Accurate springback compensation method for hydroforming component based on liquid volume control

An accurate springback compensation method for hydroforming component based on liquid volume control, comprising the steps of:

• (a) inducing an elastic deformation of a die by regulating a volume of injected liquid based on a volume difference between a theoretical volume of a target part and a volume of the part after springback, and (b) controlling a die deformation amount equal to a springback amount and realizing an accurate springback compensation control of a curved panel member, wherein said method further comprises the steps of:
• step 1:
• calculating a theoretical volume V0 corresponding to the curved panel member according to a designed profile of the curved panel member;
• step 2:
• placing a plate blank on the die and filling the die with high pressure liquid through an external pressurization system so that said plate blank begins deep drawing with liquid as a punch under an action of liquid pressure for shape forming;
• step 3:
• recording a change of liquid flow inside the die by using a flowmeter, stopping liquid filling through a control system when a liquid volume being filled inside the die reaches V0 and unloading;
• step 4:
• measuring a distance between a profile of an unloaded part and a corresponding die profile in situ and online by a displacement sensor, and calculating an actual volume V of the unloaded part, then calculating to obtain a volume difference ΔV of V0 and V;
• step 5:
• filling the die with high pressure liquid again, continuing to fill the die with high pressure liquid when a liquid volume being filled inside the die reaches V0 until the die is elastically deformed, recording a change of liquid flow inside the die by using the flowmeter, stopping liquid filling through the control system when a liquid volume being filled inside the die reaches V0+ΔV, then unloading to obtain the curved panel member;
• step 6:
• calculating the liquid volume compression amount ΔVp=β·p·(V0+ΔV) when the liquid volume being filled inside the die is (V0+ΔV) based on the relationship between the liquid volume compression amount ΔVp and the liquid pressure p:
• ΔVp=β·p·V, where β is a compression coefficient of the liquid medium;
• step 7:
• filling the die with liquid and pressurizing again for elastic deformation of the die, recording a change of liquid flow inside the die by using the flowmeter, stopping liquid filling through the control system when a liquid volume being filled inside the die reaches V0+ΔV+ΔVp, then unloading to obtain the curved panel member;
• step 8:
• proceeding batch forming of subsequent target parts using a loaded volume of V0+ΔV+ΔVp.

An accurate springback compensation method for hydroforming component based on liquid volume control, comprising the steps of:

• (a) inducing an elastic deformation of a die by regulating a volume of injected liquid based on a volume difference between a theoretical volume of a target part and a volume of the part after springback, and controlling a die deformation amount equal to a springback amount and realizing an accurate springback compensation control of a curved panel member, wherein said method further comprises the steps of:
• step 1:
• calculating a theoretical volume V0 and a die cavity volume V1 according to a designed profile of the curved panel member and a measured profile of the die cavity correspondingly, then calculating to obtain a volume difference ΔV1 of V0 and V1 equal to V0−V1 (i.e. ΔV1=V0−V1);
• step 2:
• placing a plate blank on the dice and filling the die with high pressure liquid through an external pressurization system so that said plate blank begins deep drawing with liquid as a punch under an action of liquid pressure for shape forming;
• step 3:
• recording a change of liquid flow inside the die by using a flowmeter, continuing to fill the die with high pressure liquid through an external pressurization system when a liquid volume being filled inside the die reaches V1 so that the die is elastically deformed, recording a change of liquid flow inside the die by using the flowmeter, stopping liquid filling through the control system when a liquid volume being filled inside the die reaches V1+ΔV1=V0 and unloading;
• step 4:
• measuring a distance between a profile of the unloaded part and a corresponding die profile in situ and online by a displacement sensor, and calculating an actual volume V of the unloaded part, then calculating a volume difference ΔV of V0 and V equal to V0−V (i.e. ΔV=V0−V);
• step 5:
• filling the die with high pressure liquid again so that the die is elastically deformed, recording a change of liquid flow inside the die by using the flowmeter, stopping liquid filling through the control system when a liquid volume being filled inside the die reaches V0+ΔV, then unloading to obtain the curved panel member;
• step 6:
• proceeding batch forming of subsequent target parts using a loaded volume of V0+ΔV.