TroubleshootingWhen the liquid electrostatic spray gun has paint seepage, high pressure alarm and spray midway trip, the most important thing is not to choose the position between "single change one ring" and "complete set", but to establish a complete diagnostic chain:
1. * * Locate the leak point first * *: the front end of the nozzle, the needle is tight, the paint joint, the manifold or the inside of the gun body;
2. * * Re-check the insulation pollution * *: whether the paint enters the air channel, high pressure chamber, whether there are black, carbonization and arc traces;
3. * * Then decide the scope of replacement parts * *: single piece, urgent assembly, needle/valve seat fitting pair, or barrel and high-pressure parts;
4. * * Finally, test and acceptance * *: the production can be resumed only after the pressure holding, opening and closing, shutdown, resistance and high-voltage output are all passed.
* * When it can be replaced individually, it is not necessary to blindly replace the whole set; however, when the inside of the gun is painted, insulated carbonized or the mating surface is damaged, it is not possible to replace only one seal ring in order to save the cost of accessories. * *
TroubleshootingWhen there is abnormal noise, jitter and uneven film thickness on the disk, the most effective first step is not to guess the bearing, but to establish two fault boundaries:
Disc side: residual paint weight, disc damage, distributor blockage, foreign objects on the mounting surface or eccentric assembly;
Head and control side: drive gas, bearing gas, shaping gas, brake gas, speed feedback, spindle, bearing and mounting bracket.
Clean and check the disc first, then shunt to check the gas supply and the actual speed, and finally observe whether the fault follows through the exchange of discs A/B with the same material number.Bearing or spindle replacement is fully evidenced only when the disc is intact, installed correctly, the air path is stable, the speed is normal, and the abnormality can still be repeated.
Exclude the reversible reasons first, and then decide to replace the parts; however, if cracks, gaps, bearing gas pressure loss, abnormal friction or continuous violent vibration are found, the machine should be stopped immediately, and it cannot continue to operate at risk in order to save maintenance costs.
TroubleshootingIn electrostatic powder spraying production, the most likely type of failure to cause misjudgment is "Yesterday's powder was normal, today's powder suddenly can not be sucked".The scene often suspects the spray gun, high-pressure bag or controller first, and it is easy to directly recommend changing the gun after sales.But the powdering rate is the result of the combined action of the entire spraying system, and the spray gun is only one of the nodes.
Grounding link, powder state, compressed air, fluidization and powder supply, powder pipes and venturi pumps, spray room air extraction, workpiece shape, hanger state, wire speed, gun spacing, high voltage and current limitations, any change may make the surface look like "no static electricity of the spray gun".
When the powder rate suddenly drops, it should be determined whether the fault belongs to the public system, single gun, workpiece grounding or powder process before deciding whether to disassemble the gun or replace the part.
TroubleshootingDuring continuous operation, there is a sudden pulsation of powder, intermittent vomiting of powder or a sudden decrease in the amount of powder, and the amount of powder gas, supplementary gas or atomized gas cannot be increased at the same time.A more reliable sequence of troubleshooting is:
First, confirm whether it is a single-gun failure or a multi-gun synchronous failure. → Freeze the controller and the air source. → Check the supply source and fluidization status. → Check the suction end of the Venturi pump, the seal and the throat→. Check the low point of the powder pipe, the bending and the inner wall. → Check the powder channel of the gun body and the nozzle after → cleaning. Use weighing and start-stop reproduction to verify.
Among them, three judgment boundaries need to be established first:
Vomiting powder is not equal to a certain blockage. Similar phenomena may occur when the powder bed collapses, inhaled air, valve pulsations, air supply fluctuations, pump core wear and local powder plugs in the powder pipe.
The average amount of powder discharged is normal, which does not mean stable delivery. In the short-term cycle of "less powder — accumulation — sudden release", the cumulative weighing may be close to normal, but the film thickness and appearance of the workpiece will still fluctuate.
Clearing once does not mean the root cause disappears. If the compressed air contains water and oil, powder agglomerates, the hose arrangement forms a low point, the proportion of recycled powder drifts, or the components in the pump are worn and untreated, the powder accumulation will recur quickly.
TroubleshootingIn the original stable operation of the liquid electrostatic rotating cup, the spray amplitude deviation, the edge gap, the white space in the center are enlarged or the large paint droplets are thrown out. It is not possible to "top back" by increasing the speed, shaping gas, paint pressure or electrostatic voltage.The correct order is:
Immediately control the risk and freeze the on-site evidence to → determine whether the atomization body is abnormal or electrostatic deposition abnormal Check the → actual rotation speed, whether the paint supply flow and pressure are stable → Check the rotating cup/cup head, the central paint supply nozzle and the shaping → gas channel Check the paint status and filtration → Finally verify the high pressure, grounding, spray distance and workpiece site shape.
where three boundaries should first be identified:
Leaving the center blank does not necessarily equate to a malfunction. Droplet clouds formed by high-speed rotational atomization may naturally have a circular or relatively thin central cross-section.Fault determination is more supported only if it is suddenly enlarged compared to the normal benchmarks of the equipment, cup heads, coatings and process formulations, or if it is accompanied by excessive weight of the outer ring, eccentricity, pulsation, abnormal rotational speed and large paint droplets.
Dumping large paint droplets is a priority stop spray check signal. Large droplets may come from paint shedding, liquid film rupture, paint supply pulsation, reduced speed, cup edge damage, contaminated particles or cleaning residue. Continued spraying will expand workpiece defects and may aggravate mechanical imbalance and contamination.
The stability of the set value is not equal to the stability of the actual state. It is necessary to look at the actual speed, the actual flow, the supply pressure, the actual pressure of the shaping gas, the material temperature and the alarm trend, not just the formula setpoint.
TroubleshootingIf the automatic liquid electrostatic spray gun "starts to discharge oil normally, then quickly becomes smaller until no oil is produced, and then returns to normal and repeats for a short period", it should first be judged whether the inlet pressure of the spray gun fluctuates synchronously with the oil interruption. When the pneumatic diaphragm pump is used for direct painting, the reciprocating direction of the pump will be pulsated; if there is no proper pressure stabilization, buffering, backflow or back pressure control, the pulsation may be transmitted to the nozzle. However, the flow periodically drops to close to zero. Also, focus on checking the suction end for air intake or blockage, abnormal pump air valve/one-way ball valve movement, filter mobility blockage, pressure regulator valve hunting and vibration, return flow setting errors, bubbles in the pipe, and automatic gun opening and closing air, needle or nozzle intermittent stagnation. The correct method is to press the "Pump Outlet — Filtration/Regulation - Lance Inlet — Lance Inside" section to measure and discharge after turning off the high pressure.
TroubleshootingPractical guidance based on common on-site issues, covering diagnostic methods, parameter recommendations, and equipment selection boundaries.
