One. Ten principles of ultrasonic equipment maintenance
1． Move the mouth first and then do it
For the faulty ultrasonic plastic welding machine, don’t rush to do it, you should first ask about the process of the fault and the phenomenon of the fault. For the unfamiliar ultrasonic plastic welding machine, you should be familiar with the circuit principle and structural characteristics first, and abide by the corresponding rules. Before disassembly, be fully familiar with the function, position, connection method and relationship with other surrounding devices of each electrical component.
2. External first, then internal
The ultrasonic equipment to be repaired should be checked for obvious maintenance history, the condition of ultrasonic welding, the temperature of the ultrasonic mold, the age of use, etc., and then the internal checking. Before dismantling, the surrounding fault factors should be queued up, and the equipment can be dismantled only after it is determined to be an internal fault.
3. Mechanical first, then electrical
First of all, you must first rule out the problem of the ultrasonic mold, and then carry out the electrical inspection. When checking circuit faults, use the detection instrument to find the fault location, and after confirming that there is no bad contact fault, check the operation relationship between the circuit and the machine in a targeted manner to avoid misjudgment.
4. Static first, then dynamic
When the device is not powered on, determine the electrical equipment buttons, contactors, relays and The fuse is good or bad, so as to determine the fault. Power-on test, listen to the sound, touch, measure parameters, judge faults, and finally repair.
5 ． Clean first and then repair ultrasonic welding machine
For heavily polluted electrical equipment, first clean the buttons, wiring points and contact points, and check whether the external control keys are out of order. Many failures are caused by dirt and conductive dust blocks, which are often eliminated once cleaned.
6 . The power amplifier board first, then the equipment
The failure rate of the power amplifier part of the ultrasonic plastic welding machine accounts for a high proportion of the entire ultrasonic equipment, so the power amplifier part of the ultrasonic generator is often repaired first. Do more with less.
7 . First general and then special
The failures caused by the quality of the assembly parts or the manufacturing process generally account for about 50% of the common failures. The faults of ultrasonic equipment are mostly hard faults. It is necessary to carefully and clearly check and eliminate the problem before starting the experiment easily.
8 . Peripheral first, then internal
Don’t rush to replace the damaged electrical components, and consider replacing the damaged electrical components after confirming that the circuit of the peripheral equipment is normal.
9． DC first, then AC
During maintenance, the DC voltage must be checked first, and then the dynamic operating point of the AC loop. If it is a problem with the filter loop, it will cause the whole Due to the system problems of the machine, the DC power supply of the ultrasonic plastic welding machine is generally 300V, or +-160V partial pressure.
10 . Debug first after failure
In some cases, all the damaged originals have been replaced, but it is still abnormal, so it is necessary to check the debugging of the protection system, the current is large, the frequency is large For protection, the single premise is that the FM inductor must be in a suitable position. If it deviates too far from the normal position, the power amplifier board may be damaged during the debugging process. Note that the inductance of the 20khz line in the United States is about 1.1MH, the line in Taiwan is about 0.8mh, and the FM inductance of the 15khz line in Taiwan is about 1.50mH. Be sure to rotate the inductor to the normal position before commissioning.
Second. Ultrasonic plastic welding machine maintenance method and operation practice
1 , Intuitive method
Intuitive method is based on electrical The external manifestation of the fault, the method of checking and judging the fault by looking, smelling, listening and other means.
(1 )Check steps:
Investigation : Ask the operator and the personnel present at the fault for the situation, including the external appearance of the fault, the approximate location, and the environmental conditions when the fault occurs. If there is no abnormal gas, open flame, whether the heat source is close to the electrical appliance, whether there is corrosive gas intrusion, whether there is water leakage, whether anyone has repaired it, the content of the repair, etc.
Preliminary inspection: According to the investigation, check whether there is any external damage to the electrical appliance, whether the connection is open or loose, whether the insulation is burnt, whether the fusing indicator of the spiral fuse jumps out, and whether the electrical appliance has Water, grease, whether the switch position is correct, etc.
Commissioning: After preliminary inspection, it is confirmed that the failure will further expand and cause personal and equipment accidents, and then further commissioning inspection can be carried out. During the commissioning, pay attention to whether there are serious flashovers, abnormal smells, abnormal sounds, etc. , Once found, stop immediately and cut off the power. Pay attention to check whether the temperature rise of the electrical appliance and the action procedure of the electrical appliance meet the requirements of the electrical equipment schematic diagram, so as to find the fault location.
(2 )How to check:
Watch for sparks : The contacts of electrical appliances will generate sparks when closing or breaking the circuit or when the wire ends of the wires are loose, so the electrical fault can be checked according to the existence and size of sparks. For example, when a spark is found between a normally fastened wire and a screw, it means that the wire head is loose or has poor contact. When the contacts of the electrical appliance are closed or disconnected, the circuit will flash, indicating that the circuit is connected. Action program: The action program of the electrical appliance should meet the requirements of the electrical instructions and drawings. If the electrical appliances on a certain circuit act too early, too late or do not act, it means that the circuit or electrical appliances are faulty.
In addition, it can also analyze and judge the fault according to the sound, temperature, pressure, smell, etc. Using the intuitive method, not only simple faults can be identified, but also more complex faults can be narrowed down to a smaller scope.
2 . Measurement voltage method
Measurement voltage method is to measure the voltage value of each point and the current value and compare it with the normal value. Specifically, it can be divided into step measurement method, segment measurement method and point measurement method.
3, resistance measurement method
It can be divided into step measurement method and segment measurement method. These two methods are suitable for electrical equipment with large distribution distance of switches and electrical appliances.
4, contrast, replacement element, step-by-step open (or access) method
(1) contrast method
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Compare the inspection data with the drawing data and the normal parameters recorded at ordinary times to judge the fault. For electrical appliances with no information and no usual records, they can be compared with intact electrical appliances of the same model.
When the electrical components in the circuit belong to the same control property or multiple components jointly control the same equipment, the fault can be judged by the action of other similar or the same power supply components.
(2) The method of placing conversion elements
When the failure cause of some circuits is not easy to determine or the inspection time is too long, but in order to ensure the utilization of electrical equipment, the performance of the same phase can be converted Good component experimentation to verify if the fault is caused by this appliance.
When using the conversion element method to check, it should be noted that when the original electrical appliance is removed, carefully check whether it is damaged. The new replacement element is damaged again.
(3) Step-by-step open circuit (or access) method
When multiple branches are connected in parallel and the circuit with more complex control is short-circuited or grounded, there are generally obvious external manifestations, such as smoke , with sparks, etc. When the inside of the motor or the circuit with the shield is short-circuited or grounded, it is not easy to find other external phenomena except the fuse blown. This situation can be checked by a step-by-step open circuit (or access) method.
Step-by-step open-circuit method: In case of short-circuit or grounding fault that is difficult to check, the melt can be replaced again, and the multi-branch cross-linking circuit can be disconnected from the circuit step by step or in key points, and then power-on test , if the fuse is repeatedly blown, the fault is on the circuit that has just been disconnected. This branch is then divided into several sections and connected to the circuit section by section. When a certain circuit is connected, the fuse is blown again, and the fault is on this circuit and an electrical component. This method is simple, but it is easy to completely burn out the electrical components that are not seriously damaged.
Step-by-step connection method: When a short circuit or ground fault occurs in the circuit, replace with new fuses and gradually or focus on connecting each branch to the power supply one by one, and re-test. When it is connected to a certain section, the fuse is blown again, and the fault is on the circuit that has just been connected and the electrical components it contains.
5. Forced closing method
When the electrical equipment is faulty in the queue, the fault point is not found after visual inspection, and the subordinates also If there is no suitable instrument for measurement, an insulating rod can be used to forcefully press the relevant relay, contactor, etc. with external force to make the normally open contact closed, and then observe various phenomena in the electrical part or the mechanical part,
6, Short-circuit method
The faults of equipment circuits or electrical appliances are roughly summarized as short-circuit, overload, open circuit, grounding, wiring errors, electrical appliances There are six categories of electromagnetic and mechanical failures. The most common type of faults are open circuit faults. It includes wire breakage, virtual connection, looseness, poor contact, virtual welding, false welding, fuse blown, etc. In addition to checking with the resistance method and the voltage method, there is a simpler and more reliable method for such faults, that is, the short-circuit method. The method is to use a well-insulated wire to short-circuit the suspected open circuit part. If it is shorted to a certain place, the circuit works back to normal, indicating that the circuit is open at that place. Ultrasonic repair is divided into local short-circuit method and long-short-circuit method.
Declare: The above methods are derived from the program system index or shared by netizens. They are for your reference only and do not represent the research views of this website. sex and authority.
