Insert molding service

Create strong, durable parts with thermoplastic injection molding around pre-placed inserts.

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White insert molded parts

What is insert molding?

Insert molding involves the injection of plastic around a pre-placed insert to shape a strong, durable, and permanent bond between the molded plastic and an insert. During production, an insert is placed inside an empty mold cavity which is then filled with molten thermoplastic and cooled to form a solid part. Cost-effective, precise, and consistent, insert molding is suitable for low to high volume production.

Ordering insert molded parts with Fast Radius is simple. Upload your CAD file to our Cloud Manufacturing Platform™, work with our experts to optimize your design and choose your production material, and then manufacture your products with the click of a button. We also offer heat-staked inserts as a post-processing option for other thermoplastic manufacturing projects.

For more on-demand manufacturing options, browse our injection molding capabilities, including our overmolding services.

Design considerations

Fast Radius injection molding services enable you to manufacture parts to meet a variety of functional needs. Unlock the potential of your insert molding project with the following injection molding design considerations:

Insert molding general process information
Maximum part size​800 x 800 x 400 mm
31.5 x 31.5 x 15.7 in
Minimum part size1 x 1 x 1 mm
0.04 x 0.04 x 0.04 in
ToleranceBest achievable tolerance: ±0.001″ (0.025mm)
Standard: ±0.005″ (0.127mm)
For larger part tolerances please contact a Fast Radius engineer
Lead timeAs low as 2 weeks for T1 samples
After T1 sample approval, lead time for < 10,000 parts is as low as 1 week
Tool validationStandard process is to produce a small set of T1 samples for approval before initiating full production
Maximum press size1600T
Minimum order size100 parts and $5000
Set-up fee$500 per mold per order (applies to sample runs after initial T1 samples or engineering changes)
Insert molding tooling information
Rapid toolingMolds with steel cavity and core with a shot life of 5,000-10,000 shots
Typically machined in 2 weeks
Production toolingSteel tool with shot life up to 1M shots
Ability to integrate side-pulls or cam-actions
Typically machined in 3 weeks
Multi-cavity or family moldsMultiple identical cavities or family of parts machined into a single tool
Allows for more parts to be produced per shot, minimizing unit costs
InsertsInserts are placed into the mold and molding occurs around them to extend tool life for critical features
Allows for inserts such as helicoils to be molded in your design
Thermoplastic injection molding materials
Most common materialsOther supported materialsAdditives and fiber
Acrylonitrile Butadiene Styrene (ABS)Nylon (PA 6, PA66, PA12)UV absorbers
Polyethylene (PE)Polycarbonate/Acrylonitrile Butadiene Styrene
Flame retardants
Polypropylene (PP)Polyurethane (PU)Plasticizers
Polycarbonate (PC)Polymethyl Methacrylate (PMMA/Acrylic)Colorants
High Density Polyethylene (HDPE)Glass fibers
Low Density Polyethylene (LDPE)
Polystyrene (PS)
POM (Acetal/Delrin)
Polyethylene Terephthalate (PET)
Thermoplastic Elastomer (TPE)
Thermoplastic Vulcanizate (TPV)
Polyetherimide (PEI)
Polysulfone (PSU)
Inquire for additional options
Insert materials
BrassPolypropylene (PP)
Stainless steelPolyamide (Nylon)
Aluminum 6061Acrylonitrile Butadiene Styrene (ABS)
Aluminum 7075

Injection molding finishing and

We can apply a range of injection molding finishing and post-processing options to insert molded parts:

Insert molding colors, finishing, post-processing
ColorsFinishing and post-processing options
Pantone color matchingStandard SPI finishes (A2-D3)
RAL color matchingMold-tech textures also available
Pad printing
Inserts (e.g. heat stake inserts)
Light assembly
Protective packaging / film

Get an instant quote for your insert molding project

Use our quoting platform for quick quotes on injection molded parts.

Why choose insert molding?

Versatile and cost-effective, insert molding offers the following key benefits and challenges:

  • Precision production at low or high volume
  • High quality, permanent bonds
  • Strong, durable final products with reduced assembly and labor costs
  • Multi material production possibilities
  • Different inserts offer different mechanical qualities and functions
Cross icon Challenges
  • Requirement to use suitable resins to prevent plastic cracking around insert
  • Slight increase in molding costs due to increased cycle time required for each part to add the inserts

Insert molding applications

From functional prototypes to full production runs, insert molding’s key industrial applications include:

Consumer-facing products

Insert molded parts can be created from a variety of high quality materials with finishing options that are ideal for consumer-facing products.

Low volume production

Insert molding offers consistency and cost-effectiveness and is an ideal process for low-volume manufacturing projects.

Handheld devices

Insert molding is used widely in the production of handheld devices, such as scissors, screwdrivers, remote control coverings, case assemblies, knobs, and dials. Insert molding is also used in the manufacture of medical implants.

Aerospace and automotive

Strong and durable, insert molded parts are used in a variety of aerospace and automotive contexts, where they are manufactured to meet precise industry standards and certification requirements.

Fast Radius manufacturing solutions

Fast Radius manufacturing solutions, including insert molding, are used by businesses across the world. Learn more about our manufacturing capabilities:

3D printing

Fast, scalable, and cost-effective 3D printing technology for a variety of industrial applications.

CNC machining

Automated CNC turning and 3-axis and 5-axis milling, using rotating drills, end mills, and lathes.

Injection molding

Cost-effective plastic injection molding for precision, high-volume production runs.

Urethane casting

Versatile mold-casting for the production of urethane parts customizable with colors and textures.