How to Do Installation Qualifications of CNC Machines

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  Key takeaways
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  What IQ covers and what it does not
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  Site readiness: the checks that fail most often
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  Anchoring, leveling, and geometric checks
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  Power-up, parameters, and safety verification
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  Dry run, test cut, and acceptance numbers
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  The IQ sequence, step by step
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  Typical IQ check items and pass limits

Installation qualification is the documented proof that a machine was received as ordered, installed as designed, and performs to the acceptance criteria written into the purchase order. It sits between design qualification (DQ), which happens before you buy, and operational qualification (OQ), which proves the machine holds tolerance across its full working envelope and over time. IQ answers a narrower question: is this unit, on this floor, wired and set up the way it is supposed to be?

The deliverable is a signed dossier. It holds the packing list against the PO, the site survey sheet, anchor and leveling records, utility readings, geometric test results, and the test-cut report. If a customer audit or an ISO 9001:2015 surveillance visit lands six months later, that dossier is what you show. Nothing in it should be reconstructed from memory.

IQ does not cover process capability. A machine can pass IQ with a 0.010 mm circularity reading and still be the wrong machine for a job that needs 0.005 mm. That gap belongs to OQ and to the process FMEA. Keep the two documents separate or you will sign off on capability you never measured.

GreatLight runs 127 high-precision CNC machines across three wholly-owned plants, including 16 simultaneous 5-axis machining centers. Every unit goes through the same IQ sequence before it is released to a job. The steps below are the ones we use.

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  IQ documentOne dossier per machine serial number, signed by the installer and the process engineer.
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  Who owns itThe process engineer signs acceptance. Maintenance keeps the records.

Pull the foundation drawing from the machine supplier and walk the floor with a level and a tape. Check floor load capacity in kN/m², not just "concrete is thick enough." Check flatness across the footprint, typically 0.05 mm/m or tighter for a 5-axis center. Check vibration isolation if a stamping press or a grinder shares the slab. A machine anchored to a slab that moves will pass IQ in an empty shop and fail three months later.

Verify utilities at the drop point, not at the panel. Electrical: voltage, phase, frequency, and whether the control needs a separate clean earth. Compressed air: pressure at the machine inlet under flow, dew point, and filtration down to 5 μm or better. Coolant: tank location, chip conveyor discharge, and mist extraction route. Network: a live port for program transfer and remote diagnostics.

Confirm the rigging path before the truck arrives. Door clearances, overhead crane capacity, aisle width, and turning radius for the forklift. A 4,000 mm travel machine does not fit through a 2,000 mm door, and unloading it twice costs more than planning the route once.

Cross-check the packing list against the PO line by line when the crates are still sealed. Look for the tool changer, pallet system, coolant unit, chip conveyor, spare parts kit, and the documentation package. Missing documentation is the most common shortfall. Without it you cannot verify parameters or complete the IQ record.

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  Floor flatness0.05 mm/m across the footprint, or per the supplier drawing if tighter.
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  Air qualityDry, filtered to 5 μm, pressure stable at the inlet under flow.

Set the machine on its leveling pads or anchor bolts, then level the bed in two axes. Use a precision level of 0.02 mm/m resolution. Work corner to corner and re-check after each adjustment, because tightening one pad lifts the opposite corner. On a mill-turn center with a Ø400 mm rotary table, level the table separately from the bed. Target 0.02 mm/m or better; 0.01 mm/m is achievable on a good slab and is worth the extra hour.

Wait 24 hours after anchoring before the final leveling pass. Concrete and castings settle. Re-level, then torque the anchor bolts in a star pattern. Record the final readings with the serial numbers of the level and the square. This is the record an auditor will ask for first.

Run the geometric tests in the order the machine builder specifies. Squareness between X and Y, then X and Z, then spindle axis to the table. Parallelism of the table to the X axis. Spindle runout at the taper gauge line, typically within 0.005 mm. Repeat positioning on each linear axis using a laser interferometer or a ballbar. Backlash should read under 0.005 mm on a new machine.

Take the readings at the middle of travel first, then at both ends. A machine that holds 0.005 mm in the center and 0.015 mm at the end of travel has a geometry problem, not a control problem. Fix it now. It will not get better on its own.

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  Level target0.02 mm/m or tighter, re-checked 24 hours after anchoring.
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  Spindle runoutWithin 0.005 mm at the taper gauge line.

Before the first power-up, confirm the supply matches the nameplate: voltage within ±5 %, correct phase rotation, and a ground resistance that meets local code. Phase rotation is worth checking with a meter rather than assuming. A reversed phase on a coolant pump will not damage the machine but will cost you a day.

Load the parameters and the ladder from the documentation package, then compare the backup against the machine serial number. Builders ship parameter sets tuned per unit. Copying a set from a sister machine is a common shortcut that shows up later as servo tuning faults and thermal drift.

Walk the safety chain with the door open and the spindle stopped. Test the door interlock, the emergency stop on the panel and on the pendant, the light curtain if fitted, and the air pressure fault. Every one of these should stop the cycle and require a deliberate reset. Do not accept a reset that happens on power cycling alone.

Back up the parameters, ladder, and servo data to two separate media after the machine is stable. Keep one copy off the machine. The first time a board fails, that backup is the difference between four hours and four days of downtime.

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  VoltageWithin ±5 % of nameplate, phase rotation confirmed with a meter.
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  BackupsParameters, ladder, and servo data on two media, one stored off the machine.

Run the warm-up cycle the builder specifies, usually 30 to 60 minutes of spindle and axis motion, before any accuracy test. A cold machine reads differently. Record the ambient temperature and note it on the test sheet. Most acceptance numbers in a purchase order assume a controlled room, typically 20 °C ± 2 °C.

Do a dry run of the acceptance program with the tool clear of the part. Watch the tool changer through a full magazine cycle, the pallet change if fitted, and the coolant and chip conveyor sequence. Listen for a change in pitch on the spindle ramp. A dry run catches programming and interlock faults before they become a crash.

Cut the acceptance part from a material you know. Aluminum 6061 cuts differently from 17-4PH, and a machine tuned on aluminum may show chatter on stainless. Measure the features that matter to the job: bore diameter, flatness, squareness, and surface finish. Write the numbers on the sheet with the tool, the speed, and the feed.

Set the acceptance threshold before the test, not after. If the PO says ±0.005 mm and the machine holds ±0.008 mm on the first pass, that is a fail. Give the builder one chance to re-level and re-tune, then re-test. Accepting a marginal machine because the schedule is tight is how a shop ends up with a machine it cannot use on its best work.

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  Warm-up30 to 60 minutes of spindle and axis motion before accuracy tests.
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  ThresholdWritten into the PO before the test cut, not negotiated after.