Here’s a detailed checklist (plus notes and red flags) for buying a used Doosan / DN Solutions PUMA 2600SY II (or “Puma 2600 SY / SY II Y-axis / subspindle” variant) CNC turning center. Because it’s a fairly advanced lathe with additional axes (Y, subspindle, live tooling, etc.), you need to be extra thorough. I’ll also point out known specs so you can judge deviations.

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Baseline / Nominal Specifications & What to Expect

Before assessing, you should get (or confirm from seller) the full spec sheet so you know what “as new” should deliver. Some known specs / features include:

• It is a Y / SY version: PUMA 2600 SY II includes a Y-axis (±52.5 mm) in addition to X and Z.
• X-axis travel: 260 mm (≈ 10.2 in)
• Z-axis travel: 830 mm (≈ 32.7 in) for many standard versions.
• Y-axis travel: ±52.5 mm (i.e. 105 mm total stroke) for the Y version.
• Spindle speed & power: the standard main spindle is rated (on PUMA 2600 SY II) for up to 4,000 rpm, power in the range 22 kW (≈ 30 hp) for main spindle.
• Bar / through spindle capacity: ~ 81 mm bar capacity (3.2 in) for “SY” versions.
• Subspindle / secondary spindle: Many used listings show that SY versions have a subspindle, sometimes up to 6,000 rpm.
• Live tooling / milling / Y + C axes: The “SY / Y / SY II” variants often include milling & live tooling capability, and C-axis functionality, increasing complexity.
• Rapid traverse: many sources list 30 m/min (for X, Z, Y) for rapid moves.
• Turret: many models use a 12-station (or optional 24 half-station) turret with driven tooling capacity.
• Dimensions / weight: for example, the Overmach spec sheet gives machine dimensions ~ 4400 × 2100 × 2170 mm, weight ~ 6450 kg.

Use those as benchmarks: when you test the used machine, if any of these are far off (reduced travel, much lower spindle power, poor performance), that signals possible deterioration, misrepair, or damage.

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Detailed Inspection & Testing Checklist

Here is a methodical breakdown of what to inspect, test, and verify in each subsystem. Wherever possible, force the seller to allow test cuts or demonstration.

Subsystem / Feature	What to Inspect / Test	Why It Matters / Red Flags
Frame, bed, and structural integrity	• Examine the bed, base, and frame for cracks, weld repairs, distortions, or signs of collisions. • Check whether the machine is properly leveled, stable, and rigidly anchored. • Use a straightedge, granite alignment bar, or laser to check the flatness of the bed over its length, and whether there is sag or twist.	Any deformation in the bed or structural frame undermines precision. Repairs are expensive and often only partially effective.
Guideways / slide surfaces	• Visually inspect all linear ways (X, Y, Z) for scoring, nicks, corrosion, embedded chips, or wear marks. • Move axes slowly over full travel and feel for smoothness, binding zones, friction variation or “sticky” spots. • Reverse direction and feel for backlash, slop, or dead zones. • Use dial indicators or measurement equipment to check straightness or linear deviations over travel.	Wear or damage in guide surfaces is a common wear point; once worn, accuracy and smoothness suffer significantly.
Ball screws / nut assemblies / drive couplings	• Move axes at different speeds and watch for roughness, vibration, or noise. • Check for backlash or play in screw-nut assemblies, especially in reversing. • Inspect the screw threads and nuts (where accessible) for pitting, wear, metal dust accumulation. • Examine coupling between motor and screw for misalignment or looseness.	Worn screws or nuts degrade positioning, repeatability, motion smoothness; replacement is costly.
Main spindle & turning system	• Run the spindle at various speeds (low, mid, high) and listen for bearing noise, vibration, hums, roughness. • Mount a test bar or collet + indicator to measure radial and axial runout. • Let it run for a while to warm up; then check ambient vs housing temperature to detect overheating. • Inspect spindle nose, taper, seating surfaces for wear, corrosion, nicks. • If the machine has a subspindle, test its clamping, alignment, rotation, and performance.	Spindle bearings and accuracy are among the most vital—and expensive—components. Overheating, excessive runout, or noise suggest serious trouble.
Y-axis / multi-axis subsystems	• Because the “SY” versions include a Y-axis, exercise the Y movement: sideways turret motion. Test smoothness, binding, or unequal resistance. • Reverse direction and check backlash in Y-axis. • When combining Y + X + Z motion, check for interpolation errors, overshoot, or lag. • If there is a C-axis (spindle indexing) or tilting features, test them for backlash, indexing accuracy, and motion quality.	The Y-axis and any extra axes add complexity and failure risk. Poor performance here limits 5-sided machining capabilities.
Tool turret / live tooling / tool changer	• Cycle tool changes repeatedly; watch for misindexing, collisions, delays, sensor errors. • Inspect locking plungers, sensors, rails, grippers, sensors, mechanical elements. • If live tools are present, run them under load, measure runout, monitor vibration. • Test tool-to-tool repeatability (remove tool, insert back, see how close it returns).	Tooling issues cause scrap, crashes, downtime. In high-end multitasking machines, turret and live-tool reliability is critical.
Control, electronics & wiring	• Power-up and watch startup messages; note any error codes, missing modules, alarms. • Test motion commands (jog, interpolation, path sequences) and transitions. • Inspect the electrical/CNC cabinet: fans, wiring, connectors, signs of burning, discoloration, corrosion, dust. • Test encoder feedback, sensor wiring, cable harness integrity. • Confirm parameter backups, software / compensation table backups, ability to restore configuration. • Run sample programs (turn + mill + multi-plane) to test interpolation and control logic.	Mechanical parts may be perfect, but a faulty control or missing module can render the machine unusable.
Coolant, lubrication & fluid systems	• Test coolant pump, flow, pressure, nozzles, hoses, filters. • Examine coolant tank: sludge, chips, corrosion, foreign debris. • Test the lubrication systems for axis slides, turret, bearings—ensure oil delivery works, lines are clear, no blockage. • Inspect for leaks or degraded hoses, seals, piping in wet / coolant-exposed zones.	Poor lubrication or coolant systems accelerate wear, reduce precision, and can cause failures in spindles or bearings.
Chip / debris / guarding / sealing	• Check chip conveyor, chip removal paths, flushing paths, and guarding. • Ensure all covers, bellows, wipers, seals are intact and functional to keep chips / coolant out of critical areas. • On internal cavities or behind enclosures, look for chip buildup or debris ingress.	Chips and abrasive debris are adversaries of CNC lathes; missing or damaged protection is a red flag.
Thermal drift & stability	• Run the machine under load for an extended period (30–60+ minutes). • Re-measure previous reference dimensions or test cuts to see whether drift occurred. • Monitor temperatures of axes, spindle, turret, structure for uneven heating or hot spots.	Thermal behavior is often the hidden killer of precision. Excessive drift or instability under load means the machine may not hold tolerances in real production.
Test part / production trial	• Run a representative production part (turning + milling) through its full motion. • Measure final dimensions, tolerances, surface finishes, multi-surface alignment. • Repeat the process to check repeatability and consistency. • Vary speeds and feeds and see how the machine handles them (especially transitions, corners, interpolations).	A real-world job stress test often reveals latent problems that static checks do not.
Maintenance history & usage record	• Ask for build year, serial number, runtime hours (if logged), spindle hours, cycle counts. • Request maintenance logs: replaced parts, repairs, past refurbishments, crash events. • Ask about the working environment: clean shop vs harsh environment, coolant quality, chip management discipline. • Check wear of common parts (turret, ways, tool holders, chucks, seals).	Good records reduce risk. A machine with unknown or neglected history is more of a gamble.
Parts, support & documentation	• Check whether Doosan / DN Solutions still support the 2600SY / SY II model line and offer spare parts (turrets, motors, drives, electronics, spindles). • Ensure you receive operator, maintenance, electrical/wiring manuals, parts lists, calibration & compensation data, and software backups. • Ask if the seller can include spare modules, cables, consumables, tooling.	Without parts or support, downtime or failure may become ruinous.
Shop / infrastructure readiness & installation	• Confirm your power supply (voltage, phases, current) matches machine requirements. • Ensure proper grounding, clean stable electrical feed. • Check that the shop floor/foundation is rigid, level, and able to bear the machine weight without undue vibration. • Ensure space and clearance for access, maintenance, tool changes, axis motion. • Verify chip / coolant drainage, filtration, ventilation, waste handling. • Safety compliance: emergency stops, guards, interlocks must satisfy local regulations.	Even a perfectly functioning machine can fail or perform poorly if installed in a deficient environment.

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“Red Flags” & Deal Killers

Here are conditions you should treat as warning signs or potential deal-breakers:

• Spindle bearing noise, overheating, or excessive runout
• Axis motion with “hard spots,” inconsistent friction, binding zones
• Deep scratches, corrosion, or damage on guideways / slide surfaces
• Turret or tool changer misindexing, jamming, sensor failures
• Y-axis / extra axes that behave poorly or do not track well
• Control electronics with missing modules, firmware issues, corrupted backups, burned wiring
• Absent or dysfunctional coolant / lubrication systems
• Guards, bellows, or seals missing / broken, leading to chip ingress
• Excessive thermal drift or instability discovered during test run
• Machine lacking documentation, schematics, calibration data, or software backups
• No local parts or service support for the model
• Seller refusing to allow full functional testing or hiding interior parts

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Negotiation Guidance & Risk Mitigation

• Estimate refurbishment cost (guides, spindle bearings, turrets, electronics) and subtract from asking price.
• Require a test / acceptance period after installation where you can run your own sample part.
• Demand the seller provide documentation, software / parameter backups, spare parts, tooling.
• Bring a lathe / multi-axis expert to inspect with you.
• Factor in transport, rigging, alignment, calibration, leveling costs.
• If possible, tie part of payment to performance (i.e. machine must hold ±X tolerance over Y hours).
• Ask for references from prior buyers of the same model.