Below is a Technical Buyer’s Handbook / Due-Diligence Checklist for evaluating a pre-owned / used / surplus Bystronic BySprint Fiber fiber-laser cutting machine (for example, sheet size ~ 3 × 1.5 m variant), “Swiss made / From Switzerland” origin. Use this as a structured guide; adapt tolerances, subsystems, and weighting to your production needs and budget.

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1. Reference / Benchmark Specifications (BySprint Fiber Series)

Before inspection, you should collect the nominal (as-new) technical specifications for the particular variant you are evaluating. That gives you a benchmark to compare against. Some published specs for BySprint Fiber series include:

• The BySprint Fiber 3015 variant is noted as “built in Switzerland” in used machinery listings.
• The BySprint Fiber family datasheet shows specifications: positioning accuracy ± 0.1 mm, repeatability ± 0.05 mm over a 1 m measuring length (VDI/DGQ 3441)
• For the Fiber 3015 variant: cutting area 3,048 × 1,524 mm, Z travel ~ 70 mm.
• Maximum workpiece weight for 3015: ~ 890 kg (for that size).
• The maximum positioning speed (simultaneous) is ~ 140 m/min (for many variants in the series)
• The machine weights are substantial—e.g. the 3015 version is ~12,000–13,000 kg (without exhaust / auxiliary units) in used listings

These specs help you decide whether the used machine is close to expected performance or has drifted too far.

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2. Pre-Inspection / Remote Phase

Do as much groundwork as possible before visiting the site:

1. Request documentation
    - Original mechanical / electrical / optical / control manuals
    - Wiring diagrams, layout prints, optical path, beam delivery schematics
    - CNC / control (ByVision or other) parameter backups, software versions
    - Maintenance / service logs (laser source, chiller, optics, mirrors, alignment)
    - Calibration / alignment certificates (optical path alignment, beam axis, focusing)
    - History of parts replaced (fiber source, optics, galvanometer mirrors, axes motors)
    - Any modification or upgrade history (e.g. higher power source, multi-head, automation)
2. Photos & videos
    Request high-resolution images/videos of:
    – Machine frame, gantry, bridges, supports
    – Laser source / fiber module, cooling, converters
    – Beam path (mirrors, beam delivery modules)
    – Cutting head, nozzle, focusing optics
    – Linear axes (rails, carriages), drive systems
    – Electrical / control cabinets, wiring, connectors
    – Motion videos if machine still operational (axis move, laser firing, cut)
3. Ask key diagnostic questions
    - Year of manufacture, hours of use / laser on time
    - Reason for selling / decommission
    - Is the machine currently operational and under power?
    - Which major subsystems have been repaired / replaced (laser source, optics, alignment mechanisms)?
    - Are spares (optics, mirrors, nozzles) included?
    - What control / interface version is installed?
    - Was the machine used primarily on thick or thin materials, what frequency of usage?
4. Prepare measurement & test tools
    Bring or plan for:
    – Dial indicators, micrometers, straight edges
    – Laser alignment tool / beam path alignment tools, optical meters
    – Power meters / current sensors
    – Thermography camera (for hot spots)
    – Vibration sensor / accelerometer
    – Tools for opening covers, optical path inspection
5. Logistical planning
    - Evaluate machine footprint, ceiling height, crane / rigging access
    - Estimate weight and plan lifting points
    - Plan for utilities: power, cooling (chiller), compressed air, exhaust, gas supply (O₂, N₂)
    - Foundation and floor flatness / vibration isolation requirements

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3. Visual & Structural / Static Inspection (Power-Off)

Start with an in-depth walk-around before powering anything.

3.1 Machine Frame, Bridge, Gantry & Support Structure

• Inspect the main frame, gantry beams, columns, supports for cracks, weld repairs, distortion, bending
• Check for signs of alignment rework, shimming, or regrinding of guide surfaces
• Look for corrosion, rust spots, pitting, especially near coolant, exhaust, or floor contact areas
• Check way covers, protective covers, sealed sections, guards for damage or missing parts
• Inspect beam guides / rails for visible wear, dents, or debris accumulation
• Check that all fasteners, anchoring plates, shims are intact and not loose

3.2 Linear Axes, Guides & Carriages

• Examine linear guide rails, bearings, carriages for wear, scoring, lubrication condition
• Inspect rails for spalling, chips or pitting
• Check the motion of carriages (if manual push is allowed) for binding or uneven movement
• Check for play / looseness in axes mechanically
• Examine the drive mechanism (rack & pinion, ball screw, direct drive) for signs of wear, backlash, lubrication issues
• Verify lubrication / grease / oil supply lines are intact and not clogged

3.3 Laser Source, Fiber / Module, Beam Path Infrastructure

• Inspect the laser module or fiber delivery unit: housing, connectors, cooling lines
• Check fiber cables (if external), connectors, strain reliefs for wear or damage
• Inspect beam mirrors, mirror mounts, optical path enclosures for cleanliness, misalignment, damage
• Inspect the cutting head, focusing optics, nozzle, and protective windows for wear, deposits, damage
• Look for signs of contamination, smoke trails, carbon deposits near the head

3.4 Optical & Mirror Components, Beam Path Enclosures

• Inspect protective enclosures for mirrors, beam path tubes, shielding
• Open covers (if allowed) and visually inspect mirror surfaces for scratches, pitting, coating degradation
• Check that mirror mounts are rigid and adjustable, no signs of looseness
• Inspect alignment adjustment mechanisms (micrometers, fine screws) for freedom of motion and no binding

3.5 Electrical Cabinets & Wiring

• Open main control / drive cabinets and inspect internal condition: dust, moisture, corrosion, overheating traces
• Look for discolored wires, melted insulation, burned terminals
• Inspect drive modules, power supply, control boards, I/O modules
• Check cooling fans, filters, ventilation paths, dust build-up
• Inspect wiring bundles, connectors, shielding, strain reliefs
• Check power cabling to the fiber/laser, cooling pumps, exhaust system

3.6 Safety & Interlocks

• Verify existence and mechanical integrity of emergency stop (E-stop) buttons
• Inspect safety interlock switches, door sensors, enclosure safety systems
• Confirm protective enclosures over the laser cutting area are intact and not bypassed
• Inspect light curtains (if present), beam safety shielding, access doors and locks

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4. Power-Up & Functional / Dynamic Testing

With safety measures in place, proceed to power up and run dynamic tests. Use the seller’s cooperation and ensure safety protocols.

4.1 Initial Control & System Diagnostics

• Power on the CNC / control system (ByVision or variant), observe boot sequence and logs
• Check for persistent alarms or errors
• Verify parameter loading, fiber module readiness, I/O status, sensor statuses

4.2 Axis Movements & Motion Tests

• Jog X, Y, Z axes at low speed: check smoothness, direction, no binding or stiction
• Execute full traverse motions (within safe range) to inspect for irregular motion, jerk, vibration
• Command known moves (e.g. 100 mm, 200 mm) and measure with a dial indicator or gauge to test linear accuracy
• Reverse directions and check for backlash or dead-band
• Run simultaneous X + Y motion (diagonal paths) to test coordination and linear cross-coupling

4.3 Laser / Beam Firing & Cut Simulation (if permitted)

• Conduct test firing of the laser (at low power) to inspect beam alignment, focus stability, head response
• If safe, run a light test cut (thin plate) to verify cut quality, kerf, accuracy, edge quality
• Monitor the entire path—beam travel, acceleration, deceleration, head response
• Check restartability: pause the cut / path and resume, see if alignment holds

4.4 Thermal Stability / Drift Tests

• Let the machine run for an extended period (30–60 min) with motion cycles or idle to warm up
• After warm-up, re-check key dimension moves, reference points, alignment to detect drift
• Monitor temperatures in drives, laser module, cooling systems
• Use thermal imaging to detect hot spots or overheating components

4.5 Safety & Fault Behavior Tests

• Trigger emergency stop during motion or beam firing to verify immediate safe shutdown
• Hit limit switches or home switches to confirm axes stop or retract as expected
• Simulate sensor or interlock failure (if safe to do) to test error handling
• Test door / lid interlocks during operation

4.6 Endurance / Repetition / Cycling Test

• Run multiple cycles: e.g. repeated positioning, motion, beam firing or mock cut patterns
• Observe any progressive deviation, drift, noise increase
• Note consistency of motion cycles over time

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5. Precision, Accuracy & Calibration Validation

After warm-up and preliminary verification, test the machine’s precision and repeatability.

• Perform a repeatability test: move to a nominal point, retract, return, measure deviation
• Execute a grid of moves (X–Y mesh) and measure deviations from expected positions to detect nonlinearity, scale errors, geometric distortion
• Evaluate beam-to-motion overlay: whether the laser beam is accurately following commanded motion within tolerance
• Check cut-to-cut consistency over multiple parts
• If possible, use calibration tools (laser interferometer, optical measurement systems) to more precisely map motion error
• Test beam focus and optical path stability during motion
• Compare measured error magnitudes vs nominal spec tolerances (±0.1 mm, ±0.05 mm repeatability typical in spec)
• If machine has multi-head or double-beam options, test head-to-head consistency

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6. Documentation & Service / Maintenance History Review

Once the machine has been tested physically and dynamically, scrutinize its history.

• Maintenance logs, service history (especially for the laser source, optics, mirror replacement)
• Records of major repairs / replacements (laser modules, mirrors, optics, drive motors, bearing replacements)
• Calibration / alignment and optical path alignment certificates
• Modifications / upgrades (power-upgrades, additional heads, automation)
• Control / software version and upgrade history, backups
• Spare parts included (optics, mirrors, nozzles, spare laser diodes, etc.)
• Tooling, spare optical modules transferred with machine

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7. Risk Assessment, Life-Remaining Estimate & Cost Forecasting

From your observations and findings, build a risk model and cost estimates:

• Wear-critical subsystems: mirrors, optical path alignment mounts, beam delivery modules, lenses, galvanometer heads (if applicable), axes/guide rails
• Spare parts availability & cost: availability of Bystronic spare optics, mirrors, laser modules, beam delivery parts in your region
• Calibration / realignment cost: expect optical path realignment, beam axis calibration after reinstallation
• Transport / installation risk: damage to optics, misalignment in transit, shock to fine components
• Downtime & commissioning: time to get the machine up to full performance
• Control / obsolescence risk: controller, drive electronics, software obsolescence or license issues
• Fallback / salvage value: structural parts, optics, modules that may still be usable

You may create a weighted scoring table (e.g. optics, axes, laser source, control) to rate health and assign a risk-adjusted value.

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8. Contractual Safeguards & Negotiation Clauses

Use your inspection leverage to demand protective contract terms:

• Acceptance / performance clause: buyer has right to test and validate in your facility; if key metrics not met, you can refuse or adjust price
• Warranty / latent defect clause: limited warranty (e.g. 3–6 months) on optical alignment, beam delivery, source defects
• Spare parts package inclusion: seller to include critical spare parts (mirrors, optics, nozzles, laser diodes)
• Documentation handover: all manuals (mechanical, optical, electrical, software), drawings, optical path schematics, alignment data
• Damage / risk during transport clause: clarify who bears risk of damage to optical components during transit
• Installation / commissioning support: seller or authorized technician support for optical alignment and calibration at your site
• Penalty / adjustment clause: if post-commissioning metrics deviate more than X %, seller bears repair cost or price adjustment

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9. Post-Purchase / Installation & Commissioning Checklist

After the machine arrives at your site:

1. Establish rigid, vibration-isolated foundation and leveling
2. Complete connections: power, cooling, exhaust, gas supply, compressed air
3. Clean optics, flush beam path protection tubes or enclosures
4. Power-up and run through your acceptance test suite again
5. Perform optical path alignment, beam calibration, focusing, mirror alignment under your site conditions
6. Execute test cuts under your real material mix and measure performance
7. Collect baseline measurements (repeatability, drift, deviation)
8. Train operators & maintenance staff on optical alignment, safety, maintenance protocols
9. Define preventive maintenance schedule (optics checks, mirror cleaning, alignment verification)
10. Monitor early operation (first few weeks) for drift, deviation, performance degradation