Method to operate a hydraulic press for metal sheet forming
The invention is a process for forming a metal alloy component comprising: heating a metal alloy sheet blank to at least its Solution Heat Treatment temperature at a heating station; transferring the heated sheet blank to a press; initiating formation of a component by closing the press dies at a first speed then completing the formation by closing the press dies at a second speed, said second speed being slower than the first; and holding the formed component in the dies during cooling of the formed component.
1 . A process for pressing a sheet metal component of aluminum or magnesium alloy comprising the sequential steps:
i) heating a metal aluminum or magnesium alloy sheet blank to above its solvus temperature but below its solidus temperature at a heating station;
ii) transferring the heated sheet blank to a press;
iii) initiating formation of a component at an initial temperature above 350° C. by closing the press dies at a first speed to a first position within 30 mm of its absolute bottom position to complete part of the formation, then completing the formation by closing the press dies at a second speed through the remaining distance to the absolute bottom position, said second speed being slower than the first; and
iv) quenching the formed sheet alloy component by holding the formed component in the dies during quenching of the formed component.
2 . The process of claim 1 , wherein closing the press dies at a first speed comprises using a non-powered or low-powered, high speed stroke of the press.
3 . The process of claim 2 , wherein the first speed comprises a fast approach mode of the press and wherein the first speed is at least 100 mm/s.
4 . The process of claim 3 , wherein closing the press dies at a second speed comprises using a powered stroke of the press.
5 . The process of claim 4 , wherein the second speed is less than 100 mm/s.
6 . The process of claim 5 , wherein the second speed is the maximum powered speed of the press.
7 . The process of claim 6 , wherein the powered stroke is engaged at the first position.
8 . The process of claim 1 , wherein the heated sheet blank is transferred to the press within 10 seconds of being removed from the heating station.
9 . The process of claim 8 , wherein the closing of the press dies at the first speed is performed such that formation of the formed sheet alloy component is initiated within 10 seconds of removal from the heating station.
10 . The process of claim 1 , wherein the closing of the press dies at the first speed such that formation of the formed sheet alloy component is initiated, comprises closing the press dies to a first position within at least 10 mm of the die absolute bottom position.
11 . The process of claim 10 , wherein the closing of the press dies at the second speed to complete formation of the formed sheet alloy component, comprises closing the press dies through the remaining distance from the first position to the absolute bottom position.
12 . The process of claim 11 , wherein the process comprises a pause between the closing of the dies at the first speed and the closing of the dies at the second speed.
13 . The process of claim 12 , wherein the pause is less than 5 seconds.