A deep hole drilling coolant system that is commissioned incorrectly can damage pumps within minutes, flood the shop floor within hours, and produce scrap holes for days before the root cause is identified. Commissioning is not a formality — it is the systematic verification that every component, from the tank to the drill, operates at its design specification. Following a structured commissioning sequence prevents startup failures and establishes baseline data for future condition monitoring.
Pre-Commissioning Checks
Mechanical Inspection
| Check | Detail | Acceptance Criteria |
|---|
| Piping integrity | All connections tight — no visible gaps | No leaks at any joint |
| Pipe slope (return lines) | Verified with level | Minimum per pipe size table |
| Tank cleanliness | Tank interior clean — no debris, no welding slag | Visually clean — wipe test passes |
| Tank level sensors | Float or ultrasonic — free movement — wiring connected | Correct indication at empty/full |
| Pump alignment | Coupling alignment checked with dial indicator | < 0.05 mm parallel — < 0.05 mm angular |
| Pump rotation direction | Motor rotation checked (bump test) | Matches arrow on pump housing |
| Filter housings | Seals in place — filter elements installed | Correct type and micron rating |
| Valves | All valves in correct position (open/closed per startup checklist) | Per startup checklist |
| Pressure gauges | Installed — range appropriate | Calibrated — readable |
| Flow meters | Installed — flow direction correct | Arrow matches flow direction |
| Heat exchanger / cooler | Connections tight — coolant and utility connections | No leaks — correct flow paths |
| Mist collector | Duct connections sealed — filter installed | Proper connection to machine enclosure |
Electrical Inspection
| Check | Detail | Acceptance Criteria |
|---|
| Motor wiring | Motor connected to VFD or starter — correct phase rotation | Phase rotation matches pump direction |
| VFD parameters | Set per motor nameplate | Voltage, frequency, current, ramp times |
| Pressure transducer | Wiring to PLC — signal type correct | 4–20 mA or 0–10 VDC per design |
| Flow meter wiring | Pulse or analog signal to PLC | Signal type correct — no shorts |
| Level switch wiring | Normally open or normally closed per safety circuit | Correct fail-safe configuration |
| Emergency stop circuit | Coolant pump included in E-stop | Pump stops on E-stop activation |
| Alarm devices | Horn — light — PLC alarm input | Function tested — audible and visual |
| Control panel | All terminals tight — no loose wires | Torque checked per specification |
Pre-Fill Checks
| Check | Detail | Acceptance Criteria |
|---|
| Tank drain valve | Closed | No leakage |
| Pump suction valve | Open | Full flow to pump suction |
| Pump discharge valve | Initially closed (for priming) | Closed — will open after priming |
| Filter isolation valves | Open | Flow path through filters |
| Return line valves | Open | Gravity flow path clear |
| Bypass valves (if equipped) | Set to bypass initially | Coolant recirculates to tank |
| Pressure relief valve | Set to correct pressure | 10% above maximum operating pressure |
| All drain plugs | Tightened | No leaks |
Startup Sequence
Step-by-Step Startup
| Step | Action | Detail | Expected Result |
|---|
| 1 | Fill tank with coolant | Mix per specification — fill to operating level | Correct concentration — proper level |
| 2 | Open pump suction valve | Full open | Coolant flows to pump inlet |
| 3 | Prime the pump | Fill pump housing with coolant — vent air | No air in pump housing |
| 4 | Bump motor (momentary start) | Check rotation direction | Correct rotation per pump arrow |
| 5 | Start pump with discharge valve closed | Minimum load start | Pump runs — no unusual noise |
| 6 | Slowly open discharge valve | 10% increments — 30 seconds between steps | Flow increases smoothly — pressure builds |
| 7 | Check for leaks | All joints — seals — fittings | No leaks at any pressure |
| 8 | Check pump suction pressure | Gauge at pump inlet | Positive suction pressure — no vacuum |
| 9 | Check pump discharge pressure | Gauge at pump outlet | Within design range |
| 10 | Check flow rate | Flow meter | Within design range |
| 11 | Bleed air from system | Air vents at high points | All air purged |
| 12 | Adjust pressure relief valve | Set slightly above operating pressure | Correct setting verified |
| 13 | Verify flow through all branches | Each machine or outlet | Flow at each outlet |
| 14 | Check return line flow | At tank return | Smooth flow — no surging |
| 15 | Run in recirculation mode | 30 minutes at operating conditions | Stable temperature — stable pressure/no leaks |
Pump Priming Methods
| Pump Type | Priming Method | Detail |
|---|
| Centrifugal (flooded suction) | Open suction valve — coolant flows into pump | Fill pump housing — no external prime needed |
| Centrifugal (suction lift) | Fill pump housing through priming port | May need foot valve — vacuum pump for lifts > 3 m |
| Positive displacement (gear, piston) | Fill pump housing through fill port | Never run dry — even seconds of dry-run damages seals |
| Multistage centrifugal | Flooded suction required — vent air at discharge | Air vent at highest point |
| Vertical turbine | Submerged in tank — no priming needed | Ensure minimum submersion depth |
Flushing Procedure
| Step | Action | Detail |
|---|
| 1 | Fill system with clean coolant (or flushing solution) | Use fresh coolant — not production coolant |
| 2 | Circulate at operating pressure | Flow through all branches |
| 3 | Open all valves — including bypass lines | Flush all paths |
| 4 | Run for 30–60 minutes | Removes construction debris — pipe dope — welding residue |
| 5 | Check filter elements after flushing | Replace if loaded with debris |
| 6 | Sample coolant after flushing | Check for particles — debris |
| 7 | If sample is clean — flush complete | If not — extend flush and replace filters again |
| 8 | Drain flush coolant (or keep if clean enough) | Per site procedure |
| 9 | Fill with production coolant | Correct concentration — correct volume |
| 10 | Final circulation — verify all parameters | Ready for production |
Parameter Verification
Critical Parameters
| Parameter | Verification Method | Acceptance Criteria | Adjustment Method |
|---|
| Pump discharge pressure | Pressure gauge at pump outlet | Within ± 5% of design pressure | Pressure relief valve — VFD speed |
| Flow rate (total) | Flow meter at pump discharge | Within ± 5% of design flow | VFD speed — valve throttling (not preferred) |
| Flow rate (per machine) | Flow meter at each machine | Within ± 10% of design per branch | Flow control valve at each branch |
| Coolant temperature | Temperature gauge at tank | 20–30°C (or per specification) | Chiller/heater setpoint adjustment |
| Coolant concentration | Refractometer | Per coolant specification | Add concentrate or water |
| Coolant pH | pH meter | 8.5–9.5 (typical for water-soluble) | Add pH adjuster per coolant spec |
| Filtration efficiency | Particle count before/after filter | > 95% removal at rated micron | Check filter seal — element condition |
| Return line flow | Visual — flow meter at tank return | Smooth continuous flow | Check slope — check for blockage |
Temperature Control Verification
| Check | Method | Acceptance |
|---|
| Cooler capacity test | Run system at maximum heat load — measure temperature rise | Temperature stabilizes within spec |
| Heater operation (if equipped) | Activate heater — verify temperature rise | Heater reaches setpoint within 30 minutes |
| Temperature controller response | Step change in setpoint — measure response time | Stable within 5 minutes |
| Temperature sensor accuracy | Compare to calibrated reference thermometer | ± 1°C |
Safety System Verification
| System | Test Method | Acceptance |
|---|
| Low level shutdown | Drain tank to low level switch | Pump stops — alarm sounds |
| High pressure relief | Close valve downstream — let pressure rise | Relief valve opens at set pressure |
| Low flow alarm | Throttle pump discharge — reduce flow | Alarm at correct flow setpoint |
| Emergency stop | Press E-stop button | Coolant pump stops immediately |
| Mist collector interlock | Turn off mist collector | Machine alarm — operator notification |
Documentation
| Document | Content | Retention |
|---|
| Commissioning checklist | All checks completed — signed off | Life of machine |
| Parameter baseline record | All measured parameters — date — operator | Life of machine |
| Pump test report | Flow vs pressure curve — amp draw | Life of machine |
| Piping pressure test report | Test pressure — duration — leakage | Life of machine |
| Flushing report | Flush duration — filter condition — sample results | 1 year |
| Coolant analysis (initial) | Concentration — pH — bacteria — hardness | 1 year |
| As-built piping diagram | Redline markups of design drawings | Life of machine |
Common Commissioning Problems
| Problem | Likely Cause | Corrective Action |
|---|
| Pump will not prime | Suction valve closed — air leak in suction line | Open valve — check suction line gaskets |
| Low discharge pressure | Pump rotation wrong — suction restriction — worn pump | Check rotation — clean suction strainer |
| High discharge pressure (low flow) | Discharge valve closed — filter blocked — line restriction | Open valve — check filters |
| Pump noisy (cavitation) | Suction restriction — low tank level — viscous coolant | Clean suction strainer — check level — check coolant temperature |
| Coolant leaks at pipe joints | Joint not tightened — gasket damaged — pipe misaligned | Tighten — replace gasket — realign pipe |
| Return line flooding | Return line blocked — slope insufficient — tank return submerged | Clear blockage — improve slope — check tank level |
| Temperature not stable | Cooler undersized — bypass valve stuck — controller mis-set | Verify cooler capacity — check bypass — tune controller |
| Flow rate below specification | Pump speed too low — filter clogged — wrong impeller | Increase VFD speed — check filters — verify pump spec |
FAQ
What is involved in commissioning a deep hole drilling coolant system?
Commissioning a coolant system involves: pre-commissioning checks (verify piping integrity, electrical connections, pump alignment, filter installation, and valve positions), filling and priming (fill tank with correctly mixed coolant, prime the pump to ensure no air in the housing), startup sequence (start pump with discharge valve closed, slowly open valve, verify pressure and flow at each stage), parameter verification (measure pressure, flow rate, temperature, concentration, and filtration efficiency at design conditions), flushing (circulate flushing fluid to remove construction debris), safety system testing (verify low level shutdown, pressure relief, low flow alarm, and emergency stop functions), and documentation (record all baseline parameters for future condition monitoring).
How do you prime a coolant pump on a deep hole drilling system?
Priming method depends on pump type: for a centrifugal pump with flooded suction (pump below tank level): simply open the suction valve — coolant flows into the pump housing and displaces air. For a centrifugal pump with suction lift (pump above tank level): fill the pump housing through the priming port — open the air vent on the pump discharge until coolant flows out without air bubbles. For positive displacement pumps: always fill the pump housing with coolant before starting — these pumps cannot tolerate dry running even for seconds. Never start a coolant pump without verifying it is primed — dry running damages mechanical seals within seconds.
Before starting a coolant pump: verify the tank is filled to the correct operating level with properly mixed coolant, open the pump suction valve fully (closed suction is the most common startup mistake), ensure the pump discharge valve is initially closed (opens slowly after start), check pump rotation direction by bumping the motor (must match arrow on pump housing — reverse rotation damages some pump types), verify all filter housings are sealed with elements installed, check all drain plugs are tight, and confirm the emergency stop circuit includes the pump. The single most important check is the suction valve — a pump started with a closed suction valve will cavitate immediately and can damage the seal within seconds.
How long does it take to commission a coolant system?
A typical coolant system commissioning for a deep hole drilling machine takes 1–2 days: pre-commissioning checks (2–4 hours — mechanical, electrical, pre-fill), startup and parameter verification (4–8 hours — filling, priming, startup, parameter adjustment), flushing (2–4 hours — depending on system volume and debris level), and safety system testing and documentation (2–4 hours — verify all safety functions, record baselines). Complex systems with multiple machines, temperature control, and advanced filtration may take 2–3 days. The most time-consuming step is usually flushing — if the piping system was not kept clean during installation, flushing can take significantly longer.
What baseline data should be recorded during commissioning?
Record the following baseline data during commissioning: pump discharge pressure and flow rate at operating conditions (at several VFD speeds if variable speed), coolant temperature at tank and at machine inlet (steady state values), amperage draw of the pump motor (at operating pressure and flow), all pressure readings across filters (clean filter pressure drop), vibration readings on pump and motor bearings, coolant concentration and pH, pressure relief valve setting, flow rate at each machine branch, and return line flow condition (visual — smooth, no surging). This baseline data is the reference for future condition monitoring — a 10% change from baseline indicates a developing problem.
Systematic coolant system commissioning prevents startup failures, establishes baseline data for condition monitoring, and verifies that every component operates at its design specification. Follow the pre-commissioning checks, startup sequence, parameter verification, and documentation steps to ensure the coolant system is ready for production. A well-commissioned coolant system starts reliably, operates efficiently, and provides years of trouble-free service. This article reflects industry practice as of 2026.
