GP25 inspection, grease exchange and battery replacement
On the GP25, the speed reducers of the basic axes (S-, L- and U-axes) get a grease exchange, while the wrist side (R-, B-axis speed reducer and R-, T-axis gear) only gets a small grease replenishment. Inspection intervals are counted in hours with the servo power ON.
Turn the power off and tag it out before maintenance. If you disconnect the connector between a motor and the multi-port connector, the encoder absolute data (ABSO data) is lost.
Inspection items
| No. | Items | Schedule | What to do |
|---|---|---|---|
| 1 | Alignment mark | Daily | Check that the marks match at the home position, check for damage and for misalignment at the check point |
| 2 | Working area and manipulator | Daily | Check for seeped oil, cracks and damage; clean |
| 3 | Baseplate mounting bolts | 1000 h cycle | Check for missing or loose bolts and tighten |
| 4 | Connector for manipulator cable | 1000 h cycle | Check for loose connectors |
| 5 | Protective tubing (for arc welding use only) | 1000 h cycle / 24000 h | Clean the spatter, check for holes or tears / replace |
| 6 | Timing belts for B- and T-axes | 12000 h cycle | Check the belt tension and condition (replace if teeth are missing, swollen or abnormally worn) |
| 7 | Wire harness in manipulator (lead for the SLU-axes wires, power supply board included) | Daily / 12000 h / 24000 h | Check for damage and dirt / check the flexible hose / replace |
| 8 | Wire harness in manipulator (lead for the BT-axis wires) | 12000 h / 24000 h | Check the fixed part / replace |
| 9 | Battery pack in manipulator | 24000 h | Replace when the battery alarm occurs or at 24000 h |
| 10 | S, L, U, R-axis motor | 12000 h cycle | Check for grease leakage |
| 11 | S, L, U-axis speed reducer | 12000 h cycle | Check for malfunction and replace grease |
| 12 | R, B-axis speed reducer | 12000 h cycle | Check for malfunction and supply grease (hand pump or injection syringe) |
| 13 | R, T-axis gear | 12000 h cycle | Check for malfunction and supply grease (hand pump or injection syringe) |
| 14 | Overhaul | 36000 h | Done by the YASKAWA service company |
Grease used
| Inspected parts | Standard (-A00 / -A01) |
|---|---|
| S-, L- and U-axes speed reducers | Molywhite RE No.00 |
| R- and B-axes speed reducers, R, T-axes gear | Harmonic Grease SK-1A |
For the drip-proof (-C00) and food grade grease (-F40) specifications, see the variants page.
Grease exchange for the S-, L- and U-axes speed reducers
Conditions to keep
- Always remove the plug from the grease exhaust port before injecting. With the plug in place, grease can enter the motor or push out the oil seal.
- Inject with a grease pump (for example an air-operated grease gun) at 7 g/s or less. At 2 shots per second, that means 3.5 g per shot or less. Keep the air supply pressure of the grease pump at approximately 0.3 MPa or less.
- When extruding or suctioning grease out, keep the pressure at 0.025 MPa or less.
- Install the grease zerk A-PT3/8 on the grease inlet.
Amount of grease and amount of exhausted grease
| Axis to exchange grease | Amount of grease (approx.) | Amount of exhausted grease |
|---|---|---|
| S-axis | 1650 g | 50 ± 5 g (57 ± 5 cc) |
| L-axis | 750 g | 90 ± 5 g (103 ± 5 cc) |
| U-axis | 370 g | 60 ± 5 g (69 ± 5 cc) |
The maintenance manual gives no separate amount for the first supply only.
Key steps
- Remove the plugs from the grease inlet and exhaust port, install the grease zerk on the grease inlet and inject. When exchanging grease, stop when old and new grease come out in about equal amounts; when replacing the speed reducer, stop when grease can be seen at the exhaust port.
- (When replacing the speed reducer) Operate the axis about 5 times at ±45° in the teach mode, then inject again.
- Discharge the amount in the table above from the exhaust port.
- Perform the running-in operation by playback: the exchanged axis at ±45°, MOVJ VJ=50.00, timer 1.0 s after each operation, for 15 minutes.
- Wipe off the discharged grease and install the plugs with seal tape TB4501.
Plugs
| Axis | Grease inlet | Grease exhaust port |
|---|---|---|
| S-, L- and U-axes | Hexagon socket head plug PT3/8 | Hexagon socket head plug NPTF3/8 |
The tightening torque of the plugs is 16.5 N·m (1.7 kgf·m), with seal tape TB4501. When ceiling-mounted, the grease inlet and exhaust port are swapped.
Grease replenishment for the R-, B-axis speed reducer and R-, T-axis gear
Use a hand pump or injection syringe to inject a small amount of Harmonic Grease SK-1A. Grease is not exhausted from the air exhaust port, so do not inject too much. Always remove the plug (or screw) from the air exhaust port before injecting.
| Part | Amount of grease | Grease inlet / air exhaust port | Tightening |
|---|---|---|---|
| R-axis speed reducer | 7 g | Hexagon socket head plug PT1/8 (grease zerk A-PT1/8) | 4.9 N·m (0.49 kgf·m), seal tape TB4501 |
| B-axis speed reducer | 7 g | Hexagon socket head cap screw M6 (grease zerk A-MT6×1) | 6 N·m (0.6 kgf·m), apply Three Bond 1206C |
| R-axis gear | 3 g (85 g when the speed reducer is replaced) | Hexagon socket head plug PT1/8 | 4.9 N·m (0.49 kgf·m), seal tape TB4501 |
| T-axis gear | 2 g each into grease inlet 1 and grease inlet 2 | Hexagon socket head cap screw M6 | 6 N·m (0.6 kgf·m), apply Three Bond 1206C |
For the R-axis speed reducer and gear, make the U-arm horizontal to the ground first.
Replacing the battery packs in the manipulator
There are three battery packs (HW1483880-A). Replace them when the battery alarm occurs or at 24000 h.
- When the YRC1000 power can be turned on: turn ON the power supply of the YRC1000, turn OFF the servo power, and work with the emergency stop button pressed. Disconnect the old battery pack, connect the new one, put it in the protective tube and fix it with cable ties.
- When the power cannot be turned on: first connect the lead wires for battery replacement (HW1471281-A) and the battery pack for backup to the "IN" port of the multi-port connector, then replace the pack. Otherwise the encoder absolute data is lost. After the replacement, always remove the battery pack for backup (current would flow from the new battery).
Related articles
- GP25 specifications
- GP25 variants (drip-proof, food grade grease, wall-mounted, form cutting)
- Encoder battery replacement
- Alarm 4312 ENCODER BATTERY ERROR
Source: based on YASKAWA manuals HW1484719 (GP25 instructions rev 3, Japanese) and HW1484731 (GP25/AR1730 maintenance manual rev 1, Japanese). English terms follow HW1484720 (MOTOMAN-GP25 INSTRUCTIONS rev 2; one revision older than the Japanese rev 3) and HW1484732 (MOTOMAN-GP25/AR1730 MAINTENANCE MANUAL rev 1).