Fifteen common faults and troubleshooting methods of water jet

2022-08-07

Fifteen common faults and troubleshooting methods of water jet

 As a new cutting method, water jet is gradually accepted by people. After all, the water jet is a relatively complex technological equipment, and there may be more or less difficulties in operation. Through daily practical operation and continuous understanding of it, I have made a detailed summary of the common faults and solutions of water jets, which are divided into the following points, hoping to help you.

A. The high-pressure pump does not start, and the high-pressure pump motor does not start after pressing the start button.
1. The power supply is not connected well - check whether there is poor contact, or the air switch is not closed.
2. The control cable is not connected properly - some models of water jet, there is a cable connection between the high pressure pump and the CNC, check whether the connection is good.

3. Oil tank outlet valve, and oil filter alarm - some models of water jet, the oil tank outlet has a valve with electronic alarm and oil filter, if the oil outlet valve is not opened or the oil filter is blocked, it can cause trouble. start up.

B The oil pump cannot build up pressure, and the high-pressure main motor starts, but there is no oil pressure.
1. The oil outlet valve of the oil tank is not opened - open the oil outlet valve, jog the main motor several times, inject oil into the oil pump, and discharge the air.
2. The rotation of the motor is incorrect - check the rotation direction marked on the oil pump, and adjust the power phase sequence of the main motor to make the rotation direction consistent with the marking.

3. Failure of the pilot valve of the oil pump - some models of water jet, the oil pump has a pilot valve, if necessary, it should be disassembled and cleaned with diesel oil.

  C The supercharger does not commutate, the main motor starts, and the oil pressure can be established, but the supercharger does not commutate and does not cut high-pressure water.
1. Electro-hydraulic reversing valve failure - when necessary, it should be disassembled and cleaned with diesel oil. In addition, the electromagnetic coil of the electro-hydraulic reversing valve will sometimes burn out and need to be replaced immediately.

2. Reversing sensor failure - take out the Hall switch and use a magnet to check whether it works. If it is broken, it needs to be replaced immediately. At the same time, check whether the Hall switches on the left and right sides are reversely connected. If so, they can be reversed.

D The cutting water pressure is low. After the high-pressure pump is started, the supercharger changes direction quickly, but the cutting water pressure is low.
1. There is a leak in the high pressure water line - Tighten the leaking fitting or replace the leaking line section.
2. Insufficient water supply - Check if the water supply valve is not open, or if the water supply pressure is too low.
3. The oil seal of the supercharger oil piston is damaged and the oil leaks - resulting in insufficient working hydraulic oil flow, slow reversing of the supercharger, and low cutting water pressure. Replace the oil piston oil seal.
4. The gemstone nozzle is damaged and the water is too large - the gemstone nozzle needs to be replaced.

E The oil temperature rises too fast. After the high-pressure pump is started, the oil temperature rises quickly. Sometimes accompanied by oil pressure can not go up.
1. The oil temperature rises rapidly, and the oil pressure does not rise—mainly check whether the internal leakage of the oil pump is too large, whether the internal leakage of the electro-hydraulic reversing valve is too large, whether there is any dissimilarity in the safety valve in the oil circuit and the overflow valve. The valve will not close and leak oil. Lightly touch the above areas with your hands to see if there is any heat.
2. The oil temperature rises quickly, but the oil pressure and the supercharger reversal are normal - the oil pump displacement is too large, and the oil pump displacement can be reduced through the handle. Also pay attention to check whether the oil refrigeration equipment is working properly.

F The cutting water pressure drops. After the high pressure pump is started, the cutting water pressure can be built up when the water switch is not turned on, but after the water switch is turned on, the cutting water pressure drops down and the water pressure is unstable.
1. Insufficient water supply - Check if the water supply valve is not open, or if the water supply pressure is too low.
2. The jewel nozzle is damaged - the water output is too large and the pressure cannot keep up. The jewel nozzle needs to be replaced.
3. The hydraulic oil flow is small - when the working hydraulic oil flow is not enough, the reversing of the supercharger is slow, causing the water jet cutting water to drop pressure. Check whether the oil pump is leaking, and whether each valve is properly switched. In addition, the oil seal of the oil cylinder is damaged and leaked, which will also cause insufficient hydraulic oil flow.

G The action stroke of the supercharger is unstable, the commutation on both sides of the supercharger is uneven, and one side is commutated faster than the other.
1. One side of the check valve is leaking - the valve core and valve pad can be removed and ground, if necessary, replace the valve core and valve pad and reinstall the check valve; the best way is to maintain or replace all check valves valve accessories.
2. Foreign impurities enter between the check valve core and the valve gasket - remove the end cap and remove the source of pollution to avoid the problem from recurring; check the check valve carefully, and remove any foreign impurities, if necessary, re-maintain the check valve; Clean all parts and reassemble.
3. Worn or bent reversing drive cable or related parts (mechanical reversing) - remove reversing drive cable; install spare parts and check again, replace any worn parts
4. The high-pressure water plunger is separated from the hydraulic piston - it will also reduce the pressure and flow of the water, to avoid serious damage to the supercharger caused by continued operation in this condition, remove the hydraulic cylinder and piston, and replace the damaged parts .
5. The direction of the water outlet check valve core is reversed - disassemble the water outlet check valve body, take out the check valve core, and reassemble it in the correct direction.

H The supercharged cylinder has a serious impact, and a very loud impact sound is produced when the direction is reversed.
1. The inlet water pressure of the booster cylinder is too low - confirm that the inlet water pressure reaches the minimum requirement, usually 0.4MPa; 2. The inlet water filter element is old and will be blocked - replace the filter element of the filter system, and confirm to replace the filter element of the same specification.
3. Booster cylinder inlet passage blocked by impurities or rust - check filtered water inlet passage; remove end cap, check and remove any foreign matter blocking passage; check check valve.
4. Check valve poppet tends to stick - remove end cap; maintain check valve poppet gasket, reinstall.
5. The flow rate of the reversing oil circuit of the electro-hydraulic reversing valve is too large - increase the damping, or replace the electro-hydraulic reversing valve that can cut off the reversing oil circuit in advance.

I. The high-pressure water cylinder is broken, the high-pressure water cylinder is broken, and the high-pressure cutting water is sprayed out.
Metal fatigue - replace the high-pressure water cylinder. The high-pressure cylinder has a certain fatigue life. Depending on the use environment, the high-pressure cylinder must be replaced periodically; the main reason for earlier damage than expected is due to scratches on the cylinder body; Replace all high pressure water seals; document maintenance and work intervals for future reference.

J. The reversing speed of the supercharger is too fast, and the reversing frequency of the supercharger exceeds the normal number of times.
1. Supercharger problem - Check the supercharger for overheating and leakage.
2. Nozzle Problems - Check the condition of the nozzle and whether it is the correct size.
3. High Pressure Water Leaks - Check the entire assembly for leaks.
4. Too low inlet water pressure - the inlet water filter or pipeline is blocked, check the filter and pipeline, replace the relevant parts if necessary, check the filter pressure difference gauge and the inlet water shut-off valve, and replace the parts if necessary.
5. Leakage of automatic pressure relief valve - If an automatic pressure relief valve is installed in the system, check whether the temperature of the valve is too high, if so, replace the valve repair kit.

K. The cutting speed is slow, the pressure of the supercharger is normal, but the number of commutations is small, the oil pressure and high-pressure water are normal, the commutation frequency of the supercharger is slow, and the cutting speed is slow.
1. Sand pipe blockage - sometimes the inner hole of the sand pipe is partially blocked by impurities, resulting in a small water flow rate and slow cutting. The sand pipe can be installed up and down and flushed with high pressure.
2. The high pressure pipeline is blocked - the two ends of the high pressure pipeline can be reversed and installed, and flushed with high pressure.
The flow rate of high-pressure cutting water is too small - check whether the high-pressure pipeline and components are blocked, and remove any obstructions; check whether the action of the on-off valve is normal, and replace the on-off valve if necessary.
Water switch failure - if the water switch is blocked, or other problems cannot be fully opened, it will also cause the water flow rate of water cutting to be small. At this time, it is necessary to check whether the action of the on-off valve is normal, and replace the on-off valve if necessary.

L. The oil pressure is low, the cutting water pressure is also low, the oil pump output pressure is low, and the cutting water pressure is also low.
1. Booster Cylinder Problems - Check the booster cylinder for leaks or overheating.
2. Nozzle Problems - Check that the nozzles are the correct size and condition.
3. High Pressure Water Leaks - Check the entire assembly for signs of leaks.
4. Automatic pressure relief valve leaking - valve temperature is too high and valve repair kit needs to be replaced.
5. Pressure control problems - the pressure control valve is damaged, replace the control valve.

M, the water flow problem, the water sprayed by the cutter head is scattered, thick and not concentrated.
Cause - It could be that the nozzle is badly worn, causing the water jet to diverge. Solution: Replace the nozzle.

N, the nozzle life is too short, the nozzle life is too short.
1. The quality of the water is too low - check the inlet water filter, the inlet water must be filtered to 0.5 micron, the pH value is between 6-8; if it is blocked, replace the filter; if there is no problem with the filter element, check the water treatment system.
2. Conveyor system filter element clogged or ruptured - remove and inspect filter, replace element.

O. System failure, CNC operating system failure.
1. Unable to enter the control software - reinstall the program; confirm that the system is free of viruses
2. Other programs can not run - reinstall the WINDOWS system
3. The emergency stop button is not reset - please reset the emergency stop
4. There is a virus - antivirus
5. Looseness, breakpoint, damaged components on the electrical circuit - reconnect firmly; replace the damaged components

6. Motor failure - replace the shaft connector with another normal shaft connector and observe whether the shaft moves.