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Injection Molding

Get custom plastic molded prototypes and production parts in as few as 10 business days. We provide expert engineering reviews and $500 off your first mold. Dozens of materials and finishes are available.

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injection molded plastic sample parts
Molding Services
How It Works
Design Guidelines
Applications and Benefits
Why Xometry?
Customer Examples

What Is Injection Molding?

Injection molding is the most cost-effective way to make a plastic part at scale. The process involves injecting molten plastic into a mold tool, then ejecting the solidified part. This process quickly repeats hundreds or thousands of times, amortizing the cost of the mold tool and driving down the cost of each unit to a few dollars or less. Since injection molding uses the same mold tool for each part, the process offers consistent quality across every part. Injection molding also has the highest variety of materials, colors, cosmetics, polishes, and surface textures when compared to CNC machining or even 3D printing.

Xometry's injection molding service is a highly customized service providing on-demand prototype and production molding. We take a customer-first approach which means we find the right injection molding supplier within our manufacturing supplier network to mold the parts the way you need them—without design compromises—at the right price point. We offer expert consultation on each injection mold quote and project managers on every order to move your parts from design to production. Our team has experience in every industry, especially medical injection molding and liquid silicon rubber molding. First-time buyers receive $500 off their first mold with Xometry. We offer both domestic and China injection molding options, as well as ITAR injection molding.

injection molded plastic parts

Injection Molding Capabilities


Lead Time


Starts at 10 business days, including 24-hour quote responses with design-for-manufacturing (DFM) feedback


Production Options


Domestic and international




Most plastics, including custom sourcing and matching; see materials list below


Machines Available


Single, multi-cavity, and family molds; 50 to 1,100+ press tonnage; side actions including hand-loaded cores


Inspection and Certification Options


Includes FAI and PPAP. ISO 9001, AS9100, ISO 13485, UL, ITAR, and ISO 7 and 8 Medical Clean Room molding.


Tool Ownership


Customer-owned with mold maintenance


Mold Cavity Tolerances


+/- 0.005" when machining the mold and an additional +/- 0.002" per inch when calculating for shrink rate


Part to Part Repeatability


+/- 0.004" or less


Critical Feature Tolerances


Tighter tolerances can be requested and may increase the cost of tooling because of additional sampling and grooming. Xometry will mill to a steel-safe condition on critical features.


Available Mold Types


Steel and aluminum; Production grades range from Class 105, a prototype mold, to Class 101, an extremely high production mold. Xometry typically produces Class 104, 103, and 102 tools.

This table depicts the general tolerances for Xometry’s injection molding services and accounts for adequate draft, radii, and coring for manufacturability. Learn more about our injection molding manufacturing standards and injection molding tolerances.

Xometry Injection Molding Mold Classes
Class 105Class 104Class 103Class 102Class 101
Class 105

Under 500 cycles. Prototype only. This mold will be constructed in the least expensive manner possible to produce a very limited quantity of prototype parts. Also known as a Class V tool.

Example: a one-and-done market test of 100 molded units.

Class 104

Under 100,000 cycles. Low production mold. Use only for limited production preferably with non-abrasive materials. Low to moderate price range. Also known as a Class IV tool.

Example: Aluminum or MUD tooling, SPI B-3 finish, hand-loaded cores, and limited re-runs.

Class 103

Under 500,000 cycles. Medium production mold. This is a very popular mold for low to medium production needs. Most common price range. Also known as a Class III tool.

Example: Aluminum or steel tooling, automated lifts or slides, multiple re-runs with batches between 1,000-5,000 units.

Class 102

Medium to high production, good for abrasive materials and/or parts requiring close tolerance. This is a high-quality, fairly high-priced mold. Also known as a Class II tool.

Example: Steel tooling with an SPI A-2 finish, automated slides, scheduled production cycles.

Class 101

Over 1,000,000 cycles. Built for extremely high production. This is the highest-priced mold and is made with only the highest quality materials. Also known as a Class I tool.

Example: Multiple-cavity steel tooling with full automation and overnight production work centers for dedicated part manufacturing.

Additional Molding Options Available at Xometry

Insert Molding

Insert Molding Service

Make Strong, Functional Prototypes and Production Parts With Insert Molding

Insert Molding Service
Overmolding part

Overmolding Service

High Quality Process for Pilot Runs, Low-Volume Production, and Bridge Tooling

Overmolding Service

How Custom Plastic Injection Molding Works

The process of plastic injection molding requires an injection molding machine, raw plastic material, and a machined mold. The raw plastic material is first melted in the injection unit and is then injected into the mold—most often machined from steel or aluminum—where it cools and solidifies into the final plastic part. 

At Xometry, we first review your injection molding online quote, then consult with you to ensure your specifications, lead time, and price fit your project needs. We then use your 3D part data to CNC machine a high-quality injection mold. Once the mold is created, Xometry sends ten part samples (T1) for approval. Once the mold is refined and approved, Xometry begins production. Xometry molds a variety of products and parts from the smallest medical insert up to large automotive, aerospace, and defense parts.

Injection molding near me graphic

Plastic Injection Molding Materials

Rigid And Flexible Resins
Rigid And Flexible Resins

ABS | Acrylonitrile Butadiene Styrene

Rigid And Flexible Resins

ASA | Acrylonitrile Styrene Acrylate

Rigid And Flexible Resins

CA | Cellulose Acetate

Rigid And Flexible Resins

COPO | Copolyester

Rigid And Flexible Resins

HDPE | High-Density Polyethylene

Rigid And Flexible Resins

LCP | Liquid Crystal Polymer

Rigid And Flexible Resins

LDPE | Low-Density Polyethylene

Rigid And Flexible Resins

PA 6 | Polyamide 6, Nylon 6

Rigid And Flexible Resins

PA 6/6 | Polyamide 6/6, Nylon 6/6

Rigid And Flexible Resins

PARA | Polyaryl Amide

Rigid And Flexible Resins

PBT | Polybutylene Terephthalate, Valox

Rigid And Flexible Resins

PBT-PET | Polybutylene Terephthalate-Polyethylene Terephthalate

Rigid And Flexible Resins

PC | Polycarbonate

Learn more about our molding materials.

Elastomers and Synthetic Rubbers for Molding

Elastomers and Rubber-Like Materials
Elastomers and Rubber-Like Materials

EPDM | Ethylene Propylene Diene Monomer Rubber, Viton

Elastomers and Rubber-Like Materials

MPR | Melt Processable Rubber

Elastomers and Rubber-Like Materials

POE | Polyolefin Elastomer

Elastomers and Rubber-Like Materials

PVC | Polyvinyl Chloride (Shore A)

Check out more information our materials here.

Custom Sourced Materials

If you do not see the material stock you are looking for, please choose "Custom" under the material drop-down on your online quote page and submit it for an expert engineering review once you have specified features, tolerances, inspection needs, and quantities required. Xometry can also use customer-sourced or customer-supplied resin for production projects.

Injection Molding Finishes
Standard Finish

Moldmaker's choice of finish. Typically SPI B-2, depending on geometry and drafts. Interior, non-cosmetic faces, are typically as-machined.

SPI Finishes

Range of Society of Plastics Industry (SPI) finishes from Grade 3 diamond / high polish to 320 stone low polish. Finishes include: SPI A-1, SPI A-2, SPI A-3, SPI B-1, SPI B-2, SPI B-3, SPI C-1, SPI C-2, SPI C-3, SPI D-1, SPI D-2, and SPI D-3

MoldTech Finishes (Mold Texturing)

Range of finishes including matte, swirls, lines, and patterns. Our most common texture finishes include: MoldTech MT11010, MoldTech MT11020, and MoldTech MT11030. Other textured finishes can be added by request.

Other Textures - VDI

VDI 3400 Surface Finish (commonly known as VDI surface finish) refers to the mold texture standard set by Verein Deutscher Ingenieure (VDI), the Society of German Engineers. This is mainly processed by EDM machining, producing fine to coarse matte finishes.

As Molded

No secondary polishing or grinding. Part will show tooling marks.

Threaded Inserts

We can install most commonly used standard inserts in UNF and metric sizes.

Pad Printing

Transfer a 2D image onto a 3D part. All images are subject to review.

Laser Engraving

Engrave part numbers, logos, and more onto your parts.


Xometry has the ability to assemble and label molded parts. Discuss your needs with your salesperson.

Slide 1 of 1
  • SPI, Mold-Tech, and VDI 3400 mold finishes compared

A guide to injection molding finishes

Case Study

An Overview of Injection Molded Surface Finishes

Xometry offers SPI injection molding finishes and Mold-Tech and VDI injection molding finish options for polished, matte, to textured molded parts.
Read the Full Case Study

Video: 7 Ways to Save on Injection Molding

Learn seven injection molding design best practices to help you get great molded parts made cost-effectively.
7 Ways to Save on Injection Molding

Injection Molding Design Guidelines




Reduce undercuts, which will increase the complexity and cost of the tool ejection mechanisms, by adding in pass-thru coring.


Wall Thickness


Prevent wall sink and voids by maintaining an even wall thickness. Thinner walls reduce cycle time and reduce costs.




Ensure parts are designed with a minimum draft angle of 0.5°, or up to 5°, for faces with medium textures.




Ribs should be 40-60% the thickness of outer walls and should still maintain draft.




Bosses should be designed at a depth of 30% the wall thickness and with a 30% edge groove. Attach them to side walls or ribs for structural integrity.

To see these design-for-manufacturing recommendations in detail, view our Injection Molding Design Guide.

injection molding machine graphic

Ready to Get a Custom Injection Molding Quote?

Applications and Advantages of Injection Molding

Injection Molded Part
Rapid Prototyping
Injection Molded Part

Low-cost tooling allows molded parts to be produced in as fast as 10 business days at affordable prices.

Production Parts
Injection molding parts with pass thru coring

Molding can be the ideal process for low-volume production molding of 250 units to mass production molding of over 1,000,000 units. Molded parts will generally perform better than the same part CNC machined or 3D printed using the same material. Careful selection of the resins allow for a wide range of properties and solvent compatibility. Molds are CNC machined to high precision, high tolerances and are able to produce thousands of identical parts with very small and intricate details.

Range of Industries and Certifications
plastic pellets used for molding

We offer ISO 9001, AS9100, ISO 13485, UL, ITAR, and ISO 7 and 8 Medical Clean Room molding.

Injection Molding FAQs
What inudstries use injection molding?

Injection molding is used across a wide range of industries including aerospace, medical devices, consumer goods, energy, electronics, automotive, robotics, toys, and more. The process enables

What is the difference between molding and printing?

Why Use Xometry Injection Molding Services?

Massive Network Capacity

Endless Options

Choose from millions of possible combinations of materials, finishes, tolerances, markings, and certifications for your order.

Xometry Instant Quoting Engine

Easy to Use

Get your parts delivered right to your door without the hassle of sourcing, project management, logistics, or shipping.

Guaranteed Quality

Vetted Network

We are ISO 9001:2015 certified and AS9100D compliant. Only the top molders that apply to become Suppliers make it through our qualification process.

Xometry Plastic Injection Molding Case Studies

Case Study: Thermaco Uses Xometry Injection Molding to Scale Global Product Line
By Serena Ngoh
  4 min read
Case Study: An Archer Aims, Shoots, and Lands His Shot with Xometry Injection Molding
By Serena Ngoh
  7 min read
Case Study: Combating COVID-19 with a Contactless, AI-Based Thermal Imaging Device
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