What are the common fault diagnosis methods for automation equipment?

The commonly used methods for fault detection in automated assembly equipment include auscultation, touch detection, and observation. With the increasing popularity of automated sorting equipment in enterprises, the equipment failure rate also increases synchronously. The commonly used simple state monitoring methods mainly include auscultation, touch detection, and observation.

1. Auscultation method

When the equipment is operating normally, the accompanying sound always has a certain rhythm and tempo. As long as one is familiar with and masters these normal rhythms and rhythms, the human auditory function can compare whether the equipment has abnormal noises such as heavy, miscellaneous, strange, and chaotic, and judge the hidden dangers such as looseness, impact, and imbalance inside the equipment. Tap the parts with a hammer and listen for any cracking noise to determine if cracks have occurred.

Electronic stethoscope is a type of vibration acceleration sensor. It converts the vibration status of the equipment into electrical signals and amplifies them. Workers use headphones to monitor the vibration sound of the operating equipment, in order to achieve qualitative measurement of the sound. By measuring signals at the same measuring point, at different times, at the same speed, and under the same operating conditions, and comparing them, the presence of equipment faults can be determined. When the headphones produce crisp and sharp noise, it indicates a high vibration frequency, usually due to local defects or small cracks in relatively small and strong components. When the headphones emit cloudy and low pitched noise, it indicates that the vibration frequency is low, usually due to large cracks or defects in relatively large and low strength parts. When the noise emitted by the headphones increases compared to usual, it indicates that the fault is developing, and the louder the sound, the more severe the fault. When the noise emitted by the headphones appears intermittently and randomly, it indicates that some parts or components have become loose.

2. Tactile method

The touch of human hands can monitor the temperature, vibration, and changes in gaps of the equipment.

The nerve fibers in the human hand are sensitive to temperature and can accurately distinguish temperatures within 80 ℃. When the temperature of the mechanical parts is around 0 ℃, it feels cold to the touch, and if touched for a long time, it will cause a piercing pain. At around 10 ℃, it feels cool to the touch, but it is generally tolerable. At around 20 ℃, the hand feel is slightly cool, and as the contact time increases, the hand feel gradually warms up. At around 30 ℃, the hand feels slightly warm and comfortable. At around 40 ℃, it feels hot and slightly hot to the touch. When the temperature is around 50 ℃, it feels hot to the touch. If you press it with your palm for a long time, you will feel sweaty. At around 60 ℃, it feels very hot to the touch, but it can generally tolerate a long time of 10 seconds. When the temperature is around 70 ℃, it feels hot and painful to the touch. Generally, it can only endure for 3 seconds, and the touch area of the hand will quickly turn red. When touching, try to touch and then touch carefully to estimate the temperature rise of the component.

Shaking the moving parts with your hands can feel a gap of 0.1mm-0.3mm. Touching the parts with your hands can detect changes in vibration intensity, impact, and the crawling of the slide.

Using a thermometer equipped with a surface thermocouple probe to measure the surface temperature of rolling bearings, sliding bearings, spindle boxes, motors, and other components has the characteristics of quickly determining the location of thermal anomalies, accurate data, and convenient touch measurement process.

3. Observation method

Human vision can observe whether the components on the equipment are loose, cracked, or otherwise damaged; Can check whether the lubrication is normal, whether there is dry friction, running, emitting, dripping, or leaking phenomenon; You can check the amount, size, and characteristics of metal abrasive particles in the sediment of the fuel tank to determine the wear of related parts; Can monitor whether the device is moving normally and whether there are any abnormal phenomena occurring; You can view various instruments installed on the device that reflect the working status of the equipment, understand the changes in data, and use measuring tools and direct observation of surface conditions to detect product quality and judge the working status of the equipment. By comprehensively analyzing various observed information, it is possible to make judgments on whether the equipment has faults, the location of the faults, the degree of the faults, and the causes of the faults.

A simple method for monitoring wear status by observing wear particles collected from equipment lubricating oil through instruments is the magnetic plug method. Its principle is to insert a magnetic plug into the lubricating oil, collect the iron abrasive particles generated by wear, and use a reading microscope or directly observe the large quantity and shape characteristics of the abrasive particles with the human eye to determine the degree of wear on the surface of mechanical parts. The magnetic plug method can be used to observe the occurrence of larger abrasive particle sizes in the later stages of mechanical component wear. When observing, if small abrasive particles are found and the quantity is small, it indicates that the equipment is operating normally; If large abrasive particles are found, they should be taken seriously and the operation status of the equipment should be closely monitored; If large particles are repeatedly detected, it is a precursor to an imminent malfunction, and the machine should be stopped immediately for inspection, troubleshooting, and elimination.

The explanation is very detailed. These diagnostic methods require a long period of accumulated experience to make accurate judgments.

To add, auscultation can be done by aligning the tip of a screwdriver (or metal rod) with the area to be diagnosed, holding the screwdriver handle, and placing it in the ear to listen carefully. This can filter out some noise.

Temperature and tactile judgment training: Use a one node thermometer to measure several states of the metal surface, including 50 degrees, 60 degrees, 70 degrees, and 80 degrees. For low temperatures, use a thermometer to measure the time that the hand can touch and determine the temperature based on different times. When the temperature is too high to touch, you can sprinkle a small amount of water droplets to observe the evaporation state of the water, and then remember these states. When used in diagnostic equipment, it can obtain more accurate judgments.