Single Cavity vs Multi-Cavity Injection Molding: Which is Best?



Injection molding is a popular manufacturing process used to produce plastic parts in large quantities. The right mold design is crucial for ensuring high-quality, cost-effective production. In this blog, we will compare single cavity and multi-cavity injection molding to help you determine which option is best for your project.

Single Cavity Injection Molding

Single cavity injection molding is a process that involves the use of a mold with only one cavity, which forms one part per injection cycle.

Pros of Single Cavity Injection Molding

Simplified mold design: Single cavity molds are simpler in design, making them easier to produce and maintain.

Lower tooling costs: With only one cavity, initial tooling costs for single cavity molds are typically lower than multi-cavity molds.

Greater design flexibility: Single cavity molds offer more flexibility for complex part designs, as there is less concern about balancing the flow of material between multiple cavities.

Cons of Single Cavity Injection Molding

Slower production rates: As only one part is produced per cycle, single cavity molds have slower production rates compared to multi-cavity molds.

Higher per-unit costs: The slower production rates result in higher per-unit costs for parts produced using single cavity molds.

Multi-Cavity Injection Molding

Multi-cavity injection molding is a process that uses a mold with multiple cavities, allowing for the production of multiple parts per injection cycle.

Pros of Multi-Cavity Injection Molding

Faster production rates: With multiple parts produced per cycle, multi-cavity molds offer significantly faster production rates compared to single cavity molds.

Lower per-unit costs: The increased production rate leads to lower per-unit costs for parts produced using multi-cavity molds.

Increased consistency in parts production: Multi-cavity molds can produce multiple identical parts in a single cycle, ensuring consistency in part quality and dimensions.

Cons of Multi-Cavity Injection Molding

More complex mold design: Multi-cavity molds are more complex in design, requiring greater expertise and precision during mold production.

Higher tooling costs: The increased complexity of multi-cavity molds results in higher initial tooling costs.

Less design flexibility: Balancing the flow of material between multiple cavities can limit design flexibility, especially for complex parts.

Factors to Consider When Choosing Between Single and Multi-Cavity Molds

When deciding between single cavity and multi-cavity injection molding, consider the following factors:

Production volume: For low-volume production, single cavity molds may be more cost-effective. For high-volume production, multi-cavity molds can offer significant cost and time savings.

Part complexity: Complex parts may require the design flexibility offered by single cavity molds, while simpler parts can benefit from the consistency provided by multi-cavity molds.

Material selection: Some materials may be more suitable for single cavity molds due to their flow properties, while others may work better with multi-cavity molds.

Production timeline: If your project requires a fast turnaround, the increased production speed of multi-cavity molds may be advantageous.

Budget constraints: Consider the balance between initial tooling costs and per-unit costs when determining which mold option is best for your budget.


Choosing between single cavity and multi-cavity injection molding depends on your project's unique requirements. By weighing the pros and cons of each option and considering factors such as production volume, part complexity, material selection, production timeline, and budget, you can make an informed decision that best suits your needs. It's essential to consult with experienced engineers and mold makers to ensure optimal mold design and production efficiency for your project.