How to Choose the Right Injection Mold Before Mass Production

Before mass production, products require molds.
So, how do you choose the right mold?

Introduction: Why Mold Selection Matters

Today, we’ll guide you through selecting injection molds.

Molds vary drastically in quality, ranging from very cheap to very expensive. The high price isn’t due to inflated quotes from mold manufacturers, but rather because you’ve chosen an expensive mold yourself.

The key is to choose a mold that suits your product requirements and production volume.

Prototype Stage: Low Quantity Product Verification (≈100 Parts)

If you have a new product and need to verify its structural functionality, and you only need 100 parts, then using CNC machining or other processing methods will naturally increase costs.

In this case, you can consider using silicone molds or 3D printing, provided you don’t need to worry about product precision, as silicone molds or 3D printed products differ from steel molds, but the overall cost will be lower.

Small Batch Production: Test Molds / Soft Molds (Thousands to Tens of Thousands)

If you’re conducting small-batch verification experiments, producing thousands or tens of thousands of units, you can choose to have a test mold, also known as a soft mold, made with common mold steel, such as 45# steel or S50C.

In short, steel is cheaper, and a hardness between 20° and 30° makes it easier to process, which should meet your needs.

Medium to High Volume Production: Standard Injection Molds (100,000+ Cycles)

If you’re making standard mold products, costing over 100,000 RMB or more, and even requiring high surface finishes, consider molds for household appliance casings or automotive interior and exterior parts.

These require steels like P20, 718, or NAK80, with a hardness between 35° and 45°.

These mold steels offer good performance, with excellent wear resistance, polishing properties, and impact resistance. Therefore, they are suitable for mid-to-high-end molds, with a production volume of 100,000 to 200,000 cycles. This is a rough estimate.

High Volume Mass Production: Hard Molds for Millions of Cycles

If your production volume is exceptionally large, producing millions of molds annually, you’ll need hard molds—the high-end molds.

Common materials for these are S136, H13, or 2344. These mold steels generally require heat treatment, achieving a hardness between 48° and 52°.

After heat treatment, they exhibit excellent wear resistance and a long service life. The corresponding material costs will increase due to the hardness, and processing fees will also be higher. Using imported components or better hot runners also contributes to the overall cost.

Final Thoughts: The Best Mold Is the Right Mold

Also, good molds are all the result of communication.
The most expensive is not necessarily the best.

So, have you learned how to choose the right mold?