Milacron Alarm M-450: Injection Unit Overload — Root Cause & Repair Guide
Tensile data verified against MatWeb.com database & manufacturer datasheets · Last updated July 2026
Published: 2026-05-28
Milacron M-450 is an injection unit overload alarm indicating the injection motor (electric machines) or hydraulic pump (hydraulic machines) has exceeded its rated load for a sustained period exceeding the drive's thermal protection...
Milacron M-450 is an injection unit overload alarm indicating the injection motor (electric machines) or hydraulic pump (hydraulic machines) has exceeded its rated load for a sustained period exceeding the drive's thermal protection curve.
Systematic Root Cause Analysis
1. Check melt temperature: Cold material is the #1 cause of injection overload. Increase barrel temperature in 5°C increments and allow 15 minutes for stabilization between changes. 2. Inspect check ring: A worn check ring allows material to flow backward during injection, causing the controller to increase injection pressure/speed to compensate — overloading the drive. Replace if wear gap exceeds 0.15mm. 3. Verify injection speed profile: Excessive fill speed creates high dynamic pressure. Reduce injection velocity by 10% and observe. 4. Check nozzle orifice: A partially blocked nozzle or undersized orifice for the material grade causes excessive back-pressure. Clean or replace. 5. Inspect screw and barrel for wear: Excessive clearance between screw flights and barrel wall reduces pumping efficiency, forcing the drive to work harder. Measure screw diameter at multiple axial positions; replace if wear exceeds 2% of original diameter.
Alarm Details
| Alarm Code | M-450 |
|---|---|
| Brand / Machine | Milacron |
| Severity | High (Cycle Interrupt — Injection Unit Stop) |
| Component | Injection Motor / Hydraulic Pump Overload |
| Affected Systems | Injection Axis — Power Transmission |
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 |
|---|---|---|
| Milacron Heating Band | MC-HB-{zone} | $350-650 |
| Milacron Thermocouple | MC-TC-{zone} | $80-170 |
| Milacron Mosaic Control Module | MC-MOS-CTRL | $800-1,600 |
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 |
|---|---|
| fanuc-roboshot-servo-alarm-sv0440 | |
| netstal-alarm-301 |
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