KraussMaffei MC100: Hydraulic System Pressure Failure — Emergency Diagnostics
Tensile data verified against MatWeb.com database & manufacturer datasheets · Last updated July 2026
Published: 2026-05-27
KraussMaffei MC100 indicates that the main hydraulic system pressure has fallen below the minimum setpoint required for safe machine operation. This is a machine-wide stop alarm — all hydraulic axes (clamp, injection, ejector, core pulls) are...
KraussMaffei MC100 indicates that the main hydraulic system pressure has fallen below the minimum setpoint required for safe machine operation. This is a machine-wide stop alarm — all hydraulic axes (clamp, injection, ejector, core pulls) are disabled until pressure is restored.
Systematic Troubleshooting
Step 1 — Check Hydraulic Oil Level: Low oil level is the single most common cause. Check the sight glass with all cylinders retracted. Top up with the specified hydraulic oil grade (typically HLP 46 or as specified in the machine manual). Step 2 — Inspect for External Leaks: Under machine guarding, check all hydraulic hoses, fittings, and cylinder seals for active leaks. A pinhole leak in a high-pressure line can drain the system in seconds. Step 3 — Test Pressure Relief Valve: A relief valve stuck partially open will bleed pressure back to the tank. Listen for continuous flow noise at the tank return line when the pump is running but no axes are moving. Step 4 — Check Accumulator Pre-Charge: On KM machines with bladder accumulators, the nitrogen pre-charge pressure should be checked with a nitrogen gas charging kit. A ruptured bladder results in zero accumulator function, causing pressure spikes and drops. Step 5 — Pump Diagnosis: If the pump motor runs but pressure does not build, the pump itself may have internal damage (broken vanes in a vane pump, or worn pistons in an axial piston pump). Measure case drain flow — excessive case drain indicates internal pump leakage.
Alarm Details
| Alarm Code | MC100 |
|---|---|
| Brand / Machine | KraussMaffei |
| Severity | Critical (Machine Stop — Hydraulic Failure) |
| Component | Hydraulic Pump / Pressure Relief Valve / Accumulator |
| Affected Systems | Main Hydraulic Circuit — All Axes |
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-alarm-510 | |
| netstal-alarm-301 |
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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