Thermoset Vs Thermoplastic Injection Molding

The properties of thermosets and thermoplastics are very different, but their similarities and differences are often asked. The main difference between these two plastics is heat resistance and chemical resistance. Heat resistance is the main function of thermoset materials, while thermoplastics-more common-can only withstand a certain degree of heat. It is worth noting that plastic injection molding companies usually do thermoset or thermoplastic injection molding, but they rarely deal with both.

Below, we have broken down the differences between thermoset and thermoplastics in terms of the injection molding process, material availability, use, cost, and recyclability. Take a look:

Thermoset and thermoplastic injection molding: a comparison

Injection molding process

In thermoset injection molding, cold material is injected into an extremely hot mold to create a part. This process can solidify the part so that it can no longer melt.

In thermoplastic injection molding, the plastic material is melted and injected into a mold to make a part. Once this part has cooled, the mold opens and partly falls off.

Availability

The earliest plastic materials were thermoset, but today, thermoset injection molding is not common, except for electrical contact applications and liquid silicon. Therefore, thermoset Injection Molds machines are usually more difficult to find than thermoplastic injection molding machines.

THERMOSET INJECTION MOLDS

Uses

Thermoset parts are usually used where the parts must be able to withstand high temperatures. The medical part is a good example; dental tools with silicone handles and metal parts must be able to withstand the autoclave process for disinfection and reuse, so the silicone must be thermoset. Thermosets are also used for high voltage electrical applications.

Thermoplastic parts are more likely to be used in consumer plastics, which either do not come into contact with high temperatures, such as those used in milk cans or need to withstand moderate heat. For example, some polycarbonates are resistant to high temperatures and are often used to make plastic take-out cups, but they can still deform or melt at sufficiently high temperatures.

When considering thermoset and thermoplastic parts, you also need to consider whether the parts are regularly exposed to certain chemicals. For example, if you are making a plastic case for an electrocardiograph, the material used must be resistant to any hospital-grade chemical disinfectant.

Cost

The cost difference between china mold makers thermoset and thermoplastic injection molding is not black and white. The thermosetting process is usually slower—corresponding to higher cost—the material difference of thermoplastics can range from 90 cents per pound to $10 per pound, depending on performance. In other words, cost considerations should not be enough to make engineers move to one type or another—decisions should be based more on the material properties and the functions of the required components.

Recycling capacity

Thermoplastics are manufactured by melting pellets and then cooling them. This ensures that the finished part can also be remelted. This makes thermoplastics recyclable. Of course, when you melt apart, certain characteristics are different, so recycling thermoplastics does not guarantee that you get the same quality plastic parts-but it is worth noting.

On the other hand, thermosets cannot be remelted-so although thermoplastic parts can be ground and used in sandbags, their recyclability is limited.

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Advantages And Disadvantages Of Two-Shot Injection Molding

There are a variety of manufacturing methods used to create products using plastic polymers, including Two Shot Mold, compression thermoset molding, and extrusion. Although all of these are viable manufacturing processes, this process has several advantages that make it the first choice of many plastic manufacturers. The process is relatively simple; one material is injected into the mold to make the initial part of the product, and then the second injection of the second material is compatible with the original material. Many manufacturers use this method to make plastics or polymers for three good reasons.

Two-shot injection molding is cost-effective

The two-step process only requires one machine cycle to rotate the initial mold and place the second mold around the product so that the second compatible thermoplastic can be inserted into the second mold. Since the technology uses only one cycle, rather than a separate machine cycle, any production run with a lower cost requires fewer employees to produce the final product, and each run provides more items. It also ensures a firm bond between materials without the need for further assembly lines.

Strengthen product quality

Two-shot injection molding can improve the quality of most thermoplastic products from the following aspects:

Improved aesthetics. Items made of different colored plastics or polymers look better and are more attractive to consumers. If the product uses more than one color or texture, it will appear more expensive.

Improve ergonomics. Because this process allows the use of a soft-touch surface, the resulting project can have ergonomically designed handles or other parts. This is especially china mold important for tools, medical equipment, and other hand-held items.

When silicone and other rubber materials are used for gaskets and other parts that require a strong seal, it provides a better seal.

It allows you to combine the superior comfort and practicality of hard and soft polymers, even for the smallest products.

Compared to overmolding or more traditional insertion processes, it can greatly reduce the number of misalignments.

It enables manufacturers to create more complex mold designs using multiple materials that cannot be effectively bonded by other processes.

This bond is very strong, creating a product that is more durable, more reliable and has a longer lifespan.

Versatility

Product manufacturers favor a wide range of applications for two-shot injection molding, including automotive interior parts, medical equipment, tools, and toys. It allows manufacturers to combine various materials and colors to create a strong and attractive final product. Some materials can be effectively combined with this process, including silicone and thermoplastics, nylon and thermoplastic elastomers, or hard nylon and soft-touch materials.

Two-shot injection molding can solve your company’s product production difficulties. An experienced plastic manufacturer can guide you from concept to finished product and ensure a cost-effective solution.

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Two-Shot Molding vs. Overmolding

Injection molding is a popular manufacturing process, which can quickly produce complex-shaped precise parts without wasting a lot of materials.

Many different processes belong to the category of injection molding, including over-molding and two-shot molding. The two processes are similar, but there are some key differences-here are what engineers and designers need to know:

What is two-shot molding?

Two Shot Injection Molds, also known as dual-molds, double-shot molds, or multi-shot molds, are a subcategory of injection molding that allows engineers to create multi-material or multi-colored parts without adding additional assembly steps.

Through the different layers of materials or colors created by the injection molding machine, the two-shot injection molding process is best understood. The first material is injected into the mold to create the substrate, and other materials or materials will be molded around the substrate. After the substrate solidifies and cools, it is transferred by hand, robotic arm, or rotating plane to another cavity of the mold.

From there, the mold opens and rotates 180° with one side of the substrate to meet the other mold chamber and injection molding nozzle. Once the substrate is in place, the second material is injected and combined with the substrate to form a firm hold. Once the second layer has cooled, the last part will be sprayed out.

Engineers should know that Two Shot Mold can be accelerated or slowed down, depending on how the substrate is transferred to another cavity of the mold. Hand and robot arm transfer takes longer than the rotating plane, but the rotating platen molding is more expensive, usually, there are only high-efficiency options, mass production runs.

In addition, it is very important that the material of the mold is easy to bond, and the mold must be aligned to prevent deformation of the parts.

Advantages and disadvantages of two-shot molding

Two-shot injection molding is efficient and economical manufacturing technology. This process also produces highly durable terminal parts and assemblies.

From a design point of view, two-shot molding provides designers with a lot of flexibility, because this process can create complex geometric shapes and adapt to multiple colors to produce more beautiful parts.

In addition, because one machine manufactures the entire part, no post-processing is required, and engineers can greatly reduce manufacturing time, thereby reducing costs. However, it is worth noting that the initial two-shot injection molding machine may be costly, and the two-shot injection molding machine is more expensive than the standard injection molding machine. Fortunately, these costs are usually offset by labor savings and assembly costs for large-scale production runs.

What is over-molding?

Overmolding, like Two Shot Moulding, is a multi-shot injection molding process that produces a single final product from two or more different thermoplastics. This process is ideal for engineers who want to build components that are powerful, functional, beautiful, and that will not separate over time.

At the beginning of the over-molding process, engineers inject the substrate with a harder over-molding material. Then, the substrate is placed in an over-mold tool or an over-mold cavity within the same mold. The molten-over mold material is then sprayed into, onto, or around the substrate. After the molten material is cooled, the substrate and the over-mold are chemically or mechanically combined. The entire over-molding process only takes 30 seconds.

The product team must remember that all thermoplastics used in the over-molding process must be chemically or thermally compatible with each other. Compatibility with metal substrates is usually not a problem, because they can be used with any plastic over mold, but the product team may encounter compatibility issues when using plastic over molds. If the substrate and mold are not compatible, the final product may be deformed or poorly bound.

However, if two less compatible plastics must be used, the team can design mechanical bonding properties for the part after the fact, although this may result in higher costs.

Advantages and disadvantages of over-molding

Overmolding and two-shot injection mold manufacturer molding have many of the same advantages. They are ideal for quickly creating durable, reliable, and vibration-resistant parts with complex geometries, but over-molding is best suited for low-volume production runs.

Compared with two-shot molding, over-mold design is also easier, because engineers can use any standard injection molding machine to carry out this process.

In terms of disadvantages, the tolerances of over-molded parts are often lower than those of two-shot injection molding. It is also important to remember that plastic compatibility requirements may constrain designers.