Selecting the Right Injection Molding Material

There are numerous Injection Molding materials to choose from - we'll show you how to narrow down which is best for your part.

By Shilpa Garg · August 24, 2018

Injection Molding is a unique manufacturing process for a variety of reasons - one of those is the abundance of materials available for your Injection Molded parts. These materials are each engineered with a unique purpose in mind for quantities from the low hundreds to tens of thousands.

With every part you manufacture, the material you select should be intentional based on its utility, efficiency, and cost considerations. It’s important to understand that while certain materials may be more popular than others, there’s no such thing as one-size-fits all. At the end of the day, your material selection will always be connected to your part’s application.

Where Do I Start?

To find the right material for your parts, it helps to work backwards. What will the part be used for, what kind of stresses will it endure and where will it be located are great places to start. The following criteria can help you understand what factors to prioritize for the material you select:

  • Location: You must always consider where your part will live, whether that is outside, inside, under the hood, etc. Will it live in sunlight, in the outdoors, in a dark and damp environment, or somewhere else entirely?
  • Temperature: Consider the temperature when you are choosing your material. Will the product end up in a freezer, or somewhere that’s very warm or hot?
  • Life Cycle: How long do you expect this part to be used? Do you expect it to expire after 5 years, 25 years, etc?
  • Warranty: Consider the warranty. For the automotive business particularly, you have to consider that years from now it could break. What is the cost of covering its warranty?
  • Cost Constraints: There are two different types of materials. You could get a commodity plastic (such as high-density Polyethylene or Polypropylene), which are typically high-density and low-heat, readily available, and comparatively inexpensive. The second category is engineered plastics, including materials like PEEK and PEI. These are very expensive and more difficult to find, but they are high-heat and stiff.
  • Cosmetic Requirements: Does the part need to be completely transparent, or a certain color? Color matching may be required if your part needs to match others in an assembly. The Plastics Industry Association provides references for the quality of surface finish you should specify for your parts, ranging from A to D. Texture is another factor to consider.

How Do I Narrow My Decision?

Once you have those initial questions answered, you could still be looking at a handful of different material options. Consider this next series of questions to help you further narrow down a material for your part:

  • Design Functions: Consider the mechanical engineering aspect of the part. Does it need to be flexible, compressible, bondable, etc? Does it need tensile strength (meaning it cannot be pulled apart)? What’s the part’s required toughness against impact, or electrical insulation? The ideal weight of a part is also an important consideration.
  • Environment Factors: What elements will the part be exposed to? Will it be submerged in chemicals that it needs to be compatible with, or open flames that would require certain additives and retardants such as a UV stabilizer?
  • Regulatory Compliances: Adding certain compliances can quickly increase the cost of your part, which is why it’s important to evaluate what is needed and what might be superfluous. Does your part need to be food safe, and does it need to meet FDA requirements? Or medical grade, ISO, electrical compliance, etc?

Xometry Materials:

Armed with the top 4-5 things that define your material requirements, you can then evaluate material offerings to understand what will work best for your parts. Xometry offers an extensive variety of materials, each with unique properties for different applications:


MaterialAlso Known AsNotesColorsFiller OptionsAdditive Options
ABSAcrylonitrile Butadiene Styrene ABSHigh strength general purpose engineering plastic, used for many commercial products.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
PC-ABSPC Polycarbonate Acrylonitrile Butadiene Styrene PC/ABS ABSThe best of both PC and ABS. Higher strength engineering thermoplastic with slightly more flexibility than standard polycarbonate.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
Acrylic (PMMA)Polymethyl Methacrylate PMMA AcrylicA clear glass-like plastic. Good wear and tear properties. Great for outdoor use.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Clear, Tan, Natural, Custom Color, None (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
Custom (Injection Mold)Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Clear, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
Customer-supplied resinCustomer-supplied tint
Delrin (Acetal, POM)Acetal Polyoxymethylene POM DelrinAcetal resin with good moisture resistance, high wear-resistance, and low friction.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
HDPEHigh Density PolyethyleneExcellent strength-to-weight ratio and chemical resistance. HDPE is often used for fuel tanks, connector insulators, and food containters. Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
LDPELow Density PolyethyleneA flexible and tough material with lower denisty versus HDPE. LDPE does not react to acids, bases, or alcohols. Useful for trays, snap lids, and general purpose containers.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Clear, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
Nylon 6Offers increased mechanical strength, rigidity, good stability under heat and/or chemical resistance.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
Nylon 6/6Nylon 66Offers increased mechanical strength, rigidity, good stability under heat and/or chemical resistance.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
OvermoldInsert Molding Over MoldSelect this if your part requires at least two molded plastics or elastomers.Custom color
PBTValox Polybutylene TerephthalateA common electronic insulator with a polyester base. Highly used in automotive as a longer-wear alternative to nylon.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
PC-PBTXenoyA tough and rigid material resistant to lubricants, solvents, and cleaning agents. Very common in electronic enclosures.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
PEEKPolyether Ether Ketone PEEKOffering excellent tensile strength, PEEK is often used as a lightweight substitute for metal parts in high-temperature, high-stress applications. PEEK resists chemicals, wear, and moisture.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
PEI (Ultem)Ultem Polyetherimide PEIKnown best for its extremely high heat and flame resistance, PEI is used for many medical applications and is more affordable than PEEK.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
PETRynite Polyethylene TerephthalateA polyester-based polymer commonly used for liquid containers (e.g. soda bottles) and other food packaging.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Clear, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
PC (Polycarbonate)A clear or colored, light-weight, glass-like plastic.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Clear, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
PLAPolylactic Acid PLAA biodegradable and renewable plastic. PLA has a relatively low glass transition temperature and is common in short-use applications.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Clear, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
Polyethylene (PE)One of the most common plastics available. PE has high ductility, abrasion resistance, and chemical resistance.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
Polypropylene (PP)Polypropylene PPPolypropylene has excellent electrical properties and little or no moisture absorption. It carries light loads for a long period in varying temperatures. It can be molded into parts requiring chemical or corrosion resistance.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
Polystyrene (PS)Polystyrene PSA clear, hard, and brittle material widely used for food packaging, clamshell containers, and even disposable cutlery. Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Clear, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
PPE-PSNoryl Polystyrene Polyphenyl Ethers PS/PPEExhibiting high heat and flame resistance, PPE-PS has high stiffness and tensile strength even at elevated temperatures.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
PPSPolyphenylene Sulfide PPSA high-performance thermoplastic with extreme resistance to solvents.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
PSUUdel Polysulfone PSUA rigid, stiff, and transparent plastic which is a higher-performance alternative to polycarbonate.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
PVCPolyvinyl chlorideA rigid, general use plastic, that is common in plumbing, non-food packaging, and trimming.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Clear, Tan, Natural, Custom Color, Glass-Filled, 15%, 33%, customNone (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
TPE (elastomer)Santoprene, thermoplastic elastomer A rubbery material that can stretch at moderate levels and return to its molded size. Used for gasketing, bumpers, and grips.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Tan, Natural, Custom Color, None (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive
TPV (rubber)Rubber Thermoplastic Elastomer VulcanizedA rubbery material that can stretch at moderate levels and return to its molded size. Used for gasketing, bumpers, and grips.Yellow, Blue, Green, Red, White, Purple, Black, Orange, Dark Gray, Light Gray, Tan, Natural, Custom Color, None (Default Additive), UV Stabilizer, Flame Retardant, Static Dissipative, Custom Additive


Want more info on this topic? Our Injection Molding experts Greg Paulsen and Travis Minyard hosted a 40-minute deep-dive on selecting IM materials, with 4 real-world examples to walk you through the process. Watch the full on-demand webinar here!

To get a quote with pricing, lead time, and DFM feedback for your Injection Molded parts directly from an Injection Molding expert, upload your CAD files here.