SP225H / SP180H grease exchange
The SP225H, SP180H and SP180H-110 are large spot welding robots used with the YRC1000. Every axis reducer uses Molywhite RE No.00. On these models, removing a specified amount of grease after injection is part of the job.
Injection amount per axis (guideline)
| Axis | Injection amount |
|---|---|
| S | 4350 g |
| L | 2180 g |
| U | 2180 g |
| R | 2090 g |
| B | 3160 g |
| T | 3550 g |
Conditions to observe
- Inject with a dedicated grease pump (for example an air-operated grease gun) at 7 g/s or less. As a guide, at two shots per second, set each shot to 3.5 g or less. Pump supply pressure should be about 0.3 MPa or less.
- If you use push-out air to discharge grease, keep the supply pressure at 0.025 MPa or less. Higher pressure pushes out the reducer's oil seal. Grease can shoot out forcefully, so lead it into a container with a tube.
- If you fit a tube to the exhaust port, keep it within 150 mm long with an inner diameter of at least 6 mm. A long tube adds resistance, raises the pressure inside the grease bath and can push out the oil seal.
- Straight after fitting a reducer or motor, wait at least 30 minutes for the sealant to set before injecting.
Work sequence
- Move the robot into the recommended posture (see the "recommended posture for grease injection" table in the manual; for example, L axis at 0° when injecting into the L axis). If the outfitting prevents the recommended posture, choose a posture with the inlet as low and the exhaust port as high as possible. If the exhaust port is too low, the grease will not be fully replaced.
- Remove the plugs from the inlet and exhaust ports, and fit the grease nipple (A-PT3/8, supplied with the robot) to the inlet.
- Inject. The R and T axes have two inlets each. Because these reducers are hollow, inject through inlet 1 until new grease comes out of inlet 2, then plug inlet 1 and inject the rest through inlet 2.
- When to stop injecting depends on the job:
- Grease exchange: stop when the grease coming out of the exhaust port looks like a half-and-half mix of old and new, then go to step 6.
- After replacing a reducer: stop when grease appears at the exhaust port, then go to step 5.
- (Reducer replacement only) Move each axis about five times in teach mode through the angles in the table below, then inject again. Injection is complete when grease overflows from the exhaust port.
- Remove the discharge amount shown in the table. Collect it in a container and weigh it as you go, using either push-out air (0.025 MPa or less) or suction (also 0.025 MPa or less). If it will not come out, move each axis about five times in teach mode again.
- Close the inlet with its plug (clean and degrease the thread and wrap it with sealing tape), fit a grease collection bag or similar to the exhaust port, and perform the run-in motion in playback.
| Axis | Teach / run-in motion angle | Discharge amount |
|---|---|---|
| S | ±45° | Not required (0 g) |
| L | ±45° | 240 ± 30 g |
| U | ±45° | 250 ± 30 g |
| R | ±90° | 310 ± 40 g |
| B | ±45° | 470 ± 40 g |
| T | ±90° | 530 ± 40 g |
The run-in motion uses MOVJ VJ=50.00 on every axis, with a 1.0 s timer after each move, and continues for 15 minutes.
Why the discharge amount matters
If too little is removed, pressure builds up inside during operation and grease leaks. If too much is removed, lubrication becomes insufficient and the reducer wears out early.
warning
Do not enter the robot's motion range while it is moving.
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Source: Based on YASKAWA manual HW1484423.