JSW (Japan Steel Works) Alarm J310: Mold Protection Override — Critical Safety
Published: 2026-06-04
JSW (Japan Steel Works) Alarm J310 on J-ADS series machines is the most critical safety alarm — it triggers when the mold protection system detects resistance exceeding the programmed limit during low-pressure mold closing AND the operator has...
JSW (Japan Steel Works) Alarm J310 on J-ADS series machines is the most critical safety alarm — it triggers when the mold protection system detects resistance exceeding the programmed limit during low-pressure mold closing AND the operator has overridden the previous protection event. This is an emergency stop condition: the machine immediately depressurizes the clamp cylinder and freezes all movement. J310 indicates that a potential mold crash has been detected twice in succession, meaning the first warning was acknowledged without resolving the root cause.
Root cause: (1) Stuck part or sprue in the mold — the ejector system failed to fully clear the previous shot. (2) Displaced mold component — a core, slide, or ejector pin has shifted and is contacting the opposite mold half during closing. (3) Mold protection sensitivity set too high — the force limit is too close to normal closing friction, causing nuisance trips that the operator overrides. (4) Worn linear position sensor — providing inaccurate platen position feedback.
Alarm Details
| Alarm Code | J310 |
|---|---|
| Brand / Machine | JSW (Japan Steel Works) |
| Severity | Critical (Immediate Emergency Stop) |
| Component | Mold Protection System / Linear Position Sensor |
| Affected Systems | Clamp Safety / J-ADS 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 |
|---|---|
| Netstal Alarm 301 | |
| Sumitomo Demag Mold Protect Alarm |
Frequently Asked Questions
What is the correct mold protection force setting on JSW machines?
The mold protection force should be set at 150% of the force required for normal, unobstructed mold closing. To calibrate: run 10 automatic cycles with mold protection at maximum (verify no alarms), then gradually reduce the protection force in 5 kN increments until the alarm triggers during normal closing. Multiply this threshold force by 1.5 for the production setting. For a typical 500-ton JSW machine, 15-30 kN is the normal range. Recalibrate whenever the mold is serviced, lubricated, or the ejector system is adjusted.
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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