Unscrewing Molds And Injection Molding

Unscrewing Mold 101: Guide to Working, Importance, and Types

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Unscrewing molds are a crucial component in the plastic injection molding industry, particularly when it comes to manufacturing threaded parts. These molds enable the production of high-quality threaded components with precision and efficiency. This article provides a comprehensive guide to the working principles, importance, and various types of unscrewing molds.

 

How Unscrewing Molds Work

Unscrewing molds are designed to create threaded plastic parts through an intricate molding process. Unlike standard molds, which simply open and eject the part, unscrewing molds have a unique mechanism to handle threaded components. Here’s a step-by-step overview of how they work:

ㆍInjection Phase: Molten plastic is injected into the mold cavity, filling it completely, including the threaded section.
ㆍCooling Phase: The plastic is allowed to cool and solidify within the mold.
ㆍUnscrewing Mechanism Activation: Once the plastic has cooled, the unscrewing mechanism is activated. This can be mechanical, hydraulic, or motor-driven, depending on the mold design.
ㆍThreaded Core Rotation: The core of the mold, which forms the threaded part of the component, begins to rotate. This rotation unscrews the newly formed plastic thread from the mold cavity.
ㆍEjection Phase: After the threaded core has completely unscrewed, the mold opens, and the part is ejected.

This process ensures that the threaded parts are not damaged during ejection, maintaining their integrity and functionality.

Importance of Unscrewing Molds

The importance of unscrewing molds in manufacturing cannot be overstated. Here are some key reasons why they are essential:

Precision and Accuracy: Unscrewing molds allow for the precise production of threaded parts, ensuring consistency and accuracy in every component.
ㆍEfficiency: These molds streamline the production process for threaded components, reducing the time and effort required compared to manual threading.
ㆍQuality Assurance: By using unscrewing molds, manufacturers can produce parts with high-quality threads that meet stringent standards, reducing the likelihood of defects.
ㆍCost-Effectiveness: While the initial investment in unscrewing molds may be higher, the efficiency and reduction in labor costs make them a cost-effective solution in the long run.
ㆍVersatility: Unscrewing molds can be used to produce a wide range of threaded components, making them versatile tools in various industries, from automotive to consumer goods.

Types of Unscrewing Molds

There are several types of unscrewing molds, each designed to meet specific production needs. The main types include:

ㆍMechanical Unscrewing Molds
Mechanical unscrewing molds use a system of gears, cams, and racks to rotate the threaded core. This type of mold is often preferred for its simplicity and reliability. The mechanical components are typically integrated into the mold base, making them durable and easy to maintain.

ㆍHydraulic Unscrewing Molds
Hydraulic unscrewing molds employ hydraulic cylinders to drive the rotation of the threaded core. These molds are highly effective for producing large, heavy-threaded components. The hydraulic system provides powerful and precise control over the unscrewing process, ensuring smooth and accurate thread formation.

ㆍMotor-Driven Unscrewing Molds
Motor-driven unscrewing molds use electric motors to rotate the threaded core. These molds offer high precision and are particularly suitable for complex and fine-threaded components. The motors can be programmed for various speeds and rotations, providing flexibility and control in the molding process.

Conclusion

Understanding unscrewing molds is essential for anyone involved in the plastic injection molding industry, especially when producing threaded components. These molds offer precision, efficiency, and high-quality results, making them a valuable asset in manufacturing. By choosing the right type of unscrewing mold—whether mechanical, hydraulic, or motor-driven—manufacturers can optimize their production processes and ensure the integrity of their threaded parts.

If you need more information or assistance in selecting the appropriate unscrewing mold for your needs, please contact us. Our suppliers are ready to provide expert guidance and support to help you achieve the best results in your manufacturing endeavors.

Unscrewing Molds And Injection Molding

Beginner’s Guide to Design for Unscrewing Molds

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Designing molds for unscrewing parts is a crucial skill in the realm of injection molding. Unscrewing molds are commonly used for producing threaded parts, such as caps, lids, and closures. Understanding the fundamentals of design for unscrewing molds is essential for beginners looking to venture into this area. In this guide, we’ll cover the basics of designing molds for unscrewing parts, including key considerations and best practices.

 

Understanding Unscrewing Molds

Unscrewing molds are a type of injection mold designed to produce threaded parts with helical features. Unlike standard molds, which rely on straight-pull actions to release parts from the mold cavity, unscrewing molds utilize rotational movements to release threaded parts from the mold core. This rotational action mimics the process of unscrewing a cap or lid from a bottle.

Key Components of Unscrewing Molds

Unscrewing molds consist of several key components, each playing a vital role in the molding process:

Core and cavity: The core and cavity form the mold cavity where the plastic part is formed. In unscrewing molds, the core typically contains the helical threads, while the cavity corresponds to the exterior shape of the part.
Threaded core: The threaded core is a specialized component that forms the internal threads of the molded part. It is designed to rotate within the mold to facilitate the unscrewing action.
Actuation mechanism: The actuation mechanism is responsible for rotating the threaded core to release the molded part. It can be driven by hydraulic, pneumatic, or mechanical means, depending on the specific design requirements.

Design Considerations for Unscrewing Molds

When designing molds for unscrewing parts, several factors must be taken into account to ensure successful molding operations:

Thread design: The design of the threads plays a crucial role in the functionality of the molded part. Threads must be properly sized and shaped to achieve a secure fit and proper sealing when the part is assembled.
Undercut features: Unscrewing molds often involve the presence of undercut features, which can complicate mold design and tooling. Careful consideration must be given to the location and geometry of undercut features to ensure they can be adequately released during the molding process.
Draft angles: Draft angles are essential for facilitating part ejection from the mold cavity. Adequate draft must be incorporated into the design of both the core and cavity to prevent friction and binding during the unscrewing process.

Best Practices for Designing Unscrewing Molds

To optimize the design of unscrewing molds and ensure efficient molding operations, consider the following best practices:

Simplify the design: Minimize the complexity of the mold design wherever possible to reduce costs and manufacturing time. Simplifying the design can also improve mold longevity and reliability.
Optimize cooling: Proper cooling is essential for maintaining consistent part quality and minimizing cycle times. Design the mold with adequate cooling channels to ensure efficient heat dissipation during the molding process.
Choose suitable materials: Select materials with the necessary strength, durability, and wear resistance for the components of the unscrewing mold. High-quality materials will contribute to the longevity and performance of the mold.

Conclusion

Designing molds for unscrewing parts requires careful consideration of various factors, including thread design, undercut features, and draft angles. By understanding the fundamentals of design for unscrewing molds and following best practices, beginners can create molds that produce high-quality threaded parts efficiently and reliably.

For further assistance or to explore our range of molding solutions, please don’t hesitate to contact us.

NPE 2024 – WIT MOLD Invitation

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WIT MOLD will be participating in the NPE 2024 exhibition, which is scheduled to take place from May 6th to 10th in Orlando, Florida. Sincerely invite all of customers & friends to visit our booth South hall, S14207.

 

Bmc Compression Tools Molding

What Is Thermoset Molding?

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Many people are not aware of the advantages of thermoset materials. This guide describes the thermoset molding process and how it can benefit you.

 

Thermoset Molding

Thermoset molding is an irreversible molding process by which malleable forms of plastic are forced into a heated mold and formed into their final shape.

Thermoplastic molding is the reverse process where heated material is injected into a cool mold. The material is then cooled to maintain the final shape of the part.

Why Use Thermoset Molding?

Thermoset materials are generally stronger than thermoplastic materials due to the catalysts that are added to the base compound that cause chemical reactions at the molecular level, forming a harder, irreversible final form. Thermoset plastics cannot be re-melted, only ground and recycled as filler for different applications.

Thermoset molded products have electrical and thermal insulation properties, which make them ideal for electrical and electronic applications. They are resistant to corrosion and have high impact strength, depending on the resin, and are cost competitive with engineered thermoplastics. Using thermoset molding allows producers to maintain tighter tolerances during the molding process compared to similar thermoplastic materials.

Pros of Thermoset Injection Molding

Injection molded pieces may be the best fit for a piece for several reasons:

Many different types of materials may be used in injection molding, including thermoplastic and thermosetting resins, polymers, and elastomers. This offers the engineer a great deal of control over which blend of materials will yield the best outcome, especially when needing to meet specific property requirements.

Fantastic for high-volume runs.

Precision and low waste. Because of the specific tooling and material mix, there is less waste with injection-molded parts than with other processes.

Short cooling time – Injection molded pieces cool quickly, reducing the time required to release the injected piece from the mold.

Cons of Thermoset Injection Molding

While injection molding is a fantastic process for the reasons mentioned above, there are certain limitations and drawbacks. A few of these drawbacks include:

Tooling costs – These costs can be significant as precision crafted molds are required.

Flash – Flash is unavoidable when injection molding thermosets. Once the part has been created and ejected from the mold, an automated or manual next step is necessary to remove the flash (excess material). Flash isn’t an issue with thermoplastics due to the higher viscosity of the liquid plastic.

Part size – The size of the piece being created definitely matters when it comes to the molding process. Typically, smaller part sizes (0.1 lbs to 6 lbs) are injection molded, while larger parts are transfer or compression molded. The volume of the order will also dictate which molding process will be the best fit for the project. Compression molding would likely be used for larger parts with a low (or high) volume, while transfer molding would be used for medium to high volume projects. Injection molding would be ideal for high volume runs with smaller pieces.

 

WIT Mold offers Custom Plastic Molding and Tooling services, Contact us now for a competitive offer!

Bmc Compression Tools Molding

Difference between Thermoset & Thermoplastic Injection Molding

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Thermoplastics and thermosetting plastics are two separate classes of polymers that are widely used in the process of injection molding to create products of various types. Both these categories of plastics possess different properties and characteristics. Hence, choosing the right category of polymer, between the two, is of paramount importance to achieve the expected results when used in applications.  Most of the injection molding service providers usually receive a question from their clients about the differences between thermoplastic and thermoset molding process. Here, in this post, let’s see thermoset & thermoplastic injection molding comparison.

 

Defining Thermoplastic and Thermosets

Before we go deeper into the topic, it is important to understand the two terms thermoset and thermoplastic. Let’s first find out what are thermosets and thermoplastics.

What are Thermosets?

Thermoset plastics “set” after they cure and are generally stronger than thermoplastic materials. Initially, the polymer is a liquid or soft solid, which becomes rigid later when cured. Owing to their high mechanical and physical strength, resistance to heat, corrosion, and mechanical creep, thermosets are used in a variety of applications. A few amongst the common thermoset materials used in the injection molding process include alkyds, epoxy, phenolic, polyimides, thermoset polyester, and so on.

What are Thermoplastics?

In contrast to thermoset, thermoplastics liquefy and become pliable when heat is applied. Thermoplastic polymers can be reheated and reprocessed many times, which is impossible when it comes to thermosets. Usually stored in the form of pellets prior to the molding process, these categories of polymers can withstand multiple re-shaping without causing any damage to the material. They possess high strength, shrink-resistance, flexibility, high-Impact resistance, and chemical resistant, among others. A few amongst the common thermoset materials used in the injection molding process include ABS, nylon, PET, polypropylene, polyethylene and TPE, among others.

Difference between Thermoset & Thermoplastic Injection Molding

The way thermosets are molded differs with respect to thermoplastics in several aspects and both the categories require varied treatment during the injection molding process. Let’s check a few differences when molding thermosets and thermoplastics.

Where and How They’re Used

The differences inherent to thermosets and thermoplastics make them uniquely suited for differing applications.

Appliance fabrication may require a thermoset such as epoxy — the material’s high-impact resistance, microbial resistance, and general inert properties are ideal in the kitchen and cooling environment. Conversely, a thermoplastic such as polyethylene makes a great packaging film, since the material shrinks and conforms to the packaging when heated.

As a general rule, thermosets are often affiliated with manufacturing and utilities — appliances, electrical applications, and anything else involving heat that may otherwise warp thermoplastics. Thermoplastics, on the other hand, are broadly diverse and used in everything from aerospace fabrication to consumer goods and toys. The nature of the polymer used depends on the final application.

 

Now that you know how thermoset injection molding differs with respect to thermoplastic injection molding. With the information provided in the post, you would be able to make a judgment on the type of polymer category you should opt to produce molded parts. However, just knowing the differences between the materials won’t be enough, instead you would need an injection molding service provider who can mold your parts as per the right specifications provided. Partner with leading injection molding companies like WIT MOLD who own a comprehensive working knowledge regarding thermoplastic vs thermoset molding.

injection mold

Common Defects Of Injection Molds And Their Solutions

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An injection mold is a tool for producing plastic products and for giving them a complete structure and precise dimensions. Read on for more information about common problems and solutions for injection molds.

 

injection mold

 

A mismatch between mold and injection molding machine

Causes:

1. Positioning ring position is not correct, size is too big or too small.

2. Wrong position and size of the ejector hole of the mold; wrong position and size of the forced pull reset hole.

3. Mold width size is too big; mold height size is too small.

Solution:

1. Adjust the ejector hole position and size; adjust the reset hole position and size.

2. Replace the positioning ring; adjust the position and size of the positioning ring.

3. Change the tonnage of a large injection molding machine; increase the thickness of the mold.

 

Bad quality of parts

Causes:

1. The fit-gap is too large.

2. Poor glue walking, trapped air.

3. Ejector pin is too small, uneven ejection.

4. Too small bevel, burr, hardness is not enough.

5. Uneven injection pressure, insufficient strength of product form.

6. Processing error.

7. Far from the gate, low mold temperature.

Solution:

1. Trim the gate, pressure uniformity, strengthen the product strength.

2. Reasonable adjustment of clearance and grinding work part of the parting surface.

3. Improve the gate, increase the mold temperature.

4. Add local glue, add exhaust.

5. Re-processing.

6. Increase the ejector pin, evenly distributed.

7. Repair burr, increase slope, nitriding.

 

injection mold

 

The parts are difficult to fill and difficult to take

Causes:

1. The pouring system is blocked, the runner cross-section size is too small, the gate arrangement is unreasonable, and the gate size is small.

2. The limit stroke of the mold is not enough, the extraction stroke of the mold is not enough, the ejecting stroke of the mold is not enough.

Solution:

1. Check whether the limit, core extraction, and ejection strokes meet the design requirements and adjust the strokes that do not meet the requirements.

2. Check the runner and gate of each section of the pouring system, and fix the parts concerned.

 

Mold opening and closing ejecting reset action is not smooth

Causes:

1. Slanting ejector, ejector pin sliding is not smooth.

2. Mold frame guide column, guide sleeve sliding is not smooth, with too tight

3. Reset spring elasticity or pre-pressure is not enough.

Solution:

1. Increase or replace the spring.

2. Repair or replace the guide pillar, guide bush.

3. Check and repair the slanting top, ejector pin.

 

Mold water transportation is not working or water leakage

Causes:

1. Water sealing rubber ring and water pipe joint are not sealed enough.

2. The mold water channel is blocked and the inlet and outlet water pipe joints are connected in the wrong way.

Solution:

1. Check the cooling system inlet and outlet water pipe joints connection and each section of the waterway, repair the relevant parts.

2. Check the water sealing rubber ring and water pipe joints, repair or replace the parts.

 

WIT MOLD is a very professional mold design and mold manufacturer located in southern China and has passed the ISO2009:2015 international quality Our injection molding process can be customized according to your unique project. If you are interested, please feel free to contact us.

What Materials Are Used for Injection Molding?

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In the world of manufacturing, injection molding is a widely utilized process for creating intricate and precise plastic parts. The materials used in injection molding play a crucial role in determining the final quality, strength, and functionality of the produced components. In this article, we will delve into the various materials commonly used for injection molding and explore their unique characteristics. By understanding the different options available, you can make informed decisions when it comes to selecting the most suitable material for your specific manufacturing needs.

1. Thermoplastics

Thermoplastics are the most commonly used materials in injection molding due to their versatility and wide range of properties. These materials have the ability to soften when heated and solidify upon cooling repeatedly, allowing for easy molding and recycling processes. Some of the popular thermoplastics used in injection molding include:

 

Polypropylene (PP)

Polypropylene is a lightweight and flexible thermoplastic that offers excellent chemical resistance, low cost, and high impact strength. It is commonly used in the automotive, packaging, and consumer goods industries.

 

Acrylonitrile Butadiene Styrene (ABS)

ABS is a strong and durable thermoplastic that possesses good impact resistance and dimensional stability. It is often used in the production of electronic enclosures, automotive components, and household appliances.

 

Polycarbonate (PC)

Polycarbonate is a transparent and highly impact-resistant thermoplastic. It is known for its excellent optical clarity, making it suitable for applications such as safety goggles, lenses, and automotive lighting.

 

Polyethylene (PE)

Polyethylene is a versatile thermoplastic that comes in various forms, including high-density polyethylene (HDPE) and low-density polyethylene (LDPE). It offers excellent chemical resistance, electrical insulation properties, and is commonly used in packaging and piping systems.

2. Engineering Plastics

Engineering plastics are a class of materials that exhibit enhanced mechanical, thermal, and chemical properties compared to standard thermoplastics. These materials are specifically designed to withstand demanding environments and provide superior performance. Here are some notable examples:

 

 

Polyamide (PA)

Polyamide, commonly known as nylon, is a strong and lightweight engineering plastic. It possesses excellent tensile strength, abrasion resistance, and is often utilized in applications such as gears, bearings, and structural components.

 

Polycarbonate-ABS (PC-ABS)

PC-ABS is a blend of polycarbonate and ABS, combining the toughness and heat resistance of polycarbonate with the processability and cost-effectiveness of ABS. It finds extensive use in automotive, electronics, and telecommunications industries.

 

Polyether Ether Ketone (PEEK)

PEEK is a high-performance engineering plastic known for its exceptional mechanical, thermal, and chemical resistance properties. It is commonly employed in aerospace, medical, and oil and gas applications where extreme conditions are present.

 

Polyphenylene Sulfide (PPS)

PPS is a high-temperature engineering plastic that offers excellent chemical resistance and dimensional stability at elevated temperatures. It is often used in electrical and electronic components, as well as automotive parts.

3. Elastomers

Elastomers, also known as rubber-like materials, are characterized by their elasticity and flexibility. They are commonly utilized when parts require excellent sealing, cushioning, or shock-absorbing properties. Let’s explore a few examples:

 

Thermoplastic Elastomers (TPE)

TPEs are a versatile group of elastomers that combine the processing advantages of thermoplastics with the elasticity and softness of traditional rubber. They find extensive use in the automotive industry, medical devices, and consumer products.

 

Silicone

Silicone elastomers are known for their high-temperature resistance, low toxicity, and excellent electrical insulation properties. They are widely used in the medical and food industries, as well as for seals, gaskets, and electronic components.

Conclusion

In summary, the materials used for injection molding are diverse and tailored to meet specific requirements in terms of strength, flexibility, chemical resistance, and more. This article provided an overview of various materials, including thermoplastics like polypropylene, ABS, polycarbonate, and polyethylene, as well as engineering plastics such as polyamide, PC-ABS, PEEK, and PPS. Additionally, elastomers like TPEs and silicone were also discussed. By understanding the unique properties of these materials, you can make informed decisions and select the most suitable option for your injection molding needs.

 

Remember, choosing the right material is crucial in achieving high-quality and cost-effective production. Always consult with experts in the field to ensure the optimal selection of materials for your specific application. WIT MOLD can meet the demand for plastic products that are reasonably priced, durable, and require precise specifications every time. We are your one-stop supplier of high-quality, cost-competitive domestic molded plastic products using various plastic materials.

What Are The Requirements For Injection Molding Machines For Precision Injection Molding?

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高精度模具

Precision injection molding machine refers to the molding machinery and equipment suitable for the molding production of precision plastic products. For a precision injection molding machine, how should we measure or judge?

Many precision injection molding machines are also required

① High injection pressure and fast injection speed.

② The clamping system has enough rigidity and precision. The so-called precision of closing refers to the uniformity, adjustability, stability and repeatability of the closing force, as well as the high precision of the opening and closing position of the mold.

③ The pressure, flow rate, temperature and measurement can be accurately controlled to the corresponding accuracy, and the multi-stage injection can be used to ensure the reproducibility of the molding process and the repeated accuracy of the product.

Precision injection molding machines can achieve the benefits of high pressure molding

A, improve the precision and quality of precision products.

Injection pressure has the most obvious effect on molding shrinkage. When the injection pressure reaches 392MPa, the shrinkage rate of molding is almost zero. At this time, the accuracy of the product is only affected by the mold control or the environment. Experimental results show that the mechanical strength of the parts can be increased by 3 ~ 33% when the injection pressure is 98 ~ 392MPa.

 

高精度模具

B, can reduce the wall thickness of precision products, improve the molding length.

Taking PC as an example, the ordinary injection pressure of 177Mpa can form products with wall thickness of 0.8mm, while the precision injection pressure of 392MPa can form products with thickness of 0.45mm or more. Ultrahigh pressure injection machines can obtain products with higher flow ratio.

C. Increasing injection pressure can give full play to the efficacy of injection speed.

Injection molding machine performance to achieve precision injection

Injection molding products have been used in various fields, widely used to replace high-precision metal parts, so as to put forward strict requirements on dimensional accuracy, mass accuracy, apparent mass and mechanical properties of injection parts. At the same time, the technological factors affecting the quality of injection molding products also put forward higher requirements.

The ideal control state of injection molding machine is to directly control product size, mass, apparent mass, mechanical properties and other variables as feedback signals for feedback control. However, the method of direct measurement and conversion of these non-electric quantities into electrical signals has not been solved for the time being, and can only be solved by controlling the controllable variables of the injection molding machine that affect the quality of the above-mentioned products. .

We are a precision injection molding company, if you need please feel free to contact us.

Cheers for The New Year 2023!

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Last Saturday is the Beginng of Spring, our factory had a big dinner together.

We made a short summary of 2022 and had awards for our excellent colleagues. Even though the year 2022 was hard, our factory still had good performance. Here we appreciate all our customers trust and support to our factory.

After 10+ years cooperation together, our team is more and more stronger now, I believe we will have a bright future together.

Cheers for our good harvest and progresses! Cheers for the new year 2023!

 

Plastic Injection Molding: The Cooling Rate Process

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Plastic Injection Molding

 

In plastic injection molding, the cooling rate is the last section of the molding cycle.

The cooling rate is a decreasing rate from the time the plastic resin enters the mold until the last cavity of the mold is filled.

When the cooling process is complete, it is safe to remove the part from the mold.

Factors that affect the cooling rate and the final molded part

Mold Cavity Pressure

The cooling rate is monitored, measured, and displayed on a pressure curve. It is displayed this way because as the plastic resin cools, it shrinks, which reduces the mold cavity pressure.

Mold Temperature

In plastic injection molding, the temperature of the mold itself can be a factor in the cooling rate process. Aside from affecting mold cooling lines, mold temperature can affect part blemishes, like:

  • Mold Warpage
  • Sink Marks
  • Jetting

Improper mold temperature can also impact properties, such as:

  • Molded-in Stress
  • Fatigue Resistance
  • Wear Resistance
  • Creep Resistance
  • Molecular Weight
  • Dimensional Stability

The cooling rate can also be affected by the use of metals that conduct heat away.

The cooling process is complete when the temperature is no longer reducing and any additional time spent to cool the part is useless.

When the cooling process is complete, it is safe to remove the part from the mold.

TIP: During the plastic mold design phase, you must consider the best possible cooling channels for the mold. Using a plastic molder with a deep knowledge of cooling rate process optimization will allow for better control over the mold temperature, and thus, the cooling rate. It will also provide the best cycle time and the best outcome for a good, stress-reduced molded part.

How to Calculate Cooling Time?

Cooling time in injection molding is a critical part of the production process. It is the amount of time the molten plastic takes to solidify. An adequate cooling system is required to transfer heat away from the mold and maintain a stable cooling rate, ensuring the highest quality final products.

One of the quickest methods for estimating the cooling time is using a formula that accounts for the thickness of the part in an equation based on the effective thermal diffusivity. The thermal diffusivity estimates the transfer of heat in and out of material.

 

Since its establishment, WIT MOLD has successfully exported more than 2000 sets of molds with different types of structures and designs, which are applied to a variety of industries.