月: 2023年2月

What Is a Masking Compound?

A masking compound is a product and action that is used to protect a surface from solvents and prevent scratches. Masking compound also means “to cover up” or “to wrap up.”

The main products used for masking include masking tape, solid wax, and masking compound. These are important products used in the industrial and architectural fields. In recent years, however, masking tapes and masking paints have been attracting attention in the field of the arts as well, with products that offer great convenience in the creation of artwork.

This article will focus on masking compounds in particular.

Uses of Masking Compounds

Masking compounds are effective when applied as an anti-plating agent to areas where plating is not required. They can be applied by brushing or dipping. Dipping is a coating process in which the object to be painted is immersed in resin or chemicals to achieve the desired paint effect. This process is also known as impregnation.

Masking compounds include both organic solvents and water-based paints that dry at room temperature. Water-based paints are those that do not use organic solvents or significantly reduce their use by replacing them with water. Therefore, if they do not fall under the Regulations for the Prevention of Organic Solvent Poisoning, they are not subject to health examinations or other related obligations.

Room-temperature drying paints can be used for various applications. However, since solvents are primarily used, plating work cannot commence until the solvents have evaporated after application. Additionally, due to their flammability, the workspace must strictly adhere to fire safety measures.

Nevertheless, except for very small quantities, they can be used on objects of various sizes and shapes with special attention to fire safety.

As a result, room-temperature drying masking compounds are versatile masking materials.

Water-based paints are primarily used in the arts. They can be used for various purposes such as decorating windows and walls, embellishing events, creating designs on display windows, and preventing glassware from being scratched.

Principles of Masking Compounds

Using aircraft engines as an example, surface treatments applied to parts include cadmium plating, industrial chrome plating, nickel plating, silver plating, and lead/iridium plating.

When considering paint masking compounds in this context, issues related to peeling after plating must be taken into account. Apart from this concern, synthetic resin paints such as epoxy resin and urethane resin, which offer excellent resistance to acids, alkalis, and heat, can be considered. However, currently, lacquer is predominantly used as a masking compound for the majority of aircraft engines.

Lacquer is a highly volatile paint created by dissolving acrylic resin or nitrocellulose (nitrocellulose) in an organic solvent such as toluene. It can withstand room temperature and heat-based acidic solutions, as well as chrome plating solutions, for a relatively extended period. However, it is susceptible to alkaline solutions and becomes even more vulnerable when heated.

Masking with lacquer compounds should be carried out using a brush or roller, leaving the surface to be plated exposed. The application should be thick enough to prevent the formation of pinholes, and the coating should be air-dried for at least 30 minutes after the initial coat is applied. Once it is dry to the touch, apply a second coat and repeat the process.

After application, allow at least 2 hours for drying time. For removal after plating, immerse the object in a heated alkaline solution and, when the coating becomes buoyant, use compressed air to remove it.

What Is an Electronic Enclosure Seal?

An electronic enclosure seal is a software or tool that replaces traditional handwritten signatures or seals with a digital equivalent. As society moves towards paperless operations, electronic signatures and seals are gaining legal recognition, making electronic enclosure seals increasingly common in business contracts.

However, electronic enclosure seals face risks such as unauthorized stamping by someone other than the decision maker, or the data itself being tampered with. To address these issues, security measures like authentication functions, recording identification information, and time stamping are essential.

How to Create an Electronic Enclosure Seal

Electronic enclosure seals can be created for various document files, including Word and PDF formats. Depending on the file type, they can be applied without special software.

Word Files

In Microsoft Office Word, electronic enclosure seals can be created using the graphic creation tool. This involves designing a vertical oval, leaving it unfilled, and placing the name of the stamping entity in the center. However, due to the ease of tampering, such seals are not typically used in official contexts.

PDF Files

Adobe Acrobat Reader offers a more secure electronic enclosure seal function for PDF files, though concerns about tamper-proofing remain.

Security of Electronic Enclosure Seals

The security of electronic enclosure seals is crucial, considering the risks of forgery and unauthorized use. Authenticating the stamping person and protecting against tampering are key challenges. For instance, seals created using Word’s graphic tool or scanned from a physical seal can be easily misused.

Enhancing security involves incorporating authentication functions and saving identification information for each stamping record. This approach helps verify who stamped the seal and prevents identity theft. Additionally, copy protection features ensure that stamped images cannot be reused without authorization.

Prevention of Tampering With Electronic Enclosure Seals

Time stamping is another effective method to prevent tampering. When an electronic enclosure seal is applied, recording a timestamp can prove the existence of the electronic data at the time of stamping, ensuring the decision maker’s approval of the content.

Legally, time stamps are often required to validate electronic enclosure seals. For example, under the Electronic Bookkeeping Law, a timestamp of less than two months is needed to validate electronic data when using electronic enclosure seals on mediums without history retention. The trend towards paperless documentation will likely increase the use of electronic enclosure seals, emphasizing the importance of authentication, identification, and time-stamping for security.

What Is Masking Tape?

Masking means “covering” or “wrapping.”

Masking tape is used as a masking material for metal surface treatment. It can be classified by application into two types: for painting and for electroplating.

However, masking tape is mainly used as a protective material for buildings during loading and unloading. Other uses include protection of building materials in construction, prevention of paint overflow, temporary fixing, and temporary fixation. In recent years, it has been available in a wide variety of colors, the purpose of which is to prevent forgetting to peel it off.

Uses of Masking Tapes

Masking tapes are also used as curing material for concrete cobblestones. Curing is an important type of work to give concrete the required performance.

During the curing process of concrete, temperature and humidity must be well controlled so that cement hydration continues. Concrete does not form a dense, hardened structure at a young age. Therefore, it is prone to moisture dissipation into the atmosphere. Various measures have been taken to solve this problem, such as extending the period that formwork remains in place and using a film curing agent to protect the surface when the concrete surface is directly exposed to the open air.

However, due to the effects on the construction period and the effectiveness of the coating, a water retaining tape has been developed as an alternative to formwork to be applied directly to the concrete surface to prevent it from drying out.

Principle of Masking Tapes

Masking tapes are generally available in cloth and film types. Masking tapes consist of a base material on the surface and an adhesive on the reverse side. Some products are also sold with a primer layer or back treatment layer for improved convenience.

In the cloth type, the base material is made of alternating warp and weft yarns, and although it is tough, it can be cut by hand from anywhere.

The film type has only warped threads as the base material and is flexible. However, since there are no weft threads, it is easy to write letters and has a smooth surface.

Although not limited to masking tapes, in order for the tape to stick to an object, it must get close to the object at the molecular level. It is said that objects adhere to each other because an electrical force acts between molecules, attracting them to each other. This force is called intermolecular force. And it is the adhesive that takes the place of this force.

Adhesives adhere by blending with uneven surfaces of solids as a substitute for liquids or substances similar to liquids. Therefore, it is important to select a tape (adhesive) that blends well with the adherend to which the tape will be applied.

What Is Masking Tape?

Masking tape, commonly used for “covering” or “wrapping,” is mainly utilized in metal surface treatment. It is categorized into two types based on application: for painting and electroplating.

Masking tape for painting, used in spraying or brushing paint, requires specific properties like adhesion, peeling ease, solvent resistance, and prevention of discoloration or contamination. Crepe paper adhesive tape, known for its elongation and flexibility, is preferred for high-quality finishes in industries like aircraft and automotive, particularly for masking curved surfaces.

For electroplating, masking tape mainly protects base terminals from plating solutions. It necessitates properties such as chemical resistance, heat resistance, and adaptability to various metal surfaces. American masking materials, like vinyl tape, polyester tape, lead hack tape, aluminum hack tape, and solid wax from Michigan Chrome & Chemical Co., serve as typical examples.

Uses of Masking Tapes

Beyond painting and electroplating, masking tapes find applications in the construction industry for sealing and flooring protection. Paper-based masking tapes are gaining popularity in households and the art field due to their clean removability, writability, and diverse colors. The “mt art project” by Kamoi Kakoshi Co., Ltd. has played a significant role in popularizing tape art globally.

Principle of Masking Tapes

Masking tapes originated from adhesive tape. In 1874, Robert Wood Johnson began producing adhesive bandages using natural rubber, enhanced with pine resin and vegetable fillers for stickiness at room temperature. Later, the founding of Johnson & Johnson in 1886 led to the introduction of chemical-free bandages, widely used as surgical tape.

This background paved the way for the evolution of black tape, a precursor to electrical insulation tape, and eventually to masking tapes. In 1920, medical tape was adapted for car body painting. The automotive boom in Detroit, USA, saw a significant sale of Johnson & Johnson’s medical tape. However, as it wasn’t designed for masking, challenges like paint seepage arose.

In 1925, R.G. Drew of the Minnesota Mining and Manufacturing Company (now 3M) developed an improved masking tape. This tape could adhere to various surfaces at room temperature or with finger pressure and be removed cleanly, addressing issues like layer cracking or feathering through the incorporation of crepe paper with Japanese crepe.

What Is a Casting?

Casting is a process where molten metal is poured into a mold to form a product. The flexibility in shapes is a key feature of casting, as it allows the creation of complex shapes by pouring molten metal into a mold. Post-casting processes often include forging, cutting, and heat treatment.

Products manufactured by casting are commonly referred to as castings. The technique dates back to around 4000 BC in Mesopotamia, initially with copper.

Uses of Castings

Castings are widely used for various materials and applications:

1. Cast Iron: Used in car engine parts, cases, etc.
2. Cast Steel: Used in construction machinery parts, railroad couplings, etc.
3. Copper Alloys: Used in pump and piping parts, fishing bells, etc.

Additionally, nickel alloys are used for turbine blades and valve bodies, titanium alloys for pacemakers and artificial joints, magnesium alloys for laptop bodies and cell phones, and zinc alloys for door knobs and connector parts.

Types of Castings

Casting starts with melting the material in an electric furnace, followed by pouring it into a mold and allowing it to harden. After cooling, the casting is removed from the mold.

Types of casting methods include:

• Mold Castings: Uses heat-resistant molds.
• Sand Castings: Employs sand molds.
• Investment Castings: Utilizes low melting point material for the model, coated with refractory material, offering high precision.
• Additional methods such as vanishing model castings with Styrofoam, gravity mold castings with heat-resistant steel, and die castings.

Continuous casting, predominantly used in the steel industry, allows for the continuous manufacturing of products from molten metal, differing from batch production in normal casting processes.

What Is Gear Cutting?

Gear cutting is a machining process that shapes the teeth of a gear. It typically involves a rotating blade moving up and down on a fixed workpiece. This process is done using a gear-cutting machine, often referred to as a hobbing machine.

High precision in gear cutting is crucial to prevent excessive load and potential damage during gear meshing.

Uses of Gear Cutting

Gear cutting is essential for manufacturing various gear types, such as spur gears, bevel gears, and helical gears. The specific shape of the gear teeth is tailored to the machine’s requirements. Gears produced are integral in diverse fields, including automotive, aerospace, industrial machinery, agriculture, and precision instruments like watches.

Types of Gear Cutting

Gear cutting techniques can be categorized into two main methods.

1. Generating Method

This method gradually shapes the entire gear, offering efficient, uniform precision, making it ideal for mass production. Although it requires specialized machinery, resulting in higher initial costs, it achieves high precision across the entire gear. The hobbing process is an example of this method.

2. Forming Method

This method forms each gear tooth individually. It requires precise part positioning, affecting the overall machining accuracy. While less efficient than the generating method, it has the advantage of lower equipment and production costs, as it can be done using general-purpose NC machine tools. Milling machines are commonly used in this method.

Choosing the right gear cutting technique depends on a balance between accuracy and cost, tailored to the gear’s intended application.

What Is Hot Dip Galvanizing?

Hot dip galvanizing is a plating process where materials are immersed in molten zinc. This technique is primarily used for its rust protection capabilities. An important advantage of hot dip galvanizing is its cost-effectiveness due to the simplicity of the process.

Uses of Hot Dip Galvanizing

Widely used for its affordability and durability, hot dip galvanizing can protect materials from rust for about 10 years, even in environments exposed to sea breezes. Common applications include construction machinery, station buildings, public facilities, and guardrails. It’s also employed in structures that are challenging to maintain regularly, such as steel towers in remote locations, helping to control maintenance costs.

Principles of Hot Dip Galvanizing

Hot dip galvanizing is characterized by the strong adhesion strength resulting from the chemical reaction between zinc and iron. This alloying reaction ensures that the coating does not peel off easily under normal conditions, unlike conventional paints. Additionally, zinc offers both a protective coating action and sacrificial anticorrosion. It acts as a protective film resistant to water and air, while also providing sacrificial corrosion protection by dissolving before the underlying material. The process results in a thick zinc coating, offering long-term protection due to the dual action of zinc.

What Is Metal Coating?

Metal coating is a process where paint is applied to a metal surface. This process typically involves four stages: pretreatment, formulation, application, and drying. Pretreatment cleans the metal surface to enhance paint adhesion. During formulation, paints and thinners are mixed to achieve desired functions and colors. The application stage involves painting the metal surface either by brushing or spraying. Finally, the coating is dried at room temperature or using heat.

Uses of Metal Coatings

Metal coatings serve decorative purposes, protect materials, and add functionality. They can impart color, pattern, and luster to products like cars, allowing for various colors within the same vehicle model. Additionally, applying a coating film protects metal surfaces from elements such as rust, thereby enhancing durability.

Types of Metal Coatings

Various types of metal coatings exist beyond traditional brush applications, including:

• Solvent Coating: This method involves dissolving paint in a solvent like thinner and applying it using a sprayer or roller.
• Baking Coating: In baking coating, paint is sprayed onto the surface and then heated to harden. This enhances the adhesion and weather resistance of the paint film.
• Powder Coating: Powder coating involves attaching powdered paint to the object using static electricity, followed by heating to melt and form a coating film. It allows for a thicker coating in a single application compared to liquid paint.
• Electrostatic Coating: Electrostatic coating uses electrically charged paint, which adheres to the surface through static electricity, reducing waste and achieving a more uniform finish. However, high voltage usage requires precautions against electric shock and fire.
• Electrodeposition Coating: Electrodeposition coating forms a film by immersing the object in a paint container and passing electricity through it.

What Is a Polyester Coating?

A polyester coating is a coating technique utilizing polyester resin. This type of coating, available in both liquid and powder forms, is known for its thick application achieved through radical polymerization. Polyester coatings are solvent-free, allowing the application of several hundred micrometers thick layers without significant substance volatilization. These coatings are characterized by excellent abrasion, chemical, water, and hot water resistance, along with a glossy finish. However, the thickness can sometimes reduce flexibility and adhesiveness.

Uses of Polyester Coatings

Polyester coatings are frequently used on musical instruments like pianos and guitars due to their high hardness and stain resistance. They are also suitable for outdoor and architectural applications, thanks to their outstanding weather resistance. Common uses include industrial equipment like switchboard boxes, outdoor lighting, signs, aluminum and stainless steel building materials, and electrical appliances such as microwave ovens. However, these coatings are susceptible to strong alkalis, which can cause peeling.

Types of Polyester Coatings

Polyester coatings are broadly classified into liquid and powder types, each with its unique properties and applications:

1. Liquid Type

Liquid polyester coatings use styrene monomer as a diluent instead of conventional solvents like acetone or toluene. Unlike typical solvents, styrene monomer does not volatilize but becomes part of the resin after curing. This property allows for the creation of a thick film without compromising physical properties. Due to its ease of use, liquid polyester coatings are popular among both professional contractors and DIY enthusiasts.

2. Powder Type

Powder polyester coating, or powder coating, involves the use of powdered polyester resin paint. The process starts with electrostatically attaching the powder to the surface, followed by baking to melt and evenly coat the object. This method allows for forming a thick film in a single application. Unused powder can be recovered and reused, making it a cost-effective solution.

What Is a Polyurethane Coating?

Polyurethane coating, often referred to as “urethane” in the paint industry, is a painting process using a specific type of paint. This coating is known for its glossy finish, imparting a luxurious appearance. Polyurethane resin, noted for its good adhesion to metal surfaces, is a soft resin, making it durable and easy to work with.

Uses of Polyurethane Coatings

Historically, polyurethane coatings were widely used for exterior wall coatings due to their cost-effectiveness compared to other types of paints. However, they have been largely replaced by silicone coatings for exterior walls due to the latter’s higher durability. Nowadays, polyurethane coatings are primarily used for waterproofing applications in areas such as balconies and gutters. Additionally, they are commonly applied to cars, motorcycles, tableware, and furniture, offering moisture resistance superior to oil or lacquer coatings, making them especially popular for furniture applications.

Types of Polyurethane Coatings

Polyurethane coatings are categorized into water-based and oil-based types, each with distinct characteristics:

• Water-based Paints: Diluted with water, these paints are cost-effective and environmentally friendly, emitting less odor. However, they tend to be less durable and their glossiness can fade more quickly compared to oil-based paints.
• Oil-based Paints: Diluted with organic solvents like thinner or benzene, oil-based paints offer greater durability but are more expensive and have a stronger odor than water-based paints.

Both waterborne and oil-based paints are further classified into one-component and two-component types, based on the need for mixing with a hardener before use. One-component paints do not require a hardener, while two-component paints, though more labor-intensive, provide enhanced durability due to the chemical reaction between the hardener and the main paint.