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What Is Plastic Mold Technology

Plastic molding manufacturing

Plastic Molding Technology

The History of Plastic Molding Technology

The history of plastic molding technology is a fascinating journey that spans several decades, marked by significant developments and innovations. Plastic molding refers to the process of shaping plastic materials into a desired form using a mold or die. Here’s a brief overview of the key milestones in the history of plastic molding technology:

  1. Early Developments (Late 19th Century):
    • The first synthetic plastic, Bakelite, was developed by Leo Baekeland in 1907. Bakelite was initially used for electrical insulators and later found applications in various industries.
    • Injection molding, the most widely used plastic molding process today, saw its initial concept in the late 19th century, but it wasn’t until the 1930s that it became a practical manufacturing method.
  2. World War II Era (1930s-1940s):
    • The demand for mass-produced, lightweight components during World War II accelerated the development and adoption of plastic molding technologies.
    • Injection molding gained prominence during this period due to its ability to produce complex and precise parts in large quantities.
  3. Post-World War II Advances (1950s-1960s):
    • The 1950s saw the commercialization of various plastic materials like polyethylene, polypropylene, and PVC, expanding the range of possibilities for plastic molding.
    • Blow molding, a process for creating hollow objects such as bottles, became popular during this era.
  4. Rotational Molding (1940s-1950s):
    • Rotational molding, also known as rotomolding, emerged in the 1940s and gained traction in the 1950s. This process involves rotating a hollow mold with powdered plastic inside to create a uniform coating on the interior.
  5. Thermoforming (1930s-1950s):
    • Thermoforming, a process where a plastic sheet is heated and molded into a specific shape, gained popularity in the 1930s and 1940s.
  6. Computer Numerical Control (CNC) Integration (1970s-1980s):
    • The integration of computer technology in plastic molding machines, known as CNC, enhanced precision and control in the molding process.
  7. Advancements in Materials and Techniques (1990s-Present):
    • Continuous advancements in plastic materials, additives, and molding techniques have allowed for greater versatility, durability, and efficiency in plastic molding processes.
    • 3D printing technologies have also influenced plastic molding, offering new possibilities for rapid prototyping and low-volume production.
  8. Sustainability and Innovation (Recent Years):
    • In recent years, there has been a growing emphasis on sustainable practices in plastic molding, with increased interest in biodegradable and recycled materials.
    • Advanced manufacturing technologies, such as Industry 4.0 concepts, are being integrated into plastic molding processes for improved efficiency and quality control.

The history of plastic molding technology is characterized by a continual evolution driven by technological advancements, material developments, and the changing needs of various industries. Today, plastic molding plays a crucial role in the production of a wide range of products across numerous sectors.

Plastic molding technology continues evolving with the market and with the advances in science. Plastic molding is the process used in producing plastic components for a variety of industries.

plastic molding technology

When plastic resin materials are heated the resin will flow, and can then be injected into a mold. A plastic mold consists of two halves referred to as the “A” side (cavity side) and the “B” side (core side). The “A” side is where the molten plastic enters the mold, and the “B” side contains the ejector system which removes the parts from the mold.

Advancements of plastic molding technology

Advancements in plastic molding technology have been significant, driven by innovations in materials, processes, and machinery. Some notable advancements include:

  1. High-Performance Materials:
    • The development of new and advanced plastic materials with enhanced properties, such as high strength, heat resistance, and durability, has expanded the application range of plastic molding.
  2. Biodegradable and Sustainable Plastics:
    • With increasing environmental concerns, there has been a focus on developing biodegradable and sustainable plastics. Manufacturers are exploring materials derived from renewable sources or those that can easily decompose, reducing the environmental impact of plastic products.
  3. Advanced Injection Molding Techniques:
    • Micro-injection molding allows for the production of extremely small and precise plastic components, opening up new possibilities in fields like electronics and medical devices.
    • Multi-material and multi-color injection molding enable the production of complex parts with different materials or colors in a single manufacturing cycle.
  4. Additive Manufacturing and 3D Printing:
    • The integration of 3D printing technologies into plastic molding processes has facilitated rapid prototyping, tooling development, and low-volume production. This allows for faster product iterations and reduced time-to-market.
  5. Industry 4.0 Integration:
    • The incorporation of Industry 4.0 principles, including smart sensors, data analytics, and connectivity, into plastic molding machines has improved automation, real-time monitoring, and overall efficiency in production processes.
  6. In-Mold Decorating and Labeling:
    • In-mold decorating (IMD) and in-mold labeling (IML) techniques allow for the integration of graphics, textures, and labels directly into the molded plastic parts during the manufacturing process. This enhances product aesthetics and eliminates the need for additional post-processing steps.
  7. Gas-Assisted Injection Molding:
    • Gas-assisted injection molding involves injecting a controlled volume of gas into the molten plastic to create hollow sections within the molded part. This technique is used to produce lightweight components with improved strength and reduced material usage.
  8. Foam Injection Molding:
    • Foam injection molding produces lightweight, rigid, and cost-effective parts by injecting gas or chemical blowing agents into the plastic melt. This process is particularly useful for automotive and packaging applications.
  9. Insert Molding and Overmolding:
    • Insert molding involves placing metal or plastic inserts into the mold before injection, creating a part with integrated components. Overmolding involves molding one material over another, providing benefits such as improved grip, aesthetics, and functionality.
  10. Liquid Silicone Rubber (LSR) Molding:
    • LSR molding is used for producing flexible and durable rubber-like parts. It is commonly used in medical devices, automotive components, and consumer goods.
  11. Robotic Automation:
    • The use of robotics in plastic molding processes has increased precision, speed, and efficiency. Robots are employed for tasks such as part handling, assembly, and quality control.

These advancements collectively contribute to the evolution of plastic molding technology, making it more versatile, efficient, and environmentally friendly. The ongoing focus on innovation continues to shape the future of plastic manufacturing processes.


Plastic Molding Includes Many Terms and Components

Plastic molds are required to have many components in order to make high-quality plastic parts. Below is some of the terminology used to describe the components and processes that are required when producing injection molded parts:

  • Sprue – this connects the nozzle of the injection molding machine to the main runner, or cavity
  • Runner – this component conveys the melted plastic from the sprue to the gate and into the part
  • Gates – these are the openings that allow the molten plastic to be injected into the cavities of the mold
  • Cold Runner mold – this design involves the plastic entering into the “sprue” and then traveling through the “runner” where it then enters the part cavities through the various “gates.”
  • Hot Runner mold – this design is an assembly of heated components used to inject molten pPlastic moldslastic into the cavities of the mold. Hot Runner mold usually makes mold more expensive to manufacture but allow savings by reducing plastic waste and reducing the cycle time.

When observing plastic molding products, you will often see a line running between different sides of the finished plastic part. Here are some descriptions of why parts have a specific appearance:

  • The Parting Line – this occurs anywhere there are any two pieces of mold that meet.

There are also several configurations of plastic molds. These configurations are described as


  • The Two Plate Mold – consists of one parting line where the mold splits into two halves.  The sprue, runners, gates, and cavities are all on the same side of the mold.
  • The Three Plate Mold – has a runner plate in between a moving half and a fixed half.  These molds will have two parting lines and are used because of their flexibility in gating locations.
  • An Unscrewing Mold – is what is used when there is a requirement for male or female threads on a plastic component
  • The Action Mold – these consist of a mechanical cam action incorporated in their design, when a hole, slot, undercut or thread is needed that is not perpendicular to the parting line.
  • The MUD Unit Mold– these are standard frameworks for toolsets (u-frame), which allow for custom-machined tooling inserts to be made for specific components.

Large Plastic Molding Runs Cost Less 

Plastic injection molding offers many industries a huge number of benefits.  In large runs, molding is much cheaper than when machining the parts individually. The over-all manufacturing speed is much faster with this approach as well. This is one of the many reasons there are so many different types of injection molding processes. Some of these include:

Cold runner mold

Insert Molding – This is the process of putting a metal insert into a mold and then molding plastic around the insert.  Since multiple parts are manufactured together – this eliminates the need for a secondary assembly operation.

OverMolding – This is the process of over-molding, and the production of injection molded parts that seamlessly combines a rigid plastic with a rubber-like elastomer.

Family Molding – This is a process that utilizes a mold that contains various shapes of cavities to mold all the plastic components for one completed part.  Family molds are used when the different plastic components are made from the same material.

Injection Molding CleanRoom – This is the process used primarily for medical components. It is the injection molding process that is performed in a cleanroom environment in order to protect the parts from any contaminants.

When considering having plastic parts custom designed and molded – SINCERE TECH is the ideal partner for your plastic component or device.

SINCERE TECH is a China mold maker, which is  your single-source solution for your device by providing mold building, design, and engineering, injection molding as well as injection molding cleanroom and any secondary operations that may be required to complete your project. contact us now to know more information