Skip to content
February 15, 2023

Why Is Injection Molding the Ideal Technique for Mass Production?

Polymer injection molding is a versatile method of producing optical components for complex systems. Its advantages over other manufacturing types make it the preferred technique for various industries, especially for mass-produced parts.

Find out why injection molding is a must for high-volume optical parts production.

How Does the Injection Molding Process Work?

Injection molding has been around since 1872. It was ahead of its time even then, but it was far from where it’s come today. In 1956, the reciprocating screw significantly advanced the injection molding process.

With injection molding, polymer resin pellets are driven through a hopper by a reciprocating screw into a heated barrel. The melted pellets are pushed into the mold cavity with high pressure, filling every detail of the mold. The polymer hardens and cools, then it’s ejected from the mold.

In total, the injection molding process takes about 30 to 90 seconds to complete a full cycle for each unit. The parts are ready to use immediately after cooling and don’t require any post-processing.

Because the mold is reused, this process can be repeated over and over, using more molten polymer, rather than starting the tooling process over again from scratch. The materials are relatively inexpensive, allowing each unit to be produced quickly and cost-effectively over hundreds, thousands, or even millions of parts.

With these capabilities, injection molding is popular for creating consumer goods, such as LEGO bricks, disposable cutleries, crates, toys, casings for consumer electronics, and more.

Detailed Features and Geometry

Injection molds are subjected to extremely high pressure. The polymer in the molds is pressed into the mold harder than with other processes, allowing for minute details that aren’t achievable with other methods. And in mass production, these small details can be produced over and over, consistently and reliably.

In addition, the high pressure allows complex and intricate shapes to be designed and manufactured, which may not be possible with other manufacturing methods. This advantage is a must in industries requiring complex geometries for product success.

Production Efficiency

Once the injection molds have been perfected according to the design specifications, the actual molding process is quicker than other methods. All of the work to refine the prototype is done upfront, then the units can be produced over and over from the single mold.

This high production output enables the mass production of thousands – or even millions – of parts efficiently. All of the units are consistent with fast cycle times, shortening the project timeline.

High Impact Strength

In polymer injection molding, it’s possible to use different fillers in the mold to reduce the density of the plastic during the molding process. This helps add strength to the part after it’s molded, making it ideal for various use cases and industries.

Combined Polymer Materials

Different polymers and component materials have different advantages and disadvantages, creating a challenge in the design process. With injection molding, you can combine different materials to maximize their capabilities and avoid compromising key features of your design.

Cost-Effective Production

The prototyping process can be expensive as you work to refine your design and the subsequent mold. Changes require additional tooling, which adds to the cost, and you may go through several iterations before you get a viable finished product.

With injection molding, the upfront costs are an investment in the prototype that will be used to create every other unit. The more you produce, the lower the cost per unit, since the injection molding process is efficient and relatively inexpensive. Injection molding also supports automation, so you can produce a virtually limitless number of units using the same mold – even simultaneously.

Flexibility in Material and Color

Choosing the right materials and colors for a project is essential in producing a successful part. Though there have been significant advances in polymer materials in recent years, they still have drawbacks that must be considered.

Injection molding not only supports combined materials but the addition of finishes or colors that can improve the efficacy of the finished component. For example, you can add metal or rubber to manufactured parts, UV or weather resistance for components designed for harsh environments, and resins for better impact strength and tensile strength.

Along with producing ready-to-use parts, having materials and additives included in one production cycle reduces time and cost in the entire process. With some machining methods, colors or additives would need to be done in a separate production cycle, at added time and expense. Having everything in one cycle makes manufacturing more efficient, especially when you’re producing thousands or millions of units.

Environmental Sustainability and Low Waste

Injection molding is a sustainable process with low waste. Molten polymers can be melted and molded repeatedly, allowing the excess materials to be reused in the molding process. While there is a limit, this is more sustainable than other processes that produce cured plastics that will burn rather than melt.

Mass-Produced Parts with Injection Molding at Apollo Optical Systems

Polymer injection molding is the industry standard for many types of polymer projects, especially at a massive scale. But the process is only as good as the designer, so you need a capable optical manufacturer like Apollo Optical Systems. Our molding technology ensures consistent, high-quality parts that meet or exceed all industry standards. Contact us today to discuss your custom optical project!