JSW J-AD 305 Alarm: Ejector System Overload — Diagnosis & Repair
Tensile data verified against MatWeb.com database & manufacturer datasheets · Last updated July 2026
Published: 2026-06-02
JSW J-AD 305 triggers when the ejector hydraulic cylinder's pressure transducer detects resistance exceeding the set limit during the forward (ejection) stroke. This alarm protects the ejector system and mold from mechanical damage due to...
JSW J-AD 305 triggers when the ejector hydraulic cylinder's pressure transducer detects resistance exceeding the set limit during the forward (ejection) stroke. This alarm protects the ejector system and mold from mechanical damage due to excessive ejection force. Root cause: the part is sticking in the cavity and the required ejection force exceeds the set safety threshold. Contributing factors include insufficient draft angle (<0.5°), vacuum lock (polished cavity surface with no venting), molded-in stress causing post-shrinkage grip, and mechanical binding of ejector pins or return pins.
Diagnostic sequence: 1. Check if part ejects normally in semi-automatic mode (manual ejector forward) — if manual ejection works, the issue is pressure transducer setting, not mechanical binding. 2. Measure cavity surface temperature with a contact pyrometer — if cavity is >10°C above recommended, the part is not sufficiently solidified and is gripping the cavity on ejection. 3. Check draft angle: minimum 1° on textured surfaces, 0.5° on polished surfaces. 4. Verify vacuum break (air blow into cavity at end of cooling) is functioning. 5. Inspect ejector pins for galling or bending — replace any pin with >0.05mm bend.
Alarm Details
| Alarm Code | J-AD 305 |
|---|---|
| Brand / Machine | JSW (Japan Steel Works) |
| Severity | High (Ejector Stop) |
| Component | Ejector Hydraulic Cylinder / Ejector Plate |
| Affected Systems | Part Ejection |
Troubleshooting Protocol
Verify all electrical connections to the affected component. Check for loose wires, burnt connectors, or signs of arcing. Measure voltage at the component terminals.
Look for physical damage, corrosion, or wear. For heating bands: check for hot spots (discoloration). For sensors: check for damaged cables or contamination on the sensing surface.
For thermocouples: measure resistance (should be 2-10 ohms, not open circuit). For heating bands: measure resistance against the nameplate rating. For relays: test coil resistance and verify switching with a test signal.
Order the OEM replacement part (see OEM Parts table above). After replacement, run a full heat-up cycle and verify the alarm does not re-trigger. Document the replacement in the machine log.
OEM Replacement Parts
| Part Name | OEM Part Number | Est. Price |
|---|---|---|
| JSW Heating Band | JSW-HB-{zone} | $400-800 |
| JSW Thermocouple | JSW-TC-{zone} | $100-230 |
| JSW J-Watch Controller | JSW-JW-CTRL | $1,000-2,200 |
Prices are estimated US market ranges. Contact your OEM distributor for exact pricing. {zone} = zone-specific variant.
Same Alarm on Other Machine Brands
If you operate multiple injection molding machine brands, the same fault may appear under different alarm codes:
Equivalents & Cross-References
| Equivalent / Alternate | Action |
|---|---|
| Sumitomo Demag E220 | |
| Haitian H101 |
Frequently Asked Questions
What draft angle eliminates ejection force issues?
For textured surfaces (VDI 24+), minimum 1.5° per side. For polished surfaces, minimum 0.5°. Deep-draw parts (>50mm) may require 2-3° draft regardless of surface finish. If draft cannot be increased, consider: mold release coating (TiN, DLC), air-assist ejection, or stripper plate ejection instead of pin ejection.
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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