When To Choose Injection Molding Manufacturing

injection molding

Injection molding: one of the most important manufacturing processes

It might appear to be an exaggeration, but the statement holds true: injection molding stands as one of the cornerstones of modern manufacturing. Without it, the products that permeate our daily lives—within our homes, workplaces, eateries, hospitals, and beyond—would be vastly different. The products we interact with daily owe their variety, functionality, and affordability to the remarkable capabilities of injection molding.

Injection molding, in essence, is the unparalleled champion of economical and efficient high-volume plastic component production.

In this comprehensive exploration, we delve into the core factors that determine whether injection molding is the fitting manufacturing process for your specific application. We scrutinize three key aspects: the properties of the product being created, the economics of manufacturing, and considerations for prototypes and low-volume production.

Factor 1: Material, Size, and Complexity

Material Considerations

At the heart of injection molding lies a pivotal consideration: the material requirement. This process demands thermoplastic or thermoset materials that can be effectively molded within enclosed tools. For the context of this discussion, the spotlight falls on thermoplastic materials, which far outweigh thermosets in common applications, barring specific domains such as electrical, chemical, and thermal applications.

The realm of thermoplastic resins encompasses an expansive range of mechanical, chemical, physical, aesthetic, and economic attributes. These resins boast suitability for diverse applications, from toothbrushes to car bumpers.

These moldable polymers span a wide spectrum of colors, exhibiting flexibility or rigidity, remarkable strength, toughness, and exceptional chemical resistance. However, it’s the extraordinary synergy of these properties within a single polymer that renders them the materials of choice for countless injection molding applications.

Size Considerations

Evaluating injection molding necessitates gauging the size of the intended component.

At one end of the scale, micro-molded components—mere tenths of a gram—find utility in medical devices, fitting within 5x5x5mm dimensions. On the opposite extreme, components for agricultural machinery exceed 100kg, spanning dimensions surpassing 1500mm.

In practice, the majority of injection-molded components—numbering in the billions annually—encompass caps, closures, disposable items, toys, personal electronics, and more. These applications generally fall within the 1-500g weight range.

Complexity Considerations

The intricacy of geometric design profoundly influences the choice of manufacturing method.

Remarkably, injection molding yields components adorned with intricate features, intricate textures, multi-material combinations, and even molded-in metallic parts. The duration required to mold such intricate components mirrors that needed for plain, featureless counterparts.

While the laws of physics govern molten polymer behavior within a metal mold, the realm of geometric possibilities is virtually limitless.

Factor 2: Manufacturing Economics – Calculating Value

Beyond material properties, component size, and complexity, manufacturing economics emerges as a crucial factor in the decision-making process.

In its essence, manufacturing economics aims to optimize the value-generation rate relative to invested capital. This encompasses direct material and labor costs, alongside tooling and equipment investments. In simpler terms, it’s about minimizing the fully burdened manufacturing cost per component.

Injection molding excels in this arena by enabling high-production rates of complex polymer components, surpassing alternative forming methods. This is where injection molding sets itself apart.

Consider the hypothetical scenario of manufacturing a plastic office telephone handpiece cover. Comparing injection molding with CNC milling and 3D printing reveals the dramatic production disparity:

  • CNC milling involves the manufacture of the cover from an ABS block, demanding considerable time and lacking the desired surface texture.
  • 3D printing yields an ABS-based handpiece cover with compromises in surface finish and dimensional accuracy, produced at a limited rate.
  • Injection molding produces the handpiece cover with optimal properties—material, finish, and geometry—at an unparalleled speed.

The relative economics of investment capital against production rate highlight injection molding’s substantial advantage over alternative methods.

Factor 3: Injection Molding for Prototypes and Low-Volume Production

While traditional injection molding poses challenges for prototype and low-volume production due to cost and lead time, Quickparts addresses this issue, delivering value and efficiency.

Quickparts introduces a proprietary rapid injection molding process engine, streamlining design, tooling, and testing within days. Backed by our expert system and experienced professionals, this engine facilitates swift design, manufacture, and testing. Our focus on high-quality aluminum tooling accelerates the process, enabling Quickparts to provide injection-molded components in quantities as low as 25 parts within 15 business days.

For low-volume production, Quickparts’ aluminum tools—originally used for prototypes—prove remarkably efficient. As production volume increases, these tools can be adapted for automated operation, reducing cost and lead time while still outperforming traditional steel tooling.

The Journey Ahead

Injection molding currently stands as the most effective process for high-volume, intricate plastic component production. Its capacity to produce complex components from various polymers at high rates with minimal waste renders it the go-to choice for polymer parts in consumer, medical, automotive, and industrial applications.

As we venture deeper into this topic, it’s important to note that detailed insights into thermoplastics will be addressed in a dedicated article.

In Conclusion

Injection molding’s prowess is undeniable, with far-reaching implications for modern manufacturing. It embodies affordability, efficiency, and versatility, forming the backbone of myriad products that enrich our daily lives.

[1] The discussion on thermoplastics will be elaborated in a separate dedicated article. [2] This scenario suggests a production rate beyond the current capabilities of 3D printing technologies, considering post-processing and surface finish. [3] Expedited projects may have limitations and additional fees.

Should you have any inquiries about the injection molding process, don’t hesitate to contact our Technical Specialists at +1 931-766-7290 or contact@quickparts.com. We’re here to guide you and offer tailored recommendations.