Search

EP-4431201-B1 - PRESS FORMING ANALYSIS METHOD, PRESS FORMING ANALYSIS APPARATUS, AND PRESS FORMING ANALYSIS PROGRAM

EP4431201B1EP 4431201 B1EP4431201 B1EP 4431201B1EP-4431201-B1

Inventors

  • OGAWA, TAKESHI
  • SUMIKAWA, SATOSHI
  • YAMASAKI, YUJI
  • SHINMIYA, TOYOHISA

Dates

Publication Date
20260506
Application Date
20221108

Claims (9)

  1. A computer implemented press forming analysis method for predicting an influence of a shape variation of a blank taken from a metal sheet having the shape variation in a case where press forming is performed by using the blank, comprising: a first shape generation step (S1) of generating a first shape having a same shape as an actual press formed part based on measurement data obtained by measuring a shape after die release of the actual press formed part, the actual press formed part being press-formed with a predetermined tool of press forming by using an actual blank taken from the metal sheet having the shape variation; a second shape acquisition step (S3) of acquiring a shape of a press formed part after die release as a second shape by performing press forming analysis in a case where press forming is performed with a tool-of-press-forming model having a same shape as the predetermined tool of press forming by using a flat blank model having a flat shape; and a deviation amount acquisition step (S5) of determining a portion where both the shapes deviate from each other and a deviation amount by comparing the second shape and the first shape with each other.
  2. The press forming analysis method according to claim 1, wherein, in the deviation amount acquisition step, a bottom dead center shape in press forming analysis using the flat blank model is determined as a standard, and a difference between a difference from the first shape corresponding to a predetermined position of the bottom dead center shape and a difference from the second shape corresponding to the predetermined position of the bottom dead center shape is acquired as the deviation amount.
  3. The press forming analysis method according to claim 1, wherein, in the deviation amount acquisition step, a forming surface shape of the tool-of-press-forming model is determined as a standard, and a difference between a difference from the first shape corresponding to a predetermined position of the forming surface shape and a difference from the second shape corresponding to the predetermined position of the forming surface shape is acquired as the deviation amount.
  4. The press forming analysis method according to any one of claims 1 to 3, further comprising an identification step of identifying a portion where the deviation amount exceeds a preset threshold as a portion requiring a countermeasure.
  5. A press forming analysis apparatus (11) for predicting an influence of a shape variation of a blank taken from a metal sheet having the shape variation in a case where press forming is performed by using the blank, comprising: a first shape generation unit (23) configured to generate a first shape having a same shape as an actual press formed part based on measurement data obtained by measuring a shape after die release of the actual press formed part, which has been press-formed with a predetermined tool of press forming by using an actual blank taken from the metal sheet having the shape variation; a second shape acquisition unit (25) configured to acquire a shape of a press formed part after die release as a second shape by performing press forming analysis in a case where press forming is performed with a tool-of-press-forming model having a same shape as the predetermined tool of press forming by using a flat blank model having a flat shape; and a deviation amount acquisition unit (27) configured tc determine a portion where both the shapes deviate from each other and a deviation amount by comparing the second shape and the first shape with each other.
  6. The press forming analysis apparatus according to claim 5, wherein the deviation amount acquisition unit is configured to determine a bottom dead center shape in press forming analysis using the flat blank model as a standard, and acquire, as the deviation amount, a difference between a difference from the first shape corresponding to a predetermined position of the bottom dead center shape and a difference from the second shape corresponding to the predetermined position of the bottom dead center shape.
  7. The press forming analysis apparatus according to claim 5, wherein the deviation amount acquisition unit is configured to determine a forming surface shape of the tool-of-press-forming model as a standard, and acquire, as the deviation amount, a difference between a difference from the first shape corresponding to a predetermined position of the forming surface shape and a difference from the second shape corresponding to the predetermined position of the forming surface shape.
  8. The press forming analysis apparatus according to any one of claims 5 to 7, further comprising an identification unit configured to identify a portion where the deviation amount exceeds a preset threshold as a portion requiring a countermeasure.
  9. A press forming analysis program causing a computer to function as the press forming analysis apparatus according to any one of claims 5 to 8.

Description

Field The present invention relates to a press forming analysis method, a press forming analysis apparatus, and a press forming analysis program for predicting an influence of a shape variation of a blank taken from a metal sheet having the shape variation in a case where press forming is performed by using the blank. Background In the progress of improvement of collision safety of an automotive body due to tightening of an automobile collision safety standard, weight reduction of automotive body is also required in order to achieve improvement of fuel efficiency of an automobile in response to recent carbon dioxide emission regulations. In order to achieve both the collision safety performance and the weight reduction of automotive body, a growing number of metal sheets having higher strength than before are adopted in automotive bodies. An actual metal sheet from which a blank for obtaining a press formed part is taken has not been completely flat, but has a waveform (shape variation). Therefore, an actual blank taken from the metal sheet is not necessarily flat, and may have a shape variation. When a metal sheet having such a waveform is used as a blank and press-formed into an automotive part, the press formed part obtained after the press forming may deviate from targeted dimensional accuracy due to the shape variation. For example, Patent Literatures 1 and 2 are disclosed as techniques for selecting a press formed part deviating from the targeted dimensional accuracy. Citation List Patent Literature Patent Literature 1: JP S62-047504 APatent Literature 2: JP 2019-002834 A Summary Technical Problem The techniques disclosed in Patent Literature 1 or 2 compares the shapes of the press formed parts after press forming with each other, and cannot predict an influence of the shape variation of a blank before the press forming on the press formed parts after the press forming. The influence of the shape variation of a blank on the shape of a press formed part has not been predicted. Furthermore, a portion of the press formed part susceptible to the influence of the shape variation of the blank has not been identified. In addition, EP 3 919 197 A1 discloses a method for press forming analysis of a shape variation of a blank taken from a metal sheet; this known method generates a first shape having a same shape as an actual press formed part based on measurement data obtained by measuring a shape after die release of the actual press formed part, the actual press formed part being obtained from an actual blank taken from the metal sheet having the shape variation. The present invention has been made to solve the above-described problems, and an object thereof is to provide a press forming analysis method, a press forming analysis apparatus, and a press forming analysis program for predicting an influence of a shape variation of a blank taken from a metal sheet having the shape variation in a case where press forming is performed by using the blank. Solution to Problem A press forming analysis method according to the present invention predicts an influence of a shape variation of a blank taken from a metal sheet having the shape variation in a case where press forming is performed by using the blank, and includes: a first shape generation step of generating a first shape having a same shape as an actual press formed part based on measurement data obtained by measuring a shape after die release of the actual press formed part, the actual press formed part being press-formed with a predetermined tool of press forming by using an actual blank taken from the metal sheet having the shape variation; a second shape acquisition step of acquiring a shape of a press formed part after die release as a second shape by performing press forming analysis in a case where press forming is performed with a tool-of-press-forming model having a same shape as the predetermined tool of press forming by using a flat blank model having a flat shape; and a deviation amount acquisition step of determining a portion where both the shapes deviate from each other and a deviation amount by comparing the second shape and the first shape with each other. In the deviation amount acquisition step, a bottom dead center shape in press forming analysis using the flat blank model may be determined as a standard, and a difference between a difference from the first shape corresponding to a predetermined position of the bottom dead center shape and a difference from the second shape corresponding to the predetermined position of the bottom dead center shape may be acquired as the deviation amount. In the deviation amount acquisition step, a forming surface shape of the tool-of-press-forming model may be determined as a standard, and a difference between a difference from the first shape corresponding to a predetermined position of the forming surface shape and a difference from the second shape corresponding to the predetermined position of the formi