Knowledge +

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Balance calibration purposes

Reduce the vibration
Reduce the noise
Extended product life
Improve product quality
To meet customer needs

 

Reasons of imbalance

Structure tolerance
ex: casting, machining, injection and assembly and so on.
Material changes
ex: oxidation, density, and abrasive polishing and so on.
Geometry asymmetry
ex: change the type, size changes, the airflow caused by the deformation temperature caused by thermal expansion and contraction.

 

How do balance correction - through the instrument

 

How do balance correction - phase change

 

How to do the balancing adjustment-

 

The principle of Wheel Balancing

Wheel balance is mainly set the weights on the wheel flange,through the auxiliary equipment can shorten the time,provide precise adjustment of the value,and Adjusted to allow scope,Wheel of life can be extended.

Grinding wheel when in operation, the wheel in an unbalanced state,the vibration transfer will continue to other parts of machinery, equipment,and thus make the mechanical parts, equipment, operation of the state of deterioration or damage.

In addition, because the vibration of the spindle and bearings will reduce the grinding performance.

 

Effects on the operation of equipment

 

The principle of the Rotor

Machinery to contain a large number of the rotation movement of components, such as the various drive shaft, spindle, motor and steam turbine rotor, etc.
,These collectively known as the rotating body.

Swivel rotation and does not rotate, the pressure on the bearings is the same, this is balanced rotaryrotating body.
However, projects in a variety of rotary,because of uneven or rough material defects, processing and assembly errors, or even design a
have non-symmetric geometry and other factors，makes the rotary body in rotation, each tiny particle of its surface, the centrifugal force of inertia generated
not cancel each other out, the role of the machinery, causing a vibration, noise, and accelerated bearing wear，
reduced mechanical life, can cause severe destructive accident.

 

Cause of the vibration

Not perfectly homogeneous materials, precision manufacturing constraints, after use, wear and other factors, caused by the operation of the object vibration.
Measurements on rotating machinery to the vibration waveform is a vibration of many parts.

 

Vibration damage

Fatigue failure of the general rotating machinery in the 600 ~ 120,000 the CPM, with frequency proportional to the speed measurement unit.
Low frequency (typically below 600 the CPM) for displacement damage, "displacement" as the unit of measure.
High frequency (usually in the destruction of the force above the CPM 120,000), the "acceleration" is a measurement unit.

 

Vibration of elements

 

Methodof vibration diagnosis

Absolute judgment:
In some absolute benchmark for judgment in accordance with the ISO, VDI API.
Relative judgment:
Determination of the equipment on a regular basis the same location, to determine whether this value is normal, and usually use the initial value.
Spectrum analysis:
From the measured vibration, the use of Fourier transform (Fast Fourier transform) broken down into different parts of the vibration waveform can be judge by the frequency distribution of the source of the vibration; such as the shaft or bearings.
Phase analysis:
From the measured vibration, broken down into different parts of the vibration waveform, the phase difference on frequency vibration mode; such as shaft deformation or shaft is bad on the heart.

 

Spectrogram

Vibration according to physics, rotating objects, showing the sine wave.Measurements on rotating machinery to the vibration waveform is a vibration of many parts. The use of mathematical methods can be synthesized vibration, the use of mathematical methods (Fourier transform) broken down into different parts of the sine wave vibration.
Shown in (a) The grounds of mechanical measurements of the total vibration can be decomposed into the frequency of vibration of different speed. (B) the graph of the sine wave, observed by the right direction, and its side view and (c), the so-called spectrogram.
The horizontal axis represents the frequency of the speed of the frequency spectrum, the longitudinal axis of the table vibration. If the peak frequency of the mechanical spindle speed graphics, large amount of vibration in said shaft.In multiples of spindle speed peak and its multiples impeller number on behalf of the impeller of the vibration source.Peak in the high frequency region, are generally bearing a problem.

 

Vibration spectrum

 

Vibration spectrum

 

Vibration sensor

Sensor is a physical device that can detect, feel the outside of the signal, and the discovery of the information to other devices.

sensor

Can feel the vibration of the amount of mechanical movement (such as the vibration velocity, frequency, acceleration, etc.) and converted into usable output signal.
The forefront of the test system is the sensor, it is the soul of the entire test system, is the world as a cutting-edge technology.