KraussMaffei Alarm MC48: Injection Pressure Transducer Failure — Troubleshooting
Tensile data verified against MatWeb.com database & manufacturer datasheets · Last updated July 2026
Published: 2026-06-04
KraussMaffei Alarm MC48 triggers when the MC6 controller detects an implausible signal from the injection pressure transducer — either a frozen (unchanging) reading, a reading outside the sensor's calibrated range, or a sudden spike/drop...
KraussMaffei Alarm MC48 triggers when the MC6 controller detects an implausible signal from the injection pressure transducer — either a frozen (unchanging) reading, a reading outside the sensor's calibrated range, or a sudden spike/drop inconsistent with the injection cycle phase. Unlike overpressure alarms (MC45), MC48 indicates a sensor hardware fault, not a process condition. The machine cannot safely inject without accurate pressure feedback.
Root cause: (1) Melt ingress into the transducer diaphragm — polymer melt has penetrated past the transducer tip seal, solidifying on the sensing element and mechanically locking it. (2) Damaged transducer cable — the cable from the transducer to the MC6 I/O module is flexed with each injection cycle and eventually fatigues internally. (3) Transducer drift from thermal cycling — repeated exposure to 350-400°C melt followed by cooling to mold temperature causes the sensing element to drift over time, eventually exceeding the controller's acceptable deviation threshold. (4) Electrical noise — VFD or servo drive harmonics inducing false signals on the transducer's mV output.
Alarm Details
| Alarm Code | MC48 |
|---|---|
| Brand / Machine | KraussMaffei |
| Severity | High (Process Stop) |
| Component | Injection Pressure Transducer / Melt Pressure Sensor |
| Affected Systems | MC6 Controller / Injection Unit |
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 |
|---|---|---|
| KraussMaffei OEM Heating Band | KM-HB-{zone} | $500-950 |
| KraussMaffei Thermocouple | KM-TC-{zone} | $140-300 |
| KraussMaffei MC6 Temperature Board | KM-MC6-TC | $1,800-3,500 |
| KraussMaffei Relay Card | KM-MC6-RELAY | $450-900 |
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 |
|---|---|
| Engel Pressure Sensor Alarm | |
| Arburg Pressure Transducer Fault |
Frequently Asked Questions
How can I verify a pressure transducer is faulty before replacing it?
(1) Check the transducer zero reading with the injection unit depressurized (screw retracted, no back pressure). It should read 0 ±0.5% of full scale. (2) Apply a known pressure using a dead-weight tester and verify the reading matches within ±1%. (3) Compare the transducer reading during injection to a portable pressure gauge installed in the nozzle adapter — a difference >5% indicates transducer drift or damage. (4) Wiggle the transducer cable while watching the pressure display — intermittent fluctuation indicates cable damage. Transducer replacement cost: $400-800. Labor: 30 minutes with the barrel hot (care required to avoid burns).
Related Diagnostics & Materials
Netstal Alarm 102: Heating Zone Temperature Out of Range...
Netstal Alarm 102 occurs when the actual temperature of a specific heating band in the injection barrel deviates...
Arburg Error 320: Barrel Heating Control Failure -...
Arburg Error 320 is a critical interlock alarm triggered when the Selogica controller detects no current flow to one...
Engel Alarm 405: Screw Recovery Time Exceeded - Diagnostics & Fix
Engel Alarm 405 is generated by the CC300 controller when the screw recovery (plastication) time exceeds the maximum...
Netstal Alarm 301: Mold Protection Force Exceeded -...
Netstal Alarm 301 is one of the most critical safety alarms in injection molding—it triggers when the clamping unit...
Sumitomo Demag Alarm 220: Clamp Force Not Reached -...
Sumitomo Demag Alarm 220 triggers when the NC5 (or NC5 plus) controller detects that the actual clamping force...
KraussMaffei Alarm MC45: Injection Pressure Limit...
KraussMaffei Alarm MC45 is generated by the MC6 controller (KM's latest-generation control platform) when the...
Wittmann Battenfeld Alarm B6: Ejector Position Fault -...
Wittmann Battenfeld Alarm B6 triggers on the Unilog B8 (or B6/B6P) controller when the ejector system fails to reach...
Arburg Error 290: Screw Rotation Speed Deviation -...
Arburg Error 290 is triggered by the Selogica controller when the actual screw rotation speed (measured by the screw...
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