55 TECHNICAL TOOLBOX ISSUE tonnage pressed process, additive manufacturing (AM) employs a layered buildup process. This results in a structure more akin to layered casting, with no reduction for added strength and toughness. The layered buildup process also leads to the formation of small air bubbles between the layers, resulting in significant voids that may appear as cracks or surface imperfections after machining. AM tool design experts recommend using a larger radius for this reason. We recommend exercising caution when determining ejector pin placement and incorporating more draft angles compared to typical mold steels. This precaution is necessary due to the reduced toughness and the potential risk of mold insert cracking during injection and flexing during ejection. 5. Repeatability The repeatability of producing multiple insert mold and die parts using the AM layered buildup process is more challenging compared to traditional steels. 6. Reparability The preferred method for repairing AM parts is typically using silver solder or brazing rods. However, since these repairs may not be very durable, it's advisable for the molder to consider the somewhat costly option of acquiring an additional printed insert. This precaution allows for a backup in case the first insert sustains damage during the molding or maintenance process. Traditional mold steels are welded with their parent material in rod form. In summary, the biggest benefit of AM is in making prototype mold and die inserts quickly. Even though the quality of AM parts has gotten better, high tonnage pressed powdered metals still yield higher quality injection mold and die cast dies in terms of material properties, weldability, and precision and remain the preferred choice specifically for these parts. Contact: RUSS BOWEN rbowen@moldersworld.com
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