METHOD AND APPARATUS FOR ELECTRO-HYDRAULIC FORMING
One or more electro-hydraulic forming tools are operated by a press and provide formed parts to a trimming operation. A locking mechanism holds the die against the chamber during the electro-hydraulic forming (EHF) discharge. The lock may be a pin or clamp. One method of manufacturing an article includes providing three EHF tools that feed a single trimming press on a line. An alternative embodiment discloses a single EHF tool that supplies parts on a production line to an electro-hydraulic (EH) trimming tool. An electro-hydraulic pulse generator may be used to provide a stored charge to the EHF tool and the EH trimming tool.
1 . A press for forming a blank comprising:
an electro-hydraulic forming (EHF) tool defining a chamber that is filled with a liquid, and an electrode disposed within the chamber that provides a discharge;
a one-sided die reciprocated by the press relative to the chamber with the blank being disposed on the die; and
a lock connected to and operated by the press that holds the die against the chamber during the discharge.
2 . The press of claim 1 wherein the lock further comprises:
a mechanical restraining device that selectively connects a movable platen of the EHF tool supporting the die to a frame of the press.
3 . The press of claim 2 wherein the mechanical restraining device is a pin carried by the frame of the press that is shifted into engagement with the movable plate.
4 . The press of claim 1 wherein the lock further comprises:
a clamp that selectively clamps the die against the EHF tool, wherein a hydraulic ram moves the clamp relative to the die and EHF tool in a direction transverse to the direction that the die is reciprocated.
5 . The press of claim 4 wherein the clamp includes a first stop that engages the die and a second stop that engages the EHF tool.
6 . A method of manufacturing an article on a production line that includes a plurality of electro-hydraulic forming (EHF) tools and a plurality of one-sided dies that are each operated by a press, the production line also includes a trim press, the method comprising:
clamping a blank onto each of the plurality of the EHF tool and the one-sided die in a progressive sequence;
discharging each of the EHF tools in the progressive sequence to form a part shape in each of the plurality of one-sided dies; and
trimming the blanks with the part shape in a trim press.
7 . The method of claim 6 wherein the plurality of EHF tools and one-sided dies include three EHF tools and three one-sided dies that are operated by three presses, wherein the progressive sequence further comprises operating the presses in a repeating order.
8 . The method of claim 7 wherein the cycle time for the trim press is about one-third of the cycle time for each press.
9 . The method of claim 6 wherein the cycle time for the trim press is about equal to a multiplication of the cycle time for each press and the reciprocal of the number of the plurality of presses.
10 . The method of claim 6 further comprises:
filling a chamber defined by the EHF tool with water;
evacuating air from the EHF tool prior to the discharging step; and
draining the water from the EHF tool.
11 . The method of claim 10 wherein the time required for the clamping step, the filling step, the evacuating step, the discharging step and the draining step is a multiple of the time required for trimming the blanks with the part shape in the trim press that corresponds to the number of EHF tools.
12 . The method of claim 6 wherein the discharging step further comprises multiple discharges of the EHF tool to complete forming the part shape.
13 . The method of claim 6 further comprises:
switching a connection to at least one pulse generator between the plurality of EHF tools to provide energy for the discharges in the plurality of EHF tools.
14 . The method of claim 13 wherein the number of EHF tools is greater than the number of pulse generators.
15 . A method of manufacturing an article on a production line that includes an electro-hydraulic forming (EHF) tool and a one-sided die that are operated by a press, the production line also includes an EH trim press, the method comprising:
clamping a blank onto the EHF tool and the one-sided die;
discharging the EHF tool to form a part shape in the blank; and
trimming the blank with the part shape in the EH trim press.
16 . The method of claim 15 further comprising:
filling a chamber defined by the EHF tool with water;
evacuating air from the EHF tool prior to the diecharging step; and
draining the water from the EHF tool.
17 . The method of claim 15 wherein the discharging step further comprises multiple discharges of the EHF tool to complete forming the part shape.