Wittmann Battenfeld Alarm B6: Ejector Position Fault - Diagnostics & Troubleshooting
Published: 2026-05-29
Wittmann Battenfeld Alarm B6 triggers on the Unilog B8 (or B6/B6P) controller when the ejector system fails to reach the commanded position—either forward (part ejection) or retract (return to start position)—within the programmed time window....
Wittmann Battenfeld Alarm B6 triggers on the Unilog B8 (or B6/B6P) controller when the ejector system fails to reach the commanded position—either forward (part ejection) or retract (return to start position)—within the programmed time window. This alarm protects both the mold (preventing the clamp from closing on extended ejector pins) and the ejector mechanism (preventing hydraulic stall against a mechanical obstruction). On EcoPower and MacroPower series machines, the ejector position is monitored by a linear position transducer mounted on the ejector plate, providing closed-loop position feedback with ±0.1 mm accuracy.
The most common root cause sequence: (1) A molded part sticks to the ejector half of the mold (core side) rather than releasing cleanly. The ejector pins advance but encounter resistance from the stuck part. (2) The controller detects that the expected forward position is not reached within the timeout (typically 2-5 seconds, user-programmable). (3) Alarm B6 triggers, halting the cycle before the clamp closes on extended ejector pins. Secondary causes: worn ejector bushings causing pin binding, insufficient ejector stroke for the part geometry (part requires more forward travel than programmed), hydraulic pressure limit set too low to overcome normal ejector friction, or a failed ejector position transducer (Unilog B8 diagnostic display will show erratic or frozen position readings).
Alarm Details
| Alarm Code | B6 |
|---|---|
| Brand / Machine | Wittmann Battenfeld |
| Severity | Medium (Cycle Hold / Warning) |
| Component | Ejector System / Position Transducer |
| Affected Systems | Ejector / Unilog B8 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 |
|---|---|
| Sumitomo Demag Ejector Alarm | |
| Arburg Ejector Fault |
Frequently Asked Questions
What is the correct troubleshooting sequence for Wittmann Battenfeld Alarm B6?
(1) On the Unilog B8 controller, navigate to Diagnostics > Ejector > Actual Position and manually jog the ejector forward at low speed while watching the position display. If the position readout is erratic or does not change smoothly, the position transducer is suspect—check the transducer cable connection and rod alignment. (2) If position feedback is normal, check the ejector pressure setting. Wittmann recommends the ejector pressure limit be set at 120% of the pressure required for normal ejection (determined by monitoring the ejector pressure trend during a successful ejection). (3) If pressure is correct, inspect the ejector plate guide bushings for wear or contamination—binding here is common on older machines. (4) If all machine-side checks pass, the root cause is likely a mold sticking issue—adjust mold temperature, increase draft angle (if possible), or apply mold release.
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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