TL;DR
Hydraulic pressure loss on an IS machine slows the mechanisms and leads to timing errors. Check the hydraulic pump output and filter condition before tracing individual cylinder seals.
What you might see
- section mechanism moving slowly
- hydraulic pressure gauge below setpoint
- oil leak at a cylinder or manifold fitting
- gob rejection rate rising from incomplete mold closure
Likely causes
Hydraulic pump worn, reducing delivery pressure at rated speed
Hydraulic filter blocked, restricting system flow
Internal cylinder seal leaking, causing loss of operating force
System relief valve set too low or stuck partially open
Required tools
- Calibrated hydraulic pressure gauge
- Replacement filter element
- LOTO kit
Safety first
- High-pressure hydraulic oil. Never use bare hands to check for leaks.
- IS machine mechanisms move fast and with significant force. Lock out the section before any work near moving parts.
- Thermal radiation from the hot end. Wear appropriate PPE.
Procedure
- 1
Stop the section and lock out the section drive and hydraulic isolation valve.
- 2
Connect a calibrated pressure gauge to the hydraulic manifold test point.[1]
- 3
Start the hydraulic system and read the no-load pressure. Compare to the specification.[1]
- 4
Check the hydraulic filter differential pressure indicator. Replace the filter if it is in the red zone.
- 5
Inspect all accessible hydraulic fittings and cylinders for external oil leakage. Mark any wet fitting for repair.
- 6
Test the system relief valve by increasing the load on a cylinder. The pressure should reach the specified relief value without excessive leakage.
- 7
After restoring system pressure, perform a mechanism timing check before resuming production.
Sources
Bucher Emhart Glass Bucher Emhart NIS / FlexIS IS (Individual Section) Machine general technical documentation, Bucher Emhart Glass
General IS machine hydraulic system maintenance procedures (general)
More guides for Bucher Emhart Glass Bucher Emhart NIS / FlexIS
How to diagnose mold cooling failure on a Bucher Emhart NIS / FlexIS IS machine
Mold cooling failure causes heat check cracks in the containers. Check the cooling air flow to the affected section and inspect the mold cooling passages for blockage before replacing the molds.
How to diagnose plunger mechanism timing faults on a Bucher Emhart NIS / FlexIS IS machine
Uneven container walls usually trace to the plunger arriving at the wrong point in the cycle. Check the plunger timing against the section timing diagram and verify the plunger air cylinder operation.
Stop fixing the same fault twice.
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