TROUBLESHOOTING
AND DIAGNOSIS
This section is built around the symptoms that can be noticed before the machine stops. The aim is not to repair the fault but to let the operator get from the symptom to the right cause — because most waterjet and CNC faults announce themselves in cut quality days beforehand.
3 guides · from the USEL engineering team
From symptom to cause: a quick route
When cut quality drops, the first place to look is not the machine but the consumables. On a waterjet, striation on the edge and an increasing taper angle almost always point to a worn orifice or focusing tube — both can be checked in minutes.
Unstable pressure and a change in the sound from the pump end show that the high-pressure seals have reached the end of their life. Carrying on at that point turns the cost of a seal change into the cost of a cylinder repair.
On a CNC bridge saw, vibration (chatter) and wave marks on the cut face usually come from three sources: the slab workholding working loose, a blade that does not suit the material, or worn spindle bearings. The way to tell them apart is to repeat the same program with different workholding and a different blade.
The start-of-shift check habit
Most faults are not sudden; they are simply noticed late. A two-minute check at the start of the shift — pressure differential across the water filter, blockage in the garnet line, a leak at the cutting head, lubrication level — prevents most unplanned stoppages.
Because loss of accuracy creeps in slowly, the operator's eye gets used to it. The only remedy is regular measurement: cutting and measuring the same test piece at set intervals reveals the need for calibration before a complaint arrives.
Keeping records is half the diagnosis. If it is written down which fault appeared at which consumable life and on which material, solving the same problem a second time takes minutes.
TROUBLESHOOTING GUIDES
Waterjet Troubleshooting — Loss of Accuracy, Poor Cuts and the Most Common Faults
Causes of poor cut quality, lost accuracy, calibration drift, taper, burr, wavy edges and pierce failures on a waterjet — where the operator should look, step by step, and what to do.
CNC Bridge Saw Troubleshooting — The Most Common Faults and Loss of Accuracy on 4/5 Axis Machines
Chatter, loss of accuracy, rapid blade wear, spindle problems, insufficient vacuum and 5th axis head drift on a CNC bridge saw — what the operator should check at the start of a shift, and step-by-step troubleshooting.
Waterjet Pump Problems — Common Faults and Their Solutions
UHP pump pressure loss, leaks, abnormal noise, temperature problems. The 8 most common faults on KMT/BFT/Resato pumps and a step-by-step troubleshooting guide.
For faults you cannot diagnose yourself, you can open a ticket with the USEL technical service team.
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