Mold life is an important consideration when it comes to injection molding. The lifespan of a mold is impacted by various factors, including the material used to create the mold, the production environment, and changes made to the mold over time. In this blog post, we'll take a closer look at mold life, including the materials used in mold making, and the changes that can impact the mold's longevity.
Table of contents
Materials Used in Mold Making
Injection molds are typically made from one of two materials: steel or aluminum. The choice of material can impact the mold's lifespan and its cost.
Steel molds are more expensive than aluminum molds but are also more durable. Steel molds can withstand higher temperatures and are less likely to wear down over time. They are ideal for high-volume production runs or for materials that require high temperatures, like glass-filled resins.
The choice of steel for injection molds depends on various factors, such as the material being molded, the expected production volume, and the required mold lifespan. However, some steels are generally considered to be better suited for injection molding applications than others. Here are some of the best steels to use for injection molds:
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P20 Steel: P20 is a low-alloy tool steel that is commonly used for injection molding. It has good machinability and is relatively easy to polish. P20 steel is also resistant to wear and has good toughness, which makes it suitable for high-volume production runs.
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H13 Steel: H13 is a hot-work tool steel that is widely used for injection molding. It has excellent hardness, toughness, and heat resistance, which makes it ideal for applications that require high-temperature resistance, such as molding of reinforced plastics.
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S136 Steel: S136 is a stainless steel that is commonly used for injection molds. It has excellent corrosion resistance, high hardness, and good wear resistance. S136 steel is ideal for applications that require high precision and surface finish, such as optical and medical parts.
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NAK80 Steel: NAK80 is a pre-hardened steel that is widely used for injection molds. It has good machinability, excellent polishability, and good dimensional stability. NAK80 steel is ideal for applications that require high precision and surface finish, such as electronic components and automotive parts.
In summary, P20, H13, S136, and NAK80 are some of the best steels to use for injection molds. However, the choice of steel depends on various factors, and it's important to consult with a professional mold maker to determine the best steel for your specific application.
Aluminum molds are less expensive than steel molds and are ideal for low-volume production runs. However, they are less durable than steel molds and can wear down over time. They are ideal for materials that don't require high temperatures, like polypropylene or ABS.
Changes to the Mold
Changes made to the mold over time can impact its lifespan. Even small changes, like altering the gate location or increasing the venting, can impact the mold's longevity.
One of the most common changes made to a mold is to change the material being used for production. Different materials have different characteristics, such as viscosity and thermal expansion, that can impact the mold's lifespan. If a different material is being used for production, the mold may need to be modified to accommodate these changes.
Another common change made to a mold is to add or remove cavities. This can impact the mold's lifespan because it changes the amount of stress placed on the mold. If additional cavities are added, the mold may need to be reinforced to handle the additional stress.
Finally, changes to the production environment can impact the mold's lifespan. Environmental factors such as temperature, humidity, and pressure can impact the mold's longevity. It's important to maintain a stable production environment to ensure that the mold is not exposed to unnecessary stress.
Conclusion
Mold life is an important consideration when it comes to injection molding. The materials used in mold making, as well as changes made to the mold over time, can impact its longevity. Steel molds are more expensive but more durable than aluminum molds, while changes to the mold such as altering the gate location or adding cavities can impact its lifespan. By understanding these factors, you can make more informed decisions when it comes to injection molding and ensure that your molds last as long as possible.