breakdowns is not the quality of the machine; it is the quality of the preventive maintenance program. A structured PM checklist ensures that every critical system is inspected at the right interval, by the right person, with the right acceptance criteria — and that the work is documented for trend analysis and accountability.
Daily PM Checklist
Startup Checks (Beginning of Shift)
| Check Item | System | Method | Acceptance Criteria | Corrective Action if Failed |
|---|---|---|---|---|
| Coolant level — main tank | Coolant | Visual — sight glass | Between low and high mark | Add coolant to correct level — check for leaks |
| Coolant concentration | Coolant | Refractometer reading | Within ± 0.5% of target (typically 5–10%) | Adjust with water or concentrate |
| Coolant pH | Coolant | Test strip or meter | 8.5–9.5 (semi-synthetic), 8.0–9.0 (emulsion) | Add pH buffer or adjust concentration |
| Coolant temperature | Coolant | Machine display or thermometer | 20–30°C — no alarm active | Investigate if > 35°C — check cooler |
| Coolant pressure — supply | Coolant | Pressure gauge | Per machine spec (typically 20–100 bar) | Check pump — check filters — check for restrictions |
| Coolant flow rate | Coolant | Flow meter | Per machine spec (± 10%) | Check pump — check for blockages |
| Chip conveyor operation | Chip handling | Visual — listen for unusual noise | Running smoothly — no jams — no unusual noise | Clear jam — adjust tension — call maintenance |
| Filter condition — pressure differential | Filtration | Differential pressure gauge | < 0.5 bar across clean filter | Replace filter element |
| Guide bushing condition | Tooling | Visual inspection | No visible wear — no scoring — no cracks | Replace guide bushing |
| E-stop button — visual | Safety | Visual | Present — undamaged — red on yellow | Replace E-stop button |
| Coolant hoses and connections | Coolant | Visual — look for drips | No leaks | Tighten fitting — replace hose |
| Machine lubrication points | Mechanical | Visual — check sight glasses | Oil at correct level — lubricator functioning | Refill — adjust lubricator |
| Spindle runout check (quick) | Spindle | Dial indicator on test bar | < 0.01 mm TIR | Schedule detailed spindle inspection |
End of Shift Checks
| Check Item | System | Method | Acceptance Criteria | Corrective Action if Failed |
|---|---|---|---|---|
| Coolant tank — chip accumulation | Coolant | Visual | No excessive chip accumulation in tank corners | Clean tank sump |
| Filter element condition | Filtration | Visual — check if replacement needed | Not clogged — no tears — no bypass | Replace filter element |
| Machine surfaces clean | General | Visual | No coolant residue — no chip accumulation | Clean machine surfaces |
| Tools returned to storage | Tooling | Visual | All tools in designated location | Return tools |
| Report any issues | Documentation | Log book or CMMS | Any abnormal observations recorded | Record in log |
Weekly PM Checklist
| Check Item | System | Method | Acceptance Criteria | Corrective Action if Failed |
|---|---|---|---|---|
| Coolant tank — drain water | Coolant | Open drain valve at tank bottom | No water layer visible | Drain until coolant flows — adjust concentration |
| Coolant tramp oil removal | Coolant | Skimmer operation — visual | No visible oil layer on surface | Run skimmer — check skimmer operation |
| E-stop operational test | Safety | Activate E-stop while running | All motion stops immediately — manual reset required | Tag machine — repair circuit before use |
| Coolant pump strainer | Coolant | Remove and inspect | Clean — no debris | Clean strainer |
| Guide bushing — measure ID | Tooling | Bore gauge | Within wear limit (typically +0.05 mm from new) | Replace guide bushing |
| Chip conveyor lubricator | Chip handling | Check oil level | Oil level in sight glass | Refill — adjust feed rate |
| Spindle nose — clean and inspect | Spindle | Visual — lint-free cloth | Clean — no coolant residue — no scoring | Clean spindle taper — check for damage |
| Coolant return line — check flow | Coolant | Visual at return point | Good flow returning to tank | Check for blockages in return line |
| Hydraulic oil level | Hydraulics | Sight glass | Between low and high mark | Add recommended oil — check for leaks |
| Way cover condition | Mechanical | Visual | Clean — no damage — no coolant ingress | Clean — repair damage |
Monthly PM Checklist
| Check Item | System | Method | Acceptance Criteria | Corrective Action if Failed |
|---|---|---|---|---|
| Coolant filter — replace | Filtration | Replace element | New element installed — record date | Replace — record differential pressure before/after |
| Coolant — full analysis | Coolant | Laboratory sample | Concentration, pH, conductivity, bacteria, chlorides within spec | Correct based on lab report |
| Spindle runout — full check | Spindle | Dial indicator on taper and pull-stud | < 0.005 mm TIR at spindle nose, < 0.01 mm at 100 mm | Adjust or schedule spindle repair |
| Spindle bearings — vibration check | Spindle | Vibration sensor or listening rod | No unusual vibration — no bearing noise | Schedule bearing replacement if noisy |
| Coolant pump — check operation | Coolant | Pressure — flow — noise | Pressure and flow at spec — no unusual noise | Inspect pump — replace if needed |
| Heat exchanger — clean (water side) | Coolant | Brush tubes or chemical clean | Clean — no scale — no debris | Clean per procedure |
| Hydraulic system — check pressure | Hydraulics | Pressure gauge at accumulator | Per machine spec | Adjust regulator — check accumulator charge |
| Pneumatic system — check filters | Pneumatics | Replace filter element | Clean — no water in bowl | Replace — drain water separator |
| Way wipers — inspect and replace | Mechanical | Visual | Clean — no damage — sealing properly | Replace way wipers |
| Coolant hoses — full inspection | Coolant | Visual — feel for soft spots | No cracks — no bulges — no leaks | Replace damaged hoses |
| Electrical panel — check cleanliness | Electrical | Visual — open panel | Clean — no dust — no coolant ingress | Clean panel — check seals |
| Safety light curtain — test | Safety | Test with test rod | Machine stops when beam interrupted | Clean lenses — align — repair if faulty |
| Torque values — check critical bolts | Mechanical | Torque wrench | Bolts at spec — no loosening | Retorque per spec |
| Coolant nozzles — inspect for wear | Tooling | Visual — measure orifice | No visible wear — orifice within spec | Replace worn nozzles |
Quarterly PM Checklist
| Check Item | System | Method | Acceptance Criteria | Corrective Action if Failed |
|---|---|---|---|---|
| Spindle — bearing temperature check | Spindle | Infrared thermometer or sensor | < 55°C at housing (ambient + 25°C) | Schedule bearing inspection — check lubrication |
| Spindle — drawbar force check | Spindle | Drawbar force gauge | Per manufacturer spec | Adjust or replace drawbar springs |
| Coolant — full system flush | Coolant | Drain — clean — refill | System clean — no sludge — no bacterial growth | Drain, clean tank, refill with fresh coolant |
| Coolant — biocide shock treatment | Coolant | Add biocide per manufacturer | Bacteria < 1000 CFU/mL after treatment | Repeat treatment — check for biofilm |
| Heat exchanger — clean (coolant side) | Coolant | Backflush or chemical clean | Full flow restored — temperature drop 3–8°C | Repeat cleaning — check for damage |
| Guide bushings — inspect and rotate | Tooling | Visual — measure all bushings | Within wear limit — no scoring | Replace worn bushings |
| Hydraulic oil — sample analysis | Hydraulics | Laboratory analysis | ISO 4406 cleanliness ≤ 18/16/13 — no water | Change oil — replace filters |
| Mechanical alignments — check | Mechanical | Spindle-to-guideway alignment | < 0.01 mm per 100 mm | Adjust alignment |
| Coolant pump — coupling inspection | Coolant | Visual — check coupling element | No wear — no cracks | Replace coupling |
| Electrical connections — thermal scan | Electrical | Infrared camera | No hot spots > 10°C above ambient | Tighten loose connections |
| Chip conveyor — chain/belt tension | Chip handling | Measure sag per manufacturer | Within spec | Adjust tension |
| Machine level — check | Structural | Precision level | < 0.02 mm/m | Shim and re-level |
| Lubrication system — full check | Mechanical | All lubrication points | All points receiving oil — no blockages | Clear blocked lines — adjust metering units |
| Way surfaces — inspect for wear | Mechanical | Visual — feel | No scoring — no galling — no wear steps | Document — schedule re-grind if severe |
| Accumulators — check pre-charge | Hydraulics | Pressure gauge | Per manufacturer spec | Recharge or replace accumulator |
Semi-Annual PM Checklist
| Check Item | System | Method | Acceptance Criteria | Corrective Action if Failed |
|---|---|---|---|---|
| Spindle — pull-stud condition | Spindle | Visual — crack check | No cracks — no wear — no distortion | Replace pull-stud |
| Spindle — runout under load | Spindle | Dial indicator with cutting load | < 0.015 mm TIR | Schedule spindle repair |
| Coolant tank — full clean | Coolant | Drain — manual clean — refill | No sludge — no biofilm — no debris | Manual cleaning — disinfect |
| Coolant lines — flush with cleaner | Coolant | Circulate cleaning solution | System clean — no blockages | Replace lines if heavily fouled |
| Hydraulic system — change oil | Hydraulics | Drain — replace filters — refill | New oil — clean filters | Per procedure |
| Hydraulic system — check accumulators | Hydraulics | Full function test | Proper pre-charge — no diaphragm leakage | Recharge or replace |
| Pneumatic system — full service | Pneumatics | Replace all filters — check regulators | Clean — dry air — correct pressure | Replace components as needed |
| Coolant pump — bearings and seals | Coolant | Check for leaks — listen for noise | No leaks — no unusual noise | Replace seals — replace bearings |
| Gearbox — oil change | Mechanical | Drain — refill | New oil — correct grade | Per procedure |
| Ball screws — check backlash | Mechanical | Dial indicator | < 0.02 mm backlash | Adjust preload — replace if worn |
| Way wipers — replace | Mechanical | Remove and replace | New wipers installed | Replace |
| Electrical cabinet — full clean | Electrical | Vacuum — check fans — check filters | Clean — good airflow — filters clean | Clean cabinet — replace filters |
| Cable carriers — inspect cables | Electrical | Visual — check for chafing | No chafing — no broken conductors | Repair or replace cables |
| Machine anchoring — check | Structural | Torque check anchor bolts | Bolts tight — no movement | Retorque — replace anchors if loose |
Annual PM Checklist
| Check Item | System | Method | Acceptance Criteria | Corrective Action if Failed |
|---|---|---|---|---|
| Spindle — bearing replacement (if on schedule) | Spindle | Per manufacturer life recommendation | New bearings installed — run-in completed | Schedule replacement |
| Spindle — full rebuild (if due) | Spindle | Per manufacturer schedule | All components within spec | Rebuild or replace spindle |
| Coolant system — full pressure test | Coolant | Test at max operating pressure | No leaks — pressure holds | Repair leaks — replace components |
| Guide bushing holder — bore check | Tooling | Bore gauge | Within 0.01 mm of nominal | Repair or replace holder |
| Machine tool calibration | All | Full calibration per ISO 230 | All axes within spec | Adjust — compensate — repair |
| Laser alignment | All | Laser interferometer | Positioning accuracy per spec | Adjust compensation parameters |
| Ball screw — wear measurement | Mechanical | Measure backlash — preload | Within spec | Replace ball screw if worn |
| Way straightness | Mechanical | Precision level — straight edge | < 0.01 mm per meter | Scrape or re-grind ways |
| Electrical safety — ground continuity | Safety | Ground resistance tester | < 1 ohm | Repair ground circuit |
| Electrical safety — insulation test | Safety | Megger | > 1 MΩ | Identify fault — repair |
| E-stop — timed stop test | Safety | Measure stop time | Per machine spec (typically < 500 ms) | Investigate — repair braking system |
| Safety relay — replacement (if on schedule) | Safety | Per manufacturer life | New relay installed | Replace |
| Backflow preventer — test | Coolant | Certified plumber test | Pass — no leakage | Repair or replace |
| Coolant hoses — replace | Coolant | Replace on schedule | All hoses replaced | Per schedule |
PM Program KPIs
| KPI | Definition | Target | Calculation |
|---|---|---|---|
| PM completion rate | Percentage of scheduled PM tasks completed on time | > 95% | (Completed on time / Total scheduled) × 100 |
| PM compliance | Percentage of PMs completed within the interval window | > 90% | (Completed within window / Total scheduled) × 100 |
| Mean time between failures (MTBF) | Average operating time between unplanned stops | Target per machine baseline + 20% improvement | Total operating hours / Number of unplanned stops |
| Mean time to repair (MTTR) | Average time to restore machine after failure | < 2 hours (mechanical), < 1 hour (electrical) | Total repair hours / Number of repairs |
| Unplanned downtime % | Percentage of total time lost to unplanned stops | < 5% | (Unplanned downtime / Total available time) × 100 |
| Maintenance cost per operating hour | Total maintenance cost divided by operating hours | Target per machine baseline | Total maintenance cost / Operating hours |
| Open work order aging | Age of open corrective work orders | < 30 days (critical), < 90 days (non-critical) | Date opened to current date |
| Spare parts stockout rate | Percentage of maintenance events where part was not in stock | < 5% | (Stockout events / Total PM events) × 100 |
FAQ
What should a deep hole drilling machine preventive maintenance checklist include?
A comprehensive PM checklist should cover: coolant system (level, concentration, pH, pressure, flow, temperature, filtration, tank condition), spindle and drill head (runout, bearing temperature, drawbar force, vibration, lubrication), guide bushings and tooling (wear measurement, clearance, condition), hydraulics and pneumatics (fluid levels, pressure, filter condition, leaks, accumulator charge), chip handling and filtration (conveyor operation, filter pressure differential, coolant return flow), electrical and safety systems (E-stop function, light curtains, ground continuity, cable condition, panel cleanliness), structural systems (machine level, anchoring, way condition, ball screw backlash), and general mechanical condition (lubrication points, way wipers, seals, hoses). Each check item must have a clear acceptance criterion so the technician can make a pass/fail decision — without ambiguity.
How often should PM be performed on a deep hole drilling machine?
PM frequency follows a pyramid: daily checks (10–15 items — operator performs at shift start — 10 minutes), weekly checks (8–10 items — operator or technician — 20–30 minutes), monthly checks (10–15 items — maintenance technician — 1–2 hours), quarterly checks (10–12 items — maintenance technician — 4–8 hours), semi-annual checks (8–10 items — maintenance technician — 8–16 hours), and annual checks (10–15 items — maintenance technician or specialist — 1–3 days). The daily and weekly checks cover consumables and operating conditions. The monthly and quarterly checks cover component condition. The semi-annual and annual checks cover wear measurement, calibration, and component replacement. Adjust frequency based on machine operating hours and manufacturer recommendations.
Who should perform PM tasks on a deep hole drilling machine?
Task assignment by skill level: daily checks — machine operator (trained to inspect coolant concentration, level, basic machine condition — 30-minute training). Weekly checks — operator or maintenance technician (adds E-stop testing, strainer cleaning). Monthly checks — maintenance technician (adds filter replacement, coolant sampling, spindle runout check). Quarterly checks — experienced maintenance technician or lead technician (adds alignments, system flush, thermal scan). Semi-annual and annual checks — maintenance technician plus specialists (calibration technician for alignment — refrigeration technician for chiller service — certified electrician for safety testing). The operator should never perform electrical or safety system checks beyond E-stop testing — those require qualified maintenance personnel.
How do I track PM completion and results?
Track PM completion using: a CMMS (computerized maintenance management system) — the best option — it schedules PMs automatically, tracks completion, stores results, and provides KPI reports. If a CMMS is not available, use a spreadsheet with columns for machine name, check item, frequency, scheduled date, completed date, inspector, result (pass/fail), and corrective action if failed. Paper checklists are acceptable for daily and weekly checks but should be scanned and filed for at least one year (or per regulatory requirements). Each PM record must include: date, inspector name, check items with results, corrective actions taken for any failed items, and signature (physical or electronic). Review PM records monthly to identify recurring issues.
What are the most commonly missed PM items on deep hole drilling machines?
The most commonly missed PM items: coolant pH and concentration measurement (operators skip it because it takes time — but drifting concentration is the leading cause of tool life variation and coolant degradation). E-stop operational testing (operators do a visual check but do not actually press the button while the machine is running — this is the most critical safety test). Guide bushing wear measurement (the bushing wears gradually — without regular measurement, it is not noticed until oversize holes are produced). Heat exchanger cleaning (it is a dirty job — it gets postponed — and gradually rising coolant temperature produces tool life problems that are blamed on the tool instead). Coolant system full drain and clean (the quarterly or semi-annual tank cleaning is the most frequently skipped major PM — skipping it leads to bacterial growth, coolant degradation, and eventual system contamination that requires emergency shutdown).
A structured preventive maintenance checklist template ensures that every critical system on a deep hole drilling machine is inspected at the right interval with clear acceptance criteria. Customize the template for your specific machine — adjust frequencies, add machine-specific items, and assign responsibility by skill level. Track PM completion in a CMMS or spreadsheet and review KPIs monthly. The daily and weekly checks take 10–30 minutes but prevent 80% of common machine problems. The quarterly and annual checks take longer but prevent the major failures that cause extended downtime. A machine on a good PM program runs at > 95% availability — a machine without one runs at 60–70%. This article reflects industry practice as of 2026.