FANUC M-20iB/25 Robot Mechanical Unit Maintenance Manual PDF

Description

FANUC M-20iB/25 Robot Mechanical Unit Maintenance Manual

This is the mechanical unit maintenance manual for the FANUC Robot M-20iB/25, issued by FANUC America Corporation under document number MARNB20IB11161E (REV. A) and manual number B-83755EN. It deals exclusively with the robot’s mechanical unit — the arm, base, wrist, reducers, motors, cables and air tubing — and is the document a maintenance engineer reaches for when a FANUC M-20iB/25 needs to be greased, adjusted, torn down, rebuilt, or re-mastered.

Where the controller operator’s manual tells you what alarms mean, this one tells you what to do about the machine itself: which reducer takes which grease and how much, how much backlash is still acceptable, how to rig an arm before you release a brake, and how to get the robot back on its marks after a motor swap.

File Details

• Manual type: Mechanical unit maintenance manual
• Brand: FANUC (FANUC America Corporation)
• Model: FANUC Robot M-20iB/25
• Document number: MARNB20IB11161E REV. A / B-83755EN/01
• Date: November 2016
• Language: English
• Page count: 160 pages
• Format: PDF

Chapters Covered

• 1. Checks and Maintenance
  • Daily Checks
  • Periodic Checks and Maintenance
  • Confirmation of Oil Seepage
  • Confirmation of the Air Control Set (option)
  • Check the Mechanical Unit Connectors
  • Check of Fixed Mechanical Stopper and Adjustable Mechanical Stopper
  • Maintenance Tools
• 2. Periodic Maintenance
  • Replacing the Batteries (1.5 year checks)
  • Replacing the Grease of the J1 to J3 Axis Reducers (3 years / 11520 hours)
  • Releasing Remaining Pressure from the Grease Bath (J1 to J3 axis)
  • Grease Supplying Procedure for J4 to J6-Axis Reducer (4 years / 15360 hours)
• 3. Troubleshooting
  • Vibration and Noise Diagnostics
  • Rattling, Motor Overheating, Grease Leakage, Dropping Axis, Displacement
  • Backlash Measurement — Per-Axis Postures, Loads and Allowances
• 4. Replacing Parts
  • Figure of Drive Mechanism (all six axes)
  • Replacing J1, J2, J3, J4, J5 and J6-Axis Motors
  • Replacing J1, J2, J3, J4, J5 and J6-Axis Reducers
  • Replacing the Wrist Unit
  • Replacing the J5/J6 Belt
  • Replacing the Solenoid Valve
  • Sealant Application
• 5. Replacing Cables
  • Cable Wiring
  • Cable Forming
  • Replacing Cable K123 and Air Tube (Connector Panel to J2 Base)
  • Replacing Cable K102, K103, K104, K105, K106, K108 and Air Tube (J2 Arm to J3 Arm)
• 6. Adjustment
  • Adjusting Tension of Belt
  • Mastering — Overview, Resetting Alarms and Preparing for Mastering
  • Fixture Position Mastering
  • Verify Mastering
• Appendix A — Maintenance Parts
• Appendix B — Mechanical Unit Circuit Diagram and Air Pressure Diagram
• Appendix C — Periodic Maintenance Table
• Appendix D — Strength of Bolt and Bolt Torque List
• Appendix E — Insulation About Arc Welding Robot

Taken as a whole, the manual is a bench-level teardown and upkeep guide rather than a theory book. Every replacement section is built around an exploded view with numbered callouts, a parts table giving the exact FANUC specification number, quantity, locking method and tightening torque, and a numbered disassembly sequence. Grease specifications, quantities and gun-tip pressures are printed as tables, as are the belt tension measurement conditions, the backlash allowances for each axis, and the recommended bolt tightening torques. Cable work is supported by routing diagrams and forming sheets that show clamp positions and cable marking points. The result is a document you can follow step by step with the arm in front of you.

Periodic Maintenance You Can Schedule From This Manual

The manual lays out the FANUC M-20iB/25 maintenance calendar in concrete terms. Backup batteries are a 1.5-year item. J1, J2 and J3 reducer grease is replaced at three years or 11520 hours, whichever comes first — with the greasing posture for floor mount, upside-down mount and wall mount robots given separately. J4, J5 and J6 reducers are greased at four years or 15360 hours. Cables are a four-year or 15360-hour item. Alongside those fixed intervals are the daily and periodic checks: oil seepage at each joint, air control set pressure and drain, connector tightness, mechanical stopper condition, brake drop of the end effector, and positioning accuracy. Because the manual states its intervals assuming up to 3840 operating hours a year, you can scale the whole schedule to a heavier duty cycle.

Working on a FANUC M-20iB/25 Arm

This manual is written for someone who is going to put hands on the machine. Before any reducer or motor comes off, it walks you through setting a quick master reference position, rigging the arm with slings, and releasing the J2 or J3 brake only with the arm supported — the diagrams show exactly which way each arm falls under gravity. Torque values are given for every retaining bolt, from the M12 J1-axis stopper bolts at 129 Nm down to the small seal bolts on the wrist. Sealant and thread-locking compounds are called out by name at each step. Where the work involves an O-ring, a gasket or a washer that must not be reused, the manual says so.

The troubleshooting chapter is organised by symptom rather than by part. Vibration and noise are traced through base fastening, rack rigidity, overload, worn gears and bearings, grounding, and finally controller, cable and motor causes. Rattling points at loose retaining bolts and increased backlash. Motor overheating is split between ambient temperature, operating condition, parameters and mechanical faults. Grease leakage leads into the O-ring, oil seal and hexagon bolt locations. Dropping axes go straight to the brake drive relay and motor. Grease leakage and dropping axes are where a lot of older M-20iB arms end up, and this chapter gives the decision tree.

Buying the FANUC M-20iB/25 Maintenance Manual

With this manual on hand you can replace any of the six axis motors or reducers, swap a wrist unit, change the J5 and J6 belts, re-route and reform the mechanical unit cables, replace the solenoid valve, measure backlash against FANUC’s allowance figures, and perform fixture position mastering to put the robot back on its marks. Those are jobs where an incorrect grease quantity, an over-torqued bolt, an unsupported arm or a wrongly routed cable can turn a routine service into a seized reducer or a dropped arm — the manual exists precisely to keep the procedure correct.

The file is delivered instantly as a PDF after checkout. There is nothing to ship, no waiting on a supplier, and no risk of a paper copy being lost in the workshop. Read it on a laptop on the shop floor, on a tablet next to the controller, or print only the pages for the job in front of you.

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