Some injection molding materials do not bond well with other plastics and are therefore only suitable for mechanical bonding, not chemical bonding.

It is advisable to keep the backpressure of the ABS injection molding process as low as possible to prevent wear. The acceptable pressure is usually around 5 bar.

In some cases, combining materials can be dangerous. POM, for example, should never be overmolded with materials PVC or TPV, as the chemical reaction created can cause the release of deadly hydrochloric acid and an explosion.

Chemical compatibility is about more than just creating a strong bond, however. In some cases, attempting to use two incompatible materials within a mold can cause the release of toxic fumes, a dangerous buildup of pressure, or an explosion.

Due to the processability of ABS, it is the most suitable material to use in making complex parts. Its processability makes it easy to reproduce complex and functional parts using the plastic. Apart from the parts being accurately produced, they still maintain functional integrity even when used in extreme conditions, thanks to the hardness of the plastic.

Before using a piece of ABS plastic for manufacturing, it needs proper drying. The drying temperature used is within the range of 80 – 85°C done for 2 – 4 hours. Another drying method involves using a drying hopper with a temperature of 80°C. However, the latter process only lasts for 1 – 2 hours.

One of ABS plastic’s major shortcomings is its poor sunlight performance. The material tends to degrade upon constant exposure to sunlight. However, part manufacturers enhance its performance in sunlight by adding additives to the ABS plastic during molding.

Overmolding, the process of molding one material over a substrate made from another material, is a highly useful form of multi-material plastic injection molding. By combining soft and hard materials, overmolding makes it possible to make durable tools with soft hand grips, industrial components with built-in seals, and parts with high-friction surfaces.

These properties and potential for manipulation make ABS the most widely used polymer in the injection molding process. Want to find out how this plastic is used for manufacturing various finished products? Then, the next section is a must-read.

Designing the parts before the injection molding process makes it possible to determine if producing the part is actually possible. Here are some general principles that work with ABS parts design:

When trying to start an ABS injection molding batch, a few factors must be in place. These factors are vital to having successfully molded parts. They include:

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There are many reasons why ABS injection molding is one of the most popular forms of plastic molding. Some of the advantages include:

The costs here are responsible for the remuneration of the personnel carrying out the tasks and for the setup and maintenance of the machines. Examples of parameters factored in here include:

Some injection molding plastic substrate materials do not chemically bond well to any soft overmold materials, and are better suited to other forms of assembly such as fasteners. Likewise, some flexible materials, particularly thermosets like liquid silicone rubber, are generally better suited to mechanical bonds than chemical ones.

Nylon is a useful molding plastic due to its chemical resistance, strength, and many different varieties. Nylons like PA6, PA11, and PA12 can make good overmolding substrates for a variety of overmolded parts. Such materials can bond with various TPU varieties and also work well with a liquid silicone rubber (LSR) overmold.

While ABS parts usually have high tensile strength, they can’t withstand heavy loads for long periods because of their poor fatigue resistance. The ABS plastic part might degrade easily if constantly exposed to high-stress environments.

If you’re trying to produce some parts using injection molding, it is only right you find out about the cost of the whole process before going ahead. To estimate the costs involved, you need to factor in different costs. Examples of the various costs involved include:

ABS injection molding is a process that seems pretty easy to achieve. However, its technicalities that only experts understand. This is why it is important to outsource your ABS molding to companies that actually understand the practical principles of the manufacturing process.

ABS is harmless and non-toxic. This is one of many reasons it is a popular plastic material in manufacturing. However, it is not encouraged to use in medical implants.

It is also possible to carry out overmolding with two materials that do not chemically bond. However, in these instances, the part must be designed so the two components will join mechanically — for example, with undercuts that will physically lock the overmold material in place. This limits design freedom and creates a less secure bond.

The mold is quite vital in determining how the finished ABS product will turn out. Hence, the design of the mold and its gate is quite important in the process. The thickness of the ABS mold ranges between 0.025 – 0.05mm, while the gate length is set at less than 1mm. Also, the diameter of the channel through which the molten ABS flows is set at 3mm, while the vent hole width ranges from 4 – 6mm. Finally, the mold temperature used is always around a range of 60 – 65°C.

The properties the plastic possesses include chemical resistance, hardness, and heat resistance contributed by acrylonitrile. Other properties include impact resistance and toughness (bestowed by butadiene) and strength and gloss contributed by styrene. Despite its wide range of features, it is relatively one of the cheapest plastics to purchase. Also, it is one of the easiest plastics to use in injection molding due to its ease of processability.

ABS plastic has uses in different industries due to various reasons. Due to its ease of molding, the low cost of production, and resistance to physical and chemical changes, this polymer has become a manufacturer’s favorite. Here are some examples of industries where ABS plastic parts have found use:

So which overmold materials can be used with which substrate materials? This depends on a few factors, including the type of part being made and the type of bond required between the two materials.

For all overmolded parts, it is important that the substrate material has a higher glass transition temperature than the overmolding material. Otherwise, the substrate material will deform or melt within the second mold as the hot overmold material is being injected onto, into, or around the substrate.

ABS stands for Acrylonitrile Butadiene Styrene. This plastic material comprises three monomers that make up its name. Each of these monomers contributes its properties to the polymer plastic to give it a wide range of properties.

The injection molding speed depends on the grade of the ABS plastic and the finished product requirements. For example, flame-resistant ABS plastics can only use slow injection molding speeds. Also, products that require precision surface finishing could require multi-stage, high injection molding speeds.

However, before making parts with this process, it is vital to understand overmolding material compatibility. The best overmolded parts have a strong chemical bond between the substrate material and the overmolding material, but not all overmolding material combinations can produce such a bond. Furthermore, certain materials should never be combined within a single mold, as they can cause a dangerous chemical reaction.

Polypropylene is a widely used injection molding material for parts like living-hinge packaging lids due to its flexibility, impact resistance, and low cost. It is compatible with a wide range of soft overmold materials, including TPU, TPE, and TPV.

To prevent the out-gassing that comes from the flame-retardant ABS plastic absorbing moisture, you need to ensure the material is fully dried. Also, you need to ensure good temperature and residence time control during the injection molding process to prevent thermal degradation of the ABS plastic.

Strong, dimensionally stable, and very resistant to impact, PC is a popular injection molding material for transparent or opaque parts like lenses and medical devices. When combined with a soft TPU overmold material, it can also be a useful substrate for overmolding. PC can also chemically bond with several hard plastics like ABS, PET, and PEI.

The residence time is the time it takes for a plastic pellet to move from the injection molding barrel to the injection mold. For ABS plastics, the residence time is usually between 5 – 6 minutes at a temperature lower than 265°C. However, for flame-retardants grade ABS plastic, the residence time is shorter, and the temperature is way lower.

Injection molding is a common manufacturing process with different variants depending on the raw material used. One of such variants of the process is the ABS injection molding process. Just as the name implies, the raw material for this injection molding variant is ABS plastic.

To create a chemical bond between the two materials, a chemically compatible overmold material must be chosen. Many rigid materials will bond well with certain types of thermoplastic polyurethane (TPU), while materials like ABS and PP are compatible with a wider range of soft overmold materials.

Other activities carried out during ABS molding processes include decorated moldings using laser marking or hot stamping, ultrasonic welding, etc.

Controlling the temperature is crucial during ABS injection molding as overheating the plastic could lead to thermal degradation. This thermal degradation is due to the chemical bonds in the plastic breaking, which could cause brown granules on the finished part.

Specialize in CNC machining, 3D printing, urethane casting, rapid tooling, injection molding, metal casting, sheet metal and extrusion

This section highlights the various steps manufacturers must follow during the ABS plastic molding process. They include:

The recyclability of ABS makes it a perfect material for use in reusable applications. Recycling plants can easily shred the plastic parts and mix them up with fresh ABS to use for new parts production.

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This article serves as a quick guide to overmolding material compatibility, looking at which hard materials pair well with which soft materials and vice versa.

Overmolding is one of the most efficient molding processes for creating multi-material injection molded parts. Instead of assembling two or more components together — adding time and cost to production of the part — overmolding adds a second molding material directly over a molded substrate.

ABS plastic has some hygroscopic properties (it can absorb moisture from the air) and also absorb water around it. However, the presence of water in any molded ABS plastic could cause structural defects in the plastic. Hence, ensuring the ABS plastic used is properly dried is essential. There are two parameter types for drying the plastic: either dry at 80 – 95°C for 3 – 4 hours or use a dry hopper at 80°C for 1 – 2 hours.

A key advantage of overmolding is the chemical bond that can be formed between two compatible materials. By using an overmolding material that is chemically compatible with the substrate material, a strong bond will form at the the adjoining surfaces, eliminating the need for adhesives or fasteners and creating a strong, permanent bond.

Some ABS grades tend to stick to the mold screw after removing the part. So the best way to clean this up is to wait a little bit for the residue to wear off, then clean the compartments of the injection molding machine thoroughly using polystyrene.

PMMA or acrylic is another versatile transparent plastic for injection molding due to its scratch resistance and optical clarity. When used as a substrate material, it can chemically bond with certain TPUs. PMMA also bonds well with ABS, which may be useful when making a partially opaque, partially transparent part.

The overmolding process differs from two-shot injection molding, another type of multi-material molding, in that two separate molds are used: one to form the substrate and another to form the overmold. It therefore requires more manual intervention than two-shot injection molding but can be used with cheaper equipment.

This is also known as the tooling costs. This drives up the cost of the ABS injection molding process. There are three different methods used in making injection molds. They include CNC machining, 3D printing, and electrical discharge machining (EDM). These methods can range as low as $100 for low-volume simple 3D-printed molds. The price could also go as high as $100,000 for huge production runs or molds with complex designs.

After treating the material, the next step is to prepare the ABS molding machine for work. This will involve setting the parameters such as the compression ratio, clamping force, and injection molding pressure. The typical values for these parameters include a compression ratio greater than 2, a clamping force ranging from 4700 to 62000 tonnes per square meter (t/m²), and an injection molding pressure greater than 1500 bar.

This is the cost of buying the material (in this case, ABS). You’ll be able to find the material for a cost ranging from $1 to $5 per kg.

ABS molded parts are suitable for use in applications that require supporting heavy loads because of their high tensile strength. Their ability to withstand heavy mechanical impacts makes this plastic a good budget option for high tension applications.

Despite its acclaimed strength and toughness, this strong plastic isn’t so impervious to UV light. Hence it has limited outdoor use. However, part manufacturers have found ways to manipulate the properties of this plastic to withstand UV light by using various additives and fillers such as acrylic, glass, and stainless steel fibers. These additives alter the properties of the plastic and further enhance its uses for various applications.

You’ll most likely outsource your production to companies with the necessary equipment. These companies will charge you a separate fee for the equipment used. However, if you plan to get the equipment, you’ll have to dole a sum within the $50,000 – $200,000 range. Apart from buying the equipment, you’ll also have to maintain the equipment, which could cost you a fortune. The cost-effective option will be to outsource the production.

The injection molding temperature used for a particular ABS injection molding process depends on the quality/grade of ABS used. Listed below are examples of some grades of ABS plastic commonly used in ABS plastic molding and the optimum injection molding temperature used:

Working with an injection molding machine with good temperature control is essential as this process still requires a lot of heat. For example, when the ABS parts in production contain a high level of gloss, the temperature used in production is higher than normal. However, it is important to note that the higher the temperature used for the injection process, the shorter the exposure time should be.

ABS, highly impact-resistant and commonly used in injection molding for parts like handheld devices, is one of the best rigid thermoplastics for overmolding due to its high level of compatibility with both rigid and soft materials. When used as a substrate, it can bond well with flexible materials like TPU, TPE, and PVC, as well as other rigid materials like PC, nylon, and polystyrene.