The Ultimate Guide To Custom Molded Plastics

What Is Plastic?

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Plastic is a synthetic material derived from petrochemicals. It is created by heating crude oil or natural gas until they break down into smaller molecules called monomers. These monomers then polymerize (or bond together) to create long chains of polymers. When these chains are heated again, they melt into a liquid state. Once cooled, they solidify back into their original shape.

Polymerization occurs when two or more monomeric units join together to form a polymer chain. This process requires energy input and occurs at elevated temperatures under pressure. The length of the polymer chain determines its properties as well as how it will be processed into an end product.

Plastic is a versatile material that can be used in a wide range of applications. Plastic has numerous advantages over other materials, including being lightweight, durable and inexpensive. Plastic can be molded into virtually any shape, making it ideal for many industrial applications.

Types Of Plastic

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Polypropylene beads plastic pellets on white color background.

Plastic is an amazing material. It’s versatile, durable and easy to work with. It can be used for just about anything, from toys to medical equipment. And with so many different types of plastics, it’s easy to find one that fits your needs perfectly.

Here’s a quick rundown on some of the most common types of plastics:

Polyethylene (PE)

This is one of the most common types of plastic used in industry today. PE is a tough material with excellent chemical resistance properties. It’s also relatively inexpensive compared to other types of plastic. This makes it ideal for many industrial applications such as shipping containers or packaging materials for food products like milk jugs or juice bottles.

Polypropylene (PP)

This is an excellent choice for items that will be used in extreme conditions. It is impact resistant, UV stable, has good chemical resistance and can withstand temperatures up to 118 degrees Fahrenheit. It also has low moisture absorption and is often used for making molds for other materials (such as silicone).


The most common type of hard plastic is Acrylonitrile Butadiene Styrene (ABS). ABS is used for everything from automotive parts to children’s toys because it’s strong enough for heavy duty applications but still flexible enough for many uses that require flexibility. It can be transparent or opaque depending on how it is colored or finished.


Acrylics are one of the most common plastics used to make custom molded plastics. Acrylics are strong, durable and transparent with high gloss finishes. They can be made with a wide variety of colors, but are not suited for very large applications or outdoor use because they do not hold up well under sunlight or weathering conditions. Acrylics can also be easily scratched if not handled gently.

Acrylic is made up of polymethyl methacrylate or PMMA for short. This type of plastic has very low impact resistance compared to other plastics but has great light transmission qualities — it’s often used in manufacturing lenses because it absorbs little light while still allowing you to see through it clearly.


Polycarbonate is a high-impact plastic that is used in many industries for a variety of items such as bulletproof glass, car lights and even eyeglasses frames! It is lightweight, impact resistant and has excellent resistance to scratches and dents. Polycarbonates can also be colored by adding colorants during the manufacturing process (such as pigmentation). This makes them an ideal choice for making custom molded plastics since coloring them after production can be costly due to their transparency.


Nylon is a popular choice for making custom molded products because it’s strong, flexible and resistant to chemicals, UV rays and heat. It also has a high melting temperature (upwards of 300 degrees Fahrenheit), which means that items can be safely placed in boiling water or an oven without damage to the mold or product.

Nylon is strong, flexible and durable — making it perfect for all sorts of applications from clothing to automobiles! Nylon has been around since the 1930s, but it was first used commercially in 1942 by DuPont Company during World War II as a substitute for silk stockings!


PVC is one of the most popular plastics because it’s so versatile. It’s used in many products that require high strength, flexibility, and durability such as pipes and cables. PVC is also resistant to chemicals in both liquid and gaseous forms, which makes it ideal for use in products like medical supplies, food packaging, and flooring materials.

How Does Plastic Work?

When a plastic melts, it becomes soft and pliable. As it cools, it hardens and returns to its original shape. In order to make plastic molding easier, manufacturers add additives to the molten plastic to increase the viscosity. Viscosity refers to how thick a substance is. A high-viscosity substance is thicker than a low-viscosity substance. Additives also help plastic retain its shape after being molded.

When a hot plastic is poured into a mold, it cools and hardens. Depending on the type of plastic used, this can happen in just seconds or minutes. Once the plastic has cooled, you can remove it from the mold using basic tools such as ejector pins or ejection plate.

If you want to make plastic molding easier, you can add additives to the molten plastic. These additives increase viscosity and help your finished product retain its shape after being molded.These additives make the plastic softer, more flexible and easier to mold. They also increase the plastic’s ability to retain its shape after being molded. Plasticizers are usually added during the mixing stage of manufacturing. They can be natural or synthetic and come in liquid or solid form. Plasticizers are often used in conjunction with other additives such as fillers and colorants.

Advantages And Disadvantages Of Plastic

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Transparent polypropylene balls on a coral colored background.

Plastic is a material that is widely used in the manufacturing of products. The advantages of plastic make it a popular choice for many products.

Advantages of Plastic

Light weight

Plastic is an excellent material to use when you want to create something that’s lightweight and easy to carry around. Plastic parts are often used in the construction of automobiles, airplanes, toys and other consumer goods because they’re much lighter than their metal counterparts.

Low cost

Plastic is also relatively inexpensive compared to other materials like steel and aluminum. This makes it an ideal building material for consumer goods that need to be sold for low prices. Plastic parts can also be easily molded into shapes that make them easy to manufacture and assemble, which drives down costs even more since there’s no need for specialized tools or machinery when making plastic parts.

Won’t Corrode or Rust Over Time

Plastic won’t corrode or rust over time, which makes it a great choice for items that will be used in water or exposed to the elements. Plastic will not rust if it’s exposed to salt water, making it perfect for boats and other watercrafts. Plastic is also a great option for outdoor furniture and other items that will be exposed to the sun. Plastic won’t break down over time like wood or metal, making it ideal for long-term applications.

Better insulation

Plastics are better insulators than metals. They do not conduct electricity or heat very well and are sometimes used as an insulating layer between different metals in electrical appliances such as electric motors and refrigerators.

Disadvantages Of Plastic

Plastic is a great option for your custom molded products. It is durable, versatile and comes in a wide range of colors and textures. It also has some disadvantages that you need to consider when deciding whether or not plastic is the best choice for your product.

Low Heat Resistance

Plastic will melt if it gets too hot, so it isn’t suited for applications where heat resistance is required. For example, plastic can be used to make toys or kitchen utensils but not oven mitts or cookware because those items need to withstand high temperatures without melting or deforming.

Limited Durability

Since plastic is made from polymers that are molded together, it does not have a uniform structure like metal does and therefore does not have as much strength or durability as metal does. This makes it unsuitable for applications that require heavy-duty items like tools, vehicles or furniture because they will break easily if dropped on their sides or hit with enough force to cause cracks in their shells.

Toxic Chemicals

Some types of plastic contain toxic chemicals that can leach out into your body when you eat or drink something packaged in them – especially if they are heated or reheated repeatedly. The most common type of chemical found in plastics is BPA (bisphenol A), which has been linked to developmental disorders in children and hormonal imbalances in adults. Other chemicals include phthalates (DEHP), which is found in many types of plastic including vinyl flooring, PVC pipes and shower curtains; flame retardants like PBDEs (polybrominated diphenyl ethers); and heavy metals such as cadmium which can cause cancer and birth defects if ingested over time.

Not biodegradable

Plastic is not biodegradable, which means that it can take hundreds and thousands of years before it completely decomposes into smaller particles that can be absorbed by the soil and water bodies. This results in accumulation of plastic waste in our environment which is hazardous for human beings and animals alike.

Even though most plastics can be recycled, they do not decompose like other materials do. This means that once plastic enters our landfills or the oceans it will stay there for hundreds of years, if not longer. The only way plastic can be broken down is through high temperatures and pressure, which means that even if we were able to recycle all of our plastics and keep them out of landfills, they would still take hundreds of years to break down naturally.

6 factors consideration when choosing

1.Temperature is a factor in the design of materials and their use. Materials used in high temperature environments must be selected carefully to ensure that they do not fail due to thermal stress or creep.

Thermal stress occurs when the coefficient of linear expansion of a material differs from that of another material with which it is in contact. The coefficient of linear expansion is the measure of how much a material expands or contracts along its length when its temperature changes. When two materials with different coefficients of linear expansion come into contact, they exert forces on each other, called “thermal stresses”. These forces can cause cracks in components subjected to these stresses if they are not designed properly or if the stresses exceed the strength of the material.

2.Chemical resistance of plastics is the ability of a plastic material to withstand attack by a particular chemical or group of chemicals. The test method for determining chemical resistance is ASTM D4303. This specification covers methods for determining the resistance of plastics and elastomers to degradation by various organic solvents and hydrocarbon fuels. It also includes tests for determining the effect of certain chemicals on the physical properties (e.g., tensile strength, hardness) of polymers.

Different types of plastics have different levels of chemical resistance. Some plastics can be used in harsh environments where they will be exposed to chemicals such as oil, fuel, or water. Others cannot be used because they might dissolve or break down.

3.The resin’s availability is a big consideration, as it is the main factor that will affect how long it takes to get your part made. The more common resins and materials are generally easier to find.Some resins are more widely available than others, which can make them a good choice if you need a lot of material.

Not all resins are available in every country or region. You will want to check with local suppliers to see what options are available to you.

4.Material property requirements.The materials must prove heat resistant, flameproof, and able to withstand the rigors of daily use.These can vary by region or even country. For example, North America has UL 94V-0 flammability rating while Europe has EN 45544-2-10 flame spread rating.UV resistance: A measure of how well the plastic resists degradation when exposed to ultraviolet light over a period of time.

5.The surface finish of the plastic is an important consideration. Most plastics are available in a range of finishes, including glossy and matte. A glossy finish will make the plastic more resistant to scratches and give it a premium look. Matte finishes are more popular when designing products that need to be durable or have a more industrial look.

6.Resin type :There are many types of resins for different applications. Some resins are more durable than others, some have better elasticity and flexibility, and others are more resistant to chemicals or UV light. The specific resin you choose will affect how much your product will cost to manufacture.


As you can see, you have many choices when it comes to custom molded plastics. You can choose the specific features that you want in your design, leading to great looking products that also last for a long time.

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