1) Machine Overview

• Manufacturer: Pemamek Oy, Loimaa, Finland
• Model: VRWP 12200/2
• Type: Robotic Welding Gantry / Portal Welding System
• Core Application: Heavy fabrication, shipbuilding, offshore structures, pressure vessel, wind tower, and large steel component welding.
• System Concept: Dual-axis or multi-axis overhead gantry carrying robotic welding heads (typically Yaskawa Motoman or ABB robots) for automated fillet, butt, and corner welds across large panels or structures.
• Key Strength: Extremely rigid portal structure, synchronized motion control, and full offline programming integration (PEMA WeldControl 500 / PEMA Cell Controller).

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2) Documentation & Pre-Purchase Requirements

Before inspection, request the following from the seller:

• Original technical specification sheet (confirm rail length, gantry travel, robot type, welding process, and controller version).
• Robot controller manuals and backup (e.g., Yaskawa DX200 / DX100 or ABB IRC5).
• Electrical & pneumatic schematics (PEMA system diagrams).
• Commissioning reports and CE compliance certificates.
• Calibration data (robot TCP verification, vision sensor calibration if applicable).
• Maintenance logs (linear rail lubrication, gear-rack inspections, welding torch service).
• Power-on hours and robot running hours.

Red flags: Missing controller backups, incomplete wiring schematics, or no service history — especially if system was disassembled or relocated.

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3) Structural & Mechanical Integrity

Portal Frame & Rails

• Inspect the gantry beams and columns for cracks, deformation, or alignment shifts.
• Check rail straightness and parallelism (≤ 0.5 mm deviation over 10 m is acceptable).
• Verify end-stop limit switches and travel sensors.
• Inspect rack-and-pinion or ballscrew drives (depending on configuration) for backlash or wear.

Carriage & Linear Bearings

• Run gantry through full X/Y/Z travel at low and high speed. Listen for gear chatter or bearing rumble.
• Check lubrication system — confirm automatic lube pump cycles properly and oil distribution reaches each rail.
• Examine cable carriers for cracked links or twisted bundles.

Workpiece Handling Tables (if equipped)

• Verify synchronized table alignment and clamping operation.
• Ensure hydraulic or pneumatic clamping pressures meet specification.

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4) Robot Arm & Manipulator Inspection

• Robot Brand: Commonly Yaskawa Motoman EA1900N / HP20 or ABB IRB 2600/4400 series.
• Motion Test: Execute joint jogs through full range at low and high speed.
• Observe for vibration, squeal, or encoder drift.
• Backlash Test: Manually deflect each joint at servo-lock to verify stiffness.
• Calibration: Check TCP (tool center point) accuracy — ≤ ± 0.5 mm error is excellent; ≤ 1 mm acceptable for heavy welding.
• Harnesses: Inspect robot umbilical, torch cables, and coolant lines for wear or burnt shielding.

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5) Welding Equipment & Power Source

• Typical brand: Abicor Binzel / ESAB / Fronius / Kemppi / Lincoln Electric source integrated by Pemamek.
• Check:
  • Power source duty cycle (e.g., 1000 A @ 100%).
  • Feeder operation and wire feed consistency.
  • Cooling unit performance and coolant purity.
  • Torch condition: contact tip wear, nozzle erosion, gas lens alignment.
• Gas flow check: Stable shielding gas delivery at rated L/min.
• Arc start reliability: Verify ≥ 99 % success in automated start/stop cycle test.

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6) Control, Sensors & Automation

PEMA Control Interface

• Confirm PEMA WeldControl 500 / 600 software operational with all features licensed.
• Test program load/save, path editing, adaptive tracking, and data logging.
• Inspect HMI touch panel and industrial PC for display integrity.

Vision / Seam Tracking

• If equipped, verify camera calibration and proper seam detection under welding light.
• Check laser sensor cleanliness and functionality.

Safety & I/O

• Validate emergency stops, safety curtains, door interlocks, and light barriers.
• Confirm all axis limit switches and torque limit sensors respond correctly.

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7) Electrical & Pneumatic Systems

• Open electrical cabinets — ensure wiring is clean, labeled, and free of corrosion.
• Inspect servo drives, inverters, and braking resistors for dust and discoloration.
• Verify cooling fans and filter elements are functioning.
• Pneumatics: pressure regulators, FRL units, and solenoid valves should operate quietly and without leakage.

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8) Precision & Performance Validation

Robot Repeatability Test

• Run calibration routine using pointer tip and reference block.
• Acceptable: repeatability ≤ ± 0.1 mm @ 500 mm reach.

Path Accuracy Test

• Execute pre-programmed weld path on test coupon; measure deviation vs. CAD path (≤ 1.0 mm preferred).

System Synchronization

• Verify coordinated motion between gantry axes and robot arm — no lag or over-travel.

Test Weld

Perform a live weld test using standard material (S355 steel plate):

• Inspect bead uniformity, penetration, spatter level, and arc stability.
• Measure bead height and width vs. program targets (variation ≤ ± 10 %).

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9) Auxiliary Components

• Torch Cleaning Station: Verify function (wire cut, ream, air blast).
• Fume Extraction System: Check filter condition and airflow rate.
• Cooling System: Ensure coolant flow > 3 L/min; monitor temperature rise.
• Cabling & Hoses: Securely routed with strain relief; no exposed copper.

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10) Wear Components & Expected Lifetimes

Component	Typical Rebuild Interval	Inspection Focus
Spindle / Rotary Drives	20,000 h	Bearing play, vibration
Robot Harness	10,000 h	Cable wear, leaks
Linear Guide Bearings	15,000 h	Noise, lube flow
Wire Feeder	8,000 h	Motor wear, rollers
Cooling Pump	10,000 h	Flow rate
Fume Filter	2,000 h	Airflow drop

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11) Acceptance & Run-Off Test Checklist

Test	Target	Result
Rail alignment	≤ 0.5 mm / 10 m
Gantry motion smoothness	No chatter
Robot repeatability	≤ ± 0.1 mm
Weld bead accuracy	≤ ± 1 mm
Arc start success rate	≥ 99 %
Safety E-stop	Verified
HMI & software	Full control

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12) Common Issues in Used VRWP 12200/2 Systems

• Misalignment of long-travel rails after relocation.
• Cable-carrier chain cracking due to age.
• Servo amplifier fan failure or encoder drift.
• Gas hose leaks near torch rotation unit.
• Software license mismatch after control PC replacement.

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13) Evaluation Summary

Evaluation Category	Ideal Condition	Acceptable Limit
Gantry Geometry	±0.5 mm / 10 m	±1.0 mm / 10 m
Robot Calibration	≤ 0.1 mm repeat	≤ 0.2 mm repeat
Welding Quality	Consistent bead geometry	Minor spatter
Electrical Cabinet	Clean & labeled	Moderate dust
Safety & Sensors	100 % active	Minor delay tolerated
Software / HMI	All functions operational	Minor screen aging

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14) Final Verdict

A PEMA VRWP 12200/2 in verified operational condition remains among the world’s most precise heavy-duty robotic welding gantries. Finnish engineering ensures:

• Exceptional structural rigidity,
• Stable long-stroke motion,
• Superior arc automation,
• Lifetime parts support from Pemamek Oy.

When equipped with a healthy Yaskawa or ABB robot and verified system calibration, it is capable of continuous high-accuracy multi-meter welds for decades — a flagship example of Nordic automated welding quality.