Injection Molding 101: Process, Types, Advantages and Disadvantages

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I. What is Injection Molding?

II. How Does the Injection Molding Process work?

III. Main Injection Molding Parameters

IV. Injection Molding Machine Components

V. Types of Injection Molding Services

VI. Common Materials used for injection molding

VII. Advantages and Disadvantages of Injection Molding

VIII. Common injection molding defects

IX. History of Injection molding

Plastic parts play an integral part of our life with almost every gadget, appliance, or device requiring them. They play roles such as protecting us from inside electrical parts, mounting the electrical parts tightly into position, or creating functional parts. Additionally, some plastics act as stand-alone tools that we use in our daily lives.

This explains why plastic is amongst the most abundant man-made objects on earth. Back in the 1950s, the world barely produced 2 million tonnes per year. However, currently, that number is in the ceiling as the world produces more than 450 tonnes per year.

Despite relying on them to carry out our daily tasks, most people don’t know how the process of creating plastic parts works. Injection molding is one of the most popular methods for creating plastics. In this article, you will learn how injection molding works, the machine components, and the services associated with it.

What is Injection Molding?

Injection molding refers to a manufacturing process where molten plastic materials or metal, are injected into a mold at high pressure.

The process is widely used to mass-produce complex parts with consistent quality and precision.

It is important to create or select the right plastic injection molds as they can affect the final output. Furthermore, the mold also determines how details of complex parts are well captured. Every injection molding project requires a unique mold depending on size and shape.

How Does the Injection Molding Process work?

The plastic injection molding process is a meticulous sequence of steps, each playing a crucial role in the creation of high-quality plastic parts. Let’s delve into the intricacies of each stage:

Clamping

The process initiates with the clamping stage, where the mold is securely closed to prevent any leakage thermal expansion of molten plastic. The clamping unit applies pressure to hold the mold halves together, ensuring a tight seal. This phase sets the foundation for the subsequent stages, providing stability for the injection and cooling processes.

Injection

The injection phase begins with the molten plastic being injected into the mold cavity at high pressure. Molten plastic refers to the plastic that has been melted to the melting point. This step requires precise control over the injection speed, pressure, and temperature to ensure the material fills the cavity completely and uniformly.

Typically, a reciprocating screw within the injection molding machine pushes the molten material forward into the mold under controlled conditions. When the injection pressure is applied molten plastic flows through the runner system and into the mold cavity, where it takes on the shape of the desired part.

Dwelling

Following the injection of melted plastic into the mold cavity, there is a brief pause known as the dwelling phase.

During this stage, the material remains stationary within the metal mold, allowing it to settle and pack evenly. Proper dwelling time is essential to ensure that the material is distributed uniformly and fills any complex features or details of the part. This phase helps minimize potential defects such as air pockets or voids and promotes the formation of a dense and uniform structure within the part.

Cooling

After the dwelling phase, the mold undergoes the cooling stage, where the melted plastic inside the mold cavity solidifies. Cooling is achieved through various methods, such as circulation of coolant through channels within the mold or by allowing the mold to cool naturally in ambient air.

Proper cooling is crucial for achieving the desired part properties, dimensional accuracy, and minimizing warpage or distortion. The cooling rate and uniformity are carefully controlled to prevent internal stresses within the part and ensure consistent cooling across the entire mold.

Mold Opening

Once the plastic solidifies, the mold undergoes the mold opening stage, where the two halves of the mold are separated to reveal the newly formed part.

Mold opening is typically achieved using hydraulic or mechanical systems that apply force to the mold’s clamping mechanism, causing it to release and open. Precision and consistency are crucial during this phase to ensure that the part is ejected smoothly without damage. Proper plastic injection mold opening also helps prevent any deformation or distortion of the part as it is released from the cavity.

Ejection( Removal of products)

After the mold opens, the final plastic parts are ejected from the mold cavity, marking the final stage of the injection molding process. The ejected parts may be manually removed by an operator or automatically ejected using ejector pins or plates integrated into the mold design.

Care must be taken during the part removal process to avoid any damage or deformation to the parts. Any excess material, known as flash, may also be trimmed or removed at this stage to achieve the desired final appearance and dimensions of the parts.

Main Injection Molding Parameters

The injection molding cycle consists of many parameters that need to be in check in order to produce high-quality plastic components. These parameters include:

Injection pressure: The force applied to inject molten plastic into the mold cavity. It’s crucial for achieving proper filling of the mold and ensuring part quality.

Mold temperature: This refers to the temperature at which the mold is maintained during the injection molding process. It affects material flow, part cooling, and overall part quality.

Nozzle pressure: The pressure exerted at the injection nozzle to force molten material into the mold. It’s part of the overall injection pressure but specifically refers to the pressure at the entry point of the mold

Recovery rate: Refers to the rate at which the material rebounds or recovers after being compressed during the injection process.

Shrinkage rate: This refers to the percentage decrease in dimensions of the molded part from its molten state to its solid state.

Clamping force: The force applied to hold the mold halves together during injection and cooling.

Screw speed: It’s the speed of the screw within the injection molding machine barrel. Scre speed determines the rate at which plastic is fed into the mold cavity and affects both filling and cooling times.

Injection Molding Machine Components

Hopper: It is a container located at the top of the injection molding machine where raw material, typically plastic pellets or resin, is stored. It feeds the material into the barrel of the moulding machine.

Barrel: It refers to a long, cylindrical chamber within the injection molding machine where the raw material is melted and mixed. It houses the reciprocating screw and heaters.

Reciprocating screw: An important component that moves back and forth within the barrel. Its primary function is to melt and homogenize the raw material while also injecting it into the cavity under pressure.

Heaters: They are used to heat the barrel of the injection molding machine, maintaining the temperature required to melt the raw material. They ensure consistent material flow and proper molding conditions.

Movable Platen: This refers to one of the two plates that hold the halves together during the injection molding process. It can move horizontally to open and close the mold, allowing for part ejection and mold changeovers.

Nozzle: It’s the point where the molten plastic material exits the barrel and enters the mold cavity. It ensures a precise and controlled flow of material into the mold.

Mold: A precision tool typically made of steel or aluminum that forms the desired shape of the plastic part. It consists of two halves (core and cavity) that come together to create a void where the molten material is injected and solidified.

Mold Cavity: This is the void or impression within the mold where the molten plastic is injected to form the final part. It is shaped precisely to match the desired geometry of the finished product.

Types of Injection Molding Services

Conventional Injection Molding: A standard process where the molten plastic material is injected into a mold cavity, cooled, and ejected as a solid part.

Insert molding: Involves placing pre-formed parts (inserts) into the cavity before injection, resulting in a single integrated part.

Overmolding: Process where a substrate is molded over with a second material, commonly used for adding soft-touch surfaces or multi-material aesthetic.

Gas-Assisted Injection Molding: Utilizes nitrogen gas to displace molten plastic material in the cavity, creating hollow sections for reducing material usage and improving part strength.

Co-injection Molding: Simultaneously injects two or more different materials into the cavity to produce multi-material parts.

Two-shot or multi-shot injection molding: Injects different materials or colors sequentially into the same mold cavity, enabling the production of multi-material or multi-color parts in one step.

Micro-injection molding: A specialized process for producing extremely small plastic parts with tight tolerances, commonly used in electronics and medical devices.

Liquid Injection Molding (LIM): Utilizes liquid silicone rubber (LSR) or similar elastomers injected into a cavity under high pressure, ideal for producing flexible parts with complex geometries.

Common Materials used for injection molding

The choice of material is not arbitrary; it’s a strategic decision based on the intended application. Whether it’s the transparency of polycarbonate in optical components or the wear resistance of nylon in mechanical parts, each material plays a vital role in shaping the success of the injection molding process.

Polypropylene (PP)

Polypropylene, commonly known as PP, is a versatile thermoplastic with a wide range of applications in injection molding. Its low density, high chemical resistance, and excellent fatigue resistance make it a preferred choice for producing items such as packaging, containers, and automotive components.

ABS

Acrylonitrile Butadiene Styrene, or ABS, is renowned for its strength, impact resistance, and dimensional stability. These properties, coupled with its ability to be easily molded and colored, make ABS a top choice for manufacturing consumer goods, automotive parts, and electronic housings.

Polyethylene (PE)

Polyethylene, identified as PE, is a lightweight plastic known for its flexibility and low cost. With variations such as HDPE and LDPE, it finds applications in diverse industries, from packaging and containers to agricultural products and toys.

Polystyrene (PS)

Polystyrene, or PS, boasts clarity, rigidity, and affordability. Commonly used for disposable items like packaging, food containers, and disposable cutlery, PS is favored for its ease of molding and cost-effectiveness.

Nylon (PA 6)

Nylon, specifically Nylon 6 or PA 6, is recognized for its strength, toughness, and resistance to abrasion. Ideal for producing mechanical parts, nylon is widely used in applications like gears, bearings, and other components requiring high volumes, durability and precision.

Polycarbonate (PC)

Polycarbonate, known as PC, is prized for its transparency, impact resistance, and high-temperature tolerance. These characteristics make it suitable for manufacturing optical lenses, electronic components, and durable transparent parts in various industries.

POM (Acetal/Delrin)

Polyoxymethylene, or POM, commonly referred to as Acetal or Delrin, is a high-strength engineering plastic with excellent dimensional stability. Its low friction and wear and good chemical resistance make it ideal for producing gears, bushings, and other precision components.

The properties of common materials used in injection molding, as summarized in Table 1 below, offer a concise guide for material selection in the manufacturing process. From the physical characteristics to chemical resistance and typical applications, this overview provides valuable insights for informed decision-making in the dynamic realm of injection molding.

ABS

Semi-rigid, tough
thermoplastic polymer

Crystalline thermoplastic

Lightweight
flexible, low cost

Clarity, rigidity, affordability

Made from the monomer

Combination of acrylonitrile, butadiene, styrene

Variations include HDPE and LDPE

Ideal for disposable items like packaging

Lightweight,durable, and strong

Strong,impact resistant, rigid structure

Versatile applications in packaging. toys, etc.

Easy molding; cost-effective

0.89-0.91g/cm³

1.05-1.07 g/cm³

0.91-0.97 g/cm³

1.04-1.07 g/cm³

Opaque

320 °F(160°C)

176-203°F(80-95℃)

158°F(70℃)

Excellent resistance to chemicals

Very good

Excellent resistance to chemicals

Limited resistance to some chemicals

30-38MPa

40-50MPa

10-45MPa

40-50MPa

Nylon

POM

Strength, toughness, resistance to abrasion

Transparency, impact resistance.high temp

High-strength engineering plastic

Ideal for mechanical parts like gears, bearings

Suitable for optical lenses, electronic components

Excellent dimensional stability

Durable and precise

Durable and transparent

Low friction, wear resistance

1.12 g/cm³

1.20-1.22 g/cm³

1.4l g/cm³

Opaque

Transparent

Opaque

185 °F(85°C)

302°F(150°C)

212°F(100°C)

Excellent resistance to chemicals

Good resistance to chemicals

50-80MP

55-75MPa

60-70MPa

Advantages and Disadvantages of Injection Molding

The realm of injection molding is a landscape of unparalleled efficiency and precision, yet it is not without its challenges. In this section, we will explore both the benefits that make injection molding a cornerstone of manufacturing and the limitations and challenges that inject nuances into its mastery.

Pros

High Accuracy and Precision

Injection molding allows for the creation of parts with extremely tight tolerances and consistent dimensions. The process enables manufacturers to produce intricate geometries and complex shapes with remarkable accuracy, ensuring that each part meets exact specifications.

Complex Details

One of the standout features of injection molding is its ability to produce parts with intricate details and complex features. This includes thin walls, intricate patterns, undercuts, threads, and other intricate details that may be challenging or impossible to achieve with alternative manufacturing methods.

Durability

Injection-molded parts are renowned for their durability and strength. The process ensures that materials are evenly distributed, resulting in parts that exhibit excellent structural integrity and resistance to wear, impact, and environmental factors. This durability makes injection molded parts suitable for a wide range of applications across various industries.

Automation

Injection molding is highly automated, leading to increased production efficiency and reduced labor costs. Automated injection molding machines can run continuously with minimal human intervention, ensuring consistent part quality and high throughput rates. This automation also allows for rapid production cycles, enabling manufacturers to meet tight deadlines and scale production as needed.

Cost-Effective for Mass Production

While the initial tooling costs for injection molds can be significant, injection molding becomes highly cost-effective for large-scale production runs. Once the molds are created, the per-unit cost of manufacturing decreases significantly, making injection molding an economical choice for mass production of identical or similar parts.

Wide Range of Materials

Injection molding supports a vast array of materials, including thermoplastics, thermosets, elastomers, and composites. This versatility in material selection allows manufacturers to choose the most suitable material for their specific application requirements, whether it be for its mechanical properties, chemical resistance, or aesthetic appeal.

Reduced Post-Processing

Injection molded parts often require minimal post-processing, as they typically have smooth finishes and accurate dimensions straight out of the mold with minimal waste material. This reduces the need for additional machining, sanding, or finishing operations, saving time and resources in the manufacturing process. Additionally, the consistency and precision of injection molding minimize the occurrence of defects, further reducing the need for rework or corrections.

Cons

High Initial Tooling Cost

One of the significant drawbacks of injection molding is the high cost associated with creating the molds. Designing and fabricating molds tailored to specific part geometries can be expensive, particularly for complex or intricate designs. This initial investment can be prohibitive for smaller production runs or for companies with limited budgets.

Takes Longer to Get Started

Compared to some rapid prototyping methods like 3D printing, injection molding typically requires more time to set up and get started. The process involves designing and fabricating molds, conducting tooling trials, and fine-tuning process parameters before full-scale production can commence. As a result, there can be a longer lead time from concept to finished parts compared to faster prototyping methods.

Size Limitations

Injection molding may have size limitations, particularly for larger parts. The size of the injection molding machine and the capacity of the cavity can constrain the maximum dimensions of the parts that can be produced. Manufacturing oversized parts may require specialized equipment or multiple mold cavities, which can further increase costs and complexity.

Design limitations

While injection molding offers great versatility in creating complex shapes and details, there are still design limitations to consider. Certain part geometries, such as sharp corners, thin walls, or deep recesses, may pose challenges in mold filling, cooling, or ejection. Designing parts for injection molding often requires careful consideration of draft angles, wall thicknesses, and other design guidelines to ensure successful moldability and part quality. Additionally, features like undercuts or complex internal geometries may require additional mold features or secondary operations, adding complexity and cost to the manufacturing process.

Common injection molding defects

Injection molding is a finely tuned process that demands precision at every stage. However, even with meticulous attention, certain defects can emerge, affecting the quality and functionality of the final product. Understanding and addressing these common injection molding defects is crucial for achieving consistently high-quality results.

In this section, we will explore and dissect seven prevalent defects that can occur during the injection molding process. From the causes behind warping to the remedies for short shots, our journey will navigate through the intricacies of defect identification and mitigation. Let’s embark on this exploration, unraveling the challenges and solutions that contribute to the refinement of the injection molding craft.

Warping

Warping in injection molding refers to the unintended twists or bends caused by uneven internal shrinkage during the cooling process. This defect is often the result of non-uniform or inconsistent mold cooling, creating stresses within the material.

Preventing warping involves ensuring uniform wall thickness in mold design and allowing parts sufficient time to cool gradually. Materials with semi-crystalline structures are particularly prone to warping.

Surface Delamination

Surface delamination is a condition where a part’s surface separates into thin layers, resembling peelable coatings. This issue arises from contaminants in the material or excessive reliance on mold release agents.

Delamination can compromise the material’s structural integrity and appearance. Preventive measures include adjusting mold temperatures, reducing dependence on release agents, and ensuring proper pre-drying of the plastic before molding.

Sink Marks

Sink marks, characterized by depressions or dents on the surface of a molded part, can be a result of uneven cooling or insufficient packing of the already molten material or plastic. Our exploration will uncover the intricacies of sink marks, pinpointing their causes, and proposing remedies to achieve smooth and flawless surfaces.

Knit or Weld Lines

Knit or weld lines, are marks where two flows of molten resin unite during their journey through the mold. These lines typically form around holes in the geometry. When the plastic flows around a hole, the meeting point of two flows can result in a visible line.

Weld lines reduce the overall strength and durability of the component. Factors such as resin temperature, injection speed, and pressure influence the formation of weld lines. Strategic modifications to mold design, like removing partitions, can help eliminate weld lines.

Drag Marks

Drag marks, also known as streaks or scuffing, can mar the appearance of an otherwise perfect part. We will scrutinize the factors leading to drag marks, from mold temperature to injection speed, and discuss practical approaches to eliminate this defect and enhance the visual appeal of molded parts and products.

Flow Lines

Flow lines are intricate patterns, often off-color, streaks, or variations on a part’s surface. These markings are a visual manifestation of molten plastic’s journey through the injection mold. When plastic moves at varying speeds, it solidifies at different rates, resulting in these lines.

The appearance of flow lines is indicative of potential issues with injection speed or pressure. Ensuring consistent wall thickness and strategic gate placement can minimize this defect.

Short Shots

Short shots refer to instances where the resin fails to entirely fill the mold cavity, leading to incomplete and unusable parts. Factors such as restricted flow within the mold, narrow gates, blocked gates, trapped air pockets, and inadequate injection pressure contribute to short shots.

Understanding these issues is crucial for optimizing the injection molding process and ensuring complete, consistent part production.

History of Injection molding

Injection molding, originating in the late 19th century, began with John Wesley Hyatt’s patent for a machine using a plunger to mold celluloid. The 1940s saw the introduction of screw injection machines, bringing consistency to the process, while the 1950s integrated hydraulic systems and expanded material options.

In the 1980s, computer numerical control (CNC) machining revolutionized precision and automation, influencing design possibilities significantly.

Today, injection molding dominates various industries due to its efficiency in producing intricate, high-quality components at scale. It’s widely used in automotive, electronics, medical, and consumer goods sectors. This method not only streamlines production but also enables the creation of complex shapes and features, pushing the boundaries of design possibilities.

Author

Gavin Leo is a technical writer at Aria with 8 years of experience in Engineering, He proficient in machining characteristics and surface finish process of various materials. and participated in the development of more than 100complex injection molding and CNC machining projects. He is passionate about sharing his knowledge and experience.

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Plastic Injection Molding Process

Aria has over 1,00 presses with a range of sizes, from 50 to 1,000 tons of clamping force. we can produce parts in a variety of materials, including thermoplastics, elastomers, and silicone. we also offer secondary services such as machining, finishing, and assembly.

Mold Making

The mold manufacturing process can be quite complex and time consuming, but it is an important part of the plastic injection molding process. The processing is usually completed in 2 weeks

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Injection Molding

Plastic injection molding process can produce a large number of parts quickly and efficiently. It is ideal for producing complex parts with tight tolerances.

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Insert Tooling

Put the insert in the mold and mold around it to extend the tool life of key features, it allows you to mold inserts such as brass nuts in your design.

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Overmolding

Install the prefabricated parts in the mold and then cover it with new material. This two-step process achieves the flexibility of multi-material part design by creating molds with different structural materials

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What is Plastic Injection Molding?

The injection molding process is the standard operating procedure for generating large quantities of finished plastic parts used in commercial and industrial applications.

Injection molding technology involves injecting molten resin into the cavity of a metal die under high pressure. The die is then rapidly cooled to form a solid shape. If your project requires plastic injection molding services, Aria can help.

Why Choose Plastic Injection Molding

Aria is a professional injection molding supplier.
Here are four reasons to use our injection molding procedure:

limitless production possibilities

Aria’s capability includes a wide variety of plastic injection molding processes. we can handle a molding range from 60 tons to 1,800 tons.

Materials Verification

Aria issues a materials verification report for every injection molding order. Additionally, we offer certificates of compliance for all materials used.

Manufacturing support

We optimize the costs of injection molding products by providing a detailed design for manufacturing reports for every customer.

Process optimization program

We combine data from thousands of projects with our own material and molding procedures. Process optimization can quickly identify the proper machining parameters.

Plastic Injection Molding Process

Step 1

Step 2

Step 3

Plastic resin comes in raw pellets. The pellets are dried until they acquire the correct moisture content. They can then be blended with pigments or masterbatch colorants as necessary.

The dried pellets are added to the hopper of the molding machine. Inside the barrel of the molding machine is a reciprocating screw that will move the pellets into the mold.

The pellets are heated and blended until they reach the fully molten state and become liquid resin. And the heater bands keep the temperature inside barred at a stable level for the type of resin being used.

Step 6

Step 5

Step 4

The mold opens to allow the ejector rod to push the ejector pin to move forwards. So part is ejected and a new cycle begins. In the case of the robot’s hand, the cycle starts and ends when the robot hand receives a new part.

The mold is cooled to solidify the inside part. The type of resin and thickness of the part determines the cooling time. The temperature of the mold is controlled by internal cooling or heating lines where water is cycled.

The heated mold automatically closes. The resin, which is subjected to great pressure, is injected into the mold cavity by way of a gate, the injection pin’s vent empties the displaced air for injection molding products.

Step 1

Plastic resin comes in raw pellets. The pellets are dried until they acquire the correct moisture content. They can then be blended with pigments or masterbatch colorants as necessary.

Step 2

The dried pellets are added to the hopper of the molding machine. Inside the barrel of the molding machine is a reciprocating screw that will move the pellets into the mold.

Step 3

Step 4

Step 5

The mold is cooled to solidify the inside part. Type of resin and thickness of part determine the cooling time. Temperature of mold is controlled by internal cooling or heating lines where water is cycled.

Step 6

The heated mold automatically closes. The resin, which is subjected to great pressure, is injected into the mold cavity by way of a gate, the injection pin’s vent empties the displaced air.

Materials of Injection Molding Services

Words Tab

ABS

Acrylonitrile Butadiene Styrene resin is a milky white solid with a certain degree of toughness, with a density of about 1.04~1.06 g/cm3. ABS is a resin that has good mechanical toughness, wide temperature range, good dimensional stability, chemical resistance, electrical insulation properties and it’s easy to manufacture.

Common applications: Instrument panel, refrigerator, telephone, keyboard

ABS / PC

PC + ABS plastic provides better strength than ABS at a lower cost than PC. It has high impact strength even at low temperatures. In addition, adding glass fiber, mineral fillers and flame retardants to the material can change its performance.

Common applications: Electrical equipment, Computer enclosures,
Auto parts

LCP

Liquid Crystal Polymer plastic raw materials, also known as liquid crystal polymers, with a density of about 1.35-1.45g/cm3. It is a new type of polymer material, which generally exhibits liquid crystallinity in the molten state. The highly oriented and rod-like nature of the liquid crystal polymer molecules, making their tensile strength and modulus are close to that of aluminum.

Common applications: Enclosures

Nylon 6

Nylon 6, also known as PA6, polyamide 6, is a polymer compound. Except for its low melting point and wide process temperature range, its chemical and physical properties are very similar to nylon 66. Among all nylon grades, nylon 6 has the lowest modulus.

Common applications: Structural components, Bearings

Nylon 66

Polyhexamethylene adipamide, commonly known as nylon-66, is a thermoplastic resin. The performance of nylon 6-6 is better than nylon 6, and the price is not as expensive as nylon 4-6. Its abrasion resistance is the best among all nylons, and its mechanical strength, hardness, and rigidity are very high. Can be used as engineering plastics and making synthetic fibers.

Common applications: Auto parts, Instrument housing

Nylon 11

The density of nylon PA11 is 1.04g/cm3, the melting point is 185℃, the water absorption is 0.1-0.4℅, and the tensile strength is 47-58MPa. It has the advantages of low water absorption, good oil resistance, low-temperature resistance, and easy processing. Widely used in our lives due to its good cost performance.

Common applications: Enclosures

PBT

Polybutylene terephthalate (PBT), a milky white semi-crystalline thermoplastic polyester, is one of the five major engineering plastics. It has high heat resistance. Not resistant to strong acids and alkalis, resistant to organic solvents, flammable, and decomposes at high temperatures. It is widely used in the fields of automobiles, machinery, and equipment, precision instrument parts, etc.

Common applications: Household appliances, Electrical components

PC

Polycarbonate is a high molecular weight polymer containing carbonate groups in the molecular chain. It is a tough thermoplastic resin with flame retardancy. Antioxidant. It has excellent impact strength, transparency, and optical properties, mechanical properties, and can be molded to tight tolerances. PC has a wide range of applications, and there are a variety of compounds to choose from.

Common applications: Computer components, Connectors, Auto parts

PE

The full name is Polyethylene, which is the simplest polymer organic compound and the most widely used polymer material. According to the density, there are 2 types of PE: LDPE and HDPE. It has good inherent lubricity and is easy to process. It should be noted that it is very soft and cannot be used at a temperature much higher than 150.

Common applications: Enclosures

PEI

Polyetherimide (PEI for short) is an amorphous high-temperature super engineering plastic, and its cost is relatively low compared with other high-temperature materials. It has the best high-temperature resistance and dimensional stability, as well as chemical resistance, flame retardancy, electrical properties, high strength, high rigidity, etc. The performance is similar to polycarbonate, but it can work at higher temperatures.

Common applications: Automotive industry, Product packaging,
Medical equipment

LDPE

Low-density polyethylene, also known as high-pressure polyethylene (LDPE), is milky white, odorless, odorless, non-toxic, and waxy particles with a matt surface. It has good electrical insulation, transparency, easy processing, and certain air permeability. And has strong extensibility and flexibility, making it have excellent impact strength. This is offset by the permanent deformation after the impact.

Common applications: Bowls, Cabinets, Pipe couplings

HDPE

High-density polyethylene (HDPE) is a white powder or granular product. Non-toxic and odorless, the use temperature can reach 100℃. It does not have the impact strength of LDPE, but it is more elastic. Surface hardness, tensile strength, rigidity, and other mechanical strength are higher than LDPE, close to PP, tougher than PP, but the surface finish is not as good as PP.

Common applications: Storage containers, Household kitchenware, Sealing covers

PET

Polyethylene terephthalate (PET), milky white or light yellow, is a highly crystalline polymer with a smooth and shiny surface. It is non-toxic, tasteless, and has good hygiene and safety, and can be directly used for food packaging. It has excellent physical and mechanical properties in a wide temperature range, and the long-term use temperature can reach 120°C. But it is difficult to mold to very close tolerances.

Common applications: Automotive industry, Electrical components

PP

Polypropylene is abbreviated as PP, which is a colorless, odorless, non-toxic, translucent solid substance. The density is about 0.89～0.91g/cm3, and the operating temperature range is -30～140℃. It is difficult to mold to very close tolerances. Widely used in the production of clothing, medical equipment, automobiles, bicycles, parts, pipelines, chemical containers, etc.

Common applications: Automotive industry (fenders, ventilation ducts, fans)

PPA

Polyphthalamide is a kind of synthetic resin with high hardness, high strength, good chemical resistance, and low cost. Due to the excellent physical, thermal, and electrical properties of PPA, especially the moderate cost, it has a wide range of applications. Although the use and introduction of PPA are relatively late, its good design data is still very useful.

Common applications: Enclosures

PPS

Polyphenylene Sulfide is a new type of high-performance thermoplastic resin, which has the advantages of high mechanical strength, high-temperature resistance, chemical resistance, flame resistance, good thermal stability, and excellent electrical properties. It is widely used in the fields of electronics, automobiles, machinery, and chemicals.

Common applications: Enclosures

PMMA(Acrylic)

PMMA, also known as acrylic, is a tough, highly transparent material with excellent resistance to ultraviolet radiation and weather resistance. It can be colored, shaped, cut, drilled, and shaped. With its beautiful appearance, it has a wide range of applications in the construction industry.

Common applications: Automobile signal lamp equipment, Instrument panel

POM

POM is a crystalline plastic, a density of 1.42g/cm3. It has good rigidity, it is an engineering plastic with excellent comprehensive properties. POM has exhaust problems at high temperatures and is brittle at low temperatures. Glass filled, add lubrication grade available, no flame retardant grade.

Common applications: Gears, Bearings, Pipe components

Polystyrene Crystal

Polystyrene Crystal is a colorless and transparent thermoplastic with a glass transition temperature higher than 100°C, making it the cheapest thermoplastic. It has good optical performance. Its impact strength is very low. Widely used in various instrument housings, lampshades, optical chemical instrument parts, etc.

Common applications: Electrical and commercial equipment

PEEK

Peek (polyetheretherketone) is a kind of special engineering plastic with high-temperature resistance, self-lubrication, easy processing, and high mechanical strength, and other excellent properties. It can be manufactured and processed into various mechanical parts, such as automobile gears, oil screens, gear shift start plates; Aircraft engine parts, automatic washing machine runner, medical equipment parts, etc.

Common applications: Enclosures

HIPS

HIPS(High Impact Polystyrene) is a bright and pure amorphous plastic. It has the advantages of easy processing, rigidity, dimensional stability, and transparency, but its low impact strength limits its application. It has a lower modulus, better elongation, and is much more brittle than crystalline styrene.

Common applications: Enclosures

PSU

PSU is a relatively low-cost high-temperature amorphous material. It is transparent and has good radiation stability and heat resistance. Can be used at temperatures up to 300 degrees Fahrenheit. Widely used in medical equipment, machinery industry, electronic appliances, and other fields.

Common applications: Enclosures

PU

PU(Polyurethane) is an extremely elastic, wear-resistant, and tear-resistant elastic material that can be used in ether and ester-based formulations. These different formulations cover a very wide range of hardness and density.

Common applications: Enclosures

TPE

TPE(Thermoplastic Elastomer), also known as artificial rubber or synthetic rubber. It is a kind of elastomer that has the elasticity of rubber at normal temperatures and can be plasticized and molded at high temperatures. It contains thermoplastic and elastomer properties, which makes the product very easy to use in the manufacture of various products. Standard thermoplastic processing equipment and techniques can be used for processing and molding, such as extrusion, injection, blow molding, etc.

Common applications: Enclosures

TPU

Thermoplastic polyurethane (TPU) is an elastic material with good oil resistance, grease resistance, and wear resistance. It is also a mature environmental protection material. It is widely used in medical and health, electronic appliances, industry, and sports.

Common applications: Enclosures

Surface Finishes of Injection Molding Servcies

Picture

Grade

Finsishes

Descriptions

A1, A2, A3

Glossy

The surface is completely smooth, allowing no blemishes or scratches, similar to the reflection effect of a mirror.

B1, B2, B3

Semi-glossy

The surface is smooth and without obvious blemishes, but minor scratches and spots are allowed.

C1, C2, C3

Matt

The surface without luster and slightly rough, but does not affect the function.

D1, D2, D3

Textured

For some special requirements, such as anti-skid, wear, etc.

Why Choose Aria

Based on data collected from thousands of projects in conjunction with standard material and molding processes, our injection molding procedure is an optimization program that can efficiently identify the right combination of machining parameters for any given project.

Using this information, we can move a new mold from testing to production within a matter of hours. By applying the proper combination of machining parameters required to properly fill a part, we can reduce or even eliminate plastic part defection during the injection molding process.

With Aria’s process optimization, quality issues caused by these molded-in stressors are eliminated:

Warp

Colour Blends

Cracks

Surface shrinkage

Voids

Surface Sink Marks

Undersize

Surface Sheen

Injection Molding FAQs

Q: How soon can I get a precise quotation for custom plastic injection part?

A: Please send us your inquiry by email or Online quote system. Once we confirm the design (Feature details with parameters), material, color, qty, we can provide quotation within 24 HOURS.

Q: What is the typical lead time for an injection molding project?

A: This depends on a number of factors including the complexity of the part design, size of the production run and availability of the materials. Generally, An injection molding project takes 2-3 weeks for mold manufacturing and sample production, and 2-3 weeks for bulk production.

Q: What services do you provide?

A: we can provide design assistance, tooling fabrication, and production services as well as post-processing and finishing operations. Additionally, we will work with you on material selection and help ensure that quality standards are met throughout the entire process.

Q: What is involved in the design of an injection mold?

A: The design of an injection mold is one of the most important steps in any injection molding project. It requires a deep understanding of both the intended application and the injection molding process. Designers must take into account factors such as part geometry, material properties, shrinkage rates and draft angles.

Aria is a Chinese injection molding supplier, Click the following button to get Your Free Quote About Plastic Injection Molding Services Today.

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