Plastic injection molding is a widely used manufacturing process for producing plastic parts. In this process, molten plastic is injected into a mold cavity where it cools and solidifies to form the desired shape. To ensure that the plastic part is of high quality and has good dimensional accuracy, it is essential to have a properly designed mold with the right tool steel shut off.
In this blog, we will discuss the importance of tool steel shut off in plastic injection molding and the types of tool steel used for this purpose.
Importance of Tool Steel Shut Off
The tool steel shut off is an essential component of the mold in plastic injection molding. It is responsible for creating a clean parting line and preventing plastic from flowing into unwanted areas of the mold. The shut off also helps to ensure that the plastic part has good dimensional accuracy and surface finish.
A poorly designed or worn tool steel shut off can lead to several defects in the plastic part, including flash, sink marks, and warpage. Flash occurs when excess plastic flows out of the mold and leaves thin layer on the parting line. Sink marks are depressions on the surface of the part caused by uneven cooling. Warpage is a deformation of the part caused by uneven shrinkage during cooling.
Types of Tool Steel Used for Shut Off
Several types of tool steel are used for shut off in plastic injection molding, including:
- P20 Tool Steel
P20 tool steel is a low carbon, high chromium alloy steel that is widely used for shut off in injection molding. It is known for its excellent toughness, wear resistance, and dimensional stability. P20 tool steel is easy to machine and can be heat treated to achieve high hardness for long tool life.
- H13 Tool Steel
H13 tool steel is a work tool steel that is commonly used for shut off in plastic injection molding. It has high toughness, wear resistance, and heat resistance, making it suitable for high temperature applications. H13 tool steel can also be heat treated to achieve high hardness for long tool life.
- S7 Tool Steel
S7 tool steel is a shock-resistant tool steel that is often used for shut off in plastic injection molding. It has excellent toughness and wear resistance, making it suitable for applications that require high impact resistance. S7 tool steel can also be heat treated to achieve high hardness for long tool life.
- M2 Tool Steel
M2 tool steel is a high-speed steel that is commonly used for shut off in plastic injection molding. It has high wear resistance and can maintain its hardness at high temperatures, making it suitable for high-speed cutting applications. M2 tool steel is also corrosion-resistant and can be easily machined.
Conclusion
In conclusion, the tool steel shut off is an essential component of the mold in plastic injection molding. It is responsible for creating a clean parting line and preventing plastic from flowing into unwanted areas of the mold. A properly designed and maintained tool steel shut off can ensure that the plastic part has good dimensional accuracy and surface finish. P20, H13, S7, and M2 tool steel are commonly used for shut off in plastic injection molding, each with its own unique properties and advantages.