月: 2023年9月

What Is a Mold Release Agent?

A mold release agent is a substance used in the molding process to facilitate the easy removal of molded objects from the mold.

Molds play a vital role in quickly producing identical shapes in large quantities. However, simply pouring material into a mold and molding the product can lead to difficulties in cleanly detaching the product from the mold, resulting in adhesion issues.

Mold release agents are employed to enhance production efficiency by aiding the release of the molded item from the mold during the molding process.

Uses of Mold Release Agents

The primary application of mold release agents is in molding operations for creating products on the production line. Additionally, they find use in various other applications:

1. Medical Applications

They are used in surgical tools and medical equipment to facilitate easy release from the human body.

2. Construction Sites

In concrete and stone production, mold release agents are used to prevent staining and rusting.

3. Food Industry

Mold release agents are employed in shaping food products and manufacturing containers and packaging materials.

4. Manufacturing Industry

They are also essential in the production of plastic, rubber, steel, and paper products. Mold release agents chosen for these sectors are tailored to suit the respective materials.

Principle of Mold Release Agents

The presence of a mold release agent between the mold and the molding material facilitates the easy release of the material from the mold. Mold release agents are an integral part of the molding process and can be categorized based on their usage and composition.

1. Classification According to Usage

External Mold Release Agents: These are applied to the surface of the mold. In food applications, they are akin to oils or margarine applied beforehand to baking molds and pans. Various types include paint-on, baking, and spray-on options.

Internal Mold Release Agents: These agents are pre-mixed with the material to be molded. During molding, they aid in melting the material, making it more fluid, and then migrate to the interface between the mold and the material, improving de-moldability during the process. Depending on the application, both external and internal mold release agents may be used in combination.

2. Classification by Composition

In terms of composition, mold release agents can be divided into water-based, emulsion-based, solvent-based, paste-based, and oil-based types, based on components other than the mold release agent itself. External mold release agents are often applied to the mold surface at low concentrations to prevent the release agent from sticking to the product after demolding. As a result, water-based, emulsion-based, or solvent-based options, diluted with a solvent, are commonly used.

Types of Mold Release Agents

Mold release agents primarily consist of three main types of components: wax-based, silicone-based, and fluorine-based. The effectiveness of these agents varies significantly depending on the component used.

1. Wax-Based

Wax is used as a component in mold release agents. These waxes are typically low-molecular-weight polyethylene or other similar materials.

They form a layer between the mold and the molded product, causing interlayer separation known as delamination. Wax-based agents are known for their excellent application properties but may lead to issues such as significant transfer onto the product and contamination of the molds.

2. Silicone-Based

Similar to wax-based products, silicone-based agents cause delamination. They make use of the excellent lubricating properties inherent to silicone oil, resulting in a very high release capability. However, they are also associated with a high transfer rate and the potential for mold contamination.

3. Fluorine-Based

Fluorine-based mold release agents incorporate a fluorine non-adhesive agent. These agents enhance mold release by promoting interfacial delamination. They are known for their efficiency in achieving mold release with a small quantity of the agent.

As standalone products, fluorine-based agents may not provide high lubricity and are often used in combination with silicone-based agents.

How to Choose a Mold Release Agent

When selecting a mold release agent, several factors should be considered:

1. Material of the Article

The choice of mold release agent should align with the material of the article. Certain agents may be more suitable for specific molds, necessitating a careful match to the material being used.

2. Ease of Degreasing and Cleaning

While mold release agents facilitate detachment from the molded product, they may leave residues on the mold surface, potentially leading to contamination. Consideration should be given to ease of degreasing and cleaning, especially in mass production settings.

3. Health and Environmental Impact

Some mold release agents may have adverse effects on health and the environment. Particular attention is required for applications in medical supplies and food packaging materials. Selection should prioritize safety and environmental considerations.

What Is a Waterproof Screw?

A waterproof screw is a type of screw that features a sealing component on its seating surface (located behind the screw head) to create a waterproof seal, closing the gap between the screw and the fastener.

These sealing components go by various names depending on the screw manufacturer, such as sealing rings, shield rings, or O-rings. However, they all serve the same purpose. Typically, there is a small gap between the screw’s seating surface and the object it’s fastened to, which can potentially allow water or organic solvents to penetrate.

Waterproof screws are equipped with sealing components that are water-resistant and hermetically seal the gap between the screw and the object being fastened. These screws are commonly used to protect electronic circuit boards in household appliances from water splashes and to prevent rainwater from entering outdoor machinery.

Uses of Waterproof Screws

Waterproof screws find applications in safeguarding precision equipment and water-sensitive devices from water infiltration. They are particularly crucial for the following types of equipment:

– Precision equipment susceptible to water damage (e.g., computers, weighing equipment, medical devices).

– Equipment used in outdoor environments (e.g., weather instruments, solar power generation equipment).

– Equipment in locations where water exposure is likely, such as dishwashers.

When purchasing waterproof packing and screws separately, there’s a risk that they may not be the correct size or may not provide an effective seal. Choosing waterproof screws with included waterproof sealing components ensures a high level of waterproofing.

Principle of Waterproof Screws

Waterproof screws are specifically designed to withstand exposure to water. The screw body (the threaded part) is typically made from rust-resistant stainless steel. The seating surface behind the screw head is fitted with a sealing component that matches the size of the screw body, creating a seal between the screw and the fastened object.

These sealing components are often constructed using nitrile rubber, which is resistant to water and can also withstand solvents like petrol and alcohol. This makes it effective in preventing the penetration of fats, oils, and other liquids.

However, nitrile rubber is susceptible to corrosion by certain organic solvents, such as ethyl acetate and ether. For applications requiring resistance to these solvents, waterproof screws made of fluoroplastic (PTFE) should be chosen.

Other Information on Waterproof Screws

1. Proper Use of Waterproof Screws

Waterproof screws are primarily designed for use in areas exposed to water, such as external covers. Improper use may result in damage to the mating nut or the product or equipment assembled with the waterproof screw.

To prevent this, several considerations should be kept in mind:

– Ensure that the tightening force remains within permissible limits to avoid damaging the waterproof screw or mating elements.

– Repetitive forces, such as those caused by vibrations, should not exceed permissible limits for both the screw and the mating member.

– The seating surfaces of the waterproof screw must fall within permissible ranges to prevent the object being fastened (e.g., metal, wood) from caving in.

– Fastening with waterproof screws should not cause damage to the object being fastened.

2. Fastening Conditions for Waterproof Screws

When fastening waterproof screws, careful selection of fastening conditions is essential. Generally, the fastening force applied by a screw results from the screw itself undergoing elastic deformation and stretching to return to its original length. The force required to pull the screw is generated during the screw-tightening process, and the screw’s helical shape enables torque to be converted into pulling force.

Fastening with a screw is akin to moving a heavy load straight up, requiring significant force. However, sliding the load down a gentle slope necessitates much less force. Using a trolley with smooth-rolling wheels further reduces the effort required. Similarly, fastening waterproof screws involves overcoming resistance during tightening, and adequate axial force may not always be achieved. When securing components subjected to substantial external forces with waterproof screws, careful consideration of fastening conditions is crucial.

What Is Anti-corrosion Film?

An anti-corrosion film is a film that is either mixed or coated with an anti-corrosion agent. It inhibits the formation of rust on the product it protects by preventing the ingress of oxygen and water vapor.

Anti-corrosion films contain a vaporizable rust inhibitor, making them essential for the quality control of metal products. Traditionally, surfaces have been coated with grease or oil to prevent rust.

However, these coatings need to be removed before processing or assembly, incurring labor and equipment costs and having an environmental impact. Anti-corrosion films prevent rust without the use of anti-corrosion oil, eliminating these issues.

For films that prevent oxygen and water vapor, the environmental impact is even smaller because no anti-corrosion film is used.

Uses of Anti-corrosion Film

Anti-corrosion film is used as a rust-prevention measure for metal products, including steel and non-steel materials. It is commonly used in the storage of automotive parts.

Automotive parts are often stored for extended periods and may be shipped overseas, where containers can be exposed to hot and humid conditions. In such cases, metal products are particularly vulnerable to rust, making anti-corrosion film essential.

Traditionally, these products were stored using double packaging: rust-proof paper for rust prevention and plastic bags for sealing. Anti-corrosion film can replace both of these functions with a single sheet, reducing costs. Sheet-type anti-corrosion film is also available in larger sizes for packaging large machinery.

Principle of Anti-corrosion Film

Anti-corrosion film is typically made from polyethylene or other plastics containing a vaporizable rust inhibitor. This inhibitor is effective in preventing rust. When the vaporizable rust inhibitor evaporates from the anti-corrosion film, it fills the sealed space.

During the evaporation process, the rust inhibitor dissolves into the metal surfaces within the space and the moisture in the air. This inhibits the electrochemical reactions that cause rust, effectively preventing rust formation. As the anti-corrosion film uses a vaporizable rust inhibitor, it can penetrate minute crevices that may be inaccessible by other coating methods, ensuring comprehensive rust prevention.

Furthermore, the anti-corrosion mechanism can vary depending on the type of corrosion inhibitor used. For example, nitrites used in anti-corrosion films for steel applications dissolve in condensation water, inhibiting the reaction of oxygen and water with the metal. Carboxylates of amines, also used in steel applications, dissociate into carboxylic acids, which then rejoin on the metal surface, providing corrosion protection.

Barrier-type anti-corrosion films, which do not contain vaporizable corrosion inhibitors, offer corrosion protection by preventing the ingress of oxygen and water vapor. Typically, rust occurs rapidly when humidity exceeds 60-70%, making it crucial to prevent moisture ingress to avoid such high humidity levels.

Features of Anti-corrosion Film

Anti-corrosion film, which serves to prevent rusting of metal industrial products, exhibits four main characteristics:

1. Dual Role of Rust Prevention and Packaging

Anti-corrosion film can simultaneously fulfill the roles of rust prevention and packaging with a single material, eliminating the need for separate packaging materials.

2. Elimination of Rust-Preventive Oil Removal and Cleaning

Unlike rust-preventive oil, anti-corrosion film does not require removal or cleaning processes before assembly, reducing production steps and costs.

3. Versatility in Rust-Proofing Methods

Anti-corrosion film can be applied in various forms, such as sheets, boards, zip-sealed bags, and cushioning materials, making it adaptable to different product sizes and packaging conditions.

4. Reduced Environmental Impact

Anti-corrosion film is not liquid or paste-like oil or grease, minimizing the risk of contaminating the factory floor or soil due to dripping and reducing the environmental impact.

What Is a Vibration Isolator?

A vibration isolator is a device designed to mitigate the transmission of vibrations from vibration-generating equipment to the surrounding environment. It finds applications in settings requiring precise vibration control, such as precision manufacturing facilities and environments where optical experiments demand stability.

The effectiveness of a vibration isolator is determined by its natural frequency. Natural frequency refers to the frequency at which an object vibrates freely without external force. Lower natural frequencies provide better vibration isolation, as they are less responsive to external vibrations.

Vibration isolators often utilize air springs that can isolate vibrations in multiple dimensions, including the vertical axis. Air springs are adept at rapidly dampening vibrations due to air’s viscous resistance.

Uses of Vibration Isolators

Vibration isolators are commonly employed in industries where vibration-sensitive precision equipment is utilized, such as semiconductor and liquid crystal display manufacturing. They are used to minimize vibrations transmitted to the environment, especially when machinery like pumps or machine tools generate vibrations on a table.

In precision measurements and microscopic observations, where table vibrations or external disturbances can be detrimental, vibration isolators swiftly suppress vibrations, enhancing measurement efficiency.

Principle of Vibration Isolators

Vibration isolation entails preventing vibrations from vibrating machinery or other sources from propagating to the surrounding environment. Vibrations transmitted through gases are naturally attenuated by obstacles like walls, limiting their propagation. However, solid materials transmit vibrations differently, necessitating physical measures to curtail their transmission.

To reduce vibrations in solids, the material’s natural frequency (inherent frequency) must be kept low. When an object vibrates at its natural frequency due to external vibrations, it can experience resonance, leading to excessive vibration and potential equipment damage.

Therefore, effective vibration isolators aim to separate the transmitted vibration frequencies from the natural frequencies as much as possible. Methods like air springs and coil springs are used, with natural frequencies typically below 10 Hz. In the air spring method, compressed air within an air spring, consisting of metal fittings and a rubber membrane, helps dampen vibrations. Coil springs, on the other hand, do not require air but may result in tilting if the object’s center of gravity shifts.

Types of Vibration Isolators

Vibration isolators are classified into two main types based on their mechanisms:

1. Passive Type

Passive vibration isolators absorb input vibration energy using soft materials such as rubber or air springs. Most vibration isolators fall into this category, and some passive isolators may require an air supply, often from a compressor or factory air.

2. Active Type

Active vibration isolators actively counteract vibrations by detecting them with sensors and applying a force in the opposite direction using actuators to cancel out the vibration. Compared to passive isolators, active isolators require additional equipment like controllers and actuators but excel at isolating low-frequency vibrations below 10 Hz.

Additional Information on Vibration Isolators

Vibration Isolators vs. Vibration Dampers

Vibration isolators are devices on which vibration-generating equipment is placed to reduce the transmission of generated vibrations to the surrounding environment. Conversely, in a vibrational environment, a vibration isolator reduces incoming vibrations from the surroundings. While the terminology varies based on the role, in most cases, the device can be used for both vibration isolation and vibration reduction.

Another related term is vibration damping, which involves directly reducing the vibrations of a vibrating object. Vibration control, on the other hand, refers to the active mitigation of vibrations, often using damping devices.

What Is a Cast-in Heater?

A cast-in heater is a type of heating device where a heater element is embedded into a cast material.

These heaters typically involve sheathed heaters and air-cooled tubes cast into materials like brass, aluminum, and iron. Cast-in heaters directly contact the object they are heating, using conduction heat for efficient energy transfer. They are known for their durability, resistance to overuse, shock, and vibration, and provide uniform heating of metal surfaces.

The design of cast-in heaters is versatile, allowing for temperature control through rapid or slow cooling by incorporating air- or water-cooled tubes. Rapid heating can be further enhanced by attaching heat-dissipating fins to the external surface.

They are commonly used in applications requiring high-precision temperature distribution, such as in plastic molding, synthetic fibers, semiconductor manufacturing, engineering plastics, or heating parts with complex shapes.

Uses of Cast-in Heaters

Due to their uniform temperature distribution and high corrosion resistance, cast-in heaters find applications in:

1. Appliances

Used in ovens, ranges, irons, electric pots, hot plates, electric kettles, etc.

2. Commercial Equipment

Used in ovens, electric furnaces, parts casting, press surface plates, air-conditioning and heating units, kitchen equipment, electric kilns, etc.

3. Industrial Equipment

Applied in tank heating, chemical heating, heat insulation, melting low-melting-point metals, injection molding machines, extrusion molding machines, valves, pipe insulation and heating, synthetic fiber production, semiconductor manufacturing, etc.

4. Drying Equipment

Used for drying foodstuffs, food waste, sludge, livestock products, paint, wood, etc.

5. Heating and Heat-Retention Equipment

Implemented in pipelines, storage tank pipes, valves, water pipes, drainage pipes for insulation, freeze protection, defrosting, semiconductor, and liquid crystal manufacturing, pharmaceutical production, medical and chemical equipment, melting and heating of metals like lead, solder, zinc, aluminum, medical equipment, optical equipment, etc.

Principle of Cast-in Heaters

Cast-in heaters integrate a sheathed heater into a casting material for uniform temperature distribution. They are less direct than other heating methods but are easier to manage, as there’s no need to drain liquid for maintenance.

The sheath materials for these heaters include STP, SUS, Incoloy, and Inconel, chosen based on usage conditions. The maximum surface temperature varies by material: approximately 350°C for aluminum, 500°C for brass, 600°C for stainless steel, and 800°C for iron cast-in heaters.

They are used for indirect heating in spaces where direct heat sources are impractical, such as due to flammability concerns or odors. The mounting surface of the heater is machined to enhance heat conduction.

Features of Cast-in Heaters

1. Highly Efficient Heating

Aluminum and brass used in cast-in heaters have high thermal conductivity and a large contact surface area, ensuring efficient and uniform heating.

2. Capable of Heating Complex Shapes

These heaters can accommodate valves and molds with complex shapes as the castings are produced from a mold, allowing for the heating of intricate designs.

3. Vibration- and Shock-Resistant with Long Service Life

The cast-in design offers excellent environmental resilience, vibration and shock resistance, and a long lifespan. They also have strong resistance to heat and moisture, and can be customized for specific applications like chemical and corrosion resistance.

4. High Power Density and Large Heating Area

They can be set to high power densities for intense heating, and their high thermal conductivity allows for heating large areas.

5. Easy Temperature Control

These heaters enable rapid and slow cooling through the use of air or water cooling tubes. Rapid heating is also facilitated by the installation of heat-dissipating fins.

Other Information on Cast-in Heaters

Improved Serviceability of Cast-in Heaters

Cartridge heaters inserted into machined holes in an aluminum plate can be replaced without detaching the plate, allowing for flexible temperature distribution adjustments by modifying the power and layout of the heaters.

What Is a Weight Sensor?

A weight sensor is a device used to measure the weight of an object.

Currently, load cells are predominantly used for this purpose. Before their advent, mechanical lever-type scales were common, but they required frequent calibration and maintenance for accuracy.

Load-cell scales, designed without moving or friction parts, are less prone to breakage and require only simple maintenance. They are known for their high measurement accuracy and minimal temperature effects during measurement and are now widely used in various applications.

Uses of Weight Sensors

Weight sensors are used across diverse fields. Their most direct application is in measuring the weight of objects, such as weighing patients in hospital beds or checking product weights in production lines.

These sensors also measure pressure, thereby enabling the measurement of load on objects. For instance, they can determine the torque of vehicle engines and the load on their wheels.

Principle of Weight Sensors

Load cells, the most common type of weight sensor, come in various forms: hydraulic, pneumatic, and strain gauge load cells, with strain gauge load cells being the most widespread.

1. Hydraulic Load Cells

Hydraulic load cells contain fluid and measure weight based on the pressure changes within the fluid as force is applied. They are suitable for hazardous areas as they don’t use electronic components and are often used for weighing tanks and hoppers.

2. Pneumatic Load Cells

Pneumatic load cells utilize air pressure for detection. They use multiple damping chambers to enhance measurement accuracy. Being air-filled, they pose a reduced risk of contamination if broken compared to hydraulic systems.

3. Strain Gauge Load Cells

Strain gauge load cells convert force into an electrical signal. They work by detecting changes in electrical resistance caused by deformation under force. The resistance change is proportional to the force applied, allowing for accurate weight measurement.

Types of Weight Sensors

Besides load cells, there are other types of weight sensors:

1. Piezoelectric Element Type

Piezoelectric elements, made from materials like quartz or ceramics, generate an electrical charge under applied force. The change in charge is measured to determine weight or strain.

2. Capacitance Type

These sensors measure changes in capacitance caused by deformation in response to pressure, translating it into weight data.

3. Film Lamination Type

Using sheet type switches, this type is used for weight detection or to detect contact with an object.

4. Sheet/Mat Type

Sheet or mat-type sensors detect the presence or absence of weight. Known as pressure-sensitive sheets or mat switches, they consist of two layers of material that deform under weight or load, with piezoelectric or capacitive elements and contacts on their surfaces.

These sensors are used in applications like automatic doorways and bumpers of unmanned vehicles to detect human contact.

Further Information on Weight Sensors

Weight Sensors and IoT

Weight sensors are increasingly used in IoT-related applications. For instance, they detect the presence or absence of objects on automated conveyor lines or stock in automated warehouses.

They also enable automated stock counting and shipment quantification by weight. This functionality is expected to facilitate remote management of warehouse systems and other logistics applications.