月: 2023年1月

What Is a Vernier Caliper?

Vernier calipers are field-use measuring instruments that make it easy to measure the dimensions of objects.

The outer caliper jaws are used to insert the object to be measured into the calipers and read the dimensions of the inserted part. The inner jaw part can be used to measure the inside dimensions of a part or hole, and the depth bar can be used to measure the depth.

Vernier calipers have a main scale and a sub-scale (vernier scale), from which dimensions are read visually. In recent years, digital calipers, which display dimensions digitally, have become the mainstream. This is because the vernier scale can be read differently by different people, and visual readings can take some time.

Uses of Vernier Calipers

Vernier calipers are used to measure the dimensions of parts. In general, calipers with vernier scales can measure in increments of 0.05 mm, while digital calipers and dial calipers can measure in increments of 0.01 mm. Vernier calipers are the first choice for measuring dimensions in the field of parts manufacturing and assembly due to their simplicity.

It can measure the thickness, external and internal dimensions, and depth of a part, but the object to be measured must have a certain degree of hardness. For example, when measuring a roller or sheet of rubber material, if the rubber is soft when it is clamped by Vernier calipers, it will be deformed and the correct dimensions cannot be measured.

Another situation that requires caution is when measuring the wall thickness of a hollow pipe. The inside of the pipe is thicker than the actual wall thickness due to its curved surface, and the tip of the jaw is thinner to account for this.

Principle of Vernier Calipers

Vernier calipers are characterized by their ability to measure the dimensions of any part easily. Vernier calipers are often used because of the ease of reading dimensions on the Vernier scale. The main scale is usually engraved at 1 mm intervals, but vernier scales are available with 20 equal divisions of 19 mm or 20 equal divisions of 39 mm. In this case, the minimum reading on the vernier scale is 1mm divided by 20, which is the scale width of the main scale.

On the other hand, digital Vernier calipers are represented by a capacitance type and display numerical values instantly up to the 100-minute mark. It is important to note that although dimensions are displayed instantly to the hundredths, their measurement accuracy (instrumental error) is usually ±0.02 mm or better.

When measuring parts that have fit tolerances on either Vernier caliper, a micrometer or similar instrument is often used because the accuracy of the measurement cannot be met.

Structure of Vernier Calipers

Vernier calipers consist of a mainframe with a reference plane containing the main scale and a sliding jaw that clamps the object to be measured. Basically, the jaws are perpendicular to the reference plane. However, if the object to be measured is strongly clamped, the jaws may tilt slightly, which can be a cause of error. In general, Vernier calipers are not equipped with a device to apply a constant pressure to the object to be measured, so care must be taken when measuring.

One of the guidelines for designing instruments for dimensional measurement is Abbe’s principle. This states that in order to achieve high accuracy in measurement, the reference and the object to be measured should be placed on the same axis.

Vernier calipers violate this principle because they cannot place the measuring object on the same axis as the reference plane (the plane containing the main scale). However, by understanding the characteristics of Vernier calipers and using them, you can easily and accurately measure dimensions.

Types of Vernier Calipers

Even standard Vernier calipers can measure outer and inner dimensions, as well as steps and depths, but there are also calipers that are tailored to the condition of the object to be measured.

1. Point

The tip of the caliper jaw is thin and pointed, enabling measurements in tight spaces. 

2. Offset

The tips of the jaws are at different heights, enabling measurement of dimensions at different levels that are not on the same straight line.

3. Depth Gauge

The main scale part is enlarged to measure the depth of a large diameter hole. 

4. Blade

Capable of measuring the diameter of narrow grooves into which ordinary jaws cannot penetrate.

5. Type C

This model has only an inner jaw. The jaw is longer than usual and can measure the outer dimension at the back.

6. Type CN

Model CN has a short outer jaw. Vernier calipers have a fixed size that can be measured, so it is necessary to select a caliper size according to the size of the object to be measured.

What Is a Pipe Heater?

A pipe heater is a device in which a resistance heating element is placed in a metal sheath (pipe) and energized to generate heat in the pipe.

By inserting a pipe heater into a liquid, the liquid can be easily heated even if there is no existing heating device attached to it.

They come in various shapes, including U-shaped, round, and spiral shapes, and efficiently heat liquids by increasing the surface in contact with the liquid.

There are many types of sizes, shapes, and heating values, and the appropriate one should be selected according to the application.

Uses of Pipe Heaters

Pipe heaters are used to heat water or other liquids quickly.

For example, they can easily heat water in a bathtub without a water heater, or heat liquid samples for experiments.

Pipe heaters can also be used to heat water for drinking or for other purposes during outdoor work in winter.

Since heating can be done simply by throwing the pipe heaters into liquid, it can be used in various situations, including testing, experiments, and temporary construction sites.

Principle of Pipe Heaters

Most pipe heaters are U-shaped, round, or spiral-shaped, increasing the contact surface with the liquid to improve the efficiency of heat conduction.

Most pipe heaters use copper as the sheath material, which has high thermal conductivity and can efficiently heat liquids.

The surface of the sheath is often nickel-plated to prevent rust.

The heaters are small, ranging in width from a few centimeters to 10cm, and can be placed in containers of various sizes.

The heating power ranges from several hundred watts to several kilowatts, depending on the volume and type of liquid to be heated.

There are also types that can be secured by drilling holes in the sides or bottom of the container and using packing or nuts.

Note that one precaution to be taken when using these heaters is that they should not burn when they are not in contact with liquid.

Care should be taken because heat may not be transferred to the surrounding area and the heater may heat up abnormally, which could lead to malfunction or fire.

What Is a Pipe Wrench?

A pipe wrench is a tool for turning or gripping a pipe or cylindrical object.

It typically has an adjustable serrated jaw that can tighten around a pipe and a long handle that acts as leverage for turning the pipe. Pipe wrenches are often used in plumbing and mechanical work to loosen and tighten pipe fittings and other connections.

They come in a variety of sizes and styles to suit different pipe diameters and applications.

Uses of Pipe Wrenches

Pipe wrenches are used in plumbing and mechanical work to grip and turn pipes and fittings. Adjustable serrated jaws provide a firm grip on pipes without slipping.

It can also apply a large amount of force to turn a pipe without deforming it. Besides, it is useful for removing rusted or stubborn fittings that cannot be turned by hand.

Principle of Pipe Wrenches

Pipe wrenches have jaws on the top, and bottom that can be adjusted perpendicular to the handle. They adjust to the size of the pipe and grip the pipe. Generally, the jaws are serrated with fine grooves to make it easier to grip the pipe and to prevent deformation.

The principle of a pipe wrench is the same as the principle of leverage. By using this principle, pipes and fittings can be easily tightened or loosened with little force. The long handle makes it possible to work efficiently.

Types of Pipe Wrenches

There are many types of pipe wrenches, each with its own specific shape and intended use. Common pipe wrench types include the following:

1. Straight Type Wrench

It has adjustable jaws that can be tightened or loosened by turning a round nut on the handle. The jaws are perpendicular to the handle and are designed to accommodate pipes of various diameters.

2. Corner Pipe Wrench

Also called angled pipe wrench or multi-angle pipe wrench, this type of wrench has jaws positioned at 90 degrees to the handle. It allows you to reach tight places and obstacles that straight wrenches cannot reach.

3. Chain Wrench

A chain is wound around a pipe or fitting, with a handle on one end and a hook on the other. When the handle is turned, the chain tightens around the pipe, providing a strong grip to turn the pipe.

4. Belt Wrench

Uses a flexible belt, rather than serrated jaws, to grip pipes and fittings. Designed for use on delicate and vulnerable pipes, such as plastic or chrome-plated brass.

How to Choose a Pipe Wrench

There are several important factors to consider when choosing a pipe wrench.

1. Size

Pipe wrenches come in a variety of sizes, but are generally 300 mm or 400 mm in length; 300 mm wrenches are used for pipes with outside diameters from 10 mm to 32 mm, and 400 mm wrenches are used for pipes with diameters from 26 mm to 52 mm. Select the Pipe Wrench appropriate for the size of the pipe or fitting to be worked on.

2. Type

There are various types of pipe wrenches, each of which has its own purpose. Think about the specific type of work to be performed and select the appropriate type of wrench for that work. 

3. Material

The wrench should have a strong jaw for a firm grip without slipping and be made of high-quality materials, such as iron or aluminum.

4. Comfort of Use

The design of the handle, grip, and weight should be easy to use. An easy-to-use wrench is easier to use for extended periods of time and helps reduce hand and wrist fatigue.

It is important to choose a pipe wrench that is suitable for the task, of good quality, and comfortable to use. Choosing the right wrench will help you to perform your work accurately and efficiently.

What Is a Thermostatic Bimetal?

A thermostatic bimetal is a laminate of two metals with different thermal expansion coefficients. When a temperature change is applied to the thermostatic bimetal, the metal with the lower thermal expansion coefficient tries to maintain its original shape, while the metal with the higher thermal expansion coefficient tries to expand or contract. Therefore, as the temperature rises, the metal bends toward the side of the metal with the lower thermal expansion coefficient, and as the temperature decreases, the direction of bending is reversed.

Thermostatic bimetals are made by physically and electrically utilizing this curvature caused by temperature change.

Uses of Thermostatic Bimetals

The main application of thermostatic bimetals are as temperature sensors such as thermometers and thermostats that utilize the curvature of metals.

In particular, its use as a thermocouple using the Seebeck effect is well known. The use of thermostatic bimetals as thermocouples can be adapted to different applications because the range of temperatures that can be measured can be varied depending on the type of metal to which they are attached.

Its use as a thermostat is to open and close electrical contacts using the curvature of the metal. Since no power is required to turn the sensor on and off, it has a variety of uses, including temperature control functions for air conditioning and heating.

Principle of Thermostatic Bimetals

Thermostatic bimetals are made by laminating two types of metals with different thermal expansion ratios. As the temperature rises, the metal expands according to its thermal expansion coefficient, but because metals with different thermal expansion coefficients are bonded together, free expansion is restricted and the metal becomes curved. By physically and electrically utilizing this curvature of the metal, it can be used as a sensor for temperature change.

Thermostatic bimetals tip joined together can be used as a thermometer by converting the voltage generated by the Seebeck effect due to the change in temperature. Since the direction of curvature can be changed by temperature rise and fall, it can be used to open and close contacts to provide a temperature control function as well as a protection circuit for equipment by opening the contacts (turning off the power) when heated. In addition to the use of ambient temperature, the contact can also be used as a protective function for circuits due to overcurrent by opening and closing contacts due to the temperature rise caused by the energization of circuits.

What Is a Vacuum Pad?

A vacuum pad is a component that is part of a conveyor system and directly touches the workpiece (product to be conveyed) for suction.

Vacuum ejectors are used to create a near-vacuum pressure inside the pad, and the pad is designed to use that force to suction the workpiece. It is also called a vacuum pad or suction pad.

A vacuum pad directly contact workpieces of various materials and shapes, so there is a wide variety of vacuum pad in various sizes, shapes, and materials according to the type of workpiece, conveyance environment, required holding power and durability. A vacuum pad is a very important part because selecting the right vacuum pad can improve production efficiency and reduce costs in some cases.

Uses of Vacuum Pads

Vacuum pads are used in conveying systems in manufacturing and logistics.

Workpieces conveyed with vacuum pads include pressed steel sheets for automobile bodies, hot stamping forged steel sheets, sheet glass, plastics, semiconductors, corrugated boxes, blister packs, thin films, food products, and wood, and are used in a wide range of industrial fields.

Vacuum pads are required to have diverse characteristics depending on the environment in which they are used, such as high coercive force for heavy workpieces such as steel, heat resistance for hot stamping hot forging and glass manufacturing sites, and ESD resistance for semiconductor manufacturing sites.

Features of Vacuum Pads

When the vacuum ejector creates a near-vacuum condition inside the vacuum pads, the pressure between the pad and the workpiece becomes lower than the ambient atmospheric pressure. This generates a suction force proportional to the differential pressure and the suction area.

There are three types of vacuum pads shapes: flat, oval, and bellows.

The flat type is used for workpieces with flat surfaces. Flat pads are characterized by their high holding power, but there are also pads with grooves on the suction surface to further increase holding power. Oval-shaped pads can be used for long and thin workpieces such as substrates, or workpieces with a small suction area such as pipes, etc., and are characterized by the ability to suction workpieces in a short time. The bellows type is used for workpieces of varying height and is characterized by its ability to compensate for the height of the workpiece.

Vacuum pads materials include nitrile rubber, polyurethane rubber, silicon rubber, and fluorine rubber.

Nitrile rubber has high oil resistance, making it suitable for transporting thin steel plates for car bodies covered with oil film. Conductive nitrile rubber and conductive silicon rubber are suitable for semiconductor manufacturing plants and other sites where static electricity is not desired, fluorine rubber has high chemical resistance for transporting chemicals, and strong polyurethane rubber is suitable for heavy workpieces.

What Is a Battery Tester?

A battery tester is an instrument that can easily measure the internal resistance and voltage of a battery with a probe to diagnose the deterioration of a rechargeable battery.

Normally, as rechargeable batteries are repeatedly charged and discharged, their internal resistance increases, and their performance gradually degrades. Rechargeable backup batteries may also deteriorate over time, and it is important to diagnose their performance in advance.

Using a battery tester, battery performance can be diagnosed immediately without shutting down the equipment. Data is stored in the internal memory and can be transferred to a PC for easy data management.

Uses of Battery Testers

Battery testers are used to diagnose the deterioration of secondary batteries such as lead-acid and lithium-ion batteries.

In recent years, the demand for secondary batteries in smartphones and electric vehicles has been increasing, and battery testers are useful for diagnosing their deterioration.

By bringing the measurement leads into contact with the electrode terminals, measurement, and storage can be performed in a short period. This makes the tester useful in situations where you want to immediately measure the condition of batteries on-site and manage the stored data using a PC.

Principle of Battery Testers

The basic principle of a battery tester is simple: measure the voltage when a current is applied to a battery and measure its internal resistance.

Since there are various types of battery testers available, the appropriate one should be selected according to the desired measurement accuracy and budget. Here, we will explain the principle by dividing them into those that use a DC power supply and those that use an AC power supply.

1. DC Power Supply Type

In resistance measurement, the internal resistance R is measured according to Ohm’s law by applying a measurement signal current I and measuring the voltage V with a voltage system. There are two methods of resistance measurement: the 2-terminal method and the 4-terminal method. The 4-terminal method is used in battery testers because of its high measurement accuracy. An overview diagram of each method is shown below.

In the 2-terminal method, current is measured by an ammeter after flowing through wiring resistors r1, R, and r2. Therefore, in the voltage system, the voltage across the resistors (R+r1+r2) including the wiring resistor is displayed as the measurement value, resulting in a measurement error.

In the case of the 4-terminal method, the resistance of the voltmeter is sufficiently large that almost no current flows through the voltmeter and wiring resistors r3 and r4, which are connected in parallel. As a result, the voltage measured by the voltmeter is the voltage at both ends of the resistor R. Therefore, it is possible to accurately measure the internal resistance, ignoring the wiring resistors r1 to r4.

2. AC Power Supply Type

Figure 2. Filament Temperature and Intensity Distribution of Emission Spectrum

By using an AC power source, even low resistance values can be measured with high accuracy. In addition, the impedance method can be used to measure resistance while the battery is connected to the device.

Other Information on Battery Testers

Importance of a Battery Tester

Rechargeable batteries such as nickel-metal hydride and lithium-ion batteries deteriorate as they are repeatedly charged and discharged, and their internal resistance increases, resulting in a decrease in battery output after a certain number of uses or duration of use.

Failure due to a short circuit in the battery’s internal cells can also cause a drop in voltage and heat generation in the battery itself. UPS (Uninterruptible Power Supply) is a system that supplies power to PCs and other devices in the event of a power failure.

Figure 3. Schematic Diagram of UPS

UPSs contain rechargeable batteries, such as lead-acid batteries, which can be activated in the event of unexpected power failure, preventing PCs, storage, and network equipment from malfunctioning.

The condition of the batteries must be monitored for the UPS to function properly in the event of an emergency. A battery tester can be used to diagnose battery deterioration in a short time without stopping the equipment.

What Is Spring Steel?

Spring steel is a steel material used to make various types of springs.

It is available in wire, bar, and strip forms. The method of manufacturing springs can be classified into “hot forming,” in which the material is formed into a spring shape and then heat treated, and “cold forming,” in which the material is formed into a spring shape at room temperature using heat treated material.

JIS G4801 standardizes “spring steels”. In this standard, only materials for hot-formed springs (materials that have not been heat-treated) are specified, but materials for cold-formed springs (materials that have been heat-treated) are also generally called spring steels.

Uses of Spring Steel

Spring steel is used to make various types of springs. It is used to make tension coil springs, compression coil springs, threaded recoil springs, torsion bars, laminated plate springs, plate springs, etc.

1. Hot Forming Spring Steel

Hot-formed spring steel is specified by JIS as a standard size from Φ9 in the case of wire rods and is used for large springs such as automobile suspensions.

2. Spring Steel for Cold Forming

Cold-formed spring steels are available in small diameters and thin sheets and are widely used for spring products used in precision equipment, industrial machinery, toys, and general household products.

Types of Spring Steel

1. Spring Steel for Hot Forming

High-strength materials are used for spring steels. Nine types of materials for hot-formed springs are specified in JISG4801:2021, “Spring Steel Products (SUP)”. The strength of these materials is not adjusted before they are formed into spring shapes. The materials are heated at 900°C to 1,200°C until they turn bright red, cut to the required length, coiled, and formed.

Quenching and tempering are then performed to obtain spring properties. Although hot-formed springs are large, they can be processed with little force through this process. However, strict temperature control is required.

2. Spring Steel for Cold Forming

Examples of spring steels for cold forming are hard steel wire (SW), piano wire (SWP), and stainless steel (SUS). These materials for cold-formed springs are already heat-treated as raw materials and have spring properties.

Spring forming is done at room temperature, followed by annealing. Compared to hot forming, the force required during the forming process is larger, so it is suitable for processing small springs. Cold-formed springs can be processed stably, and most of the springs that we usually see are cold-formed springs.

Structure of Spring Steel

Stainless steel, alloy steel, and high carbon steel are used as spring steel materials. Spring steel is divided into two types of shapes: long and thin wire rods and flat plates.

1. Wire Rod

The wire rod or bar is long and thin. Typical examples of wire rods of spring steel for cold forming are hard steel wire and piano wire. Both are manufactured by drawing them through the holes of a die while reducing their diameter. Unlike wire-like wire, the composition of hard steel wire contains a large amount of carbon. Hard steel wire can be used for everyday items such as beds and chairs.

2. Plate

The plates are flat. Spring steel used for thin plate springs is called steel strip. Like piano wire, it can be manufactured by rolling process. Some types are used directly for spring forming after cold rolling, types that are annealed after rolling, and types that are quenched and tempered after rolling.

How to Select Spring Steel

The use of spring steel depends on the type of steel material. For example, manganese chromium steel and silicon manganese steel can be used for coil springs, plate springs, and torsion bars. Chromium vanadium steel is mainly used for coil springs and torsion bars, and silicon chromium steel is mainly used for coil springs.

Chrome molybdenum steel is used for large coil springs and plate springs, and manganese chromium boron steel is used for large coil springs, plate springs, and torsion bars.

What Is a Balancer?

A balancer is a machine equipped with a mechanism to lighten the weight load when transporting heavy objects.

Conventionally, when heavy objects were transported manually, workers lifted and carried them directly. This was very heavy work because the weight of the heavy object was directly added to the operator.

The use of a balancer, however, improves this situation. The crane mounted on the balancer can lift the load and reduce the weight to close to 0kg, and the worker only needs to guide the load to the destination to complete the transfer. This greatly reduces the workload.

Uses of Balancers

Balancers are used for transporting heavy loads.

They are often used on factory lines and loading docks and can transfer heavy loads to conveyors or pallets in a weightless-like condition.

No legal qualifications are required to use balancers. However, since it is dangerous work to lift and transport heavy objects in the air, it is recommended that balancers be handled with caution and used only after the operator has a thorough understanding of the operation.

In addition, when using balancers, it is necessary to secure heavy objects to the crane, which requires knowledge and practical experience in crane operation and slinging operations. It is recommended to acquire these qualifications or complete a training course.

Characteristics of Balancers

Various types of balancers are used depending on the weight to be transported, and each has its own characteristics. The following is a list of typical types and their respective characteristics:

1. Hoist type
   In the hoist type, a rail is built in the sky and the balancers move along the rail to reach the destination.
   For example, in the balancing hoist type, a take-up drum is mounted and the inside of the drum is a cylinder type, which moves forward and backward while the take-up drum rotates by supplying and exhausting compressed air.
2. Pneumatic type
   The pneumatic balancers are balancers that are driven solely by air. Heavy objects are held by the crane by air suction, and the crane is driven by the cylinder.
3. Electric Balancer
   Electric balancers are electrically driven balancers. The crane with a heavy load attached is driven by a motor. Since the movement is controlled by motor control technology, it has high position repeatability and is suitable for work that requires repetition of the same task in a fixed position.

What Is Balancing Machinery?

Balancing machinery is a measuring instrument that measures the rotational vibration of rotating parts.

When rotating parts are machined and assembled, the center of rotation and center of gravity do not necessarily coincide due to errors in machining or misalignment during assembly. Therefore, when used as is, rotational vibration is generated during use. Rotational vibration not only causes discomfort during use but can also lead to machine breakdowns and damage.

Balancing machinery measures the vibration and indicates the amount of disproportion (correction amount) so that the rotational vibration can be kept within the standard value.

Uses of Balancing Machinery

Balancing machinery is used in the manufacture of many rotating products.

A familiar product is an automobile tire. Tires consist of a rubber portion on the outer circumference and a wheel in the center. The center of gravity of each part is misaligned during manufacturing, and the misalignment remains even after they are combined. If the tires are mounted on the vehicle as they are, vibration is generated in the steering wheel and the entire body when driving at high speeds. As a countermeasure, the misalignment is measured by balancing machinery before installation and corrected using weights.

In addition to tires, important parts such as axles, engine crankshafts, and flywheels are always measured for disproportionality.

Principle of Balancing Machinery

In addition to the vibration caused by the misalignment of the center of gravity of the entire rotating body (first-order vibration), vibration (second-order vibration/even force vibration) is caused by the different centers of gravity at both ends of the shaft. Since the even force vibration cannot be measured when the rotating body is stationary, it must be measured by rotating the body.

Measurement of unbalance is performed by attaching both ends of a test object, such as a shaft, to the rotating shaft of balancing machinery. The rotating shaft is equipped with an angle sensor and a displacement sensor to measure how much and at what angle displacement occurs during rotation. By using different displacement sensors at each end, it is possible to measure the displacement of the center of gravity at both ends, which is the cause of the generation of the even force vibration. This is called a two-plane unbalanced measurement.

There are two types of methods for measuring displacement during rotation: hard type and soft type. The hard type has a rotating shaft with high rigidity support, which enables stable measurement even at high rotational speeds. On the other hand, the soft type supports the rotating shaft with a leaf spring, which is less rigid but can detect slight vibrations and enable high-precision measurement.

Due to the characteristics of the vibration that occurs during rotation, care must be taken when selecting a balancing machine to ensure that the resonance point of the balancing machinery does not coincide with the rotational speed to be measured.

What Is a Beaker?

A beaker is a container for liquids used mainly in chemistry experiments.

Even people who are not chemical manufacturers or science faculty members have used a beaker at least once in elementary school or other science experiments.

Glass is the main material used because it does not react with chemicals and can be easily stored and stirred.

In addition to glass, beakers made of quartz, stainless steel, plastic resin, and other materials are also available and are used for different purposes.

Uses of Beakers

Beakers are used for temporary storage of chemicals, stirring or mixing liquids, and dissolving solids.

Beakers are not suitable for long-term storage, as they have no lid. However, they can be used to store liquids for a few hours until the next operation.

For mixing and dissolving, they are used with a magnetic stirrer, which uses magnetic force to stir the material.

As most of them are made of glass, they can break if they are handled roughly or dropped. Since dangerous chemicals are kept in them, safety precautions must be taken.

Principle of Beakers

Beakers are designed with a wide mouth to allow easy loading and unloading of chemicals and the addition of solids, such as powders.

On the other hand, they are not suitable for weighing chemicals. Although beakers are marked with a scale, they have a numerical error of 1 to several percent and should not be used for weighing in chemical experiments that require precision.

In addition to ordinary beakers, conical beakers, and tall beakers are used for chemical experiments.

Conical beakers have narrower mouths than the bottom. This makes it easier to add chemicals to the beakers from the top, such as for neutralization titration and also makes it easier to hold and stir the beakers by hand.

Tall beakers are narrower and taller than standard beakers. Taller beakers prevent chemicals from spilling when stirring.

Tall beakers are also easy to set in heating equipment such as mantle heaters, making them suitable for heating experiments.