Arburg Error 290: Screw Rotation Speed Deviation - Diagnostics & Fix
Published: 2026-05-30
Arburg Error 290 is triggered by the Selogica controller when the actual screw rotation speed (measured by the screw motor encoder) deviates from the commanded set-point by more than the programmed tolerance during the plastication (recovery)...
Arburg Error 290 is triggered by the Selogica controller when the actual screw rotation speed (measured by the screw motor encoder) deviates from the commanded set-point by more than the programmed tolerance during the plastication (recovery) phase. Unlike a simple motor fault, Error 290 is a process deviation alarm—the motor is running but the screw is not rotating at the commanded speed, which can indicate either an electrical/drive issue or a mechanical issue creating excess resistance to screw rotation.
On Arburg ALLROUNDER machines with servo-electric screw drive (standard on ALLDRIVE and GOLDEN ELECTRIC series, optional on hybrid machines), the diagnostic screen will show: commanded speed (RPM), actual speed (RPM), motor torque (% of rated), and the speed deviation tolerance band. For servo-electric machines, a steady torque reading >80% during plastication with speed below command indicates a mechanical resistance issue (frozen polymer, worn screw/barrel, or material bridging at the feed throat). A fluctuating torque with erratic speed indicates an encoder or servo drive problem. For hydraulic screw drive machines (older ALLROUNDER S and some hybrid configurations), the same diagnostic logic applies but torque is inferred from hydraulic pressure drop across the screw motor.
Alarm Details
| Alarm Code | 290 |
|---|---|
| Brand / Machine | Arburg |
| Severity | Medium (Warning / Process Deviation) |
| Component | Screw Drive Motor / Encoder |
| Affected Systems | Plasticizing Unit / Selogica Controller |
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 405 | |
| Sumitomo Demag Screw Speed Alarm |
Frequently Asked Questions
What is the most common mechanical cause of Arburg Error 290?
The feed throat bridging phenomenon: granules in the feed throat zone fail to flow into the screw flights, creating a void at the screw root—the screw spins with reduced material to plasticate, then the bridge collapses and a slug of cold material jams the screw, causing a momentary speed drop. This is most common with low-bulk-density materials (regrind, long-glass-fiber compounds) and in humid conditions where moisture causes granule clumping. Solution: (1) Verify feed throat temperature is within 40-60°C—too hot softens granules causing them to stick; too cold allows condensation. (2) Install a hopper vibrator or auger feeder for difficult bulk-density materials. (3) Check that the hopper magnet grate is not clogged with metal fines. (4) Verify the screw cooling circuit at the feed zone is functioning—excessive feed zone temperature causes premature melting and bridging.
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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