JP6044571B2 - DAMAGE DAMAGE DAMAGE PREDICTION METHOD FOR CUT DIE AND CUT DIE DAMAGE PREVENTION METHOD USING THE PREDICTION METHOD - Google Patents

Description

  The present invention relates to a method for predicting a risk of damage to a cut mold used in a cutting process in press working, and a method for preventing damage to a cut mold using the prediction method.

  In the field of manufacturing, press working with dies is often used. In recent years, in the field of automobiles, the use of high-strength materials is increasing from the viewpoint of reducing the weight of vehicles to improve fuel efficiency or improving collision safety, and the performance required for molds that process these materials is severe. It has become a thing.

  In promoting the expansion of the application of ultra-high tensile materials (ultra-high-strength steel) with a tensile strength of 980 MPa or more, especially in the press forming process, such as a trim process for cutting parts into a predetermined shape and a punching process for drilling. A significant increase in maintenance man-hours due to damage to the cut mold in the cutting process has become an issue. As a cause of damage to the cut mold, it is known that a problem such as wear or chipping occurs due to an increase in deformation resistance accompanying the increase in strength of the material and an increase in load or contact pressure on the mold. Yes.

  Conventionally, various tool steels have been developed as countermeasures against mold damage, and wear resistance and toughness have been improved. For example, Patent Document 1 proposes a mold steel that is improved in machinability with sulfides and has reduced cracking susceptibility by controlling the forging ratio and cooling rate, and Patent Document 2 discloses Cr with respect to the C content. Cr / C, which is the ratio of the content of Cr, and cold tool steel that can suppress deformation at a high tempering temperature by defining the Mn and N content within an appropriate range based on Cr / C Has proposed.

  In addition, it is desirable to extend the life of a die used for press working as much as possible, and development of a die life prediction technology has been developed. For example, Patent Document 3 stores the number of times of application set for each die, counts and records the number of times of impact pressure for each die, and outputs a stop signal when the number of impact times reaches the number of times of application. A die life management device that stops the press machine is proposed, and Patent Document 4 detects the maximum load at the time of punching and the punch intrusion force thereafter, and discriminates edge damage from the maximum load based on the material of the material to be processed. In addition, a device is proposed that prevents the occurrence of strip errors (loss of material to be removed from the punch) from the punch thrust force.

JP 2005-171305 A Japanese Patent No. 4860774 JP 63-068236 A JP 05-212455 A

  Although tool damage improvement effect is expected by applying tool steel with improved wear resistance and toughness, it is difficult to damage the mold because there are some parts that are easily damaged and difficult to be damaged by actual mold damage. If measures are taken up to the point, the cost increases, and if the damaged part of the mold can be identified in advance, it is possible to efficiently implement the countermeasure against the damaged mold.

  Die life prediction technology predicts the maintenance period of the mold from the transition of the load during machining and the past press work results, but it is useful for the management and efficiency improvement of the production process. It cannot be a fundamental mold damage countermeasure technology.

  Therefore, the present invention makes it possible to easily implement an efficient countermeasure against damage to a mold by predicting a risk of damage in advance for a cut mold used in a cutting process in press working, and to reduce maintenance man-hours. It is an object of the present invention to provide a method for predicting a risk of damage to a cut mold that can be reduced, and a method for preventing damage to a cut mold using the prediction method.

The method for predicting the risk of damage to a cut mold of the present invention that achieves the above-described object
A process of performing a cutting process analysis at a predetermined cutting position on a workpiece shape to obtain a product shape after the cutting process;
A step of performing a springback analysis on the obtained product shape after cutting and obtaining a product shape after springback;
Compare the product shape after cutting with the product shape after spring back, extract the part protruding from the predetermined cutting position of the product shape after cutting with the product shape after spring back, and risk of damage to the protruding part A process of determining a site;
It is made up of.

Further, the method for preventing damage to the cut mold of the present invention using the prediction method,
A process of performing a cutting process analysis at a predetermined cutting position on a workpiece shape to obtain a product shape after the cutting process;
A step of performing a springback analysis on the obtained product shape after cutting and obtaining a product shape after springback;
Compare the product shape after cutting with the product shape after spring back, extract the part protruding from the predetermined cutting position of the product shape after cutting with the product shape after spring back, and risk of damage to the protruding part A process of determining a site;
A step of performing a cutting process at a predetermined cutting position with a cut mold in a state in which the protruding movement of the part determined to be the risk of damage of the intermediate product after the molding process is constrained;
It is made up of.

  According to the method for predicting a risk of damage to a cut mold according to the present invention, a cut shape analysis is performed at a predetermined cutting position on a work shape to obtain a product shape after the cut processing, and the obtained product shape after the cut processing is obtained. The product shape after the spring back is obtained by performing the spring back analysis to obtain the product shape after the spring back, and the product shape after the spring back by comparing the product shape after the cutting and the product shape after the spring back. Because the projecting part is extracted from the predetermined cutting position and the projecting part is judged as the damage risk part, the damage risk part can be predicted in advance for the cutting die used in the cutting process in press working. As a result, it is possible to easily implement an efficient countermeasure against mold damage and to reduce the number of mold maintenance steps.

  The method for predicting the risk of damage to a cut mold according to the present invention further includes a step of performing a molding process analysis on the material to be pressed to obtain an intermediate product shape after the molding process. The intermediate product shape may be the shape to be processed for performing the cutting processing analysis at the predetermined cutting position. In this way, when one or a plurality of press forming processes such as bending, drawing, and overhanging are performed in the previous process of the cutting process, the residual that occurs in the work material in the press forming process. It is possible to predict the risk of damage due to the protrusion of the workpiece material during cutting due to stress. This makes it possible to easily implement efficient countermeasures against mold damage and also to maintain the mold maintenance man-hours. Can be reduced.

  Further, according to the method of preventing damage to the cut mold of the present invention, the product shape after the cutting process is obtained by performing the cutting process analysis at the predetermined cutting position on the work shape, and the product shape after the cutting process obtained The product shape after the spring back is obtained by performing the spring back analysis to obtain the product shape after the spring back, and the product shape after the spring back by comparing the product shape after the cutting and the product shape after the spring back. Extract the part that protrudes from the predetermined cutting position, determine that the protruding part is a damage risk part, and restrict the protrusion movement of the part determined to be the damage risk part of the intermediate product after molding processing Because cutting is performed at a predetermined cutting position with a mold, damage to the mold due to protrusion of the work material can be efficiently prevented for the cut mold used in the cutting process in press working. With, it is possible to also reduce man-hours of maintenance of the mold.

  In addition, in the damage prevention method of the cut mold of the present invention, the method further includes a step of performing a molding process analysis on the material to be pressed to obtain an intermediate product shape after the molding process, and the obtained intermediate product after the molding process The shape may be the shape to be processed for performing the cutting processing analysis at the predetermined cutting position. In this way, when one or a plurality of press forming processes such as bending, drawing, and overhanging are performed in the previous process of the cutting process, the residual that occurs in the work material in the press forming process. It is possible to efficiently prevent damage to the mold due to the protrusion of the material to be processed in the cutting process caused by the stress, and to reduce the man-hours for the maintenance of the mold.

  Moreover, in the damage prevention method of the cut mold of this invention, it is good also as raising the board pressing force which clamps the site | part judged to be the damage risk site | part of the said intermediate product of the said cut mold at least. If it does in this way, the protrusion movement of the site | part judged to be a damage risk site | part of the intermediate product after a shaping | molding process can be restrained.

Furthermore, in the method for preventing damage to the cut mold according to the present invention, the shape of the cut mold that sandwiches at least the portion of the intermediate product that has been determined to be the risk of damage is the product shape before the spring back. It is good also as a shape which follows. Even in this case, it is possible to restrain the protruding movement of the part determined to be a damage risk part of the intermediate product after the molding process, and the shape along the product shape to the part holding the part determined to be the damage risk part is The adoption may be used in combination with a measure for increasing the plate pressing force for clamping the part determined to be a damage risk part.

It is sectional drawing of the metal mold | die which shows one of the factors of metal mold | die damage, (a) is before the cutting process of a workpiece material, (b) has each shown the state after a cutting process. It is a flowchart which shows one Embodiment of the damage risk site | part prediction method of the cut die of this invention. It is a disassembled perspective view which shows the structure of the drawing die in the damage risk site | part prediction method of the cut die of the said embodiment. It is a perspective view which shows the analysis shape in the damage risk site | part prediction method of the cut metal mold | die of the said embodiment, (a) is the intermediate product shape after drawing, (b) is the product shape after trim processing, (c) Indicates the product shape after springback. It is a top view which shows the analysis shape in the damage risk site | part prediction method of the cut metal mold | die of the said embodiment, (a) shows the product shape after springback, (b) shows a trim processing shape, respectively (c) is ( The A part in a) is expanded and shown. It is sectional drawing of the trim mold | die which shows one Embodiment of the damage prevention method of the cut mold of this invention using the damage risk site | part prediction method of the cut mold of the said embodiment, (a) is workpiece material Before cutting, (b) shows the state after cutting. It is sectional drawing of the trim mold | die which shows other embodiment of the damage prevention method of the cut mold of this invention using the damage risk site | part prediction method of the cut mold of the said embodiment, (a) is to-be-processed Before the material cutting process, (b) shows the state after the cutting process.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention has been conceived on the basis of the following estimation of die damage factors by the present inventors. That is, the present inventor considers not only an increase in deformation resistance but also a dimensional accuracy failure as one of the factors of damage to the mold, and FIGS. 1 (a) and 1 (b) show the states before and after the cutting of the work material. As shown respectively, an intermediate product 3 as a material to be processed is sandwiched between the lower blade 1 and the plate presser 2 of the trim mold, and the upper blade 4 serving as a cutting blade is lowered as indicated by an arrow, so that the trim line T As a result of the cutting process such as trim processing that cuts the unnecessary portion 3 'at the position of the material, the stress balance in the material to be processed changes, so that a springback occurs in the product that is the material to be processed after cutting, and the trim edge Since 5a protrudes from the trim line T which is a predetermined cutting position, the trim edge of the product 5A after the spring back and the side surface of the upper edge 4 of the trim mold strongly come into contact with each other at a specific location. 4 rises Wear and loss of the cutting edge has been estimated to occur.

  In particular, when the material to be processed is an ultra-high tensile material, in addition to an increase in springback, a gap (rattle between the trim mold and the press-molded product due to a decrease in the dimensional accuracy of the press-molded product. ), The presser foot force is reduced, the trim edge is easy to move, and the deformation resistance of the work material is high, so the cutting edge is easily worn and damaged due to the strong contact between the trim edge and the side of the cutting edge. it is conceivable that.

  FIG. 2 is a flowchart showing an embodiment of a method for predicting a risk of damage to a cut mold according to the present invention. Here, first, in the press molding analysis calculation processing step in step S1, calculation calculation processing, that is, computer simulation, for one or a plurality of press molding processes such as bending, drawing, and overhanging is performed. For this simulation, for example, general-purpose simulation software LS-DYNA Ver. 971 is used, and an ultra-high tensile steel plate having a tensile strength of 980 MPa and a plate thickness of 1.4 mm is used as a work material.

  For example, as shown in FIG. 3, a convex punch 6 corresponding to a predetermined product shape, a blank holder 7 disposed around the punch 6 so as to be movable up and down, and lifted by a cushion device of a press machine, for example, and the blank holder A flat blank 8 made of the above-mentioned work material held on 7 is sandwiched in cooperation with the blank holder 7 and formed into an intermediate product in cooperation with the punch 6. A concave shape corresponding to a predetermined product shape The drawing mold having the die 9 is set by computer-aided design (CAD) data, and in step S1, for example, the CAD data of the drawing mold together with the CAD data of the blank 8 is added to the simulation software. Then, a computer simulation of the drawing process of the blank 8 in the drawing mold is performed, and as shown in FIG. To obtain the shape of the intermediate product 3 after drawing processing of a flat blank 8.

  In the subsequent trim calculation process in step S2, for example, CAD data of the shape of the intermediate product 3 after the drawing is input together with CAD data of a predetermined trim line corresponding to the contour of the product shape to the simulation software. A cutting process for cutting the shape of the intermediate product 3 at the position of the trim line is performed by computer simulation to obtain the shape of the product 5 after the trim processing and before the spring back as shown in FIG. 4B.

  In the subsequent spring back analysis processing step in step S3, for example, the CAD data of the shape of the product 5 after the trim processing and before the spring back is generated in the simulation software, and the intermediate product 3 after the previous draw forming processing. Are calculated together with the CAD data of the following shape, and the spring back amount of each part generated when the residual stress generated in the shape of the intermediate product 3 is released by trim processing from the flat blank 8 is calculated. The amount of springback is added to the shape of the product 5 before springback to obtain the shape of the product 5A after springback as shown in FIG.

  In the subsequent step S4, for example, the CAD data of the shape of the product 5A after the spring back as shown in FIG. 5A corresponds to the contour of the product shape as shown in FIG. 5B in the simulation software. 5C is input to the trim line T indicating the predetermined cutting position, and the shape of the product 5A after the spring back is compared with the position of the trim line T. FIG. As shown in an enlarged view of part A, the part protruding from the trim line T as shown by the arrow in the shape of the product 5A after spring back is extracted, and the extracted part is extracted from the trim mold. Identified as a risk of damage.

  Therefore, according to the method for predicting the risk of damage to the cut mold according to this embodiment, it is possible to predict the risk of damage in advance for the cut mold used in the trimming process in the press working, thereby improving efficiency. Mold damage countermeasures can be easily implemented, and the number of mold maintenance steps can be reduced.

  Moreover, according to the method for predicting the risk of damage to the cut mold of this embodiment, the process further includes the step S1 of performing the drawing process analysis on the blank 8 to obtain the shape of the intermediate product 3 after the molding process. Since the shape of the intermediate product 3 after the forming process is a processed shape for analyzing the cutting process at the trim line T, when the drawing process is performed before the trim process, the process is performed in the drawing process. It is possible to predict the risk of damage due to the protrusion of the trim edge from the trim line T in the trim processing caused by the residual stress generated in the intermediate product 3 as a material, thereby facilitating efficient mold damage countermeasures. It can be carried out and the number of mold maintenance steps can be reduced.

  FIG. 6 is a cross-sectional view of a trim mold showing an embodiment of a method for preventing damage to a cut mold according to the present invention using the method for predicting a risk of damage to a cut mold according to the above-described embodiment. Before the cutting of the work material, (b) shows the state after the cutting, in which the same parts as in the conventional example of FIG. 1 are denoted by the same reference numerals.

  In the method for preventing damage to the cut mold according to this embodiment, the cut mold according to the above embodiment is used to prevent damage to the trim mold as the cut mold used in the trim processing step after the draw forming step in press working. First, the risk of damage due to protrusion of the trim edge from the trim line T in the trimming process is predicted, and then in the trimming process after the actual drawing process, The intermediate product 3 is cut at the trim line position by the trim die in a state where the protruding movement of the portion determined to be a risk of damage of the intermediate product 3 after the molding process is restricted by the trim die.

  The trim mold as the cut mold used in the method for preventing damage to the cut mold of this embodiment is a cutting blade by sandwiching the intermediate product 3 as the material to be processed between the lower blade 1 and the plate presser 2. The upper blade 4 is lowered as indicated by an arrow to cut the unnecessary portion 3 ′ at the position of the trim line T. The risk of damage of the intermediate presser 3 of the presser foot 2, particularly after the drawing process, The protrusion 2a is provided along the trim line T on the lower surface of the portion corresponding to the determined portion, and the plate when the portion determined to be a damage risk portion of the intermediate product 3 is sandwiched between the lower blade 1 and the plate presser 2 The presser force is configured to concentrate on the narrow end surface of the ridge 2a, so that the surface pressure of the plate presser 2 is particularly increased along the trim line T at the site that is determined to be a damaged site of the intermediate product 3. As shown in Fig. 6 (a), after drawing process In a state in which the protruding movement of the intermediate product 3 determined as the risk of damage is constrained by the trim mold, the trim mold performs cutting at the position of the trim line T as shown in FIG. 6B. As a result, the shape of the product 5 before spring back in which the trim edge does not substantially contact the side surface of the upper blade 4 is obtained and maintained by the plate presser 2, and the upper blade 4 rises in this state.

  Therefore, according to the method for preventing damage to the cut mold according to this embodiment, it is possible to efficiently prevent damage to the mold due to the protrusion of the work material and to maintain the mold for the cut mold used in the cutting process in press working. The number of man-hours can be reduced.

  Moreover, according to the method for preventing damage to the cut mold of this embodiment, the method further includes a step S1 of performing a drawing process analysis on the blank 8 to obtain the shape of the intermediate product 3 after the molding process, and the obtained molding process Since the shape of the subsequent intermediate product 3 is a processed shape for analyzing the cutting process at the trim line T, when drawing is performed in the pre-process of the trim process, it is used as a work material in the drawing process. The trim mold can be effectively prevented from being damaged due to the protrusion of the trim edge from the trim line T in the trim processing due to the residual stress generated in the intermediate product 3, and the maintenance work of the trim mold can be reduced accordingly. Can do.

  Furthermore, according to the method for preventing damage to the cut mold according to this embodiment, the lower surface of the portion of the trim mold plate retainer 2 corresponding to the part determined to be a damage risk part of the intermediate product 3 after the drawing process, in particular. The protrusion 2a is provided along the trim line T, and the plate pressing force when the portion determined to be a damaged portion of the intermediate product 3 is clamped between the lower blade 1 and the plate press 2 is narrow at the tip of the protrusion 2a. Since it is configured so as to concentrate on the surface, the trim mold is restrained with respect to the intermediate product 3 in a state where the projecting movement of the intermediate product 3 after the draw forming process is determined to be a damaged part by the trim mold. Can be cut at the trim line position.

  FIG. 7 is a cross-sectional view of a trim mold showing another embodiment of the damage prevention method for a cut mold according to the present invention using the method for predicting a risk of damage to a cut mold according to the above embodiment. ) Shows the state before the cutting of the material to be processed, and (b) shows the state after the cutting, in which the same parts as in the conventional example of FIG. 1 are indicated by the same reference numerals.

  Even in the method for preventing damage to the cut mold according to this embodiment, the cut mold according to the above embodiment is used to prevent damage to the trim mold as a cut mold used in the trim processing step after the drawing process in press working. First, the risk of damage due to protrusion of the trim edge from the trim line T in the trimming process is predicted, and then in the trimming process after the actual drawing process, The intermediate product 3 is cut at the trim line position by the trim die in a state where the protruding movement of the portion determined to be a risk of damage of the intermediate product 3 after the molding process is restricted by the trim die.

  The trim mold as the cut mold used in the method for preventing damage to the cut mold of this embodiment is a cutting blade by sandwiching the intermediate product 3 as the material to be processed between the lower blade 1 and the plate presser 2. The upper blade 4 is lowered as indicated by an arrow to cut the unnecessary portion 3 ′ at the position of the trim line T. The risk of damage of the intermediate presser 3 of the presser foot 2, particularly after the drawing process, The shape of the lower surface of the part corresponding to the determined part is formed so as to correspond to the shape of the product 5 before the spring back, and the part that is determined to be a damage risk part of the intermediate product 3 is closely contacted therewith without any gap 7 and the lower blade 1 so that the plate presser 2 can reliably hold the portion of the intermediate product 3 that is determined to be a damaged portion along the trim line T. FIG. ) As shown in In the state where the protruding movement of the part determined to be a risk of damage of the product 3 is restrained by the trim mold, the trim mold performs cutting at the position of the trim line T as shown in FIG. 7B. Thus, the shape of the product 5 before spring back in which the trim edge does not substantially contact the side surface of the upper blade 4 is obtained and maintained by the plate presser 2, and the upper blade 4 is raised in this state.

  Therefore, the method for preventing damage to the cut mold according to this embodiment can efficiently prevent damage to the mold due to the protrusion of the material to be processed for the cut mold used in the cutting process in the press working, and can maintain the mold. Man-hours can also be reduced.

  Moreover, the method for preventing damage to the cut mold according to this embodiment further includes a step S1 of performing a drawing process analysis on the blank 8 to obtain the shape of the intermediate product 3 after the molding process, and after the obtained molding process. Since the shape of the intermediate product 3 is the shape to be processed for analyzing the cutting process at the trim line T, when drawing is performed in the previous process of the trim process, The trim mold can be effectively prevented from being damaged by the protrusion of the trim edge from the trim line T in the trim processing due to the residual stress generated in the intermediate product 3, and the maintenance work of the trim mold can be reduced accordingly. it can.

  Furthermore, according to the method for preventing damage to the cut mold according to this embodiment, the lower surface of the portion of the trim mold plate retainer 2 corresponding to the part that is determined to be a damage risk part of the intermediate product 3 after the drawing process. The shape is formed so as to correspond to the shape of the product 5 before the spring back, and the portion determined to be a damage risk portion of the intermediate product 3 is sandwiched between the plate presser 2 and the lower blade 1 that are in close contact with each other without any gaps. In the state where the projecting movement of the part judged to be a damage risk part of the intermediate product 3 after the drawing process is constrained by the trim mold, the trim product is positioned at the trim line position by the trim mold. Can be cut.

  Although the present invention has been described based on the illustrated examples, the present invention is not limited to the above-described examples, and can be appropriately changed within the scope of the claims as required. For example, before the cutting process The molding process may be a plurality of processes, and is not limited to the drawing process, but may be a bending process or an extension process, or a combination thereof. The cut mold is not limited to the trim mold, and may be a punching mold that performs drilling, or may be used when there is no molding process before the cutting process.

  Then, in order to constrain the protruding movement of the part determined to be a damage risk part of the intermediate product 3 after the drawing process by the trim mold, the spring not shown in the structure of the plate presser 2 shown in FIG. 1, FIG. 6 or FIG. Alternatively, the plate presser load applied to the plate presser 2 by an elastic member such as synthetic rubber may be increased as compared with the conventional case, or the configurations of the plate presser 2 shown in FIGS. 6 and 7 may be combined.

  Thus, according to the method for predicting a risk of damage to a cut mold according to the present invention, it is possible to predict a risk of damage in advance for a cut mold used in a cutting process in press working. Damage countermeasures can be easily implemented, and the number of mold maintenance steps can be reduced.

  Further, according to the method for preventing damage to the cut mold of the present invention, it is possible to efficiently prevent damage to the mold due to the protrusion of the work material, and to maintain the mold for the cut mold used in the cutting process in press working. Man-hours can also be reduced.

DESCRIPTION OF SYMBOLS 1 Lower blade 2 Plate clamp 2a Projection 3 Intermediate product 3 'Unnecessary part 4 Upper blade 5 Product before spring back 5A Product after spring back 5a Trim edge 6 Punch 7 Blank holder 8 Blank 9 Die T Trim line

Claims (6)

A process of performing a cutting process analysis at a predetermined cutting position on a workpiece shape to obtain a product shape after the cutting process;
A step of performing a springback analysis on the obtained product shape after cutting and obtaining a product shape after springback;
Compare the product shape after cutting with the product shape after spring back, extract the part protruding from the predetermined cutting position of the product shape after cutting with the product shape after spring back, and risk of damage to the protruding part A process of determining a site;
A method for predicting the risk of damage in a cut mold comprising The method further includes a step of performing a molding process analysis on the material to be pressed to obtain an intermediate product shape after the molding process,
The method for predicting a risk of damage to a cut mold according to claim 1, wherein the shape of the intermediate product obtained after the forming is the shape to be processed for cutting processing analysis at the predetermined cutting position. A process of performing a cutting process analysis at a predetermined cutting position on a workpiece shape to obtain a product shape after the cutting process;
A step of performing a springback analysis on the obtained product shape after cutting and obtaining a product shape after springback;
Compare the product shape after cutting with the product shape after spring back, extract the part protruding from the predetermined cutting position of the product shape after cutting with the product shape after spring back, and risk of damage to the protruding part A process of determining a site;
A step of performing a cutting process at a predetermined cutting position with a cut mold in a state in which the protruding movement of the part determined to be the risk of damage of the intermediate product after the molding process is constrained;
A method for preventing damage to cut dies. The method further includes a step of performing a molding process analysis on the material to be pressed to obtain an intermediate product shape after the molding process,
4. The method for preventing damage to a cut die according to claim 3, wherein the obtained intermediate product shape is the shape to be processed for performing cutting processing analysis at the predetermined cutting position.   The method for preventing damage to a cut die according to claim 3 or 4, wherein a plate pressing force for clamping at least a portion of the cut product that is determined to be a risk of damage is increased. 6. The shape of a part of the cut mold that sandwiches at least a portion of the intermediate product that is determined to be a risk of damage is a shape that conforms to the shape of the product before the spring back. 6. The method for preventing damage to the cut mold according to any one of the preceding items.

Images