A Full Service Custom Plastic Injection Molding Company
ISO 13485:2016

Plastic Molding Services

Injection molding is an effective and efficient way to mass-produce plastic parts and/or products. With plastic molding, thousands or even millions of high quality, high precision parts can be manufactured with perfect repeatability and in relatively quick turnaround.

Plastic injection molding uses custom-made molds with cavities in the shape of the desired part. Raw plastic material is heated to a near-liquid state and forced into the mold under pressure (injected) to create solid or hollow plastic parts. The plastic quickly cools and the mold opens to eject the finished parts. Molds can be designed with multiple cavities to produce several parts per cycle, and can be engineered for extreme dimensional precision and tight tolerances.

Injection molding produces minimal scrap, making it far less wasteful than other plastic manufacturing processes, such as CNC machining. And, because the same mold is used to produce every part in a production run, each piece is 100% identical to the last.

Comprehensive Injection Molding Capabilities

Stack Plastics specializes in injection molding. We offer a full range of plastic molding capabilities, along with secondary services and more to give you the perfect injection molded parts for your unique application. Our plastic molding services include:

Injection Molding

We are the proven experts in plastic injection molding. We use “scientific molding” methods to experiment with different variables and collect data, which helps us optimize the injection molding process for maximum efficiency and superior quality products from the first piece to the last.

Medical Molding

Stack Plastics provides precision medical molding for stents, implants, sutures, and other medical components and sub-assemblies. Our plastic injection molding skills and experience with a variety of medical-grade plastic resins enable us to meet the stringent requirements of this demanding industry.


Micromolding is a highly specialized process used to produce miniscule parts with intricate details and features that would be impossible to manufacture via other methods. We have extensive experience in micromolding that enables us to produce precision parts for surgical devices, electronics, and other applications where space is tight.


In overmolding, the first “base” layer part is molded first, and an additional layer or layers of plastic material are molded over the original part. (Think of a toothbrush with rubberized grips over a stiff plastic handle.) Our overmolding expertise enables us to maintain tolerances as tight as 0.001” over multiple molded layers.

Insert Molding

Similar to overmolding, insert molding is the process of molding plastic parts around other, non-plastic parts (inserts). Our insert molding capabilities allow us to produce very small, high precision parts with intricate details and all manner of inserts, from knife blades to batteries to electric motors.

Pad Printing

With our pad printing capabilities, we can add lettering, logos, or nearly any other design you may need directly to the surface of your injection molded part. We use fully-automated 2-color pad printing technology and durable, quick-drying ink for fast and efficient service.

Sonic Welding

Also known as “ultrasonic bonding”, sonic welding uses extremely high frequency acoustic vibrations to fuse two or more plastic parts into a single piece. Using state-of-the-art equipment, we can create incredibly strong, permanent bonds.


In addition to sonic welding, we provide a variety of other light assembly services in-house to give you more complete finished products. Our assembly processes add value to your injection molded plastic parts and speed up your production process.

Plastic Injection Molds & Tooling

Our injection molding processes are completely customizable to your unique project. We work with numerous world-class moldmakers to create custom molds and tooling that match your exact design requirements, including single- and multi-cavity molds with up to 32 individual molding cavities.

Plastic Molding Materials

From standard thermoplastics to exotic resins, Stack Plastics has extensive experience with a wide range of materials. View our injection molding materials [link to new page] page for more information or contact us to discuss your unique material requirements.

Stack Plastics: The Injection Molding Experts

We are the experts in precision plastic molding! We provide turnkey service throughout your entire product development process, from design engineering to prototyping to mass production. With our comprehensive injection molding capabilities, we have what it takes to turn your designs into the high quality, high precision parts and products you need.

Request a quote on your injection molding project, or contact Stack Plastics for more information.