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What Is Urethane Roller?

A Urethane Roller is a component made of urethane rubber bonded to a metal roll.

They are used as conveyor parts for precision equipment such as conveyor conveyors, printers, and film packaging machines. Since Urethane Rollers are used as conveying parts for various machines, they vary in size from a palm-sized roller to a roller over 1 meter wide, depending on the machine used.
　　
The urethane rubber used as a material has abrasion resistance and chemical resistance, and is most resistant to abrasion compared to other synthetic rubbers. Therefore, it is suitable for parts used in areas subject to repeated friction.

Applications of Urethane Rollers

Urethane Rollers are used as transportation parts for precision equipment such as conveyors, printers and film packaging machines, and as wheels for industrial vehicles. Their high resistance to abrasion makes them suitable for parts of machinery that will be used for many years.

It is often used in areas where repeated friction occurs, making it ideal for use as conveyor guides for printers and other equipment and as guide rollers for film packaging machines. When used as a guide roller, it is constructed by bringing two rolls into contact and pushing paper or film between them.

In this case, the two rolls are always in contact with each other, and wear is likely to occur. Therefore, Urethane Rollers with excellent wear resistance are suitable. The same applies to conveyor belts, which are in constant contact with the conveyor belt section, so urethane rollers with high abrasion resistance are used.

Principle of Urethane Roller

Urethane Rollers are manufactured by press-fitting urethane rubber around a metal core. In this process, the surface of the urethane rubber is ground to allow fine adjustment of the urethane roller size. In some cases, grooves may be made on the surface of the Urethane Roller to prevent slipping.

The urethane rubber that forms Urethane Roller has high abrasion resistance, oil resistance, and chemical resistance. Therefore, it is also suitable as a component for packaging machines that use oil or chemicals.

On the other hand, urethane rubber has low resistance to water and moisture and is subject to hydrolysis, making it unsuitable for use in places where water is used or in humid environments. Normal urethane rubber is also susceptible to heat and may be thermally deformed when used in high-temperature locations.

The heat resistance limit temperature is said to be 100°C, and the heat resistance safety temperature is 80°C. It is said that there is no problem in using the product in an environment where the temperature is constantly 60°C, and reaches 80°C several times an hour. When used in areas that reach higher temperatures than that, heat-resistant urethane rubber should be used.

Other Information on Urethane Roller

1. Processing of Urethane Roller

Urethane Rollers are processed with various surface grooves depending on their intended use. Some alternative examples are listed below:

Threading Grooving
In threaded grooving, thread-like grooves are formed on the roller surface to increase the surface area of the roller. This process is applied to roll coaters used for chemical application.

Longitudinal Grooving
In the longitudinal grooving process, longitudinal grooves (grooves perpendicular to the roller axial direction) are formed on the roller surface to improve heat dissipation and the coefficient of friction on the roller surface. Urethane Rollers with longitudinal grooves are used for corrugated cardboard feeding rollers, film bag feed rollers, and squeezing rollers.

Horizontal Grooving
The horizontal groove process forms horizontal grooves (grooves along the roller axis) on the roller surface to soften the roller and increase the coefficient of friction, thereby preventing slippage and meandering of belts and other materials. It is used for film and cardboard feeding rollers.

Helical Grooving/Diamond Cut Grooving
Helical grooving, in which a series of diagonal grooves are processed in the width direction of a Urethane Roller, is used to control slipping and snaking of belts and other materials and to enhance heat dissipation of the roller. The same applies to diamond-cut grooving, in which multiple oblique grooves are formed on the surface of a Urethane Roller in the width direction.

Taper crown, radial crown, and reverse radial crown processing.
The tapered crown process, in which the center portion is thicker than the ends and the transition to the thicker portion is tapered, is provided to compensate for deflection of the roller body. Radial crowning, in which the center is thicker than the ends, is used to increase roller pressure.

On the other hand, the reverse radial crown process, in which the center is narrower than the ends, is suitable for use as a guide to prevent the material being conveyed from falling out.

Others
Crepe treatment on the roller surface increases the roughness of the roller surface and enhances the gripping and friction force. Low-friction treatment is a processing method to reduce the coefficient of friction on the rubber surface without damaging the characteristics of the rubber itself. It prevents dust and dirt from adhering to the roller surface and prevents films and other materials from wrapping around the roller surface. 

2. Urethane Roller Bearings

Urethane Roller Bearings are small urethane rollers with urethane rubber directly attached to the outer diameter of small diameter, deep groove ball bearings. They are used in conveyor systems and sorters, conveyor equipment in automobile and other production lines, various equipment in overhead conveyor lines in semiconductor manufacturing plants, multilevel parking lot equipment, banknote identification and conveyance mechanisms in various financial machines (ATMs), and various open/close doors such as elevator doors.

What Is Silica?

Silica is the generic name for silicon dioxide, an oxide of silicon.

Its chemical formula is SiO2, and its crystal structure is tetrahedral, consisting of silicon bonded to four oxygen atoms. The tetrahedral structure is combined to form a variety of structures, resulting in many types of silica, including crystalline and amorphous silica.

Silica is abundant in the earth’s crust and occurs naturally as silica crystals in the form of quartz (crystal), tridymite, and cristobalite. Silica is used as a raw material for silica gel, a desiccant for optical components.

Uses of Silica

Silica is a colorless, transparent solid with a very high melting point. It also has excellent chemical resistance and reacts only with some acids and alkalis.

Because of its heat resistance and chemical resistance, silica is used in chemistry laboratory equipment and spectroscopic analyzers. It is also used as a raw material for silica gel, a desiccant. Highly transparent ones are processed into optical components such as lenses and prisms.

It also plays an important role in the electronics and semiconductor industries. Silica has insulating properties and is indispensable in the manufacture of electronic components and semiconductor devices. In addition, it is widely used as a material for glass and optical fiber.

Quartz, one of the silica crystals, is known for its use in ornaments and as a quartz crystal unit.

Properties of Silica

Silica can be crystalline or amorphous, and the name silica is used especially when referring to them collectively. Crystalline silica is known as crystalline polymorphs such as quartz, cristobalite, and tridymite. Amorphous silica, on the other hand, is a generic term for materials containing silicon dioxide that do not have crystalline properties. Examples include silica aerogel and fumed silica.

The chemical formula of silica is SiO2, where one silicon atom is covalently bonded to four oxygen atoms. These form a SiO4 tetrahedral structure, with each oxygen atom belonging to two SiO4 tetrahedral structures. The crystalline polymorphism of crystalline silica, such as quartz, cristobalite, and tridymite, results from differences in the arrangement of these SiO4 tetrahedral structures.

Silica itself is not highly reactive with other substances, but it does react with some acids and alkalis. For example, when reacted with hydrofluoric acid, hexafluorosilicic acid is formed, and when reacted with sodium hydroxide, sodium silicate is formed.

Types of Silica

Silica is the general term for silicon dioxide, which comes in a variety of types, including:

1. Silica Particles

They exhibit different properties depending on their shape, such as spherical or scaly, particle size, and porosity. Colloidal silica is silica particles dispersed in a solvent such as water.

2. Fumed Silica

Fumed silica is a white powder with very low bulk density, called dry silica or highly dispersed silica.

3. Silica Aerogel

Silica aerogel is a porous material consisting of silica particles that form a three-dimensional network framework with a pore spacing of approximately 50nm.

4. Silica Glass

Silica glass is characterized by its low metallic impurities, high heat resistance, excellent light transmission over a wide range of wavelengths, and resistance to attack by acids and alkalis.

Other Information on Silica

Safety of Silica

Silica particles can adsorb impurities and are used as a filter aid in food production. An example is the filtration of beer and other alcoholic beverages and soft drinks.

Oral ingestion of silica has little serious effect on the human body, but inhalation of airborne silica particles through the nose or mouth can cause serious symptoms. In particular, inhalation of crystalline silica such as quartz has been reported to cause a type of pneumoconiosis called silicosis.

Symptoms of pneumoconiosis tend to be subjective at first, but over time symptoms such as cough, phlegm, shortness of breath, and difficulty breathing may occur. Actual cases of acute pneumoconiosis due to inhalation of silica particulates have been reported in factories that handle high-purity crystalline silica particulates. To prevent such accidents, handling should be done using protective equipment such as dust masks.

What Is a Shrink Label?

Shrink labels are resin labels that shrink when heated.

They are used for beverage and cosmetic container labels because they fit uneven or curved shapes.

Uses of Shrink Labels

Shrink labels are often used for PET bottle labels because they shrink when heated and conform to uneven surfaces. It is difficult to print pictures and text directly on the curved and uneven surfaces of PET bottles, so the most common method is to print on shrink labels and attached to PET bottles.

This is commercially very valuable because it allows for variation in the design of PET bottles by simply switching shrink labels.

Principle of Shrink Labels

Shrink labels are processed shrink films, which are processed into a cylindrical shape by pasting the edges of shrink films that have been processed into sheets together. In other words, it can be manufactured from the same material as shrink film. However, since shrink labels are used to decorate and protect tubular products such as PET bottles, they are made of a material that shrinks only horizontally, with almost no vertical shrinkage.

Typical materials used are PET (polyethylene terephthalate) and PS (polystyrene), which are the same materials used for PET bottles. A mixed of PET and PS (hybrid styrene) is sometimes used. PVC (polyvinyl chloride) is suitable when chemical resistance is required.

When used as a label for PET bottles, the prescribed printing is first applied to the shrink film, which is then processed into a cylindrical shrink label. Next, the shrink label is placed on the PET bottle, and the bottle is placed in a warm air tunnel to heat-shrink the shrink label so that it adheres to the uneven surface of the PET bottle.

The heating process may cause thermal deformation of the PET bottles and other packaged items. When working with shrink labels, it is necessary to check the temperature required for heat shrinking of the shrink film and the heat resistance temperature of the product to be packaged.

Other Information on Shrink Labels

1. Printing on Shrink Labels

When printing on shrink labels, the transparent shrink film that makes up the label will show through even when printed in color. This can result in unintended color tints or characters that are difficult to read.

As a countermeasure, there is a technique to make the contrast and text clearer by applying a white ink undercoat, and printing is performed in the following process:

1. Create the image data to be printed by dividing it into layers, and add a white-filled layer to the bottom layer. If you want to make a part of the illustration transparent, leave the part to be transparent without painting it white.
2. Place the shrink label on the printer and print only the base layer.
3. Re-insert the shrink label into the printer and print all layers except the base layer.

2. Heat Shrink Method for Shrink Labels

Heat-shrinking shrink labels requires heating with warm air or hot water. The most common means of applying heat is a warm-air tunnel, but other methods include hot baths and hair dryers.

Hot Bath
Water is heated in a water tank, and once the water reaches a predetermined temperature, shrink labels are immersed in the water to heat and shrink them. The advantage of this method is that the area immersed in the hot water can be heated evenly, but it cannot be used for items that should not be exposed to water because the shrink labels will get wet.

Dryer
Some products can be heat-shrunk with a hair dryer, usually a high-temperature dryer for shrink labels. The advantage is that it is easy to operate, but the disadvantage is that it is difficult to apply heat evenly.

3. Merits and Demerits of Shrink Labels

This section describes the advantages and disadvantages of shrink labels.

Advantages
Since shrink film is laminated together to form a cylindrical shape, the size can be set in millimeter increments, allowing for careful processing to suit the container. Printing is done after printing on the shrink film, so there is no uneven printing.

Disadvantages
PET and PS films, which are typical shrink label materials, have high shrink temperatures, and some products cannot be processed.

What Is a Shrink Tunnel?

A shrink tunnel is a device used for shrink wrapping, a process that involves heat-treating a clear film to snugly fit around a product.

Uses of Shrink Tunnels

Shrink tunnels are employed in various industries, including food packaging for beverages, seasonings, canned goods, and cup noodles, as well as packaging for books, CDs, and pharmaceutical products. These machines facilitate flow-oriented shrink-wrapping processes.

Principle of Shrink Tunnels

A shrink tunnel typically comprises a device for applying and welding shrink film and a tunnel for heat treatment. Steam-type tunnels may include a boiler. Shrink film, supplied in rolls, is cut according to a product’s packaging needs, guided by a black register mark printed on the film.

Types of Shrink Tunnels

Shrink tunnels vary by heating method and include specialized models for large items, such as pallets.

1. Hot-Air Type

Uses hot air to shrink the film, suitable for small spaces but may result in uneven finishes.

2. Steam Type

Utilizes steam for even heating, requiring a boiler and larger installation space. Offers a high-quality finish but necessitates a steam removal process.

3. Hot Whirlwind Type (Tornado Type)

A recent innovation, this combines hot air with an air current to evenly distribute heat, achieving finishes similar to steam types.

Other Information on Shrink Tunnels

Purposes and Advantages

Shrinkwrapping serves various purposes:

• Protection of Goods: Prevents the entry of foreign matter, insects, and dust, enhancing product safety during transport.
• Improved Identification: Allows for larger product information display compared to traditional labels, aiding in product differentiation.
• Support for Multiple Product Variety Production: Facilitates the use of the same packaging for different products, reducing material waste and costs.
• Reduction of Packaging Costs: Enables cost-effective bundling of products and eliminates the need for additional packaging materials.
• Improved Transportability: Enhances product stability and damage resistance during shipping, particularly for mail-order items.
• Set Sales: Allows for the bundling of diverse products for sale as a set, applicable to a wide range of items.

What Is a Motor Shaft?

A motor shaft is a linear servo motor that moves in a linear motion by means of electricity.

The first means of obtaining linear motion by electricity is a ball screw. Motor shafts have advantages over ball screws, such as high positional accuracy, high speed operation, and high quietness, as well as the ability to control multiple actuators on a single shaft, called multi-drive.

Another major difference between a motor shaft and a flat type linear motor that performs the same linear motion as a shaft motor is the coreless structure. Shaft motors do not suffer from cogging, which is a drawback of linear motors that use an iron core called a core.

Uses of Motor Shafts

Motor shafts are used in mechanisms to control linear motion. Motor shafts can be roughly divided into two categories: processing and manufacturing equipment as well as measuring and inspection equipment.

1. Processing and Manufacturing Equipment

Examples of applications in processing and manufacturing equipment include metal processing equipment, electrical discharge machining tools, laser cutting machines, precision XY stages, steppers, and coater/developers.

2. Measurement and Inspection Equipment

Examples of measuring and inspection equipment include inspection equipment for liquid crystal applications and semiconductor applications, microscopes for living organisms, spectroscopic and optical measuring instruments, as well as inspection equipment for printed circuit boards, surface inspection equipment, three-dimensional measuring equipment, probers, and scanners.

In addition to the above, motor shafts are also used when multiple mover units are required on the same shaft, when two shafts are used to move large, heavy objects, or when high environmental performance is required.

Principle of Motor Shafts

A motor shaft consists of a shaft section and a coil section. The shaft section consists of several cylindrical magnets arranged so that their N and S poles face each other and are housed in a stainless steel cylinder.

The feature of the shaft is that the magnets are arranged so that they are facing each other with the same poles, thus generating a strong magnetic force. The coil part is the component that functions as a mover, and the coil is wound to cover the shaft part. When a magnetic field is generated by passing an electric current through the coil, a thrust force is generated according to Fleming’s left-hand rule. The operating principle of the motor shaft is to control the position and moving speed of the mover by controlling the electric current.

Characteristics of Motor Shafts

Motor shafts have four main features:

1. Simple Structure

The structure of a motor shaft consists only of a shaft and a coil. The shaft part is a permanent magnet and the coil part is a wound coil. Therefore, there are no complicated mechanical parts. Since the parts do not come into contact with each other, there is no friction. Another advantage of  motor shafts is that they are easy to maintain and do not generate noise or wear powder.

2. High Positional Accuracy

Ball screws are contact mechanisms, and errors due to gaps between parts, known as backlash, are inevitable. The coreless structure of a motor shaft, however, has the advantage of eliminating cogging, or uneven motion, because the coil and shaft do not have an adsorption force.

3. Compatible With Various Drive Systems

Motor shafts can be used in parallel, tandem, and multi-shaft drive systems in addition to single-shaft drive, which is a linear motion of one shaft. Parallel drive is a method in which two parallel  motor shafts are driven simultaneously, and is used to drive large and heavy objects.

Tandem drive is a method in which two motors are driven side by side on the same axis, and a large thrust force can be obtained. Multi-drive is a drive method in which two mover units are driven separately on the same axis.

4. Easy Installation

Motor shafts can be installed by centering them within the clearance between the shaft and mover. Poor centering accuracy for ball screws can greatly affect the life of the equipment. In addition, flat-type linear motors with cores require that the mounting gap between the mover and stator be uniform over the entire length of the motor.

What Is a Signal Generator?

A signal generator is a device that generates various signals in a test manner, including function generators.

Signal generators are designed based on digital technology to generate a variety of waveforms.

A signal generator is not necessarily limited to ideal waveforms; some types are capable of generating signals with distorted waveforms or with noise added to the waveform.

A signal generator is available in stand-alone models that can be operated by the device itself or by a PC or smartphone.

Uses of Signal Generators

Signal generators are used for circuit design verification, analysis, and various experiments.

When used as test signals for products, it is necessary to always have standard signal generators available. It is also necessary to  calibrate and adjust the output of the signal generators periodically by comparing it to the standard signal generators.

Signal generators generally produce dozens of waveforms, including square waves, rectangular waves, triangular waves, sawtooth waves, and sine waves.

In addition to ideal waveforms, distortions, and noise can be added to create conditions that are even closer to real-world waveforms, contributing to highly accurate design.

Principle of Signal Generators

As mentioned above, signal generators are used to verify a designed circuit or system by simulating a virtual input signal, which is then input into the equipment to detect any defects. Based on the results, the circuit is reviewed again, and the design of the equipment is completed through a cycle of trial and error.

Generally, equipment is designed in units of circuit blocks. When conducting verification after the design of a single circuit block is completed, input signals are required, but at the initial stage of design, there is no circuit to connect to. Therefore, in such cases, verification is performed by generating the necessary signals from signal generators and inputting them into the completed circuit design.

Furthermore, when the design of each circuit block is completed, and the product is assembled, the signals generated by the signal generators are input and tested in the same way. In this process, we verify not only the ideal input signal but also the signal distortion and noise that may occur under the actual user’s operating environment.

As described above, signal generators are used in a wide range of applications, from the early design stages to near completion of the design, and even during production testing.

Signal Generators Type

There are various types of signal generators, but the following two are typical examples.

1. Function Generator
One of the most versatile signal generators is the function generator. Among signal generators, those that can generate arbitrary waveforms with a single signal generator have been developed with the development of digital technology.

Since function generators can simulate any signal, it is possible to debug and adjust the device under test by simulating it with pseudo-signals before field testing. Signal generators for generating radio frequency (RF) digitally modulated waveforms are also widely used for characterizing RF electronic components, along with spectrum analyzers and power meters.

2. Signal Generators for RF Digital Modulation Waveform Generation
Signal generators are also available for generating radio frequency (RF) digitally modulated waveforms for complex modulation waveforms such as 5G and Wi-Fi signals. It is called vector standard signal generators (digital standard signal generator), and this instrument has a built-in I/Q modulator.

Therefore, up-conversion to I/Q modulation schemes such as 1024QAM and QPSK is possible. Combined with an IQ baseband generator, this signal generator can emulate and output most signals within the information bandwidth supported by the communication system.

Other Information on Signal Generators

1. How to Use Signal Generators
Signal generators, along with voltmeters, ammeters, signal analyzers, and power meters, are central to the measurement of electronic circuits. Nowadays, instrument manufacturers provide measurement environments that can generate arbitrary signals for complex modulated digital systems by using them with dedicated software applications on PCs.

In addition to complex, state-of-the-art digital systems, kits for measuring instruments that can easily generate signals are also available for beginners in electronic and electrical circuits. Since these kits do not deal with the latest complex signals, they can be purchased at very reasonable prices through online retailers.

This signal generator kit can output basic sine, triangular, and pulse waveform signals, along with their operating frequencies, at any desired level, making it a very useful device for experimental verification of small electronic circuits, even for beginners in electronic and electrical circuits. 

2. Signal Waveform Capture to Circuit Simulators
Recently, some vendors of measuring instruments have built an EDA environment that allows circuit simulation of actual signal waveforms, which is very useful for designers of RF, analog, and digital circuits.

For example, in the past, the effect of RF nonlinear behavior on the distortion of digitally modulated signal waveforms was usually evaluated by inputting the actual modulated waveforms or verified by IMD (intermodulation distortion) behavior and fed back to circuit design.

Now, however, it is possible to incorporate the actual modulation signal waveform itself into RF analog circuits and front-end modules on a circuit simulator and to study the characteristics of communication systems, such as EVM (modulation accuracy), from a circuit design perspective on a simulator.

What Is a Thermo Controller?

A thermo controller is a device or component that sends an ON/OFF signal to an electric heater or cooler unit to maintain the object’s temperature at a constant level.

It is equipped with a control board, power supply, sensor connection, heater connection, and cooler connection.

From inexpensive devices that only turn ON/OFF near the set temperature, to PID control that detects subtle temperature changes and emits fewer ON control signals and more OFF signals when near the set temperature, and more ON signals and fewer OFF signals when away from the set temperature, maintaining the temperature near the set temperature. There are even expensive ones with built-in programs.

Uses of Thermo Controllers

Inexpensive thermo controllers are often used when the variable temperature range is narrow or the control device is small, such as when controlling the temperature of a small water tank.

Expensive thermo controllers are often used when the variable temperature range is wide, the control equipment is extremely large, or highly accurate temperature maintenance is required. They are incorporated into equipment used for research, experimentation, or testing.

These controllers are essential for environmental control kits available at home improvement stores, analyzers, and incubators used in biology and medicine. They are used to control equipment for petrochemical and food-related facilities.

Principles of Thermo Controllers

The principle and features of the thermocontroller are described below.

The ON/OFF control type thermo-controller converts the signal from the temperature sensor into a temperature and issues an ON signal when it is short of the set value and an OFF signal when it exceeds the set value, thereby maintaining the temperature of the object at a constant level by moving the heater or cooler.

There are two types of thermocontrollers: a digital type that uses a control program and an analog type that moves switches in response to temperature changes.

Expensive, high-precision thermocontrollers are mostly of the PID control type.

PID control (Proportional-Integral-Differential Controller) combines proportional action, which produces an output proportional to the difference between the current temperature and the set temperature, with integral action, which produces an output proportional to the integral value of the temperature difference.

Integral action, which produces an output proportional to the integral of the temperature difference, plus a derivative action, which produces an output proportional to the derivative of the temperature difference, minus a derivative action, which produces an output proportional to the derivative of the temperature difference, pulse width modulation of the output voltage waveform is performed to adjust the heater or cooler output.

Specifically, it is a control that approaches the set temperature as quickly as possible (proportional action), corrects excessive heating and cooling near the set temperature (integral action), and suppresses temperature increase/decrease near the set temperature (derivative action). Differential action can be compared to stepping on the brake.

What Is a Thermal Camera?

A Thermal Camera is a camera that detects the surface temperature of an object and displays it as an image. The image captured by a thermal camera is called thermography.

Thermal camera images are different from images taken with the human eye or with a normal camera in that the areas of the image with the highest temperatures are displayed in red and the areas with the lowest temperatures are displayed in blue. From this image, it is possible to determine the surface temperature, which cannot be determined just by looking at the image.

Thermal cameras can also be used in cases where it is difficult to touch the object being measured, since they can detect temperatures without making contact with the object.

Uses of Thermal Cameras

Thermal cameras are used in a variety of situations, such as:

• Measurement of human body temperature
• Machine monitoring in factories and electrical facilities

Thermal cameras are widely used to measure human body temperatures because they are non-contact and can quickly and easily determine a person’s body temperature. Also, since measurement is non-contact, temperature changes during operation of machinery in factories and electrical facilities can be measured without danger to the person being measured and without affecting the object being measured by temperature measurement.

Furthermore, thermal cameras are also used for purposes other than temperature measurement. Using their ability to sense temperature, thermal cameras can detect the presence of objects with different temperatures in an environment where the temperature is somewhat constant, such as at sea, even if the objects are so present that they cannot be seen visually. Thermal cameras can detect objects even when visibility is poor at night or in the rain because they detect temperature.

Thermal Camera Principle

Thermal cameras detect the infrared radiation emitted by an object, and measure and display the temperature of the object by judging the intensity of the infrared radiation. All objects above absolute zero emit infrared radiation, and since this energy is known to be proportional to the magnitude of the absolute temperature, it is possible to measure temperature from infrared radiation.

Thermal cameras receive the infrared light emitted from the object with an internal detector, scan it, and then process the A/D-converted and temperature-converted data into an image that is displayed as a thermographic image in red, blue, or other colors that can be easily seen by the human eye.

Since human visibility depends on the state of visible light, visibility is affected by weather conditions and time of day, but thermal camera detects infrared light emitted by the object and can display thermographic images without problems even if the state of visible light in the environment, for example, visibility is poor for humans.

Thermocouples and thermometers commonly used in the home detect temperature by contact using heat conduction from the object.

Thermal cameras, on the other hand, utilize thermal radiation from the object and can measure temperatures in a non-contact manner without directly touching the object, which is the main difference between thermal cameras and thermography.

Types of Thermal Cameras

Thermal cameras can be classified into handy type and stationary type, and on-press type and cloud type based on the data storage method.

1. Handheld and Stationary Types

Thermal cameras used to measure human body temperature can be divided into two main types: handheld and stationary.

Handheld thermal cameras are easy to carry and are used in stores, reception areas, commercial facilities, etc., to reliably measure the body temperature of a small number of people.

Stationary thermal cameras are suitable for use in places where a large number of people need to be measured at the same time or where constant temperature measurement is required. They are also available in camera and dome types, which are suitable for measuring a wide range of temperatures. 

2. On-Premises Type and Cloud Computing Type

Thermal cameras can be divided into on-premise type and cloud computing type, depending on where the measurement data is stored.

On-premise type systems use their own servers. This has the advantages of being able to use existing company facilities and having a high degree of freedom in linking with the company’s own systems. On the other hand, the disadvantage is that operation and maintenance costs are high.

Cloud computing is a system that uses cloud servers. Cloud computing has the advantages of easy data sharing among multiple locations and low operation and maintenance costs. On the other hand, some services provide a complete set of thermal cameras, applications, and a secure connection environment, although this may cause security issues in some environments.

Other Information on Thermal Cameras

1. Measuring Body Temperature With a Thermal Camera

Thermal cameras differ from regular thermometers in that they measure the surface temperature of the human skin. The surface temperature is greatly affected by the season and the external environment. Therefore, if the temperature is measured immediately after entering a room from outside in winter, the surface temperature will be detected as lower, and if the temperature is measured immediately after exercising in summer, the surface temperature will be detected as higher.

Therefore, it is important to take into account the differences in the environment before and after the measurement in order to obtain a highly accurate body temperature measurement using a thermal camera.

One method for highly accurate measurement is to use a black body. This black body is a device used to calibrate body temperature. The temperature of the black body and the intensity of the infrared radiation emitted by the black body are used as a reference for temperature compensation in the thermal camera. This allows us to minimize the error of the thermal camera itself. 

2. Thermal Camera in the Fight Against Coronavirus Infections

Daily temperature checks are extremely important to prevent infectious diseases. Thermal cameras are already being used in a variety of locations due to the following advantages:

• Measure a wide range of temperature changes in real time without touching the object to be measured.
• Capture far-infrared radiation emitted by objects, allowing detection even in darkness
• Capable of quickly capturing and detecting moving objects
• Detects even distant objects
• Far-infrared radiation is transparent, so it can detect objects even if they are blocking your view.

When considering the use of a thermal camera, there are different factors to consider depending on where the camera will be used and what is to be inspected. For example, in areas where a large number of people come and go, an AI-equipped thermal camera will be effective.

If abnormal temperatures are detected, an alert will be issued. These cameras are used at airports, hospitals, large commercial facilities, etc., where large numbers of people come and go and it is difficult to inspect each person in a timely manner.

What Is a Solid-State Relay?

Solid State Relays are contactless relays that use semiconductors to transmit input signals to output circuits.

Generally, they are suitable for situations where relays are frequently opened and closed and high-speed response is required since high response and long life can be established.

Applications of Solid State Relays

Solid State Relays are used in situations where the on/off frequency is high, such as in temperature control systems, where their high responsiveness and long life can be maximized.

In addition, unlike general contact-type relays that use magnetic force, there is no mechanical sliding contact. Since no noise is generated by the opening and closing of the contacts, they are often incorporated into products that are vulnerable to noise.

On the other hand, the transmission of signals uses light emission phenomena via semiconductors and diodes. Therefore, there is no small amount of temperature rise effect and the output stage is a semiconductor device. Care must be taken because some parts are not suitable for products with high voltage and high current.

Principle of Solid State Relay

Figure 1. The principle of semiconductor relay

As the relay is said to be contactless, the circuit on the input side is physically isolated from the circuit on the output side, and the signal is transmitted through an opto-isolated device such as a photocoupler.

When an electric current is applied to a light-emitting diode on the input side, the diode emits light, and a circuit on the output side receives the light, and the output circuit operates when the light is detected. Depending on the supplier of Solid State Relays, photodiode arrays, photocouplers, and phototriacs are used for the light-receiving circuit, and variations such as MOSFETs and triacs exist for the output section.

The use of light for signal transmission provides a very fast response. Also, since they do not have mechanical contacts, the contact parts do not wear out, and they generally have a longer service life than contact-type relays.

Other features include the fact that the input and output are completely insulated by an insulating element, so noise generated on the input side is less likely to be transmitted to the output side.

How to Select a Solid-State Relay

First, it is necessary to consider how much responsiveness is required in the circuit where the relay is needed and how often the signal is transmitted. If you do not need such high responsiveness and only low-frequency signal transmission, general contact-type relays are often smaller and less expensive.

If a Solid State Relay is required, also check the maximum current value of its input signal. Since Solid State Relays are output circuits using semiconductors, excessive current flow will damage the semiconductors themselves, rendering them unusable for further use.

Other Information on Solid State Relays

1. Comparison of Solid State Relay and Mechanical Relay

Figure 2. Semiconductor relay and mechanical relay

The difference between a Solid State Relay and a Mechanical Relay is whether they are contactless or contactless types. Semiconductor Relays, also called Solid State Relays, are contactless relays, while Mechanical Relays are contact relays.

Solid State Relays with no contacts are switched on and off by signal transmission only, with no mechanical closing or opening in the electronic circuit. A mechanical relay with contacts has movable parts built into the circuit and uses a coil to generate an electromagnetic force that causes the contacts to make contact and switch ON/OFF.

Solid State Relays and Mechanical Relays each have the following features, which can be used according to your needs.

• Features of Solid State Relays
  • Compact and lightweight
  • Long life
  • Low noise level
  • High-speed operation
  • High resistance to vibration
  • Leakage current
  • Low resistance to heat.
  • ON resistance
• Features of Mechanical Relays
  • High insulation and high voltage resistance
  • No leakage current
  • Almost no ON resistance
  • No operation noise.
  • Wear of contacts and breakdown of movable terminals
  • Influence of external magnetic field
  • Chattering

Solid State Relays have the advantage of being compact and capable of opening and closing at high speeds, and they do not suffer from contact wear and failure as mechanical relays do. On the other hand, mechanical relays have almost no ON resistance, and their strength is that they can be easily used in circuits with high voltage and high power.

2. Solid State Relays for Automotive Applications

Automobiles are equipped with many relays as parts that control the operation of lamps, windshield wipers, audio equipment, motors, blinkers, and so on. In general, mechanical relays have been used for automotive relays.

However, mechanical relays have the disadvantages of limited contact life and large installation space. In recent years, the number of electrically driven in-vehicle devices has been increasing due to the need for low fuel consumption and low power consumption and the multifunctional nature of advanced technology, which has created a need for smaller and lighter relays.

Figure 3. Example of automotive semiconductor relay specifications

Solid State Relays have been developed for automotive applications to overcome the shortcomings of mechanical relays and are gradually replacing them. Figure 3 shows an example of Solid State Relay specifications for automotive applications.

The use of Solid State Relays has made it possible to reduce size and weight, which not only secures space in the vehicle but also contributes to improved fuel efficiency. In addition, the use of high current, which has been a bottleneck, can now be handled thanks to low ON-resistance achieved through advances in semiconductor technology.

What Is an Autocollimator?

An autocollimator is an optical instrument that uses the linearity of light to measure minute angular displacements of an object to be measured.

It can measure angles without contact, and is usually used to adjust the position of parts or measure distortion in optical or mechanical systems.

Uses of Autocollimators

Autocollimators are used to inspect and adjust parallelism, straightness, optical axis, alignment, as well as precise angular measurement.

1. Straightness Measurement of Machine Tool Beds and Robot Processing Equipment

The straightness is converted from the amount of movement of the crosshair image by the plane mirror by sliding the stand with the plane mirror fixed along the guide surface.

2. Parallelism Measurement of Edge Surfaces Such as Optical Windows and Wedge Surfaces

By transmitting a single laser beam, parallelism measurement between two coaxial surfaces can be performed. For glass plates, etc., parallelism can be measured by measuring the angular difference of reflected light from the front and back surfaces.

3. Squareness Measurement

Optical square, a pentagonal prism, is used to bend the light.

4. Measurement of Rotational Angle of a Turntable

Using a multi-faceted mirror, the division accuracy of a rotary disc or indexing disc is measured.

5. Measurement of Deflection of an Elastic Piece

Fixing a reflector to an elastic piece and observing it with an autocollimator makes it possible to measure minute changes.

6. Optical Axis Adjustment

When the optical axis is aligned, such as in an astronomical telescope, the center mark of the primary mirror can be seen in multiple layers in the autocollimator’s field of view.

7. Inspection of Optical Products

The autocollimator measures the warpage and waviness of disks and wafers, and the accuracy of polygon mirrors.

Principle of Autocollimators

Autocollimator measurements are based on the principle of straightness of laser light and focusing of lenses. First, a semiconductor laser is mainly used as the light source, and the laser is converted to a collimated beam by a primary lens. This collimated light is passed through a secondary lens to form an image at the focal point.

In this case, the reflected light is spectrally split by a half-mirror in the optical path and reaches a light-receiving element such as a CCD to form an image. If the object is installed without any tilt to the irradiated laser beam, the image formed by the reflected light is exactly the same as that of the incident light. On the other hand, if the object is tilted, the image is formed with a deviation, and the angle of deviation can be determined from the degree of deviation.

Other Information on Autocollimators

1. Mirror Installation

Many mirrors that are not directly related to the measurement principle are incorporated inside the autocollimator. If all of the autocollimator’s optics are arranged in series, the size of the device is required for the optical path.

In most autocollimators, multiple reflecting mirrors are installed in order to reduce the size of the device.

2. Geometric Tolerances That Can Be Measured With Autocollimators

Autocollimators can be used to determine geometric tolerances that can be defined by straight lines or planes. Autocollimator measures the tilt of a mirror by utilizing the reflected light from the mirror, which is installed at a distance from the light source, to be displaced from the optical axis.

The angle of the mirror is replaced by the displacement and calculated, enabling measurement of the unevenness at each measurement point. By setting the starting position as zero and plotting the displacement for each measurement point, straightness can be obtained.

If the autocollimator is used to repeat the straightness determination on another line, the plotted points can be used to measure flatness because a plane can be drawn from the line. By devising how to place the autocollimator and how to hold the mirror, the measurement results can be developed into inclination and squareness as well. However, it is difficult to measure roundness and cylindricity, which are defined using curves or curved surfaces.

3. Disadvantages of Autocollimator

Autocollimator has a problem that if the light source is not at the focal point of the lens, it cannot form an image correctly, resulting in measurement error and out-of-focus of the observed image. This light source position error requires a strict accuracy of less than 0.1% of the focal length of the collimator lens.

Because this position adjustment is so severe, autocollimators are available in a variety of methods, including those that use an aperture to allow position adjustment by spot diameter and those that use a knife edge.