2018年12月7日星期五

Daily maintenance of bearings

Bearings are an important part of machinery. Its main function is to support the mechanical rotating body, reduce the friction coefficient during its movement, and ensure its rotation accuracy. Maintenance work is the top priority for bearings to work properly, maintain performance, and extend life. Everyone should take it seriously.
Next, let's take a closer look at the daily maintenance work of the bearings.
First, keep the bearings lubricated and clean
Before inspecting the bearing, clean the surface of the bearing first and then remove the parts around the bearing. Pay special attention to the oil seal, which is a very fragile part. Please be careful when inspecting and disassembling the bearing to avoid damage to the part. If you have been experiencing bad symptoms when inspecting the oil seal of bearing and its surrounding parts, be sure to replace it to avoid damage to the bearing caused by a bad oil seal.
Second, to ensure the quality of bearing lubricants
The quality of the lubricant has a direct impact on bearing service life. The inspection method for the bearing lubricant is as follows: the lubricant is rubbed between the two fingers, and if there is a contaminant, it can be felt; or a thin layer of lubricant is applied on the back of the hand, and then the sealing is checked. Then it is to replace the lubricant of the bearing.
Third, the working environment of the bearing
When inspecting bearings, never expose them to contaminants or moisture. If the work is interrupted, cover the machine with a piece of oil-paper plastic or similar material. The working environment of the bearing is also very important. 
Fourth, the bearing seal
The purpose of bearing sealing is to prevent dust, moisture and impurities from entering the bearing, but also to prevent the loss of lubricant. A good seal ensures that the machine works properly, reduces noise and extends the life of the parts.
The above is the relevant introduction of the daily maintenance work of the bearing. It is mainly explained from four aspects. In fact, these four aspects are also related to each other. Therefore, bearing maintenance work is carried out closely around the four words of clean, lubrication, sealing and environment.

2018年12月6日星期四

Installation and maintenance of slewing bearing

  1. Slewing bearings require careful handling.
  2. Slewing bearings should always be transported and stored in horizontal position and be stored in dry roofed areas.
  3. Use eyebolts for horizontal handling. Impact, particularly in radial direction, must be avoided.
  4. The surface of slewing bearing should be applied with anti-corrosion oil, and the anti-corrosion period is 6 months. Long storage (as backup, for example) periods will require special preservation.
Requirements on supporting structures
  1. The support in the companion structures must be kept aligned to the track center.
  2. In order to prevent local overload and ensure smooth rotation, the supporting structures should be processed to remove internal stress after all the welding procedures. The contact surfaces for the bearing should be machined carefully and should be within flatness tolerances.

2018年12月4日星期二

General information about Bearing test machine

       Bearing life test results is an important index of comprehensive evaluation of bearing quality. It can reveal the quality level of bearing structure design, manufacturing process, material and lubrication etc.
      This series of machine is controlled by industrial computer automatically. The load, speed, operation time and other main parameters can be preset, and the machine can work according to the set procedures. The test machine can also monitor, record automatically on bearing load, temperature, vibration, motor speed, current and other parameters. When the testing bearing failure or something wrong with the test machine, the machine will alarm downtime and record down the reason automatically, to realize unattended and intelligent management.
    Auto bearing testing machine    
     This series of machine are realized the computer automatic control, monitoring test parameters, recording, alarm downtime and other functions.
     This series of machine test subject design is unique, simulation accurately, high machining accuracy, high components configuration, so as to ensure the stability and reliability of the bearing test.
    Sealed bearing testing machine   
     This kind of machine are often used to evaluate the bearing performance of a particular level and the durability of the bearing performance, such as the seal, friction, high-speed, high temperature resistance performance. Control mode can be automatic computer control or manual control.
    Bearing parts testing machine      
    A lot of experiments and data statistics show that when bearing fatigue failure, the most probability is roller failure. Therefore, steel ball contact fatigue testing machine and roller fatigue testing machine are used to test the fatigue life of rolling elements. And then study the internal relationship between rolling element's fatigue life, material, manufacturing process, finished product quality etc.

Three Methods for Identifying Bearing Faults

Bearing as a precision part of mechanical equipment, how to improve the productivity of the factory, the first mechanical equipment must be the best performance. And mechanical equipment performance use of one of the largest relationship-bearing. Therefore, the factory in production and processing, must be mechanical equipment in the bearing good inspection. For safety reasons. China bearing network sharing bearing fault identification method, we hope to help.
1. Recognizing by sound
     There is a need for a rich experience to identify the sound through sound . It must be adequately trained to recognize the bearing sound and non - bearing sound . To do this , it should be done as much as possible . The sound of the bearing can be clearly heard on the housing with a microphone or a listening stick .
2. Identifying by working temperature
      This method is a comparative identification method, which is only used in situations where the operation state is not too varied. For this reason, continuous recording of temperature must be carried out. When failure occurs, the temperature will not only rise. Irregular changes will also occur. It is advisable to combine this method with the sound recognition method.
3. Identified by the state of the lubricant
This method is especially effective for bearing or large bearing which can not be observed near by sampling analysis of lubricant, judging whether the lubricant is mixed with foreign body or metal powder according to the degree of dirt and whether the lubricant is not mixed with metal powder.

2018年12月2日星期日

Method of Judging Grease Metamorphism

In order to provide better performance, the bearings are lubricated by lubricating grease, which can reduce the friction and temperature of the bearings, if the grease is bad. Not only does not play a related role, but is more adverse to the use of bearings, so we must learn how to buy grease to tell whether the grease has deteriorated.
  
Method of judging grease metamorphism
1. Oil flow observation method
    Take two measuring cups , one of the lubricating oil to be inspected , the other empty on the desktop , lift the measuring cup full of lubricating oil away from the table top 30 - 40 cm and tilt , let the lubricating oil slowly flow into the empty cup , observe the flowing condition , the quality good lubricating oil oil flow should be slender , uniform and continuous , if the oil flow is lost or slow , and there is large flow of oil , the lubricating oil has deteriorated .
2. Hand twisting
    Twisting lubricating oil between thumb and index finger repeatedly grinding, a better lubricating oil hand feel lubricity, less debris, no friction, if feel the sand between fingers such as a greater sense of friction, it shows that there are many impurities in the lubricating oil. New lubricating oil should be replaced if it cannot be used again.
3.Illumination method
     On sunny days, use a screwdriver to lift the lubricating oil at an angle of 45 degrees to the horizontal level. Compare the sunlight and observe the oil droplets. Under light, you can clearly see that the lubricating oil is good without debris and can continue to function. If there is too much debris, replace the lubricating oil.
4. Oil drop trace method
    Take a clean white filter paper, drop a few drops on the filter paper, after oil leakage, if the surface of black powder, with the hand touch has a sense of resistance, then the lubricating oil has a lot of impurities. Good lubricating oil without powder, touch dry and smooth with hands, and yellow marks.

2018年11月30日星期五

Common faults and solutions for CNC machine tool spindles IV

The cause of the failure and the solution:
1. System output pulse time is not enough: adjust the system's M code output time.
2. The inverter is in jog state: Refer to the instruction manual of the inverter and set the parameters.
3. The control components of the spindle line are damaged: check whether the contacts on the circuit are in good contact, check whether the DC relay is damaged which caused the contact can not self-lock. 
4. The spindle motor is short-circuited, causing thermal relay protection: find the cause of the short circuit and reset the thermal relay.
5. The spindle control loop does not have self-locking circuit, and the parameter is set to pulse signal output, so that the spindle can not operate normally: change the start and stop parameters of the system control spindle to the level control mode.
Problem six: the spindle rotation can not stop
The cause of the failure and the solution:
1. AC contactor or DC relay is damaged and uncontrollable: replace AC contactor or DC relay.

2018年11月28日星期三

Common faults and solutions for CNC machine tool spindles III

The cause of the failure and the solution:
1. System has no S01-S04 control signal output: Check whether the system has shift control signal output. If no, it is system failure, replace the IC or send the factory for repair.
2. Connection line failure: If the system hasshift control signal output, check whether there is any open circuit or poor contact on each connection line, and check whether the DC relay or AC contactor is damaged.
3. The spindle motor is damaged or open circut : Check the spindle motor.
4. Machine is not linked: hang up the gear.
Problem four: the spindle has no brake
The cause of the failure and the solution:
1. Abnormal brake circuit or strong electrical components damage: Check whethr bridge stack, fuse or AC contactor is damaged; check if the high-voltage circuit is open.
2. Braking time is not long enough: adjust the braking time parameter of the system or inverter.
3. System has no brake signal output: replace internal components or send to the factory for repair.
4. The inverter control parameters are not adjusted: Check the inverter manual and set the inverter parameters correctly.