Aluminum Alloy Extrusion Dies: Usage and Maintenance

(1) Utilize advanced instruments for online and offline detection of mold dimensions, hardness, and surface roughness. Register and store qualified molds upon acceptance, retrieve polishing mandrel workpieces for use, and assemble and inspect the flow mold, profile mold, and mold pad. Upon confirmation of accuracy, dispatch them for heating on the machine station.

(2) Preheat Temperature Regulations Before Machine Operation of Mold Tools: Extrusion cylinder: 400～450°C, extrusion pad: 350°C, mold pad: 350～400°C, flat mold: 450～470°C,分流 mold: 460～480°C;保温 time is calculated based on mold thickness (1.5～2 minutes/mm).

(3) The heating time for die molds in the furnace should not exceed 10 hours; prolonged heating can lead to corrosion or deformation of the mold cavity work zone.

(4) During the initial stage of aluminum alloy profile extrusion, pressure must be applied slowly as the impact force may cause a die blockage. In the event of a die blockage, the machine should be immediately stopped to prevent the destruction of the mold hole work area.

After the mold is dismounted, it should be cooled to 150-180℃ before being placed in the alkali bath for boiling, as the mold is prone to cracking due to thermal shock when boiled at high temperatures. It is also recommended to use advanced etching methods to recover and save alkali solution, shorten corrosion time, and achieve pollution-free cleaning.

(6) During the assembly of the分流模具, the mold repairman should gently tap the copper rod; it is not permitted to use a large iron hammer to strike forcefully, as excessive force may damage the mold.

Prior to nitriding, the mold cavity working area must be meticulously polished to achieve a surface roughness of Ra0.8 to 0.4 μm.

(8) Prior to nitriding, the mold must be thoroughly cleaned to prevent any oil contamination from entering the furnace; the nitriding process should be appropriately designed based on the equipment characteristics and mold material. The surface hardness after nitriding should be between HV900 to 1200. Over-thick or overly hard nitriding layers can lead to delamination of the nitriding layer. A set of molds typically allows for 3 to 5 nitriding cycles; complex high-gear finned radiator profiles are not subjected to the nitriding process.

(9) New molds for old products, bar molds, and round tube molds can undergo nitriding treatment without trial molding; new products and complex profile molds must pass trial molding before nitriding treatment can be performed.

After the new mold trial runs successfully, 10 additional ingots should be extruded before the machine is dismounted for nitriding treatment to prevent the workpiece from being pulled into a groove; excessive production between nitriding cycles is not advisable, with general flat molds producing 60 to 100 ingots and分流 molds producing 40 to 80 ingots being recommended, as overproduction can pierce through the nitriding layer.

(11) After use, molds are polished, oiled, and stored in inventory.