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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.

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.

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!

One of the most unique types of injection molds is unscrewing molds. Unscrewing molding is a unique injection molding process with mold technology that includes movement and rotation to produce threaded components. Some plastic parts such as caps and closures with detailed threads cannot be removed using standard knock-off methods. After they are molded, parts need to be carefully unscrewed from mold to avoid damaging the threads.

The unscrewing molds are part of everyday use, which may cause you to think that you won’t need to spend much time considering the required design. To demonstrate the wide use of this particular mold type, the following is a shortlist of the types of products that use unscrewing molds in the design:

• Bottle and milk caps

• Condition and shampoo lids

• Prescription medication bottles

• Medical supplies

• Sprinkler and showerheads

• Screws, nuts, and bolts

Here’s How It Works:

• First, the plastic is injected into the tool. After the plastic has cooled, the threaded core starts to unscrew. The unscrewing mechanism works off of a rack and pinion and is powered by a hydraulic cylinder.

• The rack turns three sets of gears which then retracts the threaded core into the ejector box.

• Once the threaded core is fully unscrewed, the mold opens and the ejector system pushes a stripper plate forward to eject the part.

• After the part is fully ejected, the hydraulic cylinder reverses, screwing the threaded core back into the molding position, and the process repeats.

What factors need to be considered?

When you need one of these types of plastic molds, there are several things you have to determine to make sure you get the right fit for your product and budget.

Volume

The volume of the product will probably determine many different aspects of the final product, including the thread count, the size of the part, and the type of material that will be used during production. While other factors are important, the design of the various unscrewing molds is more complex and costly than many of the other types of molds.

Ease of Removal

The ease by which an unscrewing mold should be removed from the final product is an important factor to consider in the design. Water bottles have only a few threads, sometimes only two or three because they need to be easy to remove. To ensure that the tops do not fall off easily, the threads are spaced out a bit more. An unscrewing mold on a medical device will likely need a lot of threads that are evenly spaced and very difficult to pull off of the device. The material required for these two vastly different uses is affected by how easily the part should be removed from the product.

The Threads

The number of threads is going to vary based on the final product. Water bottles do not require a high thread count because they are relatively light and should be easily removed. If the unscrewing mold is for a plastic part under the hood of a car, it needs to have a higher thread count to be more durable. The number of threads required plays a large role in the final cost of production, so it needs to be tested to ensure it meets the needs of the final product.

Applications and Maintenance

High volume, reliable unscrewing plastic injection molds are some of the more complex plastic injection molds that can be manufactured. Unscrewing plastic injection molds are typically utilized for high volume applications where threaded plastic parts are needed for items such as:

ㆍBottle caps

ㆍShampoo bottles

ㆍPharmaceutical Supplies

ㆍAutomotive parts

ㆍNuts and bolts

ㆍCosmetics packaging

ㆍMedical Supplies

ㆍConsumer goods

ㆍSprinkler heads, lawn & garden parts

ㆍContainer lids

Most threaded plastic parts on standard plastic injection molds are not easy to remove using standard knock-off techniques. Therefore more complex unscrewing plastic injection molds must be utilized to prevent the threads on threaded plastic parts from being damaged while the parts are coming off of the plastic injection mold.

Because these threaded plastic parts are typically needed in high volume applications for items such as bottle caps or cosmetics packaging, the unscrewing plastic injection mold most operate at a high speed to reduce cycle times thus reducing part costs. The unscrewing plastic injection molds must also be high quality and reliable to operate for a large number of cycles while only needing routine preventative maintenance.

WIT MOLD is a highly skilled mold design and manufacturing company in China, certified ISO2009:2015 international quality standard. Contact us today for your threaded plastic parts!