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What Is a Pressure Calibrator?

A pressure calibrator is an instrument used in the maintenance of pressure gauges.

Also called a pressure standard, it is used to calibrate pressure gauges. The reason why pressure gauges need to be calibrated is to ensure conformity to standards and laws, and to ensure traceability. If calibration is not performed at a certain cycle, reliability is lost and the measurement data cannot be trusted.

Also, if the calibration range is significantly out of range, large measurement errors will occur. In addition, there is a possibility of accidents such as damage to the pressure vessel. Therefore, it is necessary to consider whether calibration should be performed within the general calibration range and to determine the calibration cycle of the pressure gauge.

Calibration documents for calibrating a pressure calibrator include an inspection certificate, inspection report, traceability system chart, and a copy of the calibration certificate of the standard instrument, etc. 

Uses of Pressure Calibrators

Pressure calibrators are mainly used in industrial applications. The following are examples of applications of pressure calibrators.

• Maintenance of pressure gauges and pressure sensors
• Maintenance of pollution control equipment
• Quality assurance for product development and product manufacturing lines

As shown above, they are mainly used for maintenance of pressure gauges and other instruments. In addition, when pressure gauges are manufactured, their functions are checked using pressure calibrators. 

Principle of Pressure Calibrators

Deadweight pressure gauges, often used as pressure calibrators, are based on the most basic pressure principles and have long been highly reliable pressure calibrators. Pressure is defined as the vertical downward force multiplied by the cross-sectional area.

Deadweight pressure gauges are measured by a cylinder, a piston, and a weight of known weight on the piston. The cylinder is fitted with a piston that moves without friction. There is pressurized fluid in the cylinder, which is held back by the gravity of the deadweight through the piston.

Since a balance of forces is generated there, the pressure is calculated and measured using the gravity of the deadweight and the cross-sectional area. In order to improve the accuracy of deadweight pressure gauges for gases, the fit of the piston and cylinder and the surrounding environment may also be taken into consideration.

For this reason, the piston and cylinder are carefully cleaned, but the effect may be small if the inside diameter is large. However, more stable performance can be expected from deadweight pressure gauges for liquids than from deadweight pressure gauges for gases.

Types of Pressure Calibrators

The most commonly used pressure calibrators are deadweight testers. Deadweight testers are available for hydraulic and pneumatic pressure, and the model is selected according to the pressure gauge to be calibrated and the application. Another selection criterion is whether the pressure gauge is portable or stationary.

Deadweight testers can measure mechanical and electrical pressure, but cannot calibrate equipment that measures high vacuum conditions, such as ionization vacuum gauges. Other electronic pressure calibrators are also available.

Electronic pressure calibrators have the ability to record various types of data in memory, and are sometimes used to calibrate pressure transmitters, pressure switches, and electro-pneumatic/air-electric transducers. There are two types of pressure gauges mainly used in pressure calibrators: digital pressure gauges and mechanical pressure gauges.

Other Information on Pressure Calibrators

Calibration Method of Pressure Gauges

The calibration method uses a gas or liquid as the pressure medium, repeatedly raises and lowers the pressure, and calculates the calibration value from the average value. Calibrators generally used for calibration are dead-weight pressure balances and digital pressure gauges.

What Is a Frequency Meter?

A frequency meter is an instrument that measures signal frequency.

It is an electronic device or component that outputs frequency as a number, also called a frequency counter. It measures the number of periodic pulses of an electrical signal and outputs the frequency.

A frequency meter is used in many applications related to high-frequency radio technology to measure frequency signals with high accuracy. They provide accurate and precise measurements and allow detailed analysis of signal waveforms and frequency characteristics. The frequency meter is widely used in various areas of electrical testing to measure the frequency of repetitive signals.

Uses of Frequency Meters

Frequency meters are widely used in the fields of electrical engineering and communication engineering.

1. Equipment Reliability Evaluation

A frequency meter is widely used to evaluate the reliability of electronic equipment. Examples include noise generated in power circuits and evaluation of the operation of frequency conversion circuits.

2. Evaluation of Frequency Characteristics

Frequency meters are also used to evaluate frequency characteristics. For example, frequency response can be evaluated in acoustic equipment, such as amplifiers and speakers. They are also used to evaluate the characteristics of frequency filters.

3. Telecommunications Engineering

Frequency meters are also important measurement instruments in communications engineering. For example, they are used to adjust the frequency of transmitters and to evaluate the frequency of receivers. They are also used for fault analysis in wireless communications.

4. Power Measurement

A frequency meter is also used for power measurements. For example, they are used to evaluate the frequency of generators and transformers. They are also used to evaluate the efficiency of AC power in frequency converters.

5. System Design

A frequency meter is also used in system design. For example, they are used to evaluate the frequency response of an entire system or to design a frequency conversion circuit.

6. Acoustic Measurement

A frequency meter is used as a monitor to check the reflection and absorption of sound in an acoustic space, to create a uniform sound field, and to check the strength and frequency of vibrations emitted from equipment.

For example, a complex acoustic space is created in a car interior by sound reflection from the windshield and rear glass, sound absorption from the seats and floor, and engine noise. To create a comfortable sound, the frequency and signal strength distribution are checked with a frequency meter, and the highs and lows are strengthened or weakened with an equalizer to create a comfortable acoustic space.

Principle of Frequency Meters

A frequency meter is often used in combination with other measuring instruments, such as oscilloscopes. Frequency meter types include desktop, portable, high frequency, low frequency, RF (radio frequency), and microwave.

A frequency meter consists of a waveform shaping section, a reference time pulse generator, a gate section, and a display section. The input signal is shaped into a pulse train in the waveform shaping section, and a pulse with a precise time width of 0.1 or 1 second is generated in the reference time pulse generator.

The gate section switches the input signal shaped into a pulse train with pulses having this time width. The number of pulses obtained here is processed and output to the display section. For example, if the time width is 1 second and the number of input pulse trains is 10, the frequency is 10 Hz.

Care must be taken when measuring, because if noise is included, the pulse waveform may become unstable and the wrong frequency may be measured.

Other Information on Frequency Meters

1. Advantages of Frequency Meters

The advantage of a frequency meter is that it can measure not only frequency but also period, duty, etc. A frequency meter is a measuring instrument to check the performance of electronic circuits by digitally displaying the frequency.

They can be used as monitors to adjust the oscillation frequency to a predetermined value or to check the oscillation stability (frequency jitter). The principle is utilized in vibration and acoustic measurements. In this application, the input signal is Fourier transformed and displayed graphically as a spectrum.

Other applications include waveform observation and signal processing in the electronics field, ultrasonic measurement in the medical field, electromagnetic wave measurement, environmental surveys, and many others.

2. Application of Frequency Meters

A frequency meter comes with an application that not only quantifies the frequency of the input signal but also graphs it. While it is not possible to check for wobble or noise components using only numbers, FFT operations can be used to isolate the frequency components and graph their respective intensities.

Applications are provided to express signal quality in an easy-to-understand visual manner, such as displaying the strength of side lobes that appear next to the main signal, averaging the input signal to remove abrupt noise for accurate measurement, and expressing the wobble of the signal in terms of color shade.

What Is a Marking Press?

A marking press is a device used to apply letters or patterns to various materials and shapes without using ink. Instead, it physically scrapes or chemically discolors the object. Markings made by a marking press are resistant to friction and do not fade easily.

Traditional methods used a needle or mold to apply pressure, but laser printing has emerged as a prominent method for non-contact printing.

Uses of Marking Presses

Marking presses are used for applying production dates, serial numbers, and lot numbers on parts and products to assure quality and enhance control systems. The adoption of laser marking presses has grown due to their ability to print on complex shapes without physical contact, offering detailed printing at higher speeds without requiring special molds.

Principles of Marking Presses

Marking presses are categorized into contact and non-contact types.

1. Contact Marking Presses

Contact marking presses are subdivided into those requiring a typeface and those that use needle-printing.

Impact
Impact marking presses include type set in a holder or dialed, and pressure is applied to make an indentation.

Needle-Printing
Needle-printing uses a marking pin to create dots on the surface, forming an engraving. Precision grinders, another type, shave the surface with a rotating needle. However, due to their manual operation and low processing capacity, they are less common in industrial use.

2. Non-contact Marking Presses

Non-contact marking presses, or laser markers, add contrast through a chemical reaction, like oxidation, when irradiated by a laser.

Other Information on Marking Presses

1. Impact Marking Presses

Impact marking presses operate manually or air-driven, using spring repulsion to impact the material directly. They are simple to use and provide durable markings. Manual models allow adjustable imprinting loads, while air-driven presses offer the convenience of marking with an air source, including portable, handheld models.

2. Laser Marking Presses

Laser marking presses use a laser beam to thermally alter the surface of metals and resins for engraving or marking. Controlled by computers, these presses achieve precise, high-speed engravings without impacting the product. Fiber lasers, known for their small beam spot and excellent quality, are commonly used for their efficiency in cutting, marking, and welding applications. UV lasers, with a high absorption rate and minimal heat damage, are preferred for high-quality printing on sensitive products.

What Is an Arc Welding Robot?

Arc welding robots are robots that perform arc welding in place of humans.

Compared to other welding robots, arc welding robots are somewhat smaller. Arc welding emits intense light and powerful ultraviolet rays from the arc discharge, so the welding point becomes very hot. Therefore, there is a high risk of burns, even when protected by goggles and work clothes.

Inhalation of fumes from metal vapors is also harmful and is one of the tasks for which robots are in high demand as an alternative. Robots have the advantage of being able to perform welding at high speeds and with stable quality, which also contributes to cost reduction.

Uses of Arc Welding Robots

Arc welding is used to connect metals such as steel to steel, aluminum, and titanium. It is a welding method applicable to almost all metal structures. 

The following are examples of products for which arc welding robots are used:

• Steel frames and construction machinery
• Land transportation machinery such as automobiles and railcars
• Large air transportation machinery such as aircraft
• Large marine transportation machinery such as ships

Arc welding robots are used in manufacturing plants for the above products. In recent years, the rationalization of welding has been progressing, and the number of cases in which arc welding robots have been introduced is on the rise. Arc welding robots can also be used for TIG welding and mag welding, which are types of arc welding.

Principle of Arc Welding Robots

Arc welding is a welding method that uses electrical discharges into the air. An electric current is passed through the welding rod, which serves as the electrode, and when it comes into contact with the metal to be joined and is slowly pulled apart, an arc discharge occurs. The arc is so hot, reaching temperatures of up to 20,000°C, that the metal is quickly melted and joined.

The robot has six to seven vertically mounted articulated axes for precise motion. Each axis has a specific angle and speed at which it can move, and a qualified operator teaches the robot the welding conditions. The conditions and positioning at this time are important and are sometimes determined while performing actual welding.

The part that actually performs the welding is called the welding torch, which is fixed to the tip of the robot. The torch and contact tip must be selected according to the object to be welded.

Structure of Arc Welding Robots

The structure of an arc welding robot consists of a manipulator, a controller, and a programming pendant.

1. Manipulator

The manipulator consists of a base, motor and end-effector. The welding torch attached to the end-effector can be replaced to accommodate various welding conditions. It also has a multi-axis articulated structure with servo motors. 

2. Controller

The controller consists of data storage and communication equipment with the manipulator. Welding conditions and other data are stored in the controller.

3. Programming Pendant

The programming pendant is an interface through which a person teaches welding conditions to the robot. Data describing the manipulator’s operating procedures can be created, changed, or modified. Control parameter changes and teaching are also performed by the programming pendant.

How to Select an Arc Welding Robot

Arc welding robots must be selected according to the welding material, stroke, and installation method. Welding materials include steel and aluminum. Select a robot that corresponds to the material to be welded.

The stroke is the distance the robot can extend its arm. The longer the stroke, the farther the robot can work, but the more expensive it is. When welding large parts, multiple robots may be installed.

Installation methods include wall-hanging and ceiling-suspension, depending on the conditions in which the robot is to be installed. Select an installation method suitable for the location where the robot is to be installed.

Other Information on Arc Welding Robots

Arc Welding Robot Market

The global arc welding robot market is expected to reach US$11.7 billion by 2026. In addition, the automotive industry is expected to remain strong and demand will continue to grow beyond 2024. The prevalence of automation, especially in developed countries, and labor shortage issues are also factors driving demand.

Arc welding robots are generally sold at prices starting at around several million yen. The amount varies depending on the materials to be welded and the conditions of use.

What Is a Force Sensor?

A Force Sensor is a sensor that measures the magnitude of a force or moment.

It is used to reproduce the human sense of touch by detecting the amount and direction of physical force. Its main application is in robotics.

Force Sensors are basically 6-axis type Force Sensors, which means they can detect forces in three dimensions (X, Y, and Z) and moments around each of these axes (X, Y, and Z).

Applications of Force Sensors

Force Sensors are used in industrial robots to automate tasks that previously had to be performed manually.

1.Detection of External and Reaction Forces

Force Sensors can simultaneously measure forces and moments. Installed at the work end of a robot, it can work with appropriate force while measuring external and reaction forces. 

2. Automation of Precision Work

Force Sensors can measure accurate forces and moments so that robots can work with appropriate forces. This enables automation of precision work by robots.

Specific tasks include insertion of electronic components and connectors with soft terminals, mating with little play, precision screw tightening, deburring, polishing with subtle force, picking work, and independent control of a biped robot.

3. Tactile Diagnosis and Remote Medical Treatment

A terminal equipped with a Force Sensor can be positioned beside a patient, allowing a doctor to access and interpret the forces and moments detected by the Force Sensor, which enables remote tactile diagnosis.

Principle of Force Sensor

Force Sensors detect the amount of deformation caused by a force and convert it into a force or moment.

Strain gage, piezoelectric, optical, and capacitive force sensors are representative among the detection methods of Force Sensors.

1. Strain Gage Type Force Sensor

The strain gage type is a method of converting force or torque by utilizing the property of metal resistive materials whose electrical resistance changes according to the tensile or compressive force applied to the sensor part. This method is widely used for force sensors because it is compact, highly accurate, and responsive. 

2. Piezoelectric Force Sensor

Piezoelectric Force Sensors use piezoelectric materials such as quartz crystal or PZT (lead zirconate titanate) for the sensor part to measure force. They are compact, highly responsive, and relatively inexpensive. However, the accuracy is not as high as strain gage type or capacitance type. 

3. Capacitive Force Sensor

The structure of the capacitive type sensor involves electrodes made of metallic materials arranged facing each other in a capacitor-like configuration. This method detects changes in capacitance due to changes in distance caused by strain between conductors due to force.

The capacitance type is characterized by its relatively simple configuration and low cost. If the electrodes are made of film, they can be made smaller and thinner. Accuracy and response are also excellent. 

4. Optical Force Sensor

In the optical method, a pattern is marked on the object to be measured at regular intervals. The change in the pattern that occurs when a force is applied is detected by an optical sensor such as a camera or laser, and the magnitude of the force is calculated and obtained.

The greatest advantage of the optical method is that it enables non-contact measurement. On the other hand, accuracy, responsiveness, miniaturization, and cost are inferior to other methods. It is limited to special applications that require non-contact measurement.

5. HDR Force Sensor

There are what are called HDR (High Dynamic Range) Force Sensors, which are characterized by a wide dynamic range, e.g., from 10 g to 20 kg.

By combining AI and robot technology with HDR Force Sensors, fine assembly operations can be performed while adjusting for minute forces. Robots are increasingly automating and upgrading assembly work at production sites.

6. Capacitive Force Sensor

The capacitive Force Sensor is characterized by its ability to measure 6-axis components by detecting changes in the distance between two parallel plates. A simple structure can be realized and the price can be kept low.

Force Sensors with an anti-overload stopper mechanism inside the sensor are also available. Recently, these sensors are widely used in the industrial robot field. Demand is expected to grow more and more due to the increasing automation in the manufacturing industry.

Other Information on Force Sensors

Application of Force Sensors

Cooperative work between humans and robots can be realized by having humans operate robots that use Force Sensors. Fine work that requires minute force adjustment can also be performed.

In particular, in the manufacturing field, the use of Force Sensors has realized automation of tasks that can only be performed by skilled craftsmen, thereby improving productivity. In the medical field, Force Sensors are expected to be used in remote medical examinations where the condition of the affected area can be determined by tactile diagnosis.

What Is a Height Gauge?

A height gauge is a measuring instrument used to measure the distance in the direction of height from a certain reference plane for machined parts.

Height gauges not only measure the height of the object to be measured, but can also be used for marking. The base point is the horizontal surface on which the height gauge is placed, such as on a surface plate, and the height from this reference point is measured.

When measuring, a sub-measure called a vernier is used to precisely measure the height. Height gauges also use a measuring tool called a scriber. The scriber is made of hard material and has a pointed tip, so it can be used to mark a line parallel to the surface plate on the object to be measured at a precise height.

Uses of Height Gauges

Height gauges are mainly used to check the manufacturing quality of processed metal products and in product development. For example, height gauges are used to check whether the height of a fabricated metal product is within the drawing specifications.

Height gauges can be used to measure the height from a flat surface accurately, such as a surface plate. The height can be measured in increments of 0.01 mm by using a vernier scale to read the scale. It features easy operation and precise height measurement, and can be used in a wide range of situations, from the measurement room to the lineside.

Height gauges are also made of a hard, sharp material at the tip, which can be used to scrape lines in the direction of height. It is important to perform the staking by securing the slider with a set screw firmly tightened to prevent the tip from moving.

Principle of Height Gauges

A height gauge consists of a main body base, a main scale with a scale on it, a column on which the main scale is mounted, a vernier that takes minute readings, a slider that is moved up and down for height measurement, and a scriber that serves as the measuring tool.

The height gauge is a measuring instrument that is placed on a surface plate together with the object to be measured. In measurement, the slider is lowered from the top and the bottom of the scriber is brought into contact with the object to be measured. This height is the measurement value. The reading is taken at the point where the main scale and vernier scale overlap.

For accurate measurement, it is important not to apply more measuring force than necessary to the scriber and to read the scale from the front. Also, the scriber must be parallel to the bottom of the base. If the scriber is not adequately secured, or if the flatness of the base plate or other surface is not ensured, stable measurement will not be possible.

After many years of use, the height gauge may tilt over the column due to aging or other factors. Attach a lever-type dial gauge or the like to the point where the scriber is mounted, and while holding it against the side of a straightedge or the like, move the slider part up and down to see how the value changes. If the pillar is tilted, it needs to be adjusted or repaired.

Other Information on Height Gauges

1. Error Factors of Height Gauges

Height gauge measurements can be subject to measurement error due to a variety of reasons. For example, excessive measuring force, thermal effects due to the temperature difference between the object to be measured and the measuring instrument, and parallax effects due to the angle at which the scale is read. It is particularly important to note that errors due to the structure of the measuring instrument are unavoidable.

The main sources of error arising from the structure of the measuring instrument are those arising from the bending of the column and the tilt of the scriber. Scriber inclination is unavoidable due to its measurement method and construction. Because the height gauge has a scriber extending from a slider mounted on the column, not only does the scriber tilt when it is mounted, but over time, gaps and rattles in the parts can cause the scriber to tilt.

Deflection due to the weight of the scriber and mounting parts can also cause the scriber to tilt. A certain amount of these structural errors occur even in new products. If the error is smaller than the resolution of the measuring instrument, there is little need to be concerned, but if the error becomes larger over time, caution is required.

Therefore, in addition to daily inspections, it is essential to perform periodic management such as calibration at a certified calibration laboratory. 

2. Precautions for Using Height Gauges

The bottom surfaces of the main scale and base must be cleaned before and after use to prevent scratches, rust, and oil from deteriorating the sliding action. Some manufacturers and products specify the parallelism between the measuring surface of the scriber and the base bottom surface of the height gauge. Dust, chips, etc., on the surface plate during use or in storage can cause scratches or chipping on the base bottom surface, resulting in deterioration of parallelism.

Storage in locations subject to rapid temperature changes is also undesirable. Repeated expansion and contraction due to thermal effects will not only deteriorate the accuracy, but also cause deformation of the measuring instrument itself.

If the instrument is located near a window or wall with inadequate insulation, it will be subject to thermal effects from temperature differences. Even if the instrument is located indoors and not exposed to direct sunlight, it is still a good idea to be cautious.

What Is an In-Circuit Board Tester?

In-Circuit Board Tester is a testing device used to evaluate the electrical characteristics of individual electronic components mounted on an electronic circuit board inside an electronic device.

For an electronic device to function properly, the internal electronic circuit board must operate properly. In-Circuit Board Tester inspects the board with the electronic components mounted on it.

In-Circuit Board Testers can test the electrical characteristics of individual components mounted on the board with a very small amount of power. They can locate defective parts without damaging the board, and can reliably detect defective parts that are difficult to detect with the naked eye.

In-Circuit Board Tester Applications

In-Circuit Board Testers are widely used in the inspection process of development and mass production lines in factories that handle electronic circuit boards with electronic devices and components. There are two types of In-Circuit Board Testers: press-type In-Circuit Board Testers and Flying Probe Testers.

Press-type In-Circuit Board Testers are capable of high-speed inspection and are suitable for mass-production boards. They are also used for inspection jigs. Flying Probe Testers do not require inspection jigs and are suitable for low-volume, high-mix boards, while handling fine patterns.

Specific inspection items include short/open defects of solder mounting components, defects due to wrong constants of capacitors, coils, and resistors, defects of missing components such as capacitors, coils, resistors, diodes, and transistors, and lead float defects of ICs and connectors, photocouplers and digital transistors. The test is also used to check the operation of photocouplers, digital transistors, and Zener diodes.

Special tests include image inspection of electrically inaccessible components, adhesion (solder) defect inspection of SOPs, QFPs, etc., and simple function tests.

In-Circuit Board Tester Principle

In-Circuit Board Tester extracts defects such as component constants and functions, as well as open or short signal lines including internal vias, by applying a probe to the required location on the electronic board and causing a very small electrical signal to be applied separately from the bias during normal operation.

The system has the internal configuration necessary to smoothly perform various types of inspections, and usually consists of a measurement section for electrical inspection, a scanner section for capturing and recognizing measurement lines, a probing section for bringing the measurement lines into energized contact with specific locations on the board to be inspected, and a control section for controlling these sections. The scanner is used to capture and recognize the measurement line.

The constant of an electronic component is measured from the values of voltage and current when a measurement signal is applied to the probing unit. Since electric circuits generally form a network, it is difficult to measure the constants of individual elements. However, many In-Circuit Board Testers are equipped with various functions to improve inspection accuracy.

Other Information on In-Circuit Board Testers

1. In-Circuit Board Tester Functions

Guarding function
This function electrically isolates the effect of errors caused by current due to parallel connections.　

Phase Separation
When an AC signal is applied to a circuit network composed of resistors, inductors, and capacitors, a phase difference is generated between the current and voltage. This phase difference can be used to accurately measure the constants of each element.

2. Flying Checker

A flying checker is one type of In-Circuit Board Tester, which is an inspection device that primarily applies a probe to determine open-shorts of mounted components on a board. It takes longer to inspect than a standard press-type In-Circuit Board Tester, but is used when the emphasis is on the fact that it does not require preparation of a program or pin board.

Also called a flying probe checker, it creates a net list from Gerber data and uses that data to inspect for broken wires by applying a probe to the beginning and end of the board. It then inspects for shorts by applying a probe between one of its nets and an adjacent net.

Many types of flying checkers are modified from bare board checkers and can be used as general in-circuit tests after mounting. The specific inspection method involves clamping the board from both sides with two or four probes. This testing equipment inspects the open and short-circuit conditions of a printed circuit board. There are two types of testing equipment, one that checks electrical continuity and the other that measures C-capacitance to find short circuits, with the C-capacitance method generally taking less time.

3. Function Tester

A Function Tester serves a distinct purpose compared to the In-Circuit Board Tester, despite often being compared in the context of inspecting similar boards during the board manufacturing process. While the primary role of the In-Circuit Board Tester is to examine the board’s assembly condition, including components and circuit continuity (such as identifying open or short circuits), the Function Tester is designed to verify whether the circuit’s functionality, such as input and output operations, is operating correctly.

This test is usually called a function test, in which electrical signals specified in the specifications are applied to the input terminals of the board to be tested. The purpose is to verify whether the board functions correctly by checking if the specified output signals are generated in accordance with the specifications. Other tests are also performed for components such as switches and LEDs that are difficult to check with just an open-short test using In-Circuit Board Tester, as well as for integrated circuit operations and software writing for MCUs and various types of ICs.

In general, when comparing in-circuit testing and function testing, function testing is more important from the perspective of confirming product operation, and most products prioritize function testing.

What Is a Coordinate Measuring Machine (CMM)?

A coordinate measuring machine (CMM) is an instrument capable of measuring surface features at the submicron level(smaller than 1/1,000 of a millimeter). 3D coordinate measuring machines can capture the shape of a part in three dimensions and perform a variety of measurements.

They are also used to measure the surface roughness, height, and thickness of electronic component substrates and semiconductors. They are characterized by high speed, high resolution, and high accuracy.

There are also various types of coordinate measuring machinery depending on the installation and measurement methods. There are stationary and portable types in terms of installation method, contact-and non-contact types, laser tracker, layout machine, etc. in terms of measurement method.

Uses of Coordinate Measuring Machinery (CMM)

Applications of coordinate measuring machinery are as follows:

1. Line Roughness Measurement

Coordinate measuring machinery can measure typical surface roughness parameters such as Ra, Rz, etc., as well as a stylus-type surface roughness.

2. Surface Roughness Measurement

Coordinate measuring machines can measure waviness and steps between surfaces with high accuracy by measuring the entire surface. Examples include washer waviness evaluation and block gauge step measurement.

3. Plane Measurement

Coordinate measuring machines are used to measure the distance between two points: straight lines, circular centers, and various other flat surfaces. They are used in all industries, including the medical device, archaeology, molding, and watch industries.

Principle of Coordinate Measuring Machinery 

Most coordinate measuring machinery (CMM) uses white light interferometry, a measurement method that uses a white light interferometer. Light interference is a phenomenon that occurs when there is a difference in the phase of light from two sources. Optical interferometers use this phenomenon to measure the state of surface irregularities, for example.

The interference of light causes a stripe pattern to appear due to the optical path difference generated by the unevenness of the sample surface. The number of stripes indicates the height of the unevenness of the sample surface. In actual use, an objective lens with a built-in reference mirror, called an interference lens, is used. White light is irradiated onto the reference mirror and objective lens, and the interference signal is observed by a camera while the objective lens is moved up and down.

Some models are also equipped with a high-sensitivity CMOS, a semiconductor that converts light entering through the lens into electrical signals. A solid-state imaging device using CMOS can capture an external image at the same time as the shape, allowing surface observation and measurement at the same time. The analysis contents are converted into data, such as a 3D model, which can be viewed on a CAD system.

More Information on the Coordinate Measuring Machinery 

1. 3D Coordinate Measuring Machinery (CMM) Functions

Coordinate measuring machines (CMM) available on the market today use the latest technology and can easily perform measurements that were impossible in the past. The 3D coordinates of a specific point from a virtual origin are considered difficult to measure with common measuring instruments, such as calipers and micrometers.

Also, measurements using virtual points and lines and geometric tolerances are also extremely difficult to conduct with other measuring instruments, but coordinate measuring machinery (CMM) can perform them. Recently, it has become possible to read the shape of a prototype in 3D and create a 3D object using a 3D printer to check the shape in the same way as the actual product.

2. Issues and Solutions for Coordinate Measuring Machinery (CMM)

The efficiency of measurement work has been dramatically improved by the highly accurate measurement technology of coordinate measuring machinery (CMM) and the increased processing speed of measurement data, but there are also the following issues:

• High cost of installation
• Large installation space and high maintenance requirements
• The size of the CMM itself is limited, which in turn limits the size of the objects that can be measured.

CMM with an articulated arm have emerged as a solution to these problems. Originally developed for manufacturers of prosthetic arms and legs, the technology is now used in transportable CMM.

The ability to move the arm at the will of the operator has further expanded the range of measurements that can be taken. The introduction of non-contact measurement using lasers has also made it possible to measure large objects.

What Is a Humidity Sensor?

A humidity sensor is a sensor that measures humidity in the air.

Generally, it refers to a sensor that measures the relative humidity of the saturated water vapor content. It is sometimes used in combination with a temperature sensor in the form of a temperature/humidity sensor. Of course, there are also humidity sensors that detect absolute humidity, but humidity sensors that detect relative humidity are more common.

Humidity sensors are used not only in home appliances such as air conditioners and dryers but also in machine maintenance and food processing.

Uses of Humidity Sensors

Humidity Sensors are widely used in home appliances, office automation equipment such as printers, air conditioning in homes, buildings, and facilities, and industrial facilities such as factories and warehouses.

Examples of each application are as follows:

1. General Household Products

Humidity sensors are installed in products for general household use. For example, they are used in air conditioners, refrigerators, automobiles, dryers, air purifiers, humidifiers, etc. Humidity sensors are indispensable for air conditioning products that regulate the air environment. 

2. Office Automation Equipment

Humidity sensors are also used in office automation equipment such as printers, etc. Since office automation equipment does not tolerate extreme dryness or humidity, humidity sensors are used to measure the external environment and prevent equipment malfunctions.

3. Industrial Applications

Humidity sensors are also widely used in industrial applications. They are used to control humidity in food processing plants and plant cultivation plants, as well as in semiconductor and other manufacturing sites and storage areas. Humidity sensors are also used in places where humidity control is important, such as in the manufacturing and operating environments of medical equipment and in the aerospace industry.

4. Storage Applications

Humidity control is also very important in the storage of exhibits in museums and art galleries. Therefore, humidity sensors play an important role in controlling humidity in storage locations.

Principle of Humidity Sensors

Humidity sensors are built to measure relative humidity. A humidity sensor measures the humidity in the air and calculates it as a relative value to the saturated humidity at the temperature in the environment to derive the relative humidity.

Humidity sensors meant to measure absolute humidity, on the other hand, measure the amount of water vapor per cubic meter in the space. This absolute humidity is independent of temperature and indicates the amount of water vapor in the space, and is also called volumetric absolute humidity.

Types of Humidity Sensors

Electronic polymer humidity sensors are the most common type of humidity sensor and are further classified into “resistance change type” and “capacitance change type.” Both types consist of an electrode and a polymer membrane, and changes in humidity due to moisture absorption by the polymer membrane are extracted as changes in electrical signals between the electrodes.

1. Resistance-Type Humidity Sensor

A resistance-type humidity sensor detects electrical signals corresponding to changes in humidity by capturing changes in electrical resistance. It has a structure in which electrodes in the shape of a comb are arranged so that they face each other, and a polymer membrane is arranged to fill the gap between the electrodes facing each other in the shape of a comb.

When the polymer membrane absorbs moisture and water is adsorbed, the ions in the membrane can move freely, and the resistance of the membrane changes due to these ions. This change in membrane resistance causes a change in resistance (impedance) between the electrodes, so humidity can be detected by the change in electrical resistance.

Humidity sensors of the electrical resistance change type have a simple structure and can be mass-produced. They are also relatively inexpensive and durable, and since they measure electrical resistance, they have the advantages of being resistant to noise and suitable for areas with high humidity. However, it has the disadvantage that detection does not work well when humidity is low.

2. Capacitance Change Type Humidity Sensors

The “capacitance change type” humidity sensor applies capacitor technology to detect electrical signals corresponding to changes in humidity by capturing the electrical capacitance. It consists of a moisture-permeable electrode placed between a dielectric of a polymer film such as cellulose or PVA, which absorbs moisture, and an electrode on top of a regular electrode.

On the moisture-transmitting electrode side, moisture in the air is absorbed by the polymer membrane regardless of the presence or absence of an electrode, and the capacitance of the polymer membrane dielectric changes according to the amount of moisture absorbed. As a result, differences in moisture content, or changes in humidity, can be detected as changes in capacitance.

The advantage of the capacitance change type Humidity Sensor is that it is more sensitive and has a faster response time than the resistive type. However, capacitance change Humidity Sensors have the disadvantage of complicated circuits.

Other Information on Humidity Sensors

1. Types of Humidity Sensors

There are two types of humidity sensors: one is in the form of a small element that is connected to an electronic circuit, and the other has a humidity sensor placed inside a probe-shaped measuring section. Some types are resistant to condensation, while others are weak against condensation, so it is necessary to select the appropriate type according to the application. 

2. Life of Humidity Sensor

Humidity sensors gradually deteriorate over many years of continuous use, and naturally, their measurement accuracy declines. In addition, the joint between the humidity sensor and the external output will also deteriorate. Considering these factors, the life span of a sensor is about 2 to 5 years, depending on the operating environment and the type of sensor installed. 

3. Humidity Sensor for Smartphones

In recent years, an increasing number of smartphones have been equipped with temperature and humidity sensors. In order to measure temperature and humidity with such smartphones equipped with temperature/humidity sensors, it is necessary to download a free application or other software.

In many cases, smartphones that do not have a temperature/humidity sensor can be used to measure temperature and humidity by attaching an external sensor.

Wireless sensors that work with smartphones include temperature and humidity sensors with Bluetooth functionality. Such external sensors are generally called “environmental sensors.” Many of these environmental sensors have multiple sensor functions such as temperature, illumination, air pressure, noise, etc., in addition to a humidity sensor.

What Is a High Frequency Welder?

A high frequency welder is a device that welds materials using high frequency dielectric heating.

It is suitable for thermoplastic resins like polyvinyl chloride (PVC) and nylon. Welding with a high frequency welder offers higher weld strength and a cleaner finish compared to other external heating methods.

Unlike microwave heating, a high frequency welder can achieve targeted and deeper heating by using electrode plates to heat the material between them.

Uses of High Frequency Welders

High frequency welders are utilized to bond sheet materials, including:

• Tents and life jackets.
• Business card cases and book covers.
• Bags made of artificial leather.
• Exterior packaging for seasonings and toothpaste.

Due to its operating principle, the range of materials compatible with a high frequency welder is limited. However, the seamlessness of the welds results in a visually appealing finish, making it ideal for aesthetically sensitive products and ensuring airtightness and waterproofness for items like tents.

Principle of High Frequency Welders

A high frequency welder generates heat through dielectric heating, where a high-frequency voltage agitates the material’s molecules to create frictional heat, uniformly warming the material from inside. This method is effective only for dielectric materials such as vinyl chloride and polyethylene.

By applying high frequency voltage and pressure between electrodes, the material is heated to 248-266°F within seconds, reaching a semi-liquid phase. Cooling under pressure then allows the materials to fuse together.

Other Information on High Frequency Welders

1. The High Frequency Welder Process

This process is notable for not causing appearance defects like scorching, as it heats the weld area locally without affecting the surroundings. The process is smoke-free and does not emit harmful substances, offering a safe and environmentally friendly solution.

2. Materials to Be Welded With High Frequency Welder

Main materials include:

• PVC (Vinyl Chloride): Commonly used for vinyl sheets and artificial leather due to its softness and thermal processing ease.
• TPU (Thermoplastic Polyurethane): Chosen for its elasticity in items like hoses and smartphone case bumpers.
• POF (Polyolefin): Includes polyethylene and polypropylene, used for packaging bags for condiments and toothpaste.

3. High Frequency Welder Frequencies

Selection of power and frequency depends on the material and thickness of the object. Frequencies range from 40 MHz to 200 MHz for plastic sheets, and 10 MHz to 50 MHz for thermosetting plastics, with 2.45 GHz also being used for specific applications.

4. Price of High Frequency Welders

Prices vary widely based on size and output capacity, with smaller units starting around 3,000,000 yen and larger equipment for industrial use ranging from 5,000,000 to 10,000,000 yen.