Understanding Plastic Injection Moulding

plastic injection molding

Injection Molding is the most common manufacturing process for assembling plastic parts. Injection-molded parts are ideal for large volume production of plastic molded parts with the use of a wide range of thermoplastic polymers, elastomers, and resins. The process requires the application of an injection molding machine, mold, and raw plastic material to manufacture a variety of products that vary greatly in size, complexity, and application.

To create a part, plastic is melted with the use of an injected molding machine. It is then injected into the mold where it cools down and forms into the final part. Because of the tight tolerances, injection molding is very suitable for intricate and standard plastic molded parts of different sizes.


Use Of Injection Molding Technique

To begin with, the injection molding technique is used to produce thin-walled plastic parts with the most cost-effective production methods. With the use of diverse injection molding machines, custom plastic molding requirements can be met. Apart from that, companies offering plastic moulding near me can produce plastic injection moldings from 1 kg to 48 kg in weight with a surface area up to 1.5m2. With customized molding capabilities, companies like CadDeziners, manufacture complex large injected molded parts with precision, functionality, and aesthetic attributes.

Every client wishes to reduce the cost of injection molding to create manufactured parts. The easiest way to reduce the cost per piece in injection molding is by increasing the manufactured quantity. The initial upfront cost to create and design the injected mold is amortized over maximum parts. For example, companies can mold up to 25,000 parts or more from the same tool.

The cost of injection molding can be compared to manufacturing processes like 3D printing and CNC machining where the process of plastic injection molding manufacturing creates thousands of parts that reduce the cost of mass production. The cost of injection molding is determined by the combination of several factors. The most important determinant of molding cost is the amount of time required to produce tooling. The cost of plastic mold manufacturing a part increases with its complexity of design or geometry. It is more affordable to fabricate parts without undercuts and advanced surface finishes.


Process Of Injection Molding

The process of injection molding is very short ranging from 2 seconds to 2 minutes consisting of the following four stages-

Clamping– Before injecting the material, the two halves of the mold must be closed securely with a clamping unit.

Injection-The raw material in form of pellets is placed into the injection molding machine. During the process, the raw material is melted by heat and pressure. The amount of material injected is referred to as a shot. The injection time depends upon shot volume, injection power and injection pressure.

Cooling– The molten plastic inside the mold begins to cool down as it makes contact with interior surfaces. As it cools down, the molten takes the shape of the desired part. The mold should not be opened before the cooling time.

Ejection-As reasonable time passes, the cooled part can be injected from the mold. When the mold is opened, an effective mechanism is used to push the part out of the mold. Force has to be applied to eject the molded part as it may shrink when it cools down.

After the cycle is complete, some post-processing is required. The excess material must be trimmed from the part with the use of cutters. For some materials like thermoplastics, the scrap material as an outcome of trimming can be recycled by placing it into a plastic grinder known as granulators.


Selecting Materials For Injection Molding Services

It is relevant to discuss what type of material is ideal for plastic injection molding services. Before choosing the right material, you need to consider various parameters and factors that meet the project requirements. The parameters are hardness, durability, chemical resistance, heat resistance, etc. that are determined by use and operating environment.


  • ABS or acrylonitrile butadiene styrene provides high tensile strength, versatility, and high resistance that makes it a perfect choice for injection molding.
  • Polycarbonate- It is a strong thermoplastic polymer with high stiffness and impact strength, and strength retention at high temperatures. It is easy to use and manufacture a variety of plastic molded parts with this material.
  • Ultem has lower impact strength and temperature properties. It is a highly dimensional stable plastic resistant to environmental stress and cracking.
  • PEEK’s unique features like high chemical resistance to high temperatures, hardness, strength, and stiffness offer versatility, and durability. It is used to replace metal as it can withstand autoclave sterilization and high temperatures.
3d Printing Services
3d Printing Services


Why Companies Prefer ABS Injection Molding?

ABS is a common thermoplastic polymer used in injection moulding services. The attributes of ABS are versatility, moderate heat performance, and good machinability that make it an ideal choice for applications as it is strong, inexpensive, and stiff plastic. Using ABS plastic molding offers numerous benefits like:


  • At first, High impact strength and toughness
  • Secondly, Good machinability and heat resistance
  • Thirdly, High stability under load
  • Next, Premium tensile strength and stiffness
  • Effective dimensional stability
  • Exhibits resistance to oils, alkalis, and acids
  • Maintains its characteristics and performance in extreme temperatures
  • Recyclable
  • Effective dielectric properties

Further, the team of designers has extensive experience in creating injection molded parts for decades with the use of ABS material. The material is used for several applications, for instance, automotive, electronics, consumer goods, fittings, sports equipment, recreational products, etc. Designers offer a variety of injection molding services to meet the specific requirements of the project and client specifications. In addition, ABS injection molding services are used for several projects like insert molding, micro-molding, over-molding, 3D printing injection molds, pad printing, ultrasonic molding, assembly, etc.

To reduce the cost of the molding process, clients can consider the various options. For instance, avoid unnecessary features, get rid of undercuts as they lead to complications in design (it is good to minimize as much as possible), mitigate cosmetic finishes and appearances, give importance to the part size, choose on-demand production, use a family or multi-cavity mold, consider DFM analysis, try to modify and reuse molds and prefer core cavity approach.


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