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What Is Plactic Injection Molding?


Plastic injection molding is the most widely-used manufacturing technique for the production of mass units of plastic parts that serve industrial and commercial purposes. Plastic injection molding also has the highest range of materials, color, and configuration when put side-by-side with processes like CNC machining or Additive manufacturing.






· As manufactured

Also dubbed "As machined," the part will be as molded with tool marks remaining visible.This finish is suitable for parts that don't have any cosmetic emphasis or hidden industrial components.

 Plastic Injection Molding | First Part

Rapid Prototyping and On-demand Manufacturing


First Part specializes in the use of rapid prototyping and mass-manufacturing techniques to produce high-end plastic injection molded parts and mold tools. Our plastic injection molding process is capable of making custom prototypes and end-use parts in as quick as 7 days. At First Part, cost-efficiency is optimized by using aluminum mold tooling that can reproduce thousands of parts and accelerate your product development cycle. 


We stock over 100 plastic resin materials to choose from and complement molded part with an array of finishes. To get started, Click here to upload your project design information and receive an instant quote.

· Scalability and repeatability

Injection molding can produce thousands to millions of parts that are exact and identical to the master mold tooling.

· Cost-effectiveness

An Injection molding tool made from steel can make hundreds of thousands of parts, spreading the tooling cost over a large volume and ultimately lowering the cost-per-part.

· Material diversity and options

Injection molding is the most diverse manufacturing technique when it comes to material selection and considerations. Injection-molded parts can be made even stronger by using fillers and composite materials into the liquid resin to improve its tensile strength.

· Low-volume manufacturing

Aluminum tooling lower setup and tooling costs, ensuring that injection molding can be used for rapid prototyping and low-volume manufacturing.

· High-functional end-part production

Injection molding is widely used in making functional end-use parts that will replace metal parts in most components. Choose from materials to finishes to make high-quality parts that are of high strength and less weight than metal counterparts.

First Part Injection Molding Operations can be applied in:


· Rapid tooling/Mold making

We can use our optimized injection molding process to manufacture molds, tooling (cores and cavities), and dies for use in making any range of budget, volume, and production times.

· Polyphenylene sulfide (PPS)

· Polypropylene (PP)

· Acetal polyoxymethylene (POM)

· Acrylonitrile butadiene styrene (ABS)

· Glass-filled polycarbonate (PC-GF)

· High-density polyethylene (HDPE)

· Low-density polyethylene (LDPE)

· Polybutylene terephthalate (PBT)

· Thermoplastic vulcanizates (TPV)

· Polycarbonate (PC)

· Polyolefin Elastomer (POE)

· Polymethyl methacrylate (acrylic) (PMMA)

· Nylon 66 (PA66)

· Glass-filled, polyamide (PA-GF)

· Polystyrene + polyphenyl ethers (PS-PPE)

· Thermoplastic elastomer (TPE)

· Thermoplastic polyurethane (TPU)

· Custom-sourced Resins

· Customer-supplied materials

Plastic, Elastomers and Synthetic Rubber

Finishing options


Molded parts can be finished in many ways that may cover purely aesthetic finishes or offer some form of protection to the part. Finishes should beautify and enhance the sophistication and functionality of any part. At First Part, our Injection-molded parts may be finished in any of the following options:

· Bead blasting

Bead blasting is used to even and create a uniform surface finished on machined parts.

· Pad printing

Pad printing is used as a decorative technology to transfer ink marking, logos, or texts from a pad unto the part.

· Etching

Etching is a method of inscribing a pattern, marking, or text on a molded part's surface.

· Textured finish

The molded part is leveled with fine stone powder before being sandblasted to obtain a textured surface appearance. Suitable for finishing parts that favor a dull or satin surface finish.

· Laser finishing

The use of laser beams to etch, engrave or inscribe graphics, texts, logos or markings on a molded part.

· Semi-Glossy

Semi-glossy parts have a low amount of shininess and gloss achieved by smoothing with a fine-grit sandpaper.

· Matte

Matte finishes are suitable when trying to remove machining marks from mold parts without overdoing the visual appearance. The mold is smoothed with the aid of fine stone powder. Matte finishes are used on diecast, or thermoset injection molded parts.

· Custom

Choose from an array of custom finishing that is unique or a combination of some standard finishes.

Can't find the desired finish? Click here to go to our finishing page and learn more about our array of finishing options in detail. We also offer custom finishing touches to help you achieve the desired finish or finishes for various parts. 


Request A Quote


Ready to get started? Contact us with details of your project to take advantage of our automated electronic quoting service, design verification process and excellent customer feedback program. With an extensive amount of finishing options to compliment a wide range of material types, over 100 CNC machining centres and deeply-rooted industry experience, Firstpart is always willing to collaborate and deliver functional end-use parts with quality you can trust every time.


Click here to get in touch with us and get a free quote now!

· Glossy

Glossy finishes are used for achieving mirror-like and smooth finishes in molded parts. The part is smoothed and polished with a diamond buff. These parts have the smoothest surface finish relative to other finishing options.

The process essentially involves the injection of molten plastic material (resin) under high pressure into the cavity of a metal die before cooling the mold to solidify the shape into its final part. Depending on the part size, material, and design complexity, the injection molding cycle may span anywhere from a few seconds to a couple of minutes. 

In First Part China Limited, we can handle the plastic injection molding rapid tooling for both high-volume and low-quantity parts production. Using the technical maturity to produce high quality custom plastic molded parts for defense, automotive, medical, aerospace and consumer products.


At First Part, we design our plastic injection molded parts in 6 quality-driven steps:


Our Plastic Injection Molding Process


1.Material preparation

Dry plastic pellets may be used as they come or blended with colorants or fillers.



The pellets are loaded into the hopper of the molding machine and transported by a screw in the barrel towards the mold.



The dry pellets are then heated inside the barrel of the machine until they form the liquid resin, in a fully molten state. The mold is also heated.



The molten resin is injected under high pressure into the heated mold cavity through a gate. The resin fills the cavity and takes the form of the mold tool.



The mold is cooled to solidify the part within.



The cooled and now-solid part is ejected into the loading bin by opening the mold. Ejector pins aid the removal of the part from the mold. A new injection molding cycle may now commence.

At First Part, our injection molding operation focuses on part quality and cosmetic excellence, making us a result-driven manufacturer that leverages interoperable solutions. The beauty, functionality, and quality of injection molded parts are often achieved with the use of one of the combinations of some of the techniques listed below:

· Mold Making


Our competence and capabilities are centered around integrating digital manufacturing technologies with conventional manufacturing processes. This is why we can use high-quality 3D designs to rapidly manufacture high-precision mold tools in a matter of days. 


We offer rapid tooling, mold making, and die manufacturing for both low-volume production, mass production, and prototyping. Our expertise includes steel, and aluminum tooling, and mold maintenance, redesign services.

· Overmolding


Overmolding is an injection molding operation that is used to make a single part from multiple materials. At First Part, we can mold a thermoplastic material into a second material to leverage certain performance and characteristic attributes of the materials to complement functionality. An example is the solid plastic body and rubberized handles of toothbrushes. Overmolding is very effective for creating composite parts, costing lesser than other production techniques that require assembly of separate components.

Injection Molding Operations


· Insert Molding


Insert molding is one of First Part's injection molding capabilities, enabling us to create or integrate plastic fragments and components (inserts) to the pre-fabricated metal part. Through our expertise in cross-technology fabrication, we can use sheet metal and CNC machining to make units of your metal part and employ insert molding to introduce plastic parts. Insert molding can be used in making tools that are sharp and require a grip. Examples include scalpels, fasteners, bushings, or clips.

· Plastic Injection Molding 


First Part uses high-quality thermoplastic materials to deliver top-grade plastic injection molded parts in as quick as 7 days. From our instant quoting service to design evaluation, toolmaking, die, and mold production, and finally injection molding, we stay true to our promise of quality.
Our entire injection molding capabilities include insert molding, mold making, rapid tooling, and overmolding.


· Rapid Prototyping

Take advantage of low-cost tooling options to allow you to make highly-functional parts that are suitable for functionality testing. Even when tooling with aluminum molds, our injection molded parts are almost certain to outperform 3D printed or CNC machined parts from the same material. A low-cost mold can be made in a shorter window, and depending on size and geometry, it could be used in making many volumes. (up to thousands of prototypes)

· Quality and Detail

The high pressure involved in Injection molding means that the molten material penetrates the nook and cranny of the mold before solidification and curing. This allows engineers to design complex parts, inscriptions, details, and elements into their part with the assurance that every part will be made just as they imagined.

Speed, cost-effectiveness, and diversity are the major highlights of Injection Molding. Here are some of the biggest benefits of using Injection molding to create your parts:

· Custom Surface Finishes

With the proper process optimization techniques, injection molded parts can be ejected ready-to-use or finished in an array of popular or custom methods to ensure that your part look and feel as intended.

· What Injection molding capabilities does First Part have?

First Part's Injection molding capabilities are reliable, precise, and scalable. Our robust manufacturing hubs make us one of the most trusted outlets for general metal and plastic fabrication. Here's a summary of all our injection molding capabilities:

· What are the advantages of Plastic Injection Molding?

Plastic injection molding is one of the cost-efficient methods of making thousands of finished parts quick and accurate. One tooling has been completed, the other parts can be fabricated in large volumes that any other manufacturing technique.

· What are the advantages of Plastic Injection Molding?

Plastic injection molding is one of the cost-efficient methods of making thousands of finished parts quick and accurate. One tooling has been completed, the other parts can be fabricated in large volumes that any other manufacturing technique.

· How long does mold tooling take?

Depending on the volume of parts, the need for heat treatment, design, and geometric complexities, a standard plastic injection molding tool can take anywhere between 7 – 10 days to manufacture.


Plastic Injection Molding Service

Rapid Prototyping and On-demand Manufacturing in As Quick As 7 Days

Low Volume Production

Sheet Metal


Plastic Injection


Learn more about our other capabilities  



Although more popular in some than others, Injection Molding is currently used in making parts for existing and upcoming industries including:


Advantages of Over-molding & Insert-molding?


Injection Molding Applications


The above materials are the most common stock material options. If your desired material is not listed above, please contact our team here. You may learn more about our other options and custom material applications by clicking here to go to our materials page.


Why Choose Us


With over ten years' experience in Injection Molding, Insert molding, and Overmolding services, First Part is one of the best prototyping and Injection molding manufacturers in China. Here’s why:

Quality and Reliability

First Part is dedicated to meeting high-quality standards, delivering part on time with precision, accuracy, and reliability. We follow strict quality control measures to guarantee that only the best parts are produced.

Cost-effectiveness and Turnaround

Over-molding and Insert molding are primed for budget maximization and design optimization. This makes it excellent for achieving cost-effectiveness and quick turnarounds.

Capacity and Network

Excellent in-house capacity and capabilities guarantee that your parts are made from top quality from start to finish. Enjoy non-disclosure agreements and take advantage of our instant quoting system network, injection molding services, and digital manufacturing services to make parts your parts right from home.


Material Options


Our plastic injection molding material options are summarized under three broad headings namely Elastomers, Plastic Materials, and Silicone Rubbers. We work with many plastic and resins as required for the application industries. In addition to our stock material options, First Part can source for desired materials and provide molding with customized raw materials that will match the desired application of your part.

FAQs  Plastic Injection Molding