Importance of Material Selection in Plastic Injection Molding

Plastic injection molding is a unique manufacturing process, which enables producing large volumes of plastic products in complex shapes, precise dimensions and in varied materials. More than 85,000 commercial options of plastic materials, which are categorized under thermosets and thermoplastics, are being utilized by the injection molding companies in their production house on a daily basis. This is exactly where the challenge and confusion arises. Owing to a wide range of properties and the cost associated with injection molding plastic materials, it becomes always a daunting task for the product designers, molders, and others to choose the most appropriate material. This post thus lists a few points that must be considered during material selection in plastic injection molding.

What are the commonly used Materials for Plastic Injection Molding

As mentioned earlier, there are a wide range of quality materials available to develop plastic injection molded component. A few amongst them that are widely used to build products are listed below.

• Acrylonitrile Butadiene Styrene
• Acetyl
• Acrylic
• Nylon
• Polyether ether ketone
• ULTEM
• Polystyrene
• Polyurethane
• Polyester
• Polycarbonate
• Polypropylene
• Liquid Crystal Polymers
• Copolymer Polypropylene
• Polybutylene Terephthalate (PBT)
• High Density Polystyrene (HDPS)

Guidelines to Material Selection in Plastic Injection Molding

Being one of the most decisive components that determine the overall part quality, it is critical not to overlook the material selection process. Consider the following points before making a selection.

• Durability:Shelf life differs from material to material. Hence, ensure that the material you have chosen meets the durability requirements of the applications.


• Resistance to Environmental Conditions: Products made from plastics are put to application in varied environmental conditions. They may be subjected to extreme environment conditions such as cold, hot, or moisture. Hence, consider the area of usage while selecting the material, as a wrong selection may lead to discoloration, cracks, among others.


• Flexibility: Some plastic materials possess the capability to bend extremely without breaking, while others break on bending. A few applications demand the plastic parts to be bent to a certain level. Consider such application requirements stringently before making a selection.


• Impact Resistance: Plastic products are used in several hostile conditions where they are subjected to impact and stress of varied kinds. If the material used in their making is not rugged enough, it will lead to part breakage, deformation, and so on.


• Tensile Strength: It refers to the resistance of the material to break under tension. Tensile strength of one material differs with respect to another.


• Minimal secondary Operation: There are several secondary operations like custom inserts, trimming etc. required for some plastic materials, which in turn leads to an increased overall production cost. Know about such materials and try to get an alternative that possesses the properties as same as the other material.


• Material Cost: It is not necessary to always opt for expensive materials having an assumption that the quality increases with increasing rate. If you are sure to get the performance as expected with a cheap alternative, then go for the same than spending on expensive ones.

Other than the aforementioned points, it is equally important to consider the following points as well.

• Mold design
• Intended end use of the part
• Special appearance considerations
• Chemical exposure
• Machinability

It is easier to just pick a material from hundreds of options available. However, choosing the best and the right material is important, and that is wherein the several injection molding service providers go wrong. As choosing the wrong materials affects the performance of the end product, it is important for the plastic injection molding service provider to have a good understanding of the materials they use in their molding process. As a customer, you must ensure to partner with a production house such as Veejay Plastic who possesses molders and designers who own ample knowledge of the material types.