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How To Carry Out Lubrication Spot Check Of Stamping Machinery?

Lubricating device refers to the device that provides lubricating oil when the machine is running.

It is widely distributed in industrial machinery, including stamping machinery, and plays a vital role in its moving parts.

How To Carry Out Lubrication Spot Check Of Stamping Machinery

The usual lubrication method can be divided into liquid lubricating oil (thin oil) and semi-solid lubricating grease (yellow grease) and solid lubrication (graphite) according to different lubricating material between the friction pairs..

Characteristics of each lubrication method

Liquid lubrication

Liquid lubricating oil usually refers to thin oil lubrication, which needs to be combined with oil machine for circulating lubrication.

Generally, the applicable parts include gear transmission, rolling bearing, sliding surface between metals, etc., but the properties of the oil used are different with different places of use.

For example, gear oil is a factor that must be considered for gear load in order to prevent damage between gears.

If the type of lubricating oil is used incorrectly, the service life of the equipment will be reduced.

Therefore, important parameters such as the type and viscosity of lubricating oil should not be mistaken.

The lubrication of bearing and sliding surface is shown in Fig. 1.

Because the oil machine device can automatically supply lubricating oil circularly, each oil supply device, such as oil machine, distribution valve, flow detection valve, etc., must be checked to confirm that the oil is indeed in a flowing state during daily spot inspection.

For the bearing bush structure of sliding friction (Fig. 2), the connection between the eccentric mechanism of punch and connecting rod basically adopts metal shaft and bearing bush.

However, unlike rolling bearings, metal shafts are subject to different loads, and lubricating oil is very important.

If the amount of lubricating oil is insufficient, it will cause burns and mechanism bite in a short time.

Special attention should be paid, as shown in Figure 3, which is the physical photo of bearing bush.

Semi solid grease

Semi solid grease usually refers to yellow grease, which is roughly the same as that of lubricating oil.

Because the grease is semi-solid lubrication, it needs to have a certain hardness.

The choice and use of hardness is determined by the load or temperature of the lubricating part.

There are several ways to supply grease, such as automatic pump supply, manual grease gun supply, sealing grease during assembly, etc.

The daily spot inspection methods of various oil feeding methods are as follows.

Automatic supply by pump (Fig. 4) the electric pump uses the piping to supply grease to several lubrication points, and it is necessary to confirm whether there is leakage in the piping supplying grease at each part.

If there is grease leakage from the piping (Fig. 5) at the connecting part of the piping, there is a high possibility that all cannot be supplied.

oil supply pipeline

Fig. 5 oil supply pipeline

In order to avoid such problems, the parts that can be supplied with manual grease gun will sometimes be equipped with emergency butter nipples for standby.

Since copper alloy is commonly used for this kind of connecting pipe, the nut may be damaged if a screw wrench is used for locking, so it is recommended to use a special wrench for locking.

Solid lubrication

Solid lubrication may not be heard often. Its main components are graphite, molybdenum disulfide, etc.

Many people should have used a knife to sharpen the black refill of a pencil when they were young.

Touching the black powder is slippery.

The powder of this pencil is a solid lubricant.

Ability judgment of routine inspection personnel

Solid lubrication and semi-solid lubrication are adopted in the operation of the machine.

The method of lubrication and the oil or grease used depend on the distinguishing ability of the equipment designer and maintenance point inspector.

The following are the capabilities that the daily point inspection equipment should have, as shown in Table 1.

Fig. 6 is a network diagram of the ability of spot inspection personnel.

capacity network distribution

The red circle generally refers to the ability range of newcomers, and the green circle refers to the ability of senior personnel.

1 means completely unable to understand;

2 means you can tell the related factors and symptoms of lubrication

3 refers to the abnormal diagnosis method that can explain the stress of the rotating shaft;

4 means that you can master the measurement method of shaft vibration, including speed, acceleration, displacement and other measurements;

5 indicates the cycle number analysis method that can explain the vibration and the degree of damage caused thereby.

Lubrication spot inspection method

The most common problem of stamping machinery is the bearing part. The abnormal bearing can be manifested by heating, vibration and abnormal sound.

The cause of abnormality is poor lubrication or mixed with foreign matters.

The following is a brief list of several methods of bearing lubrication point inspection.

Table 1 ability evaluation of routine inspection personnel

Serial numberSelf evaluationAbility
1 Understand the types, additives, extreme pressure agents and viscosity of lubricating oil
2 Understand the lubrication method of rotating shaft and the purpose of rolling bearing and bearing bush. Characteristics, etc
3 Understand the judgment method of lubricant deterioration. Differences between lubricating oil and grease
4 It can identify the causes and solutions of shaft heating
5 You can master the measurement method of shaft vibration. Including velocity, acceleration, displacement and other measurements
6 Understand the types and uses of thermometers and the differences between reversible thermometers and irreversible thermometers
7 Master the applicable temperature, types and characteristics of lubricating oil
8 Understand the differences between lubricating oil and grease, their supply methods and service environment

Temperature spot check method

When a bearing has a problem, it usually produces a heating condition.

When heating is caused by early deterioration of lubricating oil or grease, maintenance should be carried out in advance.

However, when the bearing is hot, it is good if it can be found in advance during daily spot inspection.

Sometimes it will be normal during spot inspection, and then it will be abnormal.

Setting temperature detection is also a common method in daily routine inspection.

There are two kinds of thermometers: reversible thermometers and irreversible thermometers. Reversible thermometers are used to measure the rise and fall of temperature, while irreversible thermometers represent the temperature when the temperature rises to the highest value.

In case of abnormal bearing, the temperature can be detected and the data record can be left.

Stick the irreversible temperature tape (Fig. 7) on the bearing.

temperature tape

When the temperature rises, it turns black, which indicates the highest temperature.

During daily spot check, it is easy to confirm whether the temperature indicates any abnormality with the previous one.

This device is often used on electrical distribution boards.

When the bearing is abnormal, the degree of temperature rise varies according to the number of revolutions or load, but it can rise to the temperature of molten steel.

It can be seen from the bearing with abnormal heating (Fig. 8) that the steel ball is deformed due to heating after high temperature.

abnormal heating bearing ball

If the steel ball turns purple, the bearing part may have been heated to 800 degrees Celsius.

Abnormal heating of bearings may lead to fire accidents, which should be paid special attention.

Bearings are not only used in punch machines, but also in other machines or conveyor belts. Sensors are often set as emergency stop mechanisms in case of abnormalities.

Vibration measurement with vibrometer

Use professional vibration meter to measure the vibration of bearing.

It can measure various vibration elements, displacement, speed and acceleration of vibration, and confirm the imbalance and damage of the bending or rotating part of the bearing shaft.

The vibration meter can quantitatively measure the vibration and grasp the state of the bearing. It is widely used as a State Benchmark monitoring tool.

However, using vibration timing, it is necessary to grasp the measurement method of vibration and the significance of vibration value.

It takes considerable time to learn such skills.

In addition, the damage state of each part of the bearing (outer wheel, inner wheel and ball) can be grasped by analyzing the measured vibration value by cycle number.

Generally, measuring vibration displacement, velocity and acceleration is called simple diagnosis.

To do cycle number analysis, vibration value and grasp the damage state is called precise diagnosis.

According to the importance, simple diagnosis and precise diagnosis are carried out on the production site respectively.

Measured with abnormal sound stethoscope

The method of measuring with the abnormal sound stethoscope is to use the stethoscope or stethoscope rod, and directly use the ear to confirm whether the sound generated from the rotating bearing is the same as that heard during normal use.

This requires spot inspectors to understand all kinds of abnormal sounds and reach a very skilled level.

For the lubricating oil and grease used in the bearing, use the direct microscope to confirm the oil analysis method of bearing metal

This method is to take out the lubricating oil or grease of the bearing, or directly confirm the type, shape and capacity of the metal powder used in the bearing with instruments such as microscope.

This method can directly take out the damage piece from the bearing in a physical way to confirm and grasp the initial damage state of the bearing.

However, this method is the same as the vibration meter.

The learning of technology and skills requires special knowledge and equipment.

Conclusion

Nowadays, in the actual work and production, there are many technologies and skills to grasp the abnormal bearing, and how to choose the most suitable method from these technologies and skills is the most important.

For the use of the selected technologies and skills, the spot inspectors must learn more, test more and analyze more.

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