ES2310429B1 - TROQUEL MANUFACTURING PROCEDURE. - Google Patents

Abstract

Die manufacturing process.

This manufacturing procedure allows obtain dies whose dimensions are properly corrected to compensate for the deviations that occur in the pieces obtained, taking into account all the parameters that they can influence the final dimensions of the piece obtained, including the complete three-dimensional geometries of all elements that constitute the complete mechanical assembly, that is, of the press, die and support bench.

Description

Die manufacturing process.

Object of the invention

The process object of the invention allows obtain dimensionally accurate dies and therefore not require subsequent manual adjustments so that the die has proper operation in obtaining the part correspondent.

For this, the process of the invention takes into account all the factors that can cause the pieces obtained have dimensional deviations, obtaining a die whose geometry is properly corrected for compensate for said deviations and thus obtain directly the parts required within the established tolerance range.

Background of the invention

As is well known, a die is a tool that It consists of a matrix or mold that is mounted on a table or bench, a punch that is mounted on a press and some treadmills or hydraulic cushions that hold the sheet, such that the sheet to form or cut is arranged on the matrix, proceeding then to actuate the treadmills until they hold the sheet, and then the punch of the punch that conforms or cuts The plate. Obviously, when it comes to getting complex pieces, with very demanding tolerances, it is very complicated and laborious to obtain a die with the precise forms for the Parts manufacturing.

Currently, the manufacture of dies is  starts with obtaining the theoretical geometry of the surface of contact between the sheet and the die, introducing these data in a simulation program that allows checking the validity of the geometry obtained for the contact surface, or what It is the same, that with a surface like the one you can get parts without breaking the sheet or wrinkles occur in the same.

These simulation programs take into account only the geometry of the matrix contact surface, punch and traders and the thickness of the sheet or piece to obtain now that only try to simulate the flow of the sheet between the punch and die, checking that a piece can be formed No cracks or wrinkles.

Once the viability of the surface is validated contact, we proceed to the design, through a CAD system, of a complete three-dimensional model of the die, that is, a matrix, a punch and some treadmills, which will present a surface contact with the geometry validated through the program of simulation. Obviously, the pieces that make up the die they have a complex configuration and are generally large dimensions, so they cannot be obtained in a single piece but are made up of various pieces that will be joined mechanically to determine the final shape of the die, presenting the different pieces a series of emptyings and nerves of reinforcement designed specifically for each die and that have Aim to reduce the weight of the die but without losing it The required resistance.

Well, this three-dimensional model obtained, although it has a contact surface that reproduces with accuracy the dimensional geometry of the desired piece obtain, in practice does not allow the manufacture of parts, within of the tolerances required.

Therefore, on the three-dimensional model obtained, a series of corrections are applied, based on the knowledge and experience of technicians, reaching a theoretical geometry corrected for the die, with which we proceed to the manufacture and assembly of it.

Then they start testing of manufacturing parts with the manufactured die, performing successive adjustments on the areas in which the parts obtained do not have the required characteristics because the die and the punch are not coupled as intended.

These adjustments are made manually, and They consist of eliminating or contributing material.

This process is repeated again and again, until  the piece obtained conforms to the characteristics of the piece and required operation, it may take several months of work until the die allows to manufacture the desired piece in the tolerances required.

Subsequently, the die obtained and tested in  the die maker's facilities, it takes and installs on the machine or machines of the end customer that will manufacture the corresponding pieces, happening many times that this die that was perfectly adjusted no longer produces the pieces inside of the required tolerances.

This difference is due to the machine and the working conditions at the manufacturer's facilities dies may differ substantially from those found in the facilities of the final manufacturer.

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To reduce the time needed for the die machining, various methods are used that allow fundamentally quickly and intuitively determine the zones in which it is necessary to remove or provide material. So by For example, it is very common to coat the die with paints or resins that allow visually detect areas where the blow of press is more or less and, therefore, where to remove or contribute material but, in any case, it requires a huge amount working for the final adjustment of the die.

In this sense, the PCT patent is known 01/89734 in which an optical measuring device is used the dimensions of the die, whose data is compared with the data Theorists of the piece previously stored on a computer, obtaining the deviations existing in the die for they feed a machine, computer controlled, which deals of the complete grinding of the die.

In European Patent No. 0 550 390, the die incorporates a sensor that can measure pressure, temperature, vibration and displacement thereof, to determine the deviation of these parameters with respect to those expected theoretically, thus allowing to improve the mathematical model used for the obtaining the die.

Also, in European Patent No. 0 417 311, describes a procedure according to which information is obtained about the machine used to manufacture the parts, data which are introduced into the CAD system and in accordance with the information generated by it, the molds are manufactured by means of a CAM system to finally assemble the molds in the machine and carry out the machining operation of the same through the classic trial and error procedure.

In any case, all procedures mentioned above finally require a machining of the die, so the time and cost of manufacturing them It is very high.

Description of the invention

The procedure that is recommended allows the manufacture of dies avoiding subsequent manual adjustments, based on that in the modeling of the die they are taken into account all the parameters that influence so that the manufactured part present deviations from the desired values.

To do this, they have studied in depth the events that occur during the manufacture of the pieces, as well as the different parameters involved and their possible effects, discriminating those that really have a direct effect on the dimensional imperfections of the piece, as well as the form of correct the initial theoretical model of the die.

For example, it has been determined that the fundamental factor that influences so that the theoretical geometry of die does not result in a dimensionally correct part, is linked to the tremendous impact that the press has and the deformations that it causes in all the elements of the set mechanic constituted by the press, bench and die.

It has also been observed that in deformation which suffers the die influence the structure of the die itself, is say, how has this been configured, especially as regards to the position and dimension of the nerves and voids provided for lighten the weight of the die and also the configuration of the tool of the press or punch and even the geometry and characteristics of the table or bench on which the die matrix rests.

Obviously, you also have to take into account the characteristics and operation of the machine, mainly in what refers to the force exerted by it and the points in that applies

Therefore, the procedure subject to invention is based on calculating the deformations suffered by the complete mechanical assembly, taking into account the 3D, solid 3D geometries of all elements of the mechanical assembly, that is, of the press, bench and die in instead of considering only the surface geometry of die contact and assume that die and press do not suffer deformation In addition, it is assumed for the calculation that the piece to be manufactured has thickness 0, or what is the same, as the matrix and The punch is in permanent contact.

Specifically, the procedure object of the The invention is based on the following phases:

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Mechanical assembly modeling constituted by the die and the press, through the data significant of them that will be described more ahead.

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Treatment of geometric data and of operation of the press and die using the method of finite elements, obtaining a map with the deformations provided for the die.

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Obtaining the corrected geometry for the die, based on theoretical data and the map of deformations

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Manufacture by CAM of a die with the corrected dimensions.

The modeling of the mechanical assembly is carried out  from the complete three-dimensional geometry in 3D CAD, solids, of all the elements of the mechanical assembly, that is, of the press, bench and complete die composed of matrix and awl. The arrangement and geometry of the internal and contour nerves of the die.

The characteristics are also taken into account of materials of the mechanical assembly, the force produced by the press and data fixing and support of the table or bench on the one that the die matrix is arranged.

With all this data, an FEM model is obtained which takes into account the complete geometry of all the elements that constitute the mechanical assembly and the forces and reactions that act on it, as well as the points of application of these forces.

However, it is possible to use hypotheses of simplified calculations that allow you to eliminate any of the components of the mechanical assembly replacing them with the effects which produces on the rest of the mechanical assembly.

For example, you could simplify the data used for modeling the mechanical assembly at following:

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Three-dimensional data geometry Theorists planned for the die matrix, including internal and contour nerves.

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Material characteristics of set consisting of the press and parent company.

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Distribution of forces applied over the contact surface between the die and the punch.

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Data for fixing and supporting the table on which the matrix is arranged of the die

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Table material features Matrix support.

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Data of operation and characteristics of the press.

With this procedure you get a geometry corrected for the die that allows to obtain pieces, with a precision of tenths of a millimeter, without grinding manuals on the die.

In this way, by eliminating repeated and successive machining of the die, the time is greatly reduced and cost of obtaining them.

Description of the drawings

Figure 1 represents a flow chart corresponding to the different phases of the procedure.

Figure 2 represents the mesh of the set mechanical, before the application of efforts.

Figure 3 represents the mesh of the set mechanical, once the pressing force is applied, observing clearly the deformations suffered by the matrix and support table Of the same.

Figure 4 represents the deformation map of the matrix contact surface.

Preferred Embodiment of the Invention

In an application example, it starts from a 1200 ton press, with a 120 ton tread force and a force of drawing of 500 Tn.

A bench with dimensions of 5000x2500x650 mm and a die with a contact surface of maximum dimensions 1275x850 mm and an area of 0.84 m 2.

According to the method object of the invention, first of all you get the 3D CAD geometry, in solids, of all the elements that make up the mechanical assembly that is going to study, performing an automatic mesh.

Next, the conditions of contour, relative to the bench and the press, that is, the forces and reactions due to these elements, performing a assembly of the meshes of the elements of the mechanical assembly in which defines all the necessary boundary conditions, as supports, forces and contacts. This FEM model is represented in figure 2.

Next, the FEM model is introduced in a  calculation system that obtains the stresses and deformations of the mechanical assembly, considering that the piece to be obtained has a thickness 0. The deformations obtained are clearly observed in the figure 3.

From the results of the calculation the data related to the deformations provided on the face of contact between the die and the punch, that is, what we could denominate a deformation map on the contact surface, as depicted in figure 4.

With the formation map data and the theoretical geometry of the die and punch a geometry is obtained corrected for die contact surface.

These values that are obtained from the calculations, can be subsequently processed by a CAM system that we allows the manufacture of the die and the punch that constitutes the die with corrected dimensions that allows obtaining parts without requiring manual adjustments to the die

Claims (7)

1. Process of manufacturing dies that eliminates manual adjustments, characterized in that the design of the die is carried out taking into account the deformations suffered by the complete mechanical assembly defined by the die and the press, including the support bench. 2. Process for manufacturing dies, according to claim 1, characterized in that for the calculation of the deformations of the mechanical assembly it is assumed that the piece to be manufactured has a thickness 0, considering as if the die and the punch constituting the die were in contact during the entire drawing or forming operation. 3. Process of manufacturing dies, according to previous claims, characterized in that the calculation of the deformations of the mechanical assembly is carried out from the three-dimensional geometry in 3D CAD, solids, of all the elements of the mechanical assembly, that is, of the press , bench and die. 4. Process of manufacturing dies, according to previous claims, characterized in that for the calculation of the mechanical assembly simplified calculation hypotheses are used that allow eliminating any of the components of the mechanical assembly, replacing them with the effects thereof. 5. Process of manufacturing dies, according to claim 4, characterized in that the calculation is carried out taking into account the 3D geometry of the die and bed and the forces or effects of the punch, press and presses on them. 6. Process of manufacturing dies, according to claim 4, characterized in that the calculation is carried out taking into account the 3D geometry of the punch and press and the forces or effects exerted on them by the die and bed. 7. Process for manufacturing dies, according to claim 1, characterized in that it comprises the following operational phases:

to)

Obtaining theoretical data three-dimensional die matrix, including geometry of the internal and contour nerves of the matrix.

b)

Obtaining data from operation and characteristics of the press.

C)

Obtaining geometric data and  fixing and support of the bench on which the matrix.

d)

Obtaining the distribution of forces on the surface of the matrix.

and)

Mesh of the data obtained in the Sections a) and c).

F)

Obtaining a FEM Model with the meshing of section e) and the data of sections b) and d).

g)

Introduction of the FEM model of previous section in a calculation system using the method of the finite elements that get the tensions and deformations of the mechanical assembly, considering that the piece to be obtained has thickness 0.

h)

Obtaining deformation data of the matrix contact surface.

i)

Obtaining the corrected geometry for the contact surface of the matrix, based on the data theoretical for it and the deformation data obtained in section h).

j)

CAM manufacturing of a matrix and punch from the corrected geometries obtained in the section i).