月: 2023年6月

What Is Polyimide Tape?

Figure 1. Image of polyimide tape

Polyimide tape is an adhesive tape that uses polyimide film as the tape base material.

Polyimide has excellent heat resistance and insulation properties due to its high thermal decomposition temperature. Its main applications are heat-resistant masking of electronic substrates and heat-resistant insulation.

Polyimide is a general term for polymers that are polymerized by imide bonds. The first industrial application of polyimide film was commercialized by DuPont of the United States, which used aromatic polyimide.

Many polyimide tape products use a silicone adhesive, which has the advantage of leaving no adhesive residue after removal.

Uses of Polyimide Tapes

Polyimide tape is mainly used under high temperatures and high voltages due to the ultra-high and ultra-low temperature resistance of the base material, polyimide film. It can be applied in a variety of places, from repairing railroad and aircraft parts that require heat resistance to insulating circuits.

Many of them are thin and translucent, making them suitable for repairing small parts and fine electronic circuits. Since it is removable again, it can also be used in situations where repeated fine adjustments are required. Common uses include masking electronic circuits during soldering operations and insulating and insulating printed circuit boards.

In addition, since many products have high chemical resistance, they are often used for fixing when applying strong acidic chemicals or for protection during partial etching.

Principle of Polyimide Tapes

Figure 2. Imide bonding and polyimide

The majority of polyimide tape consists of a polyimide film coated with a silicone adhesive. Some rubber-based adhesive products and acrylic adhesive products are also available for applications where silicone residue must be prevented.

Polyimide tape is characterized by the properties of the polyimide film and adhesive. Since polyimide has a higher heat resistance temperature than the adhesive, the heat resistance temperature of the product is generally determined by the type of adhesive.

Properties of Polyimide

Polyimide is a general term for high-molecular compounds that are polymerized by imide bonds. Polyimide tape is made of aromatic polyimide, which is a polymer of aromatic compounds polymerized by imide bonds. Because of the extremely strong bonding, polyimide tape has high strength and excellent heat resistance and insulation properties. The thermal decomposition temperature is 500°C or higher.

The specific properties of the molecular structure that give it excellent heat resistance are as follows:

• Aromatics are conjugated to each other via imide bonds.
• The aromatic rings are located in the same plane and the molecular chains are tightly packed together.
• Highly polar imide bonds have strong intermolecular forces.

It also has a low expansion coefficient when heated, so it does not expand much even when used at high temperatures, thereby minimizing dimensional errors.

Other Information on Polyimide Tape

Adhesives for Polyimide Tape

Figure 3. Kapton® Structure and Characteristics

Adhesives used in polyimide tape include silicone adhesive, rubber adhesive, and acrylic adhesive, each with different properties such as adhesive strength and heat resistance. Among polyimide tape, products using the polyimide film Kapton® by E.I. du Pont de Nemours and Company (DuPont) of the United States are sometimes called Kapton® Tape.

1. Silicone Adhesive
Silicone adhesives are adhesives consisting of silicone rubber and silicone resin components. Although silicone rubber does not have high adhesive properties, it has excellent cold and heat resistance. As a result, it can be used in a wide range of temperatures, from -60°C to 250°C.

Silicone resin is an adhesive agent component that complements the adhesive properties of silicone rubber. By changing the composition ratio of the silicone rubber component to the silicone resin component, the required adhesive properties can be obtained. Cross-linking agents such as benzoyl peroxide are also used to further improve heat resistance from the original properties.

Adhesion to silicone rubber and fluororesin is also possible, and it has excellent water and chemical resistance. It can also be used in places where it is exposed to strongly acidic aqueous solutions. Another advantage is that air bubbles do not easily form when applying the film because it is easy to release air. It also has excellent removability, so it can be peeled off without leaving adhesive residue.

2. Non-Silicone Adhesives
Polyimide tape with acrylic or rubber-based adhesive is also available, although not in large numbers. Although inferior to silicone-based adhesives in terms of heat resistance, they are used to prevent soldering defects caused by siloxane gas or silicone residue. It is used for masking during reflow soldering of electronic components, temporary fixing, protection of components and lenses, and transportation of components.

What Is an NC Router?

An NC router is a device that uses numerical control (NC) technology to cut wood, plastic, and metal materials with a blade.

Once numerical control data is created, the same product can be produced many times with the same accuracy. NC routers are a type of machine tool and have a long history as one of the first automated machining technologies.

They automate traditional manual cutting operations and enable fast, accurate, and efficient machining. It is particularly good at machining complex curved surfaces and drilling holes. Today, NC routers are also called CNC (Computed NC) because of their computer numerical control capability. The computer-controlled nature of this equipment makes it suitable for mass production, as well as for advanced cutting operations.

CNC technology has led to the development of NC routers that can process a wide variety of materials and are widely used in manufacturing industries such as automotive, furniture, and construction materials. They will continue to be an increasingly important piece of equipment as demand grows in industrial fields where precision machining is required.

Uses of NC Routers

NC routers are used for cutting wood, plastic, and metal materials. Numerical control technology enables high-precision and high-speed processing and is characterized by its superiority in processing products with fine details and complex shapes that are difficult to achieve by hand.

It is also widely used as indispensable equipment for the production of prototype parts and small-lot parts for products. For example, it can be used in a wide range of industrial fields, including commercial products, home appliances, housing equipment, and automotive products. Since prototype parts and small-lot parts are generally small in quantity, manual processing reduces productivity. NC routers can process a large number of parts at one time by creating numerically controlled data.

In addition, NC routers are also used to process molds for molding resin parts. Molds are required for the manufacture of resin parts, but advanced processing technology is needed to manufacture the molds. NC routers play an important role in the manufacture of molds because they enable high-precision cutting.

NC routers are not only widely used in the manufacturing industry because of their ability to handle a wide variety of materials, but also have a wide range of application areas, including the production of crafts and the processing of building materials.

Principle of NC Routers

The principle of NC router lies in processing parts by numerical control. The part is fixed to the table on the NC router by a chuck and is processed by a rotating blade from above. The movement of the blade or table is controlled by the numerically controlled data to be processed. Some NC routers are equipped with a device that automatically switches the blade, allowing the user to change the blade depending on the part to be processed. Some devices can process multiple parts at the same time.

NC routers require numerical control data, called NC data, for processing. NC data can be directly input into an NC control panel, but this takes a lot of time, so these days it is more common to convert CAD/CAM data.

CAD is software for design, and CAM is a system that creates NC router machining data based on the shape data created on CAD. NC routers are widely used in the manufacturing industry.

Types of NC Routers

There are three main types of NC routers: NC router for woodworking, NC router for metal, and NC router for plastic.

1. NC Router for Woodworking

NC routers specialized for woodworking are suitable for processing wood products. Since the blade can be switched according to the type and thickness of wood, a wide range of wood types can be processed. Also, it is capable of high-precision processing and can produce fine parts and ornaments for woodworking products.

2. Metal NC Router

This NC router is specialized for metal processing and can switch blades in consideration of the strength and tenacity of the metal material. It is suitable for fabricating metal parts and processing machinery and can be used for mass production because of its high accuracy and high-speed processing.

3. NC Router for Plastic

This NC router is specialized for processing plastic materials and is suitable for manufacturing plastic products. There are many types of plastics, and by selecting the appropriate blade for each material, high-precision machining is possible.

In addition, plastic materials are softer and more sensitive to heat than metal, so care must be taken in temperature control. NC routers for plastics are designed with these characteristics in mind.

What Is a Differential Pressure Sensor?

A differential pressure sensor is a pressure sensor used to measure the difference in pressure between two points connected to a sensor.

The purpose of a differential pressure sensor is to measure the difference between two points. Therefore, it does not matter whether the pressure to be measured is atmospheric, negative, or fluid pressure. In addition, since differential pressure sensors do not measure absolute values, the device itself is relatively small, and many inexpensive products are available.

Another feature of differential pressure sensors is that they can be easily calibrated.

Uses of Differential Pressure Sensors

Differential pressure sensors are general-purpose sensors and are widely used in various fields of industry. The main applications are anemometers and air conditioning equipment.

In industrial equipment, they are also used to monitor the operating status of pumps, compressors, and other equipment, as well as to monitor filter clogging. A typical example of a filter-clogging application is in diesel engines for automobiles.

Diesel engines are equipped with a diesel particulate filter (DPF), which removes particulate matter emitted from the diesel engine. A differential pressure sensor is used to measure the particle build-up in the DPF.

In addition, it is also useful for measuring the volume of liquid in tanks. The structure of the differential pressure sensor can also be used to measure the differential pressure between different phases (forms), such as the liquid in the tank and atmospheric pressure.

Principle of Differential Pressure Sensors

Differential pressure sensors can be broadly classified into two types: those using strain gauges and those using capacitance sensors. The principle of measurement is the same for both types of sensors, utilizing the deformation of a diaphragm caused by the difference in pressure between two points. The method used to measure the amount of deformation (strain) of the diaphragm is selected according to the characteristics of each method.

1. Using a Strain Gauge

In the method using strain gauges, a strain gauge is attached to a diaphragm and the change in resistance of the strain gauge due to deformation of the diaphragm is measured. Since there is almost no change in resistance over time, this type of sensor is suitable for long-term, static force measurement applications.

2. Using a Capacitance Sensor

In those using a capacitance sensor, the distance between two electrodes placed on a diaphragm changes as the diaphragm deforms, resulting in a change in the capacitance between the electrodes. The capacitance sensor measures the amount of this change in capacitance.

Although differential pressure sensors using capacitance sensors structurally change their output values slightly over time, they tend to be robust to dynamic measurements because of the high rigidity of the sensor housing and its high natural frequency.

Other Information on Differential Pressure Sensors

1. Types of Pressure in Pressure Measurement

There are three types of pressure measured by various measuring instruments. It is helpful to correctly remember the meaning and relationship of each value.

Absolute Pressure
Absolute pressure is the pressure relative to an absolute vacuum. An absolute vacuum is a state in which there is no matter in a certain space.

Gauge Pressure
Gauge pressure is the pressure relative to atmospheric pressure. Since atmospheric pressure also changes with location and time, gauge pressure changes with location and time even if the measured value is the same.

Differential Pressure
Differential pressure is the difference between the pressure at a certain location and a standard. Therefore, when measuring differential pressure, the reference pressure must always be measured as a set in addition to the object of measurement.

2. How to Measure Gauge Pressure With a Differential Pressure Sensor

A differential pressure sensor is a device that measures the difference in pressure between two points. One can measure atmospheric pressure and the other can measure gauge pressure.

To measure gauge pressure with a differential pressure sensor, it is common to connect the HIGH side of the differential pressure sensor to the object whose gauge pressure is to be measured and leave the LOW side open to the atmosphere.

What Is an Enamelled Bathtub?

An enameled bathtub is a bathtub manufactured using a material called enamel.

It is used not only for bathtubs but also for tableware and pots, and is characterized by its beauty and durability.

Enamel products themselves are made by baking a glassy substance (mainly silicon dioxide) onto the surface of a metal plate or metal casting at high temperatures. The use of metal makes enamel bathtubs more durable than bathtubs made of other materials. The glassy surface makes for a very beautiful bathtub.

Uses of Enamelled Bathtubs

Enamelled bathtubs are considered to be for high-end homes due to their high cost, but artificial marble bathtubs, which are less expensive than enamelled bathtubs, are also being used. Artificial marble is used as a substitute for marble not only in bathtubs but also in kitchens and washstands. After bathing, the bathtub can be kept clean by simply rinsing the surface off. It is becoming increasingly popular in recent years because of its excellent heat retention properties and resistance to mold growth.

Principle of Enamelled Bathtubs

Enamelled bathtubs and other enamelled products are made through the following processes:

1. Metal Shaping and Processing Engineering

Steel sheets are finished into a specified shape by sheet metal working or press working, etc., and then welded and formed into a product shape. In some cases, the product is cast from a mold instead of being pressed or otherwise processed.

2. Pretreatment Process

Here, oil and other contaminants adhering to the steel plate are removed. In addition, the steel plate is dipped in a nickel solution to change the surface of the steel plate to a state where glaze (silicon dioxide) can easily adhere to the surface. In some cases, steel sheets are dipped in sulfuric acid before being dipped in the nickel solution to roughen the surface and make it easier for the glaze to adhere to the steel sheet.

3. Glazing

Glaze is sprayed and applied to the pretreated steel plate. Glazes are made of glass powder mixed with silica stone, feldspar, metal oxides, borax, soda ash, etc. Many types are available depending on the color and characteristics of the product.

4. Yakiaki Project

After applying the glaze, allow it to dry thoroughly before firing. Firing is performed at 800 to 850 degrees Celsius for 5 to 10 minutes to complete the process. Depending on the product, the glazing and firing processes may be repeated multiple times.

Other Information About Enamelled Bathtubs

1. Life of an Enamelled Bathtub

Enamelled bathtubs have a lifespan of approximately 20 to 30 years. Deterioration is noticeable at this time, but if the enamelled bathtub is kept in hot water for a long time, the glaze on the surface of the bathtub tends to peel off and deteriorate in as early as 15 years or so.

2. Repair of Enamelled Bathtub

A common symptom of enamelled bathtub deterioration is cracking (cracking) or peeling of the glassy surface of the bathtub. In some cases, holes are formed and metal parts inside the bathtub are exposed. Water seeping into the interior can also cause the metal parts to rust.

Glass deterioration cannot be repaired by polishing alone because the original luster and texture of the enamel is lost. Painting for repair will cost 500 to 1500 USD.

If there are holes in the enamelled bathtub, the metal inside is often rusted, in which case replacement of the bathtub itself is recommended. In order to prevent soap scum and other stains from adhering to the bathtub, a clear coating treatment can be applied only in cases where the deterioration symptoms are not too severe. The cost is approximately 150 to 250 USD.

If you are considering DIY to reduce the cost of repair, you need to make a careful decision because of the difficulty of the work. If the metal inside the enamelled bathtub has rusted, not only will it recur if not completely removed, but the paint suitable for painting enamel is special, making it difficult to adhere to the repaired area and prone to peeling off. It is said that enamel painting is prone to construction defects, even by professional painters, so it is advisable to ask a professional who is good at painting from the beginning.

What Is an Antistatic Gun?

An antistatic gun is a machine that neutralizes the static charge of an object.

It neutralizes the static charge of an object by ionizing the air and discharging it along with the air toward the object. It is also called a static eliminator gun because its role is similar to that of an ionizer gun type.

Since high-pressure air is released onto the object, it is possible to remove dust attached to the object as well. They are used in painting and manufacturing to remove dust caused by static electricity.

Uses of Antistatic Guns

When an antistatic gun is aimed at an object to be painted, it can remove not only static electricity but also dust and dirt, thereby reducing defects. A large number of objects require painting, including automobiles, furniture, musical instruments, gas stoves, and plastics, for which antistatic guns are used for pre-treatment of the surface to be painted. Depending on the application, antistatic guns with high air pressure and especially high dust removal capability are preferred.

They are also used to prevent static electricity damage in the manufacture of electronic components, printed films, semiconductors, liquid crystals, and magnetic heads, as well as in the assembly and repair of various measuring instruments.

Principle of the Antistatic Guns

An antistatic gun consists of two main functions: to neutralize static charge by ionizing air, and to remove dust adhering to the surface of the object by blowing air simultaneously.

1. Neutralizing Function

The surface of an object can become charged or unevenly charged with an excessive amount of + or – charges due to various reasons. Therefore, an antistatic gun is used to neutralize the charge by irradiating the surface with + and – ions.

Most antistatic guns use a method called the corona discharge type. Corona discharge is a weak electrical discharge that occurs at the tip of a metal needle when a high voltage is applied to it. This discharge ionizes some of the air near the needle, and the charged object is neutralized when ions with opposite positive and negative charges come into contact with it.

The amount and cycle of ions generated by a corona discharge type antistatic gun vary depending on the voltage applied. The type of voltage applied can be DC (direct current), AC (alternating current), pulsed DC, pulsed AC, high-frequency AC, or SSDC. Since the performance of static elimination, such as the range of ionization, speed, and ion balance, varies, it is necessary to select a voltage type that is appropriate for the application.

The method using AC, which is commonly used for antistatic guns, produces + and – ions periodically. Instead of having a good ion balance, a low voltage slows down the speed of static elimination. Also, since both positive and negative ions are emitted from the same electrode needle, charge recombination tends to occur as the distance from the electrode needle increases, resulting in a decrease in static elimination capability.

Tungsten, silicon, SUS, and other materials are used for electrode needles. The electrode and its surrounding area become dirty during use and must be cleaned periodically. In addition, after a long period of use, metal atoms are said to pop out from the tip of the discharge electrode, and the shape of the electrode changes as if the electrode has been worn away, so the electrode needles need to be replaced periodically (one to two years).

This phenomenon must be avoided in the semiconductor industry, for example, where air pollution is a problem. It is necessary to take countermeasures such as attaching a thin quartz cover or using electrode needles made of silicon.

2. Function to Remove Surface Dust

Dust adhering to the surface of an object may be electrically charged. Therefore, air is used to remove foreign matter adhering to the object’s surface, and ions are simultaneously irradiated to remove the static charge and prevent reattachment.

However, since winded static eliminators blow foreign matter or roll up dust, which can cause foreign matter defects, non-wind-type static eliminators have become mainstream in recent years.

The static-eliminating effect of antistatic guns varies greatly depending on the installation distance, angle, and air volume/pressure.

Other Information on Antistatic Guns

1. High-Power Antistatic Guns

A powerful antistatic gun with not only high static-eliminating capability but also high impact force is required to remove static from objects with high static charge.

The high-powered antistatic gun is equipped with a large-flow solenoid valve that minimizes pressure loss, and its internal structure has been optimized to achieve highly efficient air discharge. The nozzle shape is also ingenious, such as the Laval nozzle, which features a contraction and expansion shape with fine nipples. The housing of the high-power antistatic gun is designed to be even sturdier than a typical antistatic gun to withstand the high-pressure air emitted from the tip of the gun.

The initial velocity of the air at the nozzle tip exceeds the speed of sound. This power is effective even at a distance and can spray compressed air with a maximum wind speed of 50 m/s (at 0.7 MPa) at an object approximately 30 cm away, which is close to actual working conditions.

2. The Dust Removal Function of the Antistatic Gun Is Indispensable for Reliable Static Elimination.

Appropriate dust removal is an essential process for the effective removal of static electricity from objects. Even if the static is removed, the pre-treatment process is incomplete if dust remains on the object.

Typical dust elimination functions that allow the antistatic gun to fully utilize its static elimination capabilities are the pulse air function and the dust check light.

Pulse Air Function
By controlling the movement of the solenoid valve, intermittent release of powerful air is possible. Pulsed air injections ensure that vibrating air is poured evenly and omni-directionally around the object, providing more reliable static electricity removal and powerful dust removal capability. The efficiency of the pulsed air is approximately twice that of continuous injection, offering the labor-saving advantage of achieving the same effect with half the output.

Dust Check Light
Before and after using the antistatic gun, it is important to check for dust, dirt, and other foreign matter attached to the object. An antistatic gun equipped with a surface-emitting LED on the nozzle surface is useful as a highly luminous and even working illumination. This makes it easy to see minute particles that would be missed without the light, contributing to a reduction in defect rates and improved work efficiency.