BR102016030406A2 - hot stamping system for production of a set of parts - Google Patents

Abstract

The hot stamping system for producing a set of parts comprises the present invention to a hot stamping system of automotive parts to enable the production of the body parts ("body in white" and "moving parts") that form the body of a car in a single production plant (1) from blanks. This system consists of two by two equipment operating groups (2 and 3), namely: a group for fixed parts and a group for moving parts, each consisting of production units (4) which are supplied (5) by blanks previously cut individually to the required dimensions (5) and inspected (6) for entry into the stamping tool (die) in accordance with the shape and dimensions of the part to be made in the respective unit; being distributed (7) to both the fixed parts group and the moving parts group (3). each of the production units: a blank feed rack (8), two to three manipulation robots (9, 11 and 13), a joule heating device (10) , a press (12) with the tool (die) relative to the part to be stamped, and a storage rack (14).

Description

(54) Title: HOT STAMPING SYSTEM FOR THE PRODUCTION OF A SET OF PARTS (51) Int. Cl .: B21D 22/02; B21D 24/12 (73) Owner (s): AETHRA SISTEMAS AUTOMOTIVOS S / A (72) Inventor (s): PIETRO SPORTELLI (74) Attorney (s): SOARES ASSESSORIA EMPRESARIAL S / C LTDA.

(57) Abstract: HOT STAMPING SYSTEM FOR THE PRODUCTION OF A PARTS SET Comprises the present invention patent for a hot stamping system for automotive parts to enable the production of the parts set ("body in white" and? Moving parts?) that form the body of an automobile, in a single production plant (1), from sheets ("blanks"). Said system consisting of two by two groups (2 and 3) of operational equipment, namely: a group for fixed parts and a group for moving parts, each composed of production units (4) that are supplied (5) by blanks, previously individually cut to the required dimensions (5) and inspected (6), to enter the stamping tool (matrix) in compliance with the shape and dimensions of the part to be executed in the respective unit, being distributed (7) both to the group of fixed parts and to the group (3) of moving parts. Containing each of the production units: a plate feeding rack (8) ("blank"), two to three handling robots (9.11 and 13), a heating device (10) by effect? Joule? , a press (12) with af (...) \

1/7 “HOT STAMPING SYSTEM FOR THE PRODUCTION OF A SET OF PARTS”

001- Refers to the present invention patent, which concerns the manufacturing industry, particularly the automotive industry, to a hot stamping system for automotive parts that makes it possible to produce the set of parts (“body in white”, “ closures ”), which form the body of an automobile in a single production plant, thus reducing costs and labor.

002- The hot forming technique, especially in the automotive industry, has been successful in the manufacture of parts with complex shapes and greater mechanical resistance. This technique takes advantage of both the good conformability resulting from the highest deformation temperatures reached and the transformations that austenite undergoes during the cooling of the part. That is, promoted by the use of temperable plates with less thickness which contributes to reduce the weight of the vehicles, also decreasing the fuel consumption in automobiles.

003- The major problem to be solved or at least minimized in the process is the fact that the increase in the mechanical strength of steel impairs its stamping. However, after forty years of continuous metallurgical evolution led to the advent of the so-called advanced high strength steels (AHSS, “Advanced High Strength Steels”), which seek to reconcile the greater mechanical resistance of the plates with minimal losses in their conformability, but the search ceaseless for improvements means that the advances achieved so far, although spectacular, are not enough. This is because the stamping of “AHSS” steels, greatly improved, is still inadequate in many practical situations. The main problem is not

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2/7 exactly the conformability, but the so-called “spring effect” or elastic return (“springback”) that occurs after the stamping operations, and that is quite accentuated in the “AHSS” steel sheets. The sheet is shaped, but it is distorted immediately after leaving the die due to residual stresses. This distortion affects, to a greater or lesser degree, the dimensional accuracy of the part.

004- A solution to this problem is to disconnect the processing and application characteristics of the material. So, why not heat the plates before stamping? The scientific explanation for this procedure is that, under higher temperatures, the crystallographic plans for slipping disagreements are activated, making their migration easier.

005- The hot forming process is relatively simple. First, the blanks are cut from low carbon steel coils microalloyed with boron, then introduced into a continuous oven (40 to 60m long on average) for austenitization between 850 and 950 ° C, if making the steel surface protected against the rapid oxidation that occurs under these high temperatures. In this case, the most common alternative is to coat its surface with an AlSi layer, but eventually it is possible to dispense with this coating and use a protective atmosphere inside the oven.

006- After a warm-up period that can take four to ten minutes, the plate (“blank”) is sent to the stamping press, where it is formed. Where, also, the plate tempering immediately occurs, inside the water-cooled matrix. After a cooling period, which lasts between 15 and 25 seconds, the quench is complete, the burrs of the part are removed and it is extracted from the

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3/7 matrix at a temperature of approximately 150 ° C. The subsequent cooling of the part is done in contact with the air, with a tempering effect.

007- Hot stamping is not exactly a new process, as it was originally developed in Sweden in 1973, precisely in the year in which the first major challenges for the automobile industry arose, due to the uncontrolled increases in oil prices. However, its industrial application was restricted until the beginning of the new millennium, when its acceptance increased exponentially. Currently, hot stamping is basically used for the production of anti-intrusion components and structural reinforcements for passenger cars, whose characteristics, such as the relatively large size, the complex shape and high levels of mechanical resistance, make the use of AHSS steels difficult. cold stamped.

008- It is estimated that in 2004 this process consumed 60,000 to 80,000 tons of sheet metal in Europe alone. In 2008, just before the crisis, it was predicted that the process would consume the following year 300,000 t of plates in Europe alone, and that another 20 new hot stamping lines would be implemented in that continent.

009- The hot stamping process was also successful in the USA: in 2004, 33 versions of bumpers made by hot stamping were compiled in the country for various vehicle models in various manufacturers, such as “Volkswagen”, “General Motors”, ”Citroen”, “Ford” and “Smart”. The main steels used were SAE 10B21 and 15B21, in the form of “blanks” (sheets) with thicknesses between 1.50 and 3.50 mm. The average values of typical posthumous properties were: yield limit of 1,140 MPa; resistance limit

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4/7 of 1,520 MPa; total elongation of 12% and hardness of 479 HV. Currently 22Mn B5 steel is widely used.

010- In hot stamping, the most critical step in defining the mechanical properties of the finished part is tempering, which is usually done within the water-cooled die. Therefore, the chemical composition of the steel to be used is defined according to the final required mechanical properties, the thickness of the part and the cooling speeds obtained during tempering in the die, ensuring an adequate level of temperability.

011- The best alloy designs for steels intended for hot stamping adopt carbon contents of the order of 0.20% and relatively high manganese contents. Although the limits of cold forming of AHSS steels have not yet been reached, Currently, hot stamping is the only process route that allows the manufacture of components with complex shapes and high mechanical resistance. The austenitization of steel, in addition to facilitating the forming process due to the lower mechanical resistance and greater ductility of the material under processing, also allows to take advantage of the phenomena resulting from the subsequent metallurgical transformation to obtain profiles with mechanical properties that allow to reduce the weight of the parts improve your performance.

012- However, the use of large ovens (with an average length of 30 to 60m) and the high temperatures reached make the process and forming equipment more complex which implies high investments, high energy consumption to heat the part and loss of productivity caused by the time spent in the heat treatment stages.

013- The present patent in order to improve the production of

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5/7 stamped parts, used in the automotive industry, features a hot stamping system that allows stamping the entire set of parts ("body in white", "car body" or "closures") that form the body of a car in a single industrial plant. It is a production system that uses a hot stamping process (“hot forming”) and specific heating equipment by joule effect (whose patent applications were filed by the same owner at this institute). A stamping system that aims to reduce vehicle weight, optimizing energy efficiency, and increase vehicle safety given the possibility of using high mechanical strength steels

014- In this system the conventional oven is replaced by the heating equipment, promoting a significant reduction in the space occupation of the conventional installation area (from 1,800m ² to 300m2). As a result, the costly maintenance of the oven is eliminated, making it possible to intermittently stamp parts without the need for soaking, which is a high cost factor in the use of conventional ovens, especially in continuous production, as it is necessary to use high soaking temperatures; therefore, the energy consumption and deterioration of equipment used to heat the furnace atmosphere are higher.

015- The present system also allows, through the process mentioned above, the use of steel with hot-dip and electrolytic metallic coatings (Zn, ZnFe, ZnNi, among others produced in their respective coating processes), something that in the conventional process are steels with AlSi metallic layer coatings are used. In addition, the conventional process produces a superficial layer on the parts that provides the presence of micro

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6/7 cracks, minimized in the process used in the present system.

016- The hot stamping system for the production of a set of stamped parts, object of this patent, can be better understood by referring to the attached figures, which are part of this specification and contain numerical references together with the description of its technical particularities. . These figures, which do not restrict its configuration as to its dimensions, proportions and eventual types of finishes inserted, nor the scope of its practical application.

017- Figure 1 is a flowchart of the production process, showing the operational phases of production.

018- Figure 2 is an illustration of the production unit, showing the equipment involved in stamping.

019- According to these figures and their numerical references the object of this patent refers to a system of hot stamping (“hot forming”) for the production of the set of fixed and moving parts (“body in white”, “body car ”Or“ closures ”) that form the body of the automobile, stamped on a single production plant (1). This system, formed by two operational groups (2 and 3) of equipment, one group (2) for fixed parts and another group (3) for moving parts. Said groups (2 and 3) composed, each one, of production units (4) (in quantity necessary for the production of the set) that are supplied (5) by plates (“blanks”), previously cut, individually, in the dimensions required (5), after inspected (6), placed in conditions of entry in the stamping tool (matrix) in compliance with the shape and dimensions of the part to be executed in the respective production unit (4), being distributed (7) both to the group (2) of fixed parts as well as to the group (3) of moving parts.

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020- In groups (2 and 3), the production units (4), one for each specification of part to be produced, are composed of a feed rack (8) of plate (“blank”), two handling robots (9 and

11) and a stamping unit formed by a heating device (10) by "joule" effect and a press (12) with the tool (matrix) related to the part to be stamped. In them, the first robot (9) supplies the heating device (10) by removing the plate (“blank”) from the supply rack (8), placing it in the heating device (10). After the plate is heated, this robot (9) removes the heated part and feeds the tool over the press (12) for conformation and determined shape. Then the second robot (11) removes the shaped part from the press (12) and deposits it in a deposit rack (13).

021- The movement of both hot and cold parts can be carried out either by robotic arms or by dedicated “transfer” movement systems, designed specifically for the applications, and in the case of moving the hot part they are made of material that supports the temperature and radiation from the plate, without being damaged.

022- In the heating device (10) the heating takes place by the electric conduction process (heating by Joule effect), reaching heating rates of up to 400 ° C / sec. Its arrangement next to the press (12) occupies a little area larger than the part to be heated thus obtaining a greater use of the area used by each of the production units (4).

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Claims (7)

1) “HOT STAMPING SYSTEM FOR THE PRODUCTION OF A SET OF PARTS”, characterized by allowing the hot stamping of the set of fixed and moving parts (“body in white”, “body car” or “ closures ”), which form the body of the automobile, in a single industrial plant (1); said system formed by two groups (2 and 3) of operational equipment, one group (2) for fixed parts and another group (3) for moving parts; said groups (2 and 3) composed, each one, of production units (4) (in quantity necessary for the production of the set) that are supplied (5) by plates (“blanks”), previously cut, individually in the required dimensions (5); after being inspected (6), placed in conditions of entry in the stamping tool (matrix) in compliance with the shape and dimensions of the part to be executed in the respective production unit (4), distributed (7) both to the group (2 ) of fixed parts as well as to the group (3) of moving parts. 2) “HOT STAMPING SYSTEM FOR THE PRODUCTION OF A SET OF PARTS”, according to claim 1, characterized in that, in groups (2 and 3), the production units (4), are destined, each of them, the stamping of a type of part, according to its specifications and determined shape. 3) “HOT STAMPING SYSTEM FOR THE PRODUCTION OF A SET OF PIECES”, according to claim 1, characterized in that each of the production units (4) is composed of a blank feed rack (8) ”), Two manipulation robots (9 and 11) and a stamping unit formed by a heating device (10) by“ joule ”effect and a press (12) with the tool (matrix) related to the part to be stamped. Petition 870160078660, of 12/23/2016, p. 12/18 2/2 4) “HOT STAMPING SYSTEM FOR THE PRODUCTION OF A SET OF PARTS”, according to claims 1 and 3, characterized in that, in each production unit (4), after the first robot (9) removes the plate (“blank”) from the supply rack (8) and places it on the heating device (10) and then once the plate is heated, remove the heated part and feed the tool over the press (12) for forming and cooling through ice water, once the part is formed the second robot (11) removes the shaped part from the press (12) and deposit in a deposit rack (13). 5) “HOT STAMPING SYSTEM FOR THE PRODUCTION OF A SET OF PARTS”, according to claims 1 and 4, characterized in that the movement of the parts, both hot and cold, can be carried out by both robotic arms and by dedicated “transfer” movement systems, designed specifically for the applications; and in the case of moving the hot part, they are made of material that withstands the temperature and radiation from the plate, without being damaged. 6) "HOT STAMPING SYSTEM FOR THE PRODUCTION OF A SET OF PARTS", according to claim 1, characterized in that the heating equipment (10) is arranged next to the press (12) occupying an area slightly larger than the part to be be heated. 7) "HOT STAMPING SYSTEM FOR THE PRODUCTION OF A SET OF PIECES", according to claims 1 and 6, characterized in that the heating device (10) heats the plate by Joule effect; reaching heating rates of up to 400 ° C / sec. Petition 870160078660, of 12/23/2016, p. 13/18 1/2