When evaluating a pre-owned / surplus Wire EDM machine like the Agie Charmilles CUT 20P (Swiss-made EDM), you must go well beyond just “does it power up.” Wire EDM is a precision electro-erosion process, and small degradations, wear, or undocumented modifications can drastically affect accuracy, surface finish, and long-term reliability. Below is a rigorous, technically grounded inspection framework (and red-flag checklist) tailored to a machine like the the CUT 20P.

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1. Understand the “Baselines” / Nominal Specs

Before inspection, have the nominal specs in hand to compare. For the CUT 20P model, some known parameters are:

• Travel (X × Y × Z): approx. 13.8″ × 9.8″ × 9.8″ (≈ 350 × 250 × 250 mm)
• U / V axis (taper / offset axes): ~1.77″ (≈ 45 mm)
• Table / work surface: ~27.55″ × 18.89″ (≈ 700 × 480 mm)
• Part load capacity: ~ 882 lb (~400 kg)
• Dielectric tank capacity: ~211 gallons
• Wire diameter range: from ~0.004″ up to ~0.012″ (≈ 0.10 mm to 0.30 mm)
• Auto threading (automatic wire threading) is a standard feature on this model
• The machine is typically submerged (workpiece under dielectric fluid)

These specs set your benchmark. If a used unit deviates substantially (especially in motion travel, U/V range, or table load), that’s a warning sign or indication of a mis-labeled/modified unit.

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2. Pre-Visit Document Review

Before visiting the seller:

• Service / maintenance logs — especially consumables: wire guides, nozzles, flushing system, dielectric filtration, high-voltage generator maintenance
• Total “cut hours” vs idle hours — many issues in EDM stem from high-on-time vs actual cutting-on-time
• Original factory drawings, schematics, parts lists
• Software / controller version & licensing — make sure the control, firmware, and EDM generator versions are supported or documented
• Spare parts history: Has the generator been rebuilt, exchanged? Are original wire guides, servo amps, power modules, pump spares still available?
• Calibration / alignment records, prior accuracy tests

This gives you a baseline to compare what you see.

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3. Visual & Physical Inspection (On-Site)

Once on-site, you should perform a careful walk-through, focusing on structural, mechanical, and erosion components.

3.1 Frame, Structure & Tank

• Frame integrity: Look for cracks, stress fractures, weld repairs, distortions in the machine base, gantry, column, or tank walls
• Tank / dielectric vessel: corrosion, pitting, leaks, liner condition
• Fluid level indicators, overflow systems: are they intact, free from blockage or corrosion
• Seals, gaskets, access hatches: condition, leaks, tampering

3.2 Guideways / Linear Motion & Positioning

• Guide rails / linear ways / cross-slides: inspect for scoring, dents, wear tracks
• Sliding friction / stick-slip: manually move axes (if possible, with power off) and feel for smoothness
• Ball screws / lead screws (if present for U/V or Z): check backlash, axial play, runout, wear
• Encoders / feedback scales: look for damage to scale surfaces or read heads, cleanliness, alignment
• Wiper seals & scrapers: should keep grit, dielectric and wire debris out
• Cross-axes coupling / stiffness: check squareness, that axes remain perpendicular under motion

3.3 High-Voltage Generator & Power Electronics

• Generator / power module: visually inspect for burn marks, loose wiring, replaced modules, signs of repair
• Cooling & ventilation: fans, heatsinks, filters — are they clean and operating
• Power cables, bus bars, insulators: check for signs of voltage flash, surface discoloration, insulation breakdown
• Control cabinet: cleanliness, moisture ingress, wiring harness condition, damaged PCB components
• Grounding & shielding: critical for precision EDM — inspect for proper grounds

3.4 Wire Feed / Guides / Flushing System

• Wire guides and guide blocks: check for wear, carbonization, misalignment, burrs
• Wire tensioning mechanism: ensure it moves smoothly, tension is adjustable and holds steady under test
• Wire spools, payout reels, spool tensioners: check bearings, alignment, smooth feed
• Flushing pumps, filters, filters media, recirculation: dielectrics must be clean; check for clogged filters or damaged plumbing
• Dielectric filtration and purification: e.g. paper filters, ion exchange, filtering cartridges
• Nozzles, break-off point, wire exit path: check for wear, erosion, burrs

3.5 Mechanical / Moving Parts & U/V Taper Axes

• U / V axes (for taper / offset): travel range, smoothness, backlash, alignment
• Pivoting / tilting hardware: check for wear, play, binding
• Collision protection / limit switches: verify that stops, sensors, interlocks are present and functional

3.6 Soft Components & Wear Items

• Wire guides (ceramic or hardened materials) — these wear over time
• Nozzles / orifice / electrodes
• Seals and O-rings — in hydraulic or pneumatic systems if used
• Dielectric hoses / tubing / valves — check for abrasion, cracks, brittleness
• Filters, cartridges, screens

3.7 Calibration / Reference Components

• Test artifact (if available): block or part with precision dimensions used to test the machine
• Leveling / alignment standards: check if machine base is level, if ways are aligned

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4. Functional & Performance Testing

This is the “acid test” — even a visually great machine may fail in real operation.

4.1 No-Load / Dry Motion Test

• Jog all axes through full travel, at slow and moderate speeds, listening and feeling for jerks, binding, stiction
• Reverse direction, stop/acceleration tests
• Check for consistency, repeatability under no load

4.2 Wire Threading / Auto Thread Test

• Execute the automatic wire threading cycle
• Observe repeatability, reliability (how often does it fail)
• Check log of threading cycles in past usage

4.3 Simulated Cut / Path Test (Without Cutting)

• Run a simple contour (square, circle) movement under CNC commands
• Pause mid-run, reverse, circle back — check for drift, positional errors
• Use a dial indicator or displacement sensor to verify commanded moves vs actual

4.4 Wet Cutting Test (Preferred)

• Perform an actual cut on typical material you intend to use
• Cut test shapes: squares, circles, slits, taper cuts
• Measure results (kerf, taper, surface finish, dimensional accuracy) versus expected benchmarks
• Inspect surface quality: look for striations, recast layer, rounded edges, undercuts

4.5 Long-Run / Thermal Test

• Run extended cutting (or at least sustained motion + dielectric circulation) for multiple hours
• Monitor for drift, overheating, changes in accuracy, power drift

4.6 Repeatability / Backlash Test

• Perform repeated movements (e.g. back-and-forth 10×) and measure deviation
• Test in multiple axes and quadrants

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5. Red Flags & Deal-Breakers

Watch out for these warning signs — any of them can significantly diminish the machine’s value or viability.

Red Flag	Why It’s Critical	Comments / Severity
Heavily corroded or pitted tank & structural damage	Indicates poor maintenance or exposure to harsh environment	Potential leaks, distortions, contamination
Worn or scored guideways, rails, or slides	Degrades motion accuracy, introduces backlash	Major repair / regrind needed
Missing or damaged wire guides / nozzles / wear parts	Hard or expensive to replace; critical for performance	Without originals, acceptable tolerance may degrade
Unreliable automatic wire threading	Frequent failures slow production	Manual threading is cumbersome; also suggests guide wear
Control / generator modules with signs of overheating or repair	May fail or be out of spec	Replacement modules could be expensive or obsolete
Lack of service / maintenance records	Unknown wear history raises risks	Hard to trust claimed performance
Obsolete / unsupported control / firmware	Cannot update, maintain or integrate with modern systems	May limit future capability
Unable to perform a real cut test	You can’t verify capability	Accept only after test cuts
Lack of calibration / alignment references	Without baseline, you can’t check performance	Means unknown accuracy
Missing or incompatible spare parts	Hard to maintain, more downtime	Risk of being “stranded”
Excessive wiring modifications or cabling mishmash	Indicates prior “fixes” or poor maintenance	Hidden issues
Dielectric filtration in poor condition	Dirty dielectric degrades EDM performance heavily	May increase wear on generator & wire path

Any machine that shows multiple red flags should cause you to reconsider the purchase or negotiate a steep discount.

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6. Risk Estimation & Lifecycle Assessment

• Determine the remaining life of high-wear consumables (wire guides, nozzles, seals)
• Understand lead times and costs for exotic replacement parts (especially generator modules, outdated controller boards)
• Assess whether the machine’s accuracy performance (after refurbishment) justifies its price
• Build in contingency budget for re-calibration, part replacement, retrofit
• Consider whether the seller will guarantee performance or accept return if cut test fails

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7. Contract Safeguards & Negotiation Tactics

• Acceptance / Test-Cut Clause: Only finalize payment after successful test cut to your satisfaction
• Holdback / Escrow: Retain part of payment until acceptance
• Spare Package: Insist that seller include wire guides, nozzles, filters, spare modules
• Documentation & Licensing: Secure all manuals, schematics, software licenses in writing
• Warranty / Guarantee: Even if limited, get a short-term warranty for core systems (generator, control, major mechanicals)
• Reconditioning / Overhaul Agreement: If possible, commission a refurbishment before shipping