SPI Mold Standard: The 5 Types of SPI Mold Classifications

What’s SPI Mold Standard?


SPI, which stands for the Society of the Plastics Industry, has developed a classification system for molds used in plastic injection molding. This system, known as the SPI Mold Classification, is widely adopted in the plastics industry to standardize the design and communication of mold specifications. It helps ensure that molds are built to consistent standards and that manufacturers can easily understand and meet their clients’ requirements.


The 5 Types of SPI Mold Classifications


The SPI Mold Classification system consists of four primary classes: Class 101, Class 102, Class 103, and Class 104. These classes are designed to represent different levels of mold complexity, precision, and durability. Here is an overview of each class:

  1. Class 101: Extremely High Production Molds. Life expectancy: >1,000,000 cycles
    • These molds are built to the highest standards of precision and durability.
    • They are intended for high-volume production and must maintain tight tolerances.
    • Materials used in Class 101 molds are of the highest quality.
    • Expected to have a long production life and fast cycle time.
  2. Class 102: Medium to High Production Molds. Life expectancy: < 1,000,000 cycles
    • These molds are used for large volume production runs.
    • They offer good quality and precision but not to the extent of Class 101.
    • Class 102 molds are fairly high priced and made with materials of high quality.
    • Suitable for parts with abrasive materials and/or tight tolerances.
  3. Class 103: Medium Production Molds. Life expectancy: < 500,000 cycles
    • Class 103 molds are used for moderate production volumes.
    • They offer reasonable quality and durability that allow them to be very popular.
    • Materials used are less expensive compared to Class 101 and 102.
    • Class 103 molds fall within common price range.
  4. Class 104: Low Production Molds. Life expectancy: < 100,000 cycles
    • These molds are primarily intended for low production runs.
    • Good for limited-production parts with non-abrasive materials.
    • Materials used are often less expensive and may not be as durable as higher classes.
    • Class 104 molds fall within low to moderate price range.
  5. Class 105: Prototype Molds. Life expectancy: < 1,000 cycles
    • These molds are primarily intended for prototyping and very short production runs.
    • They have the lowest level of precision and durability among the SPI classes.
    • Materials used are often less expensive and may not be as durable as higher classes.
    • Suitable for very limited production quantities.

In addition to these primary classes, SPI also provides guidelines for mold components, such as mold bases, ejector systems, and cooling systems, to further standardize mold design and construction.

The advantages to apply SPI Mold Classifications


The SPI Mold Classification system offers several advantages:

  • Clear Communication: It provides a common language for mold designers, manufacturers, and customers to discuss mold requirements.
  • Quality Assurance: It helps ensure that molds are built to the appropriate level of precision for their intended use, reducing production issues.
  • Cost Control: Clients can choose the appropriate class to match their production needs and budget.


In conclusion, the SPI Mold Classification system is a valuable tool in the plastic injection molding industry, facilitating effective communication, standardizing mold quality, and ensuring that molds are tailored to specific production requirements. Manufacturers and clients alike benefit from this standardized approach to mold classification and construction.

Your custom SPI mold Partner @GEMS-MFG


Merely looking at an injection mold classification chart is not sufficient, since each mold classification has its own distinct parameters. Therefore, it is more important to collaborate with a molder who is well-versed in these mold standards and classifications. The guidance of the molder is crucial in choosing the most suitable mold type that aligns with your production requirements, cost considerations, and quality goals.

At GEMS-MFG, we specialize in manufacturing high quality plastic molds with custom SPI standard that always meet our customer expectations. We are very willing to share clients about our solid experience and expertise in mold making, so as to maximize productivity, reduce waste, and continuously improve production efficiency and safety. We look forward to helping you bring your custom SPI molds into fact. To get started, please request a quote through our convenient online form or call us.



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With the passing years, we are proud to build up a manufacturing veteran team with rich experience and full expertise to fulfill your specific demand. From mold making, injection molding, die casting, stamping and sheet metal, to 2nd processes like CNC machining, oil spraying, powder coating and chrome plating, and then assembling and packaging and related, we always have someone in house to be an expert to resolve the issues in different stages of product development. We also specialize in providing charger, cable and hub, plus other electronic accessories that support a complete set of product.

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“Think global, execute local” is the principle of our work. Time, quality and cost are the three key elements to be considered throughout the product development from concept design to mass production. A detailed plan with weekly conference call update is a critical gateway to ensure these three key elements are successfully implemented, also assuring that all parties are on the same page. Communication is the Secret to Success . Everyone works independently to take care his own job, but together we are a team to get things done and are your daily eyes and ears onsite in China.

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We offer a wide variety of products, such as mold, component and assembly product, and certain value-added services. For logo or branding product, we have in house resources to complete a color mix that can perfectly match a brand’s unique colors in fast and cost-effective way. Understood the client needs production parts but having a hard time to find a vendor since the order quantity is as low as 1000 or lower. GEMS is well set up for low volume injection molding or die casting projects. Surely our team is also capable of building SPI Class 101 mold that is designed & made for 1 million cycles or more of producing the same high quality parts consistently.