High pressure CNC water jet systems are more versatile cutting alternatives to plasma, mechanical and laser cutting machines. Over the past decade the water jet system has made some quite changes.
The newest systems are more precise and can cut faster. Advanced system problems can easily crop up now and warm to the problem before the system starts. Most problems can be quickly resolved by following simple waterjet troubleshooting tips. This advanced technology makes water jets more reliable and more predictable with reducing downtime now.
Most common problems of water jet are over stroking, short seal life, water leaks, hydraulic pressure failure and low water pressure (intensifier based water jet system problem).
1) Over stroking:
During start up, it is common for intensifiers to peak and change between pressures. But during normal operation, it should work smoothly to the left right way with the same speed. However, if hydraulic piston travel faster too much in one or both directions than the pump can support and an alarm will be heard.
If over stroking is happens, your first step is to reset the alarm and then:
Cutting heads turn off
Pump turn on and give time to build up pressure
Cutting heads turn on
Intensifier stroke rate monitor either by manually or by operator surface indicator.
2) Short Seal Life:
While seals live naturally short. Some actions you can follow to help them to extend the last longer interval are:
Make sure to use the right quality of water within a satisfactory range.
During seal replacement, clean all parts thoroughly to get rid from debris.
Ensuring no cracks, check all parts of the high pressure cylinder.
Verifying the water volume and pressure meets the minimum required standard.
To make sure plunger bearing is not worn.
3) Water leaks:
Another troubleshooting area is water leakage. The most common case of water leaks are high pressure hoops and seals damaging the intensifier. However, you want to focus on how leaks are happening and where they are coming from.
If you observe a drip of water in every few strokes, it means that seals’ lives are nearing the end point and have to be replaced within a reasonable time period.
If warm water leaking on the adapter from the weep hole, it means high pressure water tubing fitting is not tight enough and their end is damaged or the adapter has failed.
If you notice the warm water leaking on the check valve from the weep hole, it means that the output adapter is loose and fails the high pressure poppet seat or check valve is damaged.
If cold water leaks from the end bell that means the check valve O-ring has failed and it needs to be replaced.
Hot or warm water coming from the end cap which indicates the static end cylinder high pressure seal has failed and needs to replace.
If cylinder dynamic end water leakage happens that means the high pressure seals on their end have failed.
4) Hydraulic fluid pressure failure troubleshooting:
If the pump is unable to produce enough pressure then what you should to do:
To make sure the pressure controlling knob is correctly set and controlled manually by your machine.
To verify that compensator can increase pump pressure by pump compensator isolation from CNC water jet pressure control circuit.
Measure the hydraulic relief valves temperature. If increases in temperature indicate that the relief valve is opening compared to the surrounding component. After intensification, the most common problem is indicated by the operator usually.
5) Low water pressure:
If you notice low water pressure when the cutting head on, when water travels from the intensifier away. You should take these steps.
To make sure the orifice is in good working order, is not defective or damaged. If it does not work well, replace it.
Verify the leaking is happening or not by checking the on/off valve. If leaking happens, repair it.
Check valves, if necessary repair or replace it after examination.
Double check the intensifier not stroke, when the cutting water jet head is turned off. If stroke, check the high pressure tubing leaks and bleed down valve and replace or repair it. If no leaks and problems are created by poppets of high pressure and low pressure then replace or repair the poppets.
If the water jet system senses low pressure of water travelling to the in testifier. The system will be protected by the shut pump off without running intensifier enough pressure.
If this happening, do following steps:
Make sure that the water comes to the pump.
Water filters swap out
Make sure inlet cutting water valves have not clogged or failed