Acceptance Requirements Before Installation of a CNC Horizontal Lathe

Start at the loading dock. The machine has just traveled several thousand kilometers, and shipping damage is the most common reason a lathe fails its first inspection. Photograph every crate face before you cut a band. Compare the packing list against the bill of lading line by line, then walk the pallet and tick off each item. Chucks, steady rests, tailstock quills, tool holders and the leveling pads are usually packed separately and go missing more often than the bed itself.

Open the electrical cabinet and look for condensation, loose terminal screws and cracked cable glands. Sea freight across a humid season can leave water inside a sealed enclosure. If you find rust on the ways or on the ball screw, stop and file a claim. Do not wipe it off with a rag and proceed. That decision removes the evidence you need later.

Record the machine serial number, the spindle run-in hours if the builder logged them, and the software version on the control. Photograph the nameplate. Once the machine is anchored and wired, it is much harder to prove what condition it arrived in. The goal here is not to find fault. It is to build a dated record that protects both sides.

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  Crate photosShoot all four sides and the top before opening anything.
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  Accessory auditMatch chucks, rests, holders and pads against the packing list.
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  Cabinet checkLook for moisture, loose lugs and cracked glands.
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  Serial recordLog numbers, software version and any run-in hours.

A horizontal lathe is stiff, but it is not infinitely stiff. The bed will twist to match whatever surface it sits on. Before the machine comes off the skid, check the foundation drawing against what was actually poured. Concrete grade, anchor bolt spacing and pad positions all matter. A 4,000 mm bed needs a foundation that has cured properly, not one poured the week before.

Measure the floor with a precision level in two directions. Flatness across the pad footprint is what counts, not the flatness of the whole shop floor. Any gap under a pad should be shimmed or grouted, never closed by tightening the anchor bolt and hoping the casting pulls down. That trick bends the bed and shows up later as taper on long shafts.

Power quality deserves the same attention. Confirm the supply voltage, phase rotation and frequency against the nameplate. Phase rotation is easy to get wrong and expensive to discover when a hydraulic pump spins backward. Check that the breaker rating matches the machine demand and that a clean earth is available. A lathe with a weak ground will throw encoder faults that look like control problems.

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  Foundation cureConfirm concrete grade and cure time against the drawing.
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  Pad flatnessLevel across the pad footprint, not the whole floor.
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  Phase rotationVerify rotation before the first hydraulic start.
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  Earth qualityA poor ground shows up as encoder and drive faults.

Once the machine is leveled and the anchor bolts are snug, the geometry checks begin. These are done cold, with no cutting load. Level the bed first and re-check after 24 hours, because castings settle. Then measure spindle runout at the taper and at the faceplate. Runout at the taper should sit inside the builder tolerance, typically a few microns for a lathe of this class. If it does not, check for a burr before blaming the spindle.

Check squareness between the spindle axis and the Z-axis travel. Long shafts will show taper if the headstock is out of square, and no amount of tool offset will fix it. Measure parallelism of the tailstock quill to the Z-axis, and confirm the tailstock center height matches the spindle center height. A tailstock that is high or low by 0.02 mm will produce a visible step on a shaft turned between centers.

Turret or tool post indexing accuracy belongs here too. Index to each station and measure the repeat position. Repeatability matters more than absolute position, because the control can compensate for a consistent offset but cannot compensate for scatter. Write every number down on the acceptance sheet with the instrument used. If you cannot repeat a reading, it is not data.

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  Re-level after 24 hCastings settle once weight is on the pads.
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  Spindle runoutMeasure at the taper and the faceplate, cold.
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  SquarenessSpindle axis to Z travel drives taper on long parts.
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  Turret repeatabilityScatter cannot be offset out by the control.

Run-in is not the same as a production trial. The purpose is to bring bearing temperatures up slowly and confirm that lubrication reaches every point. Follow the builder warm-up schedule. Most lathes need a stepped ramp, low rpm first, then increasing in stages, with a dwell at each step. Skipping straight to maximum rpm is the fastest way to damage a spindle before it has ever cut a part.

Log spindle bearing temperature during the ramp. A steady rise that plateaus is normal. A rise that keeps climbing after 30 minutes is not. At the same time, watch hydraulic oil temperature and listen to the pump. A whine that changes pitch under load usually means air in the circuit or a clogged suction strainer, not a bad pump.

The load trial comes last and should use a material you already understand. Turn a test bar, face a disc, and cut a thread. Measure diameter, taper, roundness and surface finish. Compare against the machine specification, not against the last lathe in the shop. Run a short program with rapid moves and tool changes to check the turret under cycle conditions. If the machine holds size across a batch of ten parts, the control and the mechanics are talking to each other.

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  Stepped warm-upRamp rpm in stages with a dwell at each step.
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  Temperature plateauA rising bearing temp past 30 min is a stop point.
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  Test bar cutCheck diameter, taper, roundness and finish.
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  Batch of tenHolding size across the batch proves the setup.

Sign off when every geometry number is inside tolerance, the warm-up curve flattens, and a batch of test parts holds size. Do not sign off on a promise to fix it later. Once the machine is in production, every repair window costs you output, and the supplier has less reason to move quickly.

Hold the machine when you find bed twist that will not shim out, spindle runout outside the builder tolerance, or repeatability scatter that the control cannot offset. These are not commissioning issues. They are build or transport issues, and they belong to the supplier to resolve. A short delay now is cheaper than a year of chasing taper.

One more thing worth doing: keep the acceptance sheet with the machine. When a problem appears six months in, the original numbers tell you whether the machine drifted or was never right. That record is the reason to measure carefully on day one.

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  Sign offGeometry in tolerance, warm-up flat, batch holds size.
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  HoldBed twist, spindle runout, or scatter that cannot be offset.
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  Keep the sheetBaseline numbers separate drift from a build fault.