The emergence of the injection mold industry

The birth of the injection mold industry is a history that closely followed the Industrial Revolution, evolving alongside materials science, mechanical engineering, and the demands of mass consumption. Its emergence fundamentally changed the way products were manufactured, propelling "individual manufacturing" into an era of "mass replication."

Its development can be summarized in the following key stages:

I. Emergence and Pioneers: The Emergence of Injection Molding Concepts (19th Century) The principle of injection molds can be traced back to die casting of metals. However, what truly laid the foundation for plastic injection molding was:

1868: American John Wesley Hyatt invented "celluloid" to win a competition to manufacture alternatives to ivory billiard balls. This was the first thermoplastic material in history.

1872: Hyatt and his brother Isaiah invented the first plunger-type injection molding machine. This very primitive machine injected heated and softened celluloid into a mold through a simple plunger, used to produce items such as combs, buttons, and collars.

Characteristics of this stage:

Limited materials: Celluloid is flammable, and the processing is dangerous.

Rudimentary equipment: Machines are manual, with extremely low pressure and control precision.

Narrow applications: Only very simple daily necessities can be produced.

II. The Real Takeoff: The Catalyst for Modern Industry (First Half of the 20th Century)

During this period, key breakthroughs cleared the way for the formation of the injection molding industry.

Invention of key materials:

1909: Baekeland invented phenolic plastic (Bakelite), the first fully synthetic plastic. It is non-flammable, has stable properties, and is suitable for electrical insulation parts and radio casings, etc., but it is a thermosetting plastic, and its molding process is closer to compression molding.

1920s-1930s: Thermoplastic plastics such as polystyrene (PS), polyvinyl chloride (PVC), especially polypropylene (PP), and polyamide (nylon) were successively invented. These new materials provided a broad stage for injection molding technology.

The impetus of World War II:

World War II created an urgent need for large-scale, low-cost, and highly efficient production of military supplies. Injection molding was ideally suited for the rapid manufacture of standardized parts such as buttons, clips, and instrument housings, and the industry experienced substantial growth spurred by the war.

III. Revolutionary Breakthrough: The Advent of the Screw Injection Molding Machine (1950s)

This was the most crucial milestone in the maturation of the injection molding industry.

1956: American H. William Siemons invented the first reciprocating screw injection molding machine.

Revolutionary significance:

High-quality plasticizing: The rotation of the screw allows for thorough shearing, mixing, and heating of the plastic, resulting in a more uniform melt.

High injection speed and pressure: Significantly improved production efficiency and product quality.

Precise process control: Laid the foundation for the production of complex and precision parts.

The widespread adoption of screw-type injection molding machines made injection molding a truly efficient, reliable manufacturing process suitable for mass production of complex parts, directly giving rise to a professional injection mold design and manufacturing industry.

IV. Modernization and Globalization: Continuous Technological Iteration (Second Half of the 20th Century to Present)

In the following decades, the injection mold industry entered an era of rapid development and refinement:

Emerging New Materials: The emergence of engineering plastics such as ABS, PC, POM, and PBT expanded the application range of injection molding, extending from consumer goods to high-tech fields such as automotive, electronics, and medical.

Modernization of Mold Technology:

The widespread adoption of hot runner technology reduced waste and increased automation.

The application of CAD/CAM/CAE technology (Computer-Aided Design/Manufacturing/Engineering) enabled mold design to move from experience to science; mold flow analysis can predict and solve production problems in advance.

Precision machining technologies such as CNC machining, EDM, and wire cutting made the manufacturing of complex, high-precision molds possible.

Automation and intelligence: robotic arms for picking up parts, centralized material supply systems, and MES (Manufacturing Execution System) constitute a modern "lights-out factory".