What is CBM (Condition based Maintenance)?

CBM stands for "Condition based Maintenance," and refers to the concept of predictive maintenance, in which the state of an object is monitored to determine the need for maintenance prior to failure.

CBM has been one of the biggest challenges facing many companies in recent years. This is especially true in the industrial machinery industry, where replacement is difficult because of the large opportunity loss in the event of failure and the high unit price.

This time, we introduce IMV's vibration pickup sensor VP8021-A, which plays an important role in realizing CBM.

Flow for realizing CBM

First of all, what kind of flow take to realize CBM? The flow can be broadly divided into the following three categories:

• Sensing machine status.
• Processing of sensing data
• Fault criteria based on processing data

Flow Each requirement definition differs depending on the target equipment. The flow that is particularly important and requires verification is generally referred to as "sensing of machine status."

If the sensing data is wrong, the other two flows do not make sense no matter how many demonstrations are repeated. The following sections provide an in - depth discussion of device state sensing.

Determination of sensing objects

The first thing you need to decide when sensing equipment status is "what" to be sensed. The sensing object includes many elements such as vibration, current, and temperature, but the sensing object used in CBM is "vibration".

Deterioration curve of the equipment

This is a diagram showing the deterioration of the machine. Of course, as time goes by, the state of the machine changes. Vibration is the first sign of deterioration in the curve from the initial state to failure. By measuring the vibration, the failure of the machine can be judged earlier.

To measure failure oscillations

Then, what kind of mechanical vibration is used to measure failure, and what kind of vibration sensor should I use?

Type of vibration at each frequency

This diagram shows the types of vibration by frequency.
Mechanical vibration is generally said to be from 10 Hz to 20000 Hz, and we can see that it is a frequency wave many times higher than the vibration we usually see.

Vibration sensors commonly used to detect machine vibration are divided into the following three types.

• Mechanical servo type acceleration sensor
• General capacitance type acceleration sensor (MEMS)
• Piezoelectric vibration pickup sensor

Type of vibration sensor for each frequency

The sensor that can measure even high frequencies is a piezoelectric vibration pickup sensor. However, many piezoelectric vibration pickup sensors are expensive, and in some cases, the expensive ones cost more than 100,000 yen.

The capacitive vibration pickup sensor VP8021-A developed by IMV Co., Ltd. can solve the biggest problem of piezoelectric sensors : cost.
Let's take a closer look at VP8021-A.

What is VP8021-A?

The VP8021-A is a capacitive vibration pickup sensor. Inside the product, the ADXL1002 MEMS accelerometer provided by Analog Devices, which can measure high-frequency vibrations at low cost, is used.

By using this sensor, it is possible to obtain the same vibration data as the conventional piezoelectric vibration pickup sensor while suppressing the cost.

It can be purchased for 25,000 to 30,000 yen at the time of mass production, and the introduction itself can be made cheap.

VP8021-A Key Features

The features of IMV's VP8021-A are described below.

Data processing acquired by VP8021-A

Since the data acquired by the VP8021-A is high frequency, a processing terminal capable of AD-converting signals up to 10 kHz is required.
Macnica provides a SENSPIDER for processing high-frequency signals and implementing AI to enable edge computing. 

Vibration sensor & Senspider

Application Example

• Injection molding machine
• Boiler
• Stirrer
• Compressor
• Other industrial equipment with motors and bearings VP8021-A