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Production Injection Molding Processes

Production Injection Molding

Get low mold costs and volume pricing on production injection molded parts from our diverse factory network.

black plastic injection molded part

Injection Molding Fabrication Facilities

We offer injection molded parts in a variety of countries 

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Vietnam

We offer injection molding in Vietnam.

Malaysia

We offer injection molding in Malaysia.

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Eastern EU

We offer injection molding in Eastern EU.

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China

We offer injection molding in China.

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What is injection molding?

Injection molding is a manufacturing process used to produce parts by injecting molten material into a mold. Typically used with plastics but also applicable to metals, glass, and elastomers, injection molding is highly effective for creating complex, durable parts in large volumes. The process begins with heating the material until it becomes liquid, then forcing it into a custom-designed mold under high pressure. Once the material cools and solidifies, the mold opens to release the formed part. Injection molding is known for its efficiency, cost-effectiveness, and ability to produce high-precision, repeatable parts, making it widely used in industries like automotive, consumer goods, electronics, and medical devices.

Green injection molding machine

Why choose injection molding for your parts?

Choosing injection molding for your parts offers several advantages, especially for high-volume production. Injection molding is highly efficient and cost-effective, allowing manufacturers to produce consistent, high-quality parts quickly once the initial mold is created. This method supports complex geometries and fine details, enabling the production of intricate designs with minimal material waste. Additionally, a wide range of materials can be used, from durable thermoplastics to flexible elastomers, providing options to suit different performance requirements. With its precision, repeatability, and scalability, injection molding is an ideal choice for industries needing reliable, large-scale manufacturing of durable, customized parts.

finished injection molded components on black plastic beads

Injection Molding Design Guidelines

Guidelines for designing cost effective injection molded parts

Undercuts

Minimize undercuts to avoid increasing the complexity and cost of the tool's ejection mechanisms by incorporating pass-through coring.

Wall Thickness

Maintain consistent wall thickness to prevent sink marks and voids. Thinner walls can also help lower cycle times and reduce overall costs.

Drafts

Design parts with a draft angle of at least 0.5°, and up to 5° for surfaces with medium textures, to facilitate easy release from the mold.

Ribs/Gussets

Ribs should be 40-60% of the thickness of the outer walls and should include a draft angle for easier molding.

Bosses

Design bosses with a depth that’s 30% of the wall thickness and include a 30% edge groove. Connect them to side walls or ribs to enhance structural stability.

Plastic Injection Mold Finishes

Injection-molded plastic can be finished using a variety of methods to achieve the desired appearance and functionality.

Standard Finish

A standard finish in plastic injection molding typically refers to a basic surface finish that results directly from the mold without additional processing. Standard finishes can range from a high-gloss, polished finish to a matte or textured surface, depending on the mold’s preparation and the specific requirements of the part. Common options include SPI finishes (set by the Society of the Plastics Industry), where finishes are categorized from high-gloss (A-grade) to medium or matte textures (B and C grades), offering both aesthetic appeal and functionality, such as improved grip or reduced visibility of wear.

Consumer electronics, automotive interiors, household appliances, medical devices, industrial equipment, where consistent surface quality and functionality are essential.

As Molded

An as-molded finish refers specifically to the natural surface texture and appearance of a plastic part as it comes directly out of the mold, without any additional polishing or finishing processes. This finish is largely determined by the mold surface itself, as well as factors like cooling time and material flow, which can cause slight variations. Compared to a standard finish, which may include specific polishing or texturing techniques (like SPI grades) to achieve desired gloss or texture, an "as-molded finish" typically reflects the raw, unaltered quality of the molded part. This can be cost-effective for applications where appearance is secondary to functionality.

Industrial components and internal parts in electronics and automotive industries often use as-molded finishes, as their appearance is secondary to functionality.

SPI Finishes

Standard SPI (Society of the Plastics Industry) finishes are categorized into grades based on the level of polish and texture applied to the mold surface:

A-Grade Finishes (High Polish)

A-1: Mirror finish with a diamond buff, highly polished for a reflective, glass-like surface.

A-2: Medium-diamond buff for a glossy, smooth finish.

A-3: Coarse-diamond buff for a polished finish with slight gloss.

B-Grade Finishes (Medium Polish)

B-1: Fine-grit stone finish, resulting in a smooth but non-reflective surface.

B-2: Medium-grit stone for a uniform matte finish.

B-3: Coarse-grit stone for a textured matte finish.

C-Grade Finishes (Matte)

C-1: Fine dry-sand finish for a light matte surface.

C-2: Medium dry-sand finish for a textured, non-reflective surface.

C-3: Coarse dry-sand finish, offering a rougher matte texture.

D-Grade Finishes (Textured)

D-1 to D-3: Textured finishes achieved with media blasting for a uniform, non-glossy surface.

These standard SPI finishes are selected based on functional and aesthetic requirements, such as minimizing glare, enhancing grip, or achieving a high-quality appearance.

SPI finishes are applied in consumer electronics for high-gloss surfaces, in automotive interiors for glare-reducing matte finishes, in medical devices for smooth, easy-to-clean surfaces, and in household appliances for durability and aesthetic appeal.

MoldTech Finishes

MoldTech finishes are standardized surface textures applied to injection molds through chemical etching or laser engraving, enabling a wide range of aesthetic and functional effects on plastic parts. Common finishes include the MT-11000 Series for fine matte textures that reduce glare, MT-12000 Series for balanced matte surfaces suited for consumer goods, and MT-13000 Series for coarser textures providing a rugged look, ideal for automotive interiors. The MT-14000 Series mimics natural materials like leather or fabric, adding visual appeal in applications such as automotive and home appliances, while the MT-15000 Series offers a very coarse texture, enhancing grip and durability for industrial and outdoor products. MoldTech finishes help manufacturers tailor the visual, tactile, and functional qualities of molded plastic components to meet specific design requirements.

MoldTech finishes are used in automotive interiors for leather or fabric textures, in consumer electronics and home appliances for matte, durable surfaces, and in industrial and outdoor equipment for grip-enhancing, wear-resistant textures.

Injection Molding Materials

Standard and custom materials are available for laser cut parts. Need a custom material quote? Contact us, we're happy to source the material and quote the project from start to finish. 

Materials

Plastics

  • ABS (acrylonitrile butadiene styrene)
  • ASA (acrylonitrile styrene acrylate)
  • CA (cellulose acetate)
  • HDPE (high-density polyethylene)
  • LCP (liquid crystal polymer)
  • LDPE (low-density polyethylene)
  • PA 6 (polyamide 6, nylon 6)
  • PA 6/6 (polyamide 6/6, nylon 6/6)
  • PARA (polyarylamide)
  • PBT (polybutylene terephthalate, Valox)
  • PBT-PET (polybutylene terephthalate-polyethylene terephthalate)
  • PC (polycarbonate)
  • PC-ABS (polycarbonate-acrylonitrile butadiene styrene)
  • PC-PBT (polycarbonate-polybutylene terephthalate, Xenoy)
  • PC-PET (polycarbonate-polyethylene terephthalate)
  • PCT (polycyclohexylenedimethylene terephthalate)

Plastics

  • PE (polyethylene)
  • PEEK (polyether ether ketone)
  • PEI (polyetherimide, Ultem)
  • PE-PP (polyethylene-polypropylene)
  • PE-PS (polyethylene-polystyrene)
  • PES (polyethersulfone)
  • PET (polyethylene terephthalate, Rynite)
  • PLA (polylactic acid)
  • PMMA (polymethyl methacrylate, acrylic)
  • POM (acetal polyoxymethylene, Delrin)
  • PP (polypropylene)
  • PPA (polyphthalamide)
  • PPS (polyphenylene sulfide, Ryton)

Injection Molding
Frequently Asked Questions

Get the answers to these questions about injection molded parts.

General injection molding FAQs

What is injection molding?

Injection molding is a manufacturing process that produces parts by injecting molten material into a mold to create complex shapes with high accuracy.

What materials are used in injection molding?

Injection molding commonly uses plastics, such as ABS, polypropylene, and polyethylene, as well as metals and elastomers for various applications.

What industries use injection molding?

Injection molding is used across industries like automotive, consumer goods, medical devices, and electronics for producing high-quality, durable parts at scale.

What are the advantages of injection molding?

Injection molding offers high efficiency, low waste, and excellent repeatability, making it ideal for high-volume production of precise parts.

Technical injection molding FAQs

What tolerances can be achieved with injection molding?

Injection molding can achieve tolerances as tight as ±0.1mm, though this can vary based on material type, part design, and mold precision.

What is the typical lead time for injection molding?

Lead times for injection molding vary but generally range from a few weeks to a few months, depending on mold complexity and production requirements.

What is a typical wall thickness for injection-molded parts?

Wall thickness for injection-molded parts typically ranges from 1 to 5 mm, with thinner walls reducing material costs and cycle times.

Can injection molding create complex shapes?

Yes, injection molding can produce complex shapes with intricate details by using advanced mold designs, including undercuts and inserts.

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