Fanuc Roboshot SV0440: Servo Overload Alarm — Troubleshooting & Preventive Maintenance
Published: 2026-05-27
Fanuc Roboshot SV0440 is a servo overload alarm indicating that the servo amplifier has detected a sustained current draw exceeding its rated capacity. On all-electric Roboshot machines, this alarm most commonly affects the injection servo axis...
Fanuc Roboshot SV0440 is a servo overload alarm indicating that the servo amplifier has detected a sustained current draw exceeding its rated capacity. On all-electric Roboshot machines, this alarm most commonly affects the injection servo axis during high-pressure, long-duration holding phases.
Immediate Diagnostic Steps
1. Check Load Meter: On the Fanuc iHMI, check the servo load monitor for the affected axis. Sustained load above 80% during holding phase indicates excessive back-pressure from the material or process. 2. Reduce Holding Pressure: Temporarily reduce holding pressure by 10-15% to determine if the alarm clears. If it clears immediately, the root cause is process-related (excessive hold pressure or time). 3. Verify Barrel Temperature: Cold barrel zones force the servo to work harder. A failed heater band on the metering zone will cascade into excessive injection servo load. 4. Check Servo Motor Cooling Fan: The Fanuc servo motor uses an integral cooling fan. Fan failure causes motor temperature to rise and the amplifier to derate. Inspect and clean the fan filter.
Preventive Maintenance
Clean servo amplifier heat sinks every 6 months. Check motor insulation resistance annually. Monitor servo load trends over time — gradual increase indicates screw/barrel wear. Replace the check ring if servo load during holding phase shows a 15%+ increase vs baseline.
Alarm Details
| Alarm Code | SV0440 |
|---|---|
| Brand / Machine | Fanuc Roboshot |
| Severity | High (Axis Stop — Overheat Risk) |
| Component | Servo Amplifier / Motor |
| Affected Systems | Injection Servo Axis or Clamp Servo Axis |
Troubleshooting Protocol
Identify which zone/component triggered the alarm. Record the error code, timestamp, and any measured deviation values shown on the diagnostic screen.
Power down the machine and follow Lock-Out Tag-Out procedures. Visually inspect the affected component for physical damage, loose connections, polymer leakage, or carbonized material.
Using a multimeter, check resistance/continuity on the affected circuit. Verify SSR functionality and fuse integrity. Compare readings to OEM specifications.
Replace the failed component with an OEM-approved part. Do not substitute with generic equivalents unless validated for the specific machine model and operating conditions.
Restart the machine, verify the alarm is cleared, run a test cycle, and document the root cause, repair performed, and parts replaced in the machine maintenance log.
Equivalents & Cross-References
| Equivalent / Alternate | Action |
|---|---|
| engel-alarm-510 | |
| arburg-error-290 |
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References & Industry Standards
- ASTM International. Standard Specifications for Engineering Plastics & Thermoplastics. astm.org
- UL Prospector. Plastics & Elastomers Material Database. ulprospector.com
- MatWeb. Material Property Data for Engineering Thermoplastics. matweb.com
- ISO 1043. Plastics — Symbols and Abbreviated Terms. iso.org