Supercharging innovation with plastic injection molding

Ideas become reality with Nelson Miller Group’s custom plastic injection molding capabilities. 

Injection molded plastic solutions

Whether you’re producing intricate medical devices, consumer electronics, or robust automotive components, injection molded plastics open up a new world of possibilities. Plastic injection molding is an innovative manufacturing process that offers unmatched precision and scalability, allowing even the most challenging designs and complex components to be produced efficiently.

From our 46,000-square-foot factory in New Jersey, our knowledgeable team provides specialized design support and advanced 24-hour injection molding capabilities.

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custom injection molded plastic

Advantages of injection molding

  • High repeatability and product consistency
  • Fast production, well-suited for large production orders
  • Low waste or scrap rate
  • Ability to design and manufacture intricate and complex geometrical shapes
  • High tolerance, precision, inserts, and color control
  • Use of multiple materials simultaneously
  • Reduced finishing requirement (parts need little work after ejection)
  • Ever-increasing options of resins and properties


Our plastic injection molding capabilities

NMG’s plastic molding machines range from 20 to 800 tons. Our varied capabilities can support a wide range of customer volume demands and design types.


  • Single- and double-shot injection molding
  • In-mold decorating
  • Overmolding
  • Insert molding
  • SLA (prototyping)

Specialty finishes

  • Silkscreen printing
  • Pad printing
  • Laser etching
  • Spray painting
  • Electroplating
  • Rubber-grip surfaces


All our partner factories are ISO 9000 certified, with many being QS 9000 or TS 16949 certified, as well.

precision plastic injection molding manufacturing
plastic injection mold design

Why partner with NMG for your injection molded plastic needs?

Our in-house engineering team combined with our state-of-the-art injection-molding facilities give you the peace of mind that your custom design requirements will be transformed into high quality, cost-effective solutions.

Computerized design and simulation services
NMG utilizes advanced computer systems to better serve our customers. With software like Pro/ENGINEER, SolidWorks, and AutoCAD, among others, we can provide flow-mold analysis and other specialty injection molding services.

In-house mold and tool fabrication
Our CNC, wire cutting and EDM machines, in conjunction with our CNC machining centers, afford NMG the ability to build your plastic injection mold and tooling in-house.

Advanced quality equipment and testing
Our skilled personnel, trained in defect detection and prevention methods, use the latest quality control equipment such as CNC, CMM, optical comparator, and roughness testers to deliver you high quality plastic parts.

injection molding machine

NMG lowers your costs and shortens lead times.

We work with you to make sure you produce the most cost-effective mold for your product and benefit from the low production costs that make injection molding such a popular choice for manufacturers. At NMG, we focus on controlling tooling costs with careful consideration during all phases of your project:

Plastic injection mold design

The design of your plastic part is always the initial driver of cost—the more complex it is, the more it will cost. We will help you scope your project and lower costs based on:

  • The core metal used to make the mold
  • The mold size
  • The cavity machining (number of details and tools required to make the cavity)
  • The number of cavities (more cavities mean more machining/tooling)

plastic injection mold design
thermoplastic resin


The resin will be your second driver of cost. Many plastics overlap in strength and functionality, but some are inherently easier to mold, driving down part costs. Certain materials require high infusion weights, which in turn require higher tonnage machines. At NMG, we consider a number of factors to determine resin selection including cost, aesthetics, resistance, environmental factors, functionality, and regulatory requirements.


Small tonnage machine sizes are used for running small molds and small parts, and large tonnage machines are needed to run large molds with more cavities and/or larger parts. Cycle time and the number of cavities in the mold are two significant determining factors in the total cost of a plastic injection molded part.

Our advanced capabilities and technology additionally allow NMG to significantly shorten your lead time:

  • Technology to design the mold, suggest part modifications, and simulate production before even starting to build the mold.
  • Ability to design and manufacture the right tool with as few cycles as possible doing corrections, calibrations, and modifications.
  • An in-house toolroom, enabling engineering work on changes or repairs to be carried out as quickly as possible.
  • Innovative manufacturing technologies (like automation and AI) that help shorten the lead time.
  • Advanced machinery that lowers the amount of injection time and employs advanced cooling systems to minimize the time it takes for your plastic parts to reach ejection temperature.

injection molded plastic equipment

NMG’s plastic injection molding process

Part design

We utilize computer-aided engineering (CAE) and computer-aided design (CAD) and consider important manufacturability and functionality issues:

  • Critical tolerances
  • Location of the parting line
  • Undercuts (avoid if possible)
  • Uniform wall thickness
  • Shrinkage and warpage considerations
  • Sharp corners (smooth trumps sharp)
  • Structural support
  • Add draft
  • Molded in or secondary operations
  • Gating and ejection

Resin selection

With over 85,000 material options for injection molded plastic parts, deciding which thermoplastic is best for the job can be overwhelming. The NMG team has in-depth understanding of the ongoing advancements in polymer science, experience with a variety of resins and applications, and the right equipment to vigorously test your first article and pre-production samples. We'll guide you through the important questions you need to consider when selecting resin.

Mold creation

A quality plastic injection molded part starts with a quality-built mold. If your tool isn't built correctly, you'll have quality issues down the road. NMG uses the highest quality mold manufacturing equipment, and our experienced engineering team is here to help you navigate through every step of this complex task.

injection molding machine

Our process involves:

  • Review of part design for Design for Manufacturing (DFM), Computer-Aided Engineering (CAE), and Computer-Aided Design (CAD)
  • Identification of mold component functionality, mold materials, and operational constraints
  • Preliminary 2D and 3D rendering of the mold
  • Moldflow simulation

Test and adjust

Your mold and first articles need to be validated before you proceed with full production. Aided with control plans and validation documents, NMG completes full functional and performance testing by relying on visual inspection, precise dimension measurement systems, and material testing. At this stage, we also review the manufacturing process to verify that moving elements move well, the plastic melt flows well, the cooling performs, etc.

Occasionally final tool or process changes are needed, falling under three categories:

  • Corrections to the mold (the part does not follow 3D data)
  • Calibrations (fine-tuning part engineering)
  • Modifications (modify the part design from the original design)

We have a strong commitment to quality and will always work to ensure your product is well-made and can be produced efficiently. Regardless of any changes needed to your mold or design, NMG will produce and test new samples until they meet your approval.

Produce and maintain

Throughout the production runs, we'll test and measure various properties of your molded parts to help you determine any issues with the mold or process. To prevent issues with your mold and wear and tear, NMG has a detailed maintenance schedule in place for regular lubrication, surface maintenance, mold cleaning, and inspection (ejection and guide parts).

plastic injection molded parts

Selecting the right plastic injection molding partner

Here are the most important differentiators you should consider when selecting an injection molder:

  • Engineering expertise and experience in plastics manufacturing (design, manufacturing, and resin selection)
  • Ability to meet your specifications without sacrifices
  • One-stop manufacturing from design to full production and shipping
  • Strong quality assurance, process monitoring, and maintenance
  • Range of machinery to keep tooling costs low
  • Technologies and machinery used to reduce lead time (see infographic below)
  • Quality of customer service and communication

Ready to start a project today?

Case studies

See real-world examples of how NMG has helped customers across the full spectrum of the supply chain, from design to delivery.

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Read our blog!

Access industry updates, helpful how-tos, engaging infographics, and other resources for engineers and supply chain professionals on the NMG Blog.

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