Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
  • B21D22/02—Stamping using rigid devices or tools

Definitions

• the present invention relates to a method of simplified production of a workpiece from a sheet blank, which comprises several steps, including a single forming step which consists of using a single stamping tool, presenting only one direction of movement of the press, to form a blank of the part.
• the present invention also relates to a method of selection between the method of simplified production of a part and a method of non-simplified production of said part, using heavy industrial means.
• a method of producing a part comprises several forming steps, each forming step using a stamping tool that makes it possible to form a part.
• a stamping tool comprises a main press and punches which move in several directions. The movement of these punches is actuated by the descent of the main press and by the presence of cams of angles.
• stamping tools which use heavy industrial means, are very complex to implement and require very large investments. However, in the case of manufacturing small series parts, such investments significantly increase the price of these parts.
• FIG. 1 shows the evolution between the cost of a stamping tool Ct and the labor time T required for an operator to be able to perform manual finishing operations on the part, once the part formed by the stamping tool.
• manual finishing operations operations of dropping parts of the part that would have required a bevel gear in the stamping tool for such a fall is done automatically during the forming step.
• manual finishing operations folding operations that are performed outside the axis movement of the press and volume retrofit operations.
• the curve F represents the variation between the increase in the cost of stamping tools and the reduction in the time spent manually finishing the workpiece. And also represented three areas:
• the first zone Z1 represents a zone in which a good balance is achieved between the time of finishing operations T which remains below a first finishing time threshold T1 and the cost of the stamping tool Ct which remains below a first cost threshold of a stamping tool Ct1;
• the second zone Z2 represents an area where either:
• the third zone Z3 represents an area where either:
• the first finishing time T1 is of the order of 4 minutes;
• the second finishing time T2 is of the order of 5 minutes;
• the second cost of a stamping tool Ct2 is of the order of 15000 Euros.
• the purpose of such a graph is above all to show that the change between the cost of a stamping tool Ct is inversely proportional to the finishing time T and that it is interesting to set limits so as not to excessively lengthen the labor time or production cost of industrial stamping tools. All this allows to have a fair investment both human and financial for the realization of a piece.
• the finishing time is not a sufficient criterion to know for sure, if the realization of a piece justifies the establishment of heavy industrial means or if a simplified method of implementation, using a single-action press, but with more manual finishing operations, is preferable.
• the object of the invention is to have a simplified method of producing a part which has a low investment cost and a process development time which is shortened.
• the object of the invention is also to have a selection process between a simplified method for producing a part and a non-simplified production method that requires the establishment of heavy industrial means. Such a selection process must make it possible, according to objective criteria, to justify such a choice.
• a simplified method for producing a part for a vehicle such as a motor vehicle, from a sheet blank, which comprises several steps, including a step single forming method which consists in using a single stamping press having only one direction of stamping, to form a blank of the part.
• the sheet blank is held in position during the forming step by means of one or more indexing hole (s) which collaborates (s) with one or more pion (s) of the stamping press.
• the indexing hole (s) is (are) formed during a preparation step that precedes said forming step.
• the preparation step comprises a succession of cutting and punching steps of the sheet blank.
• the indexing hole (s) is (are) formed in a portion of the sheet blank that is intended to be removed during a step of fretwork which follows the step of forming.
• the fretwork stage is performed by means of a laser-type cutting device with a three-dimensional definition.
• the method of simplified production of a part comprises a final finishing step comprising at least one manual shaping operation of the blank of the workpiece, said shaping operation having at least one less a deformation operation of a portion of the blank of the part being in a direction of deformation different from the drawing direction of the stamping press.
• the present invention also relates to a part intended to form a part of a vehicle, such as a motor vehicle, the part being made by the simplified embodiment comprising at least one of the preceding features.
• the present invention finally relates to a method of selection between the simplified method of producing a part comprising at least one of the preceding characteristics and a method of non-simplified production of said part.
• the selection process is such that it comprises at least two selection criteria.
• Each selection criterion is broken down into three previously established ranges of values, each range corresponding, respectively, to one of three levels of selections.
• a value of a technical characteristic of the part is determined, said value then being listed in one of the corresponding value ranges of each selection criterion, so that:
• the selection level of all the selection criteria of the part corresponds to the first level of selection, it is chosen to produce the part by the simplified production method;
• the selection level of at least one of the selection criteria corresponds to the third selection level, it is chosen to produce the part by a non-simplified production method
• the selection process can not directly determine whether the piece should be performed by the simplified embodiment method.
• a first family of selection criteria relates to the technical characteristics of the sheet blank used to produce the part
• a second family of selection criteria relates to the technical characteristics of the part as formed and / or on the positioning that the piece as intended to be positioned on the vehicle.
• one or more selection criteria correspond to either: The ratio between the elastic limit and the maximum breaking strength of the sheet blank;
• one or more selection criteria correspond to either:
• the first level of the criterion for selecting the positioning of the part of the second family of selection criteria corresponds to the positioning of the part as masked for an aspect part of the vehicle
• the second level corresponds to an appearance part of the vehicle but positioned on an inconspicuous part of the vehicle or positioned on a visible part of the vehicle but whose feasibility tests have shown that the final appearance of a part made according to the simplified embodiment method is satisfactory
• the third level corresponds to an aspect part of the vehicle which is impossible to achieve satisfactorily with the simplified embodiment method.
• FIG. 2 represents, in the form of a flowchart, the various steps of a simplified embodiment of a part according to the invention
• FIGS. 3a to 3d show the state of progress of the part during the various steps of the simplified production method according to the invention.
• FIG. 4 represents, in tabular form, the various criteria and families of criteria making it possible to select the simplified production method or a non-simplified production method.
• FIG. 2 represents, in the form of a flowchart, the various steps of a simplified production method 1 of a part 2 (as represented in FIG. 3d).
• the simplified embodiment method 1 comprises a first step 1 1 and a second step 12 which form preparation steps. These two preparation steps 1 1 and 12 precede a forming step 13, followed by a scribing step 14.
• a final finishing step 15 makes it possible to finalize the piece 2 with a finish just as necessary depending on the part of the structure of the vehicle for which the part 2 is intended to be positioned.
• the simplified production method 1 is more particularly intended to form parts 2 in small quantities, generally a few thousand pieces 2.
• FIGS. 3a to 3d represent the state of progress of FIG. the part 2 during the different steps of the simplified production method 1 (shown in FIG. 2) of the part 2.
• FIG. 3a a sheet blank 21, which is intended to form the part 2 after the different steps of the simplified production method 1.
• the sheet blank 21 is cut and punched. These first two steps are generally done offline, with an operator placing each sheet blank 21 in, respectively, a cutting machine tool and / or in a punching machine tool.
• chip cleaning operations are also performed on the sheet blank 21.
• the purpose of these operations is to have a sheet blank 21 of optimized shape for the forming step 13 (shown in FIG. 2), in particular with the formation during the second preparation step 12 of the sheet blank 21, by
• the pilot holes 23 of the sheet blank 21 are adapted to hold the sheet blank 21 in position during the closing of the press.
• FIG 3b shows a blank 22 of the workpiece 2, as formed, by a single-action type stamping tool from the sheet blank 21 (as shown in Figure 3a).
• the press used is a single action type press, having only one direction of movement of the punch 24 and / or the die and having no falling blades.
• Such a press requires that the used sheet blank 21 has a shape adapted to directly form the blank 22 of the workpiece 2.
• the pilot holes 23 collaborate.
• the pilot holes 23 guarantee the repeatability of the positioning of the blank 21 in the embossing tool and the repeatability of the positioning of the blank 22 of the workpiece 2 during the scribing step 14 (shown in FIG. 2).
• the pilot holes 23 are defined outside the so-called noble zone of the part 2.
• the noble or aspect zone of the part 2 is formed by the parts of the part 2 which are visible after the assembly of the part 2 on the vehicle.
• FIG. 3c shows the blank 22 of the piece 2 after the step of forming 13 and as positioned on a support 25 for the scribing step 14.
• the scribing step 14 comprises a succession of steps of trimming, punching and forming notches on the blank 22. To do this the blank 22 of the part 2 is positioned on the support 25 which allows a three-dimensional positioning of the blank 22 of the part 2 with a pilot index adapted to perform a fretting operation 14 of the laser cutting type 26 of the blank 22. During this scribing step 14 can be removed a portion of the blank 22 of the part 2 which has the pilot holes 23.
• Figure 3d is shown the piece 2 after the finishing step. Part 2 is now ready to be stored for assembly on the structure of a vehicle.
• the finishing step which is not shown, consists of operations of dropping parts of the part 2 that would have required a return angle in the stamping tool for such a fall is done automatically during the forming step 13. Also being understood by finishing operations, folding operations that are performed outside the main axis of movement of the press and volume up-take operations. All these operations are done manually by an operator.
• the invention as described may also include a variant, in the case where one of the presses of an already existing stamping line can be used in the context of this method of producing parts 2 in small series. In this case, the preparation steps are done offline, the piece 2 is then deposited along the stamping line upstream of the press in question and recovered downstream of this press to receive the step of fretting 14 and finishing 15.
• FIG. 4 represents, in the form of a table, the various criteria making it possible to select the simplified production method 1 or a non-simplified production method.
• a selection method comprises according to two families of selection criteria CS1, CS2:
• the first family of selection criteria CS1 relates to the technical characteristics of the sheet blank 21 (shown in FIG. 3a) used to produce the part 2; and "the second family of CS2 selection criteria relates to the geometry of the part 2 to be formed and its positioning on the vehicle.
• the two selection criteria families CS1, CS2 respectively comprise four and three selection criteria, each selection criterion comprising three values or ranges of values previously established which correspond to three levels of selections N1, N2 and N3.
• the first family of selection criteria CS1 comprises four selection criteria that characterize the technical characteristics of the sheet blank 21, namely:
• a first selection criterion RMP which corresponds to a ratio between the elastic limit and the maximum breaking strength of the sheet blank 21;
• ⁇ A second selection criterion A1 which corresponds to the percentage of maximum elongation at break of the sheet blank 21;
• a fourth selection criterion Cr which corresponds to the average anisotropy coefficient of the sheet blank 21.
• the second family of selection criteria CS2 comprises three selection criteria that define the geometry of the part 2 to be formed and / or its positioning on the vehicle, namely:
• a first selection criterion Ft corresponding to the number of manual finishing operations required in the case where the part 2 is produced according to the simplified embodiment method 1;
• a second selection criterion At which characterizes the positioning of the part 2 on the vehicle according to three levels of visibility;
• a third selection criterion Ht which corresponds to the percentage ratio between the height and the greatest length of the part 2 to be made.
• Each of the criteria RMP, Al, Cf and Cr of the first family of selection criteria CS1 includes ranges of values which make it possible to classify, according to the three levels of selections N1, N2 and N3, technical characteristics of the sheet blank 21, as we have:
• RMP1 For the first selection criterion RMP1, three ranges of values RMP1, RMP2 and RMP3 which respectively correspond to the selection levels N1, N2 and N3;
• the first value Ft1 which corresponds to the first selection level N1 and which corresponds to having no manual finishing operation to obtain the part 2 according to the method of simplified embodiment 1;
• the second value Ft2 which corresponds to the second selection level N2 and which corresponds to having only one manual finishing operation to obtain the part 2 according to the simplified production method 1;
• the third value Ft3 which corresponds to the third selection level N3 and which corresponds to having at least two manual finishing operations to obtain the part 2 according to the simplified production method 1.
• the second level At2 which corresponds to the second level of selection N2 and which corresponds to a part 2 of appearance but intended to be positioned on a not very visible part of the vehicle or intended to be positioned on a visible part of the vehicle but whose tests feasibility have shown that the final appearance of a part 2 made according to the simplified embodiment method 1 is satisfactory;
• a value Vp of a technical characteristic of the sheet blank 21 or of the part 2 is determined.
• the value Vp is then listed for each selection criterion, making it possible to obtain the corresponding selection level N1, N2 or N3, so that:
• the selection level of all the selection criteria corresponds to the first selection level N1
• the selection level of at least one of the selection criteria corresponds to the third selection level N3, it is chosen to produce the part 2 by the non-simplified embodiment method 1.
• the selection process can not determine directly whether the part 2 must be carried out by the simplified embodiment 1 or not simplified. To do this, tests are carried out. If all the tests are conclusive then one chooses to make the part 2 by the simplified method of realization 1, otherwise the part 2 is carried out by a non-simplified production method.
• the tests consist, generally in a first step, in analyzing the result of the selection criterion noted at the second level N2 on a simulator. If in doubt after this first analysis, tests on a stamping tool can be performed before the final decision on the process used.

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• 2016
  • 2016-05-03 BR BR112017023329-0A patent/BR112017023329B1/pt active IP Right Grant
  • 2016-05-03 EP EP16726356.5A patent/EP3291927A2/de not_active Withdrawn
  • 2016-05-03 WO PCT/FR2016/051038 patent/WO2016177962A2/fr active Application Filing
  • 2016-05-03 RU RU2017142086A patent/RU2732552C2/ru active

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