To properly maintain vacuum casting equipment molds, we must proceed with caution, patience, and in a step-by-step manner, avoiding hasty actions. When demolding due to malfunctions, apply adhesive tape to facilitate troubleshooting. Open the mold, inspect the tape, assess the mold's condition, and identify the cause of the failure. Before disassembling the mold, pinpoint the issue first, then clean the mold and remove any debris.
When disassembling cavity molds, note their original orientation to facilitate easy reassembly later. When replacing punches, verify that the passage through the ejector plate remains smooth. Considering the total length reduction after maintenance, check if the effective punch length is sufficient when adding shims to achieve the required length. When using new male/female inserts, carefully address transparent corners. Due to grinding wheel wear during machining, recessed net corners will result in smaller radii (R). Compared to protruding positions, these R values require manual reworking to achieve reasonable clearance. Pay attention to any small protrusions formed.
Rigorous Vacuum Sealing: It is well-known that vacuum heat treatment of metal parts occurs within a sealed vacuum furnace. Therefore, obtaining and maintaining the furnace's initial leakage rate to ensure vacuum integrity is critically important.
Consequently, the key issue for vacuum casting equipment is a reliable vacuum sealing structure. To guarantee the vacuum performance of the furnace, the structural design adheres to fundamental principles: the furnace body must be hermetically welded, openings should be minimized, and dynamic seals should be avoided whenever possible. The design minimizes opportunities for vacuum leakage. Components and accessories mounted on the vacuum furnace body—such as water-cooled electrodes and thermocouple lead-in assemblies—also employ sealed structural designs.
The furnace shell, furnace cover, electrically heated element guides (water-cooled electrodes), intermediate vacuum isolation doors, and other components of vacuum casting equipment operate under vacuum and high-temperature conditions. They function under extremely adverse conditions to ensure each component's structure remains free from deformation or damage, and that vacuum seals do not overheat or burn. Therefore, each part should be equipped with water-cooling devices tailored to different conditions to ensure the vacuum heat treatment furnace operates normally and possesses sufficient service life.