Views: 0 Author: Site Editor Publish Time: 2026-04-13 Origin: Site
When it comes to injection molding, the mold material is the foundation of product quality, production efficiency, and cost control. Choosing the right injection mold material directly impacts the mold’s lifespan, part precision, surface finish, and overall production cost. For manufacturers, buyers, and anyone involved in the injection molding industry, understanding the most common mold materials is essential to making informed decisions—whether you’re producing high-gloss electroplated parts, everyday plastic components, or small-batch prototypes. In this blog, we’ll break down the most widely used injection mold materials, their key features, applications, and how to choose the right one for your project.
Before diving into details, it’s important to clarify one common misconception: over 90% of formal production injection molds are made of mold steel, not pure aluminum. Aluminum molds are only suitable for rapid prototyping, small-batch trial production, or low-demand products. For mass production, high-precision parts, or parts requiring electroplating or high-gloss finishes, mold steel is the only reliable choice. Below are the three most common mold steel materials used in the injection molding industry worldwide.
P20 and 718H are pre-hardened plastic mold steels, and they are the most widely used materials for injection molds—trusted by manufacturers for their balance of performance, cost, and ease of processing. Here’s what you need to know:
Key Features: Pre-hardened (no additional heat treatment needed after machining), moderate hardness, good wear resistance, and low deformation. It’s easy to machine, which helps reduce mold lead time and production costs.
Suitable Plastics: Ideal for processing common plastics such as ABS, PP, PE, PS, and PC/ABS—materials used in most everyday plastic products.
Applications: Perfect for mass production, general-purpose plastic parts, painted parts, and ordinary electroplated parts. It’s the go-to choice for most外贸 (international trade) orders due to its high cost-effectiveness.
Why It’s Popular: It strikes the perfect balance between performance and cost. For most injection molding projects that don’t require extreme surface finishes or corrosion resistance, P20/718H is the most practical and economical option.
If your injection molding project requires high-gloss, mirror-like surface finishes—such as electroplated decorative parts, luxury gift boxes, or high-end consumer electronics—NAK80 is the ideal mold steel. It’s a high-polish mirror steel designed for aesthetically demanding applications:
Key Features: Exceptional polishing performance, capable of achieving a perfect mirror finish (SPI A-0 level). It has higher hardness than P20/718H, offering better wear resistance and longer mold life for high-precision parts.
Suitable Plastics: Works well with all common injection molding plastics, especially ABS and PC/ABS—materials often used for electroplated parts.
Applications: High-gloss surface parts, mirror-finish products, electroplated plastic parts (such as gold-plated egg-shaped storage boxes), and other premium decorative components. If your product requires a flawless, reflective surface, NAK80 is the top choice.
S136 and S136H are premium corrosion-resistant mirror steels, designed for injection molding projects that require extreme precision, corrosion resistance, and ultra-high-gloss finishes. They are more expensive than P20 and NAK80 but offer unmatched performance for high-end applications:
Key Features: Excellent rust and corrosion resistance, making it suitable for processing plastics that produce corrosive byproducts (such as PVC) or require high-temperature molding. It can also be polished to an ultra-high mirror finish, better than NAK80 in some cases.
Suitable Plastics: Transparent plastics (PMMA, PC), PVC, and other engineering plastics that require high temperature and pressure during molding.
Applications: High-end transparent parts, corrosion-resistant components, long-term mass production molds, and parts with the highest surface finish requirements. It’s often used in the automotive, medical, and luxury goods industries.
While mold steel is the standard for formal production, aluminum molds have a specific niche: rapid prototyping and small-batch trial production. Here’s what you need to know about aluminum injection molds:
Low cost (usually 30%–60% of steel molds) and fast machining speed, making them ideal for creating prototypes or small batches quickly.
Soft material, easy to wear, scratch, and deform—unsuitable for mass production, high-precision parts, electroplated parts, or high-gloss parts.
Only suitable for low-temperature, low-pressure plastics (such as PP and PE), not for engineering plastics or high-demand applications.
Choosing the right mold material depends on three key factors: your product’s requirements, production volume, and budget. Here’s a simple guide to help you decide:
For mass production, general-purpose parts, or cost-sensitive projects → Choose P20/718H (most versatile and cost-effective).
For high-gloss, mirror-finish parts, or electroplated components → Choose NAK80 (best for aesthetic demands).
For high-end transparent parts, corrosion resistance, or long-term mass production → Choose S136/S136H (premium performance).
For prototypes or small-batch trial production → Choose aluminum (low cost, fast delivery).
The right injection mold material is a critical investment that impacts every aspect of your production—from product quality to profitability. P20/718H, NAK80, and S136/S136H are the backbone of the injection molding industry, each serving a specific purpose to meet different project needs. By understanding their features and applications, you can choose a mold material that aligns with your product goals, production volume, and budget.
If you’re still unsure which mold material is right for your injection molding project—whether it’s a high-gloss electroplated part, a transparent component, or a small-batch prototype—leave a comment below with your product details, and we’ll help you make the perfect choice!
