Permanent Mold Casting
What is Permanent Mold Casting?
Permanent mold casting is a metalworking process that uses steel or cast iron (permanent) molds to create customized metal parts. Permanent mold casting is similar to die casting, in that it employs reusable metal molds. This process also has similarities to sand casting — since permanent mold casting also uses gravity to fill the mold cavity with molten metal and create the desired part shape.
Common metals used in permanent mold casting include Aluminum, Magnesium, and Copper alloys. Other materials such as Zinc, Steel, Iron, Tin, and Lead alloys can be cast in permanent molds made of Graphite.
How Does Permanent Mold Casting Work?
Permanent mold casting is typically used for higher-volume production of smaller parts with uniform wall thickness. The process typically occurs in six steps:
Prepare mold and create shell or sand cores, as applicable.
Pour molten metal into the pour bowl as the machine rests horizontal.
Tilt machine to vertical orientation.
Gravity-feed molten metal into a negative mold cavity.
Tilt machine back to horizontal orientation as metal solidifies.
Open mold and eject the part using a system of ejection pins.
Permanent mold tooling is typically made of Steel (H-13), Graphite, or Iron to accommodate faster cycle times. "Tilt pour" machines reduce metal tumbling during the pour. When coupled with pre-heated mold halves, tilt pouring yields superior casting properties for higher-quantity applications.
Advantages of Permanent Mold Casting
Permanent mold casting offers many advantages, some of which include:
Improved part definition and detail
Quicker solidification and better structural integrity than other gravity casting processes
Less labor inputs and faster production cycles
Can achieve complex shapes and designs
Quality surface finish
Improved mechanical properties of castings
Capacity to support high-volume production runs