Temperature measuring device for sheet metal

Abstract

Metal cutting (12), comprising: a metal sheet with a surface having at least one pair (80) of channels (70) defined therein, each channel (70) having a first section (72) extending from an edge (76) of the blank (12) and a second section (74) in an interior (78) of the blank (12); at least one pair (62) of thermocouple wires (64, 66), wherein one wire (64, 66) is attached to every second section (74); and the wires (64, 66) are welded to every second section (74); characterized by the fact that the second section (74) is wider than the first section (72); and the metal blank (12) comprises an adhesive material (90) arranged in every second section (74).

Description

TECHNICAL AREA

[0001] This disclosure relates to a temperature measuring device for sheet metal, for example, a metal stamping sheet. GENERAL STATE OF THE ART

[0002] Stamping of metal sheet (or sheet) is a common method for forming metal components. Metal stamping can involve arranging a sheet of a generally flat or planar metal, referred to as a blank, in a die set and closing the die set to form a component with a predetermined shape. In some stamping situations, the blank and / or dies may be at a temperature higher or lower than room temperature or ambient temperature. To improve the robustness and performance of the stamping process, it can be advantageous to be able to accurately measure the temperature of the blank during the stamping process.

[0003] From JP S61-296 229 A, JP S59-187 234 A, and CN 2 04 101 196 U, a metal blank comprising a metal sheet and a pair of thermocouple wires is known, wherein the thermocouple wires are fixed to the metal sheet by welding or clamping. German patent DE 24 00 563 A1 discloses a method for installing temperature sensors in metals. Conventionally, these are glued, soldered, or spot-welded into a blind hole. The method now provides that a metal material loosely surrounding the thermocouple is made to flow so that it conforms seamlessly to the shape of the thermocouple. Documents DE 28 46 740 A1, DE 43 19 019 A1, CN 101 303 320 A, CN 203 837 834 U and EP 0 195 726 A1 each disclose the gluing of thermocouples in grooves or recesses. SUMMARY

[0004] In at least one embodiment, a metal blank is provided comprising a metal sheet with a surface having at least one pair of defined channels. Each channel can have a first section extending from an edge of the blank and a second section within the interior. Each channel can also have at least one pair of thermocouple wires, with one wire attached to every second section. An adhesive material can be arranged in every second section.

[0005] The second section can be wider than the first section. In one embodiment, the first section of each channel can extend continuously into the second section of the channel, and the sections can meet at a transition area. The wires can be attached to each second section at one end of the second section opposite the first section. The wires can be welded to each second section and can contain a metal composite adhesive. A section of each wire can be secured in each first section. In one embodiment, each first section is deformed in at least one area to secure the wire. Each second section can have a length of 5 to 500 mm, a width of 0.5 to 10 mm, and a depth of 0.25 to 5 mm, and each first section can have a width of 0.25 to 3 mm and a depth of 0.25 to 5 mm.The distance between each pair of channels can range from 0.5 to 1000 mm. In one embodiment, the metal sheet is aluminum. Every second section can be substantially filled with the adhesive material. Every first section can be substantially free of adhesive material. In one embodiment, each wire extends from a fixing point in the second section of the channel through the first section of the channel and beyond the edge of the blank.

[0006] In at least one embodiment, a hot stamping system is provided. The system may include an oven, a coolable die set, and a metal blank. The metal blank may have at least two defined channels extending to an edge, each channel having a first section and a second section. A thermocouple wire may be attached in the second section of each channel and extend through the first section to the outside, past the edge. An adhesive material may be arranged in each second section. Each wire may be connected to a temperature measuring device.

[0007] The second section of each channel can be wider than the first section. The first and second sections can meet at a transition area, and the wires can be attached to each second section at one end of the second section opposite the transition area. In one embodiment, the wires are welded to each second section, and the adhesive material contains a metal composite adhesive. Each second section can have a length of 5 to 500 mm, a width of 0.5 to 10 mm, and a depth of 0.25 to 5 mm, and each first section can have a width of 0.25 to 3 mm and a depth of 0.25 to 5 mm.

[0008] In at least one embodiment, a method for producing a temperature-sensing metal blank is provided. The method may include forming at least one pair of channels in a surface of a metal sheet, each channel having a first section and a second section. The method may further include attaching a thermocouple wire in the second section of each channel, introducing an adhesive material into each second section, and securing at least one section of each wire in the first section of each channel.

[0009] The forming step can involve forming each channel with a first, narrower section and a second, wider section. Each second section can be formed within an interior of the metal sheet, and each first section can extend from an edge of the metal sheet and meet the second section at a transition area. The thermocouple wires can be attached to one end of the second section, opposite the transition area. In one embodiment, the attachment step involves welding the thermocouple wires into the second section of each channel, and the adhesive material in the insertion step comprises a metal composite adhesive. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a perspective view of a hot stamping system according to one embodiment; Fig. 2 is a perspective partial view of a stamp with a provisioning device according to an embodiment; Fig. Figure 3 is a perspective partial view of a section with channels formed therein according to one embodiment; Fig. Figure 4 is a top view of the cut from Fig. 3; Fig. Figure 5 is a perspective view of the crop from Fig. 3 with thermocouple wires attached to it, according to one embodiment; Fig. Figure 6 is a top view of the cut from Fig. 5 with an adhesive material arranged in the wide section of each channel, according to one embodiment; Fig. Figure 7 is a perspective view of a thermocouple wire secured in the narrow section of a channel, according to one embodiment; Fig. 8 a top view of a completed temperature-sensing blank, according to one embodiment; Fig. 9 a flowchart of a method for forming a temperature-sensitive blank, according to one embodiment; Fig. Figure 10 is a photograph of three sample cutting configurations that were used for testing purposes; Fig. Figure 11 is a photograph of a sample section with thermocouple wires welded to one end of each wide channel section; Fig. Figure 12 shows data from a central heating test of the three samples in Fig. 10; and Fig. Figure 13 shows data from a simulated solution annealing heat treatment and quenching test of the three samples in Fig. 10. DETAILED DESCRIPTION

[0010] The embodiments shown are disclosed with reference to the drawings. However, it must be understood that the disclosed embodiments are merely examples that can be implemented in various and alternative forms. The figures are not necessarily to scale, and some features may be exaggerated or minimized to illustrate details of certain components. The specific structural and functional details disclosed are not to be interpreted as limiting, but only as a representative basis for teaching a person skilled in the art how to implement the disclosed concepts.

[0011] Stamping of sheet metal is a common method for forming metal components, such as automotive parts. While automotive body parts have traditionally been made of mild steel, aluminum alloy body parts are gaining popularity in efforts to reduce vehicle weight. For example, a system and method for manufacturing components from high-strength aluminum are disclosed in jointly owned U.S. Patent 8,496,764 B2, the disclosure of which is incorporated herein by reference in its entirety. U.S. Patent 8,496,764 B2 generally describes a "hot stamping" process in which an aluminum alloy blank is heated and then stamped in a die set while still at an elevated temperature. The die set can be cooled, thus quenching the blank during its forming process.Hot stamping can be used to form components from 7xxx series aluminum-zinc alloys. 7xxx series aluminum alloys, when tempered to T6 or T7x, can exhibit strengths similar to those of high-strength or ultra-high-strength steels and can have yield strengths exceeding 400 MPa.

[0012] With reference to Fig. 1 and Fig. Figure 2 shows an example of a hot stamping system 10. The system 10 can include a heating device 14, a transmission mechanism 16, and a die set 18. In at least one embodiment, the blank 12 is an aluminum alloy blank 12 of an F-tempered finish from the 7xxx series. Aluminum alloys are identified by a four-digit number, the first digit generally identifying the main alloying element. For example, the main alloying element in 7xxx series aluminum is zinc, whereas the main alloying element in the 5xxx series is magnesium, and for the 6xxx series, it is magnesium and silicon. Further numbers, represented by the last "x" in the series designation, define the specific aluminum alloy.In one embodiment, a 7075 aluminum alloy can be used, which has a composition of 5.1-6.1% zinc, 2.1-2.9% magnesium, 1.2-2.0% copper and less than half a percent silicon, iron, manganese, titanium, chromium and other metals.

[0013] The heating device 14 can be provided for heating the blank 12. The heating device 14 can be an industrial furnace capable of generating internal temperatures high enough to heat blanks 12, arranged in the heating device 14, to a predetermined temperature, such as the solution or solidus temperature of the blank 12. In at least one embodiment, the heating device 14 cannot heat the blank 12 beyond its liquidus (melting) temperature. The solution temperature for a 7xxx series aluminum alloy can be approximately 460°C to 490°C.

[0014] The transfer mechanism 16 can be configured to move and position the blank 12. In at least one embodiment, the transfer mechanism 16 can be a manipulator such as a robot. The transfer mechanism 16 can be configured to quickly transfer the blank 12 from the heating device 14 to the punch set 18 to reduce the possibility of heat loss from the blank 12. For example, the system 10 and the transfer mechanism 16 can be configured such that the temperature of the blank 12 does not fall to or below its critical quenching temperature. The critical quenching temperature is the temperature at which quenching must begin to achieve adequate quenching of the material. For example, the critical quenching temperature for most 7xxx series aluminum alloys is approximately 400 °C.

[0015] The punch set 18 can be configured to form the blank 12 into a part having a predetermined shape. In at least one embodiment, the punch set 18 can comprise a first punch 20, a second punch 22, at least one actuator 24, and a delivery device 26. The first and / or the second punch 20, 22 can be configured to form the blank 12 into the part having a predetermined shape. An actuator 24 can actuate the first punch 20 and / or the second punch 22 toward or away from each other and provide force for forming the blank 12. The actuator 24 can be of any suitable type, such as hydraulic, pneumatic, mechanical, electromechanical, or a combination thereof. The combination of the punch set 18 and the actuator 24 can also be referred to as a machining press, stamping press, or quenching press.

[0016] A positioning device 26 can be provided for positioning the blank 12 between and spaced apart from the first and second punches 20, 22. Accordingly, the positioning device 26 can inhibit conductive heat transfer between the blank 12 and the punch assembly 18, thus helping to maintain the blank 12 at or above its critical quenching temperature. The positioning device 26 can pick up the blank 12 from the transfer mechanism 16 and release the blank 12 when the first punch 20 and / or the second punch 22 close and engage the blank 12. Furthermore, the system 10 can be configured such that minimal heat loss occurs from the blank 12 between its removal from the heating device 14 and the closing of the punch assembly 18.In at least one embodiment, the temperature of the blank 12 can decrease by less than 10 °C; however, the blank 12 can undergo a greater temperature loss of up to 90 °C if the blank 12 is heated to 490 °C and the critical quenching temperature is 400 °C.

[0017] The die set 18 can include pipes 28 that allow cooling of the first and / or second die 20, 22 and quenching of the part formed from the blank 12. The pipes 28 can be cavities or channels formed within the die set 18, or any combination of externally connected pipes and channels. The pipes 28 can be connected to a cooling source and can carry a heat transfer medium, such as a fluid, from the cooling source to cool the die set 18 to a desired temperature. The heat transfer medium can be any fluid capable of cooling the die set 18 to a predetermined temperature range, such as from 1 °C to 30 °C. The die set 18 can be cooled in a manner that prevents the formation of condensation on one or more surfaces of the die set 18.In a mass production environment, the temperature of the die set 18 can be cooled to the predetermined temperature range before a blank 12 is formed and quenched to remove heat that may have been transferred from a blank 12 to the die set 18 during the forming of a previous part.

[0018] The forming of the heated blank 12 into a part can take place simultaneously with the quenching of the part. The quenching rate influences the final temper strength and corrosion resistance of the material. In some embodiments, the quenching rate for the aluminum alloy, as it transitions from 400 °C to 290 °C, can be equal to or greater than 150 °C / second. The part can be further cooled to a final temperature of 200 °C to 25 °C before removal from the die set 18 to ensure dimensional stability during subsequent processing.

[0019] The system 10 can be designed to operate continuously with a number of blanks 12, which are heated in series or in parallel by one or more heating devices 14, and then transferred to at least one set of punches 18 for forming and quenching. At least one set of punches can become hotter than 30 °C during or after the forming of the blank 12 and / or simultaneous quenching of the part, which is why more than one set of punches 18 can be used to provide faster production speeds. The part can be removed from the punch set 18 by the transfer mechanism 16, another conveying device, or manually. The part is then fed to further processing, which may include flange fitting, trimming, and natural and / or artificial aging to bring the aluminum alloy part to a high-strength temper such as T6 or T7x.

[0020] With reference to Fig. Figure 2 shows an embodiment of a delivery device 26 in more detail. One or more delivery devices 26 can be provided with the punch set 18. For example, in one or more embodiments, a delivery device 26 can be provided near a corner or side of a punch 20, 22. A delivery device 26 can be arranged or configured such that it does not affect the actuation or closing of the punch set 18. In addition, the delivery device 26 can contribute to insulation or can be provided with materials that inhibit heat transfer from the blank 12 to a punch. The delivery device 26 can have a base 40, a support element 42, a finger 44, and an actuator 46.

[0021] The base 40 can be arranged on the punch set 18 and allow for the attachment of the supply device 26. The support element 42 can extend from the base 40 and be fixedly arranged on it. The support element 42 can have a slot 50. The slot 50 can be configured to accommodate and accommodate rotation of the finger 44. The finger 44 can be pivotally arranged on the support element 42. For example, in one or more embodiments, a pivot pin can rotatably couple the finger 44 to the support element 42. The finger 44 can rotate between a first position and a second position. In the first position, the finger 44 can extend away from the support element 42 and support the blank 12. The finger 44 can move relative to the support element 42 and toward or into the slot 50 to a second position (as indicated by the arrows in the figure). Fig. 2 shown) to rotate to allow the blank 12 to detach from the supply device 26 and fall onto a punch such as the second punch 22.

[0022] The actuator 46 can be located near the delivery device 26 and can be used to provide position control of the finger 44. For example, in some embodiments, the actuator 46 can be an electric motor connected to the pivot pin, which rotates the finger 44 from the first position to the second position when force is applied, with a spring 52 returning the finger 44 from the second position back to the first position when the force is removed. The actuator 46 can be controlled by an automated control system or by an operator. The actuator 46 can also be a servomechanism that uses electrical, hydraulic, pneumatic, magnetic, or mechanical principles, or any combination thereof, to provide position control of the finger 44.

[0023] During the hot stamping process, it can be important to accurately measure the temperature of the blank 12 during the heat treatment step (e.g., solution annealing) and / or during the cooling or quenching step. In the example of a 7xxx series aluminum alloy, the heat treatment generally requires heating the blank 12 to a temperature of 460 °C to 490 °C to properly solution anneal the aluminum. Afterward, the blank 12 can be quenched over a specific temperature range, such as 400 °C to 290 °C, at a specific quenching rate, such as at least 150 °C / second. The part can then be further cooled to a final temperature of, for example, 200 °C to 25 °C before removal from the die set 18. Accordingly, there are several stages in the hot stamping process in which temperature is a critical processing parameter.Temperature accuracy within ±3 °C may be required to produce a component with the desired / intended properties. Temperatures outside the specified values ​​(e.g., deviations of 10, 15, 20 degrees or more) may be unacceptable for some processes. Furthermore, the blank 12 may be relatively large (e.g., more than one foot long and / or wide), which, depending on the blank geometry, the oven 14's ability to heat the blank 12 uniformly, or other factors, can lead to temperature fluctuations within the blank.

[0024] With reference to Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. Figure 8 shows embodiments of a blank 12 that incorporates a temperature measuring device 60 (e.g., a temperature-sensing blank). The device 60 can be integrated into the blank 12 to calibrate, test, or otherwise evaluate or improve the performance of an embossing system such as the system 10. Although the device 60 is described with reference to a hot stamping system 10 for stamping aluminum metal sheet, the device 60 can be used with any embossing system and any type of metal sheet. For example, the device 60 can be used with aluminum, steel, titanium, or other metal sheets. The device 60 can also be used in other stamping processes, heat treatment processes, quenching processes, or any other processes where measuring the temperature of a metal sheet is advantageous or important.

[0025] The device 60 can have one or more pairs 62 of thermocouple (TC) wires 64, 66. Thermocouples are generally formed from two different conductive materials (e.g., wires made of metals or metal compounds). Thermocouple wires can be used as part of a thermocouple to measure the temperature of the workpiece 12. A thermocouple is a temperature-measuring device that has two dissimilar conductors that are in contact with each other or are physically / electrically connected at one or more points where the different conductors (or semiconductors) are subject to a temperature difference. If the conductors do not physically touch but are connected by an intermediate material and are electrically connected, the thermocouple can be said to have a separate junction.In general, a separated junction does not affect the performance of the thermocouple, provided the temperature at both junction points is the same. The thermocouple can generate a voltage if the temperature at one of the junctions differs from the reference temperature at other parts of the circuit. The wires 64, 66 can be connected at one end to a voltmeter (not shown) to measure the voltage generated by the wires 64, 66. The voltmeter, or electronics coupled to the voltmeter, can then determine the temperature at the tips 68 of the wires 64, 66 that are in contact with or near the area of ​​the section 12 to be measured. The thermocouple wires can be made of any suitable material, for example, those used in nickel alloy thermocouples (e.g., types E, J, K, M, N, or T), platinum / rhodium alloy thermocouples (e.g.,Types B, R or S), thermocouples made of tungsten / rhenium alloy (e.g. types C, D or G) or other known in the prior art (e.g. chromel-gold / iron alloys, type P, Pt / Mo, Ir / Rh, precious metal alloys) are used.

[0026] With reference to Fig. 3 to Fig. Figure 4 shows a blank 12 with channels 70 defined therein. The number of channels 70 can correspond to the number of TC wires 64, 66 to be attached to the blank 12. For example, if the device 60 has one pair 62 TC wires 64, 66, there can be two channels 70. If the device 60 has three pairs 62 TC wires 64, 66, then there can be six channels 70. Each channel 70 can have a first, narrow section 72 and a second, wide section 74. The terms "narrow" and "wide" can be relative, such that the wide section 74 has a greater width than the corresponding narrow section 72 for each channel 70. In one embodiment, the channels 70 can extend from an edge 76 of the blank 12 to an interior space 78 of the blank 12.For example, for a rectangular cutout 12 there may be four edges 76 and the channel 70 may extend from an edge 76 to an interior 78 of the cutout 12.

[0027] In at least one embodiment, the narrow section 72 of the channel 70 can extend from the edge 76 of the blank 12, and the wide section 74 can be located within the interior 78 of the blank 12. In one embodiment, the wide sections 74 of each channel 70 in the blank can have the same width and / or length. In other embodiments, the channels 70 can be configured as one or more pairs 80 of channels, the pairs 80 corresponding to a pair 62 of TC wires 64, 66. In this embodiment, the wide sections 74 of each channel 70 in each pair 80 can have the same width and / or length, and the narrow sections 72 of each channel 70 in each pair 80 can have the same width and / or length.

[0028] There can be a plurality of pairs 80 of channels 70 defined in the blank 12. In one embodiment, there can be a pair 80 of channels 70 located at the center of the blank 12 and near or adjacent to two opposite edges 76 of the blank 12. For example, for a rectangular blank 12, there can be a pair 80 of channels 70 on the left edge, in the center, and on the right edge of the blank 12. Alternatively, there can be a pair 80 of channels 70 on the top edge, in the center, and on the bottom edge of the blank 12. The number of pairs 80 is not limited to one or three, and any suitable number of pairs 80 of channels 70 defined in the blank 12 can be present, such as 2, 4, 5, 6, or more. In one embodiment, several pairs 80 can be present, spaced apart by a dimension (e.g. length L1 or width) of the blank 12.The pairs 80 can be spaced evenly or unevenly across the cutout 12. In one embodiment, all pairs 80 of channels 70 are aligned parallel to each other. For example, the channels 70 can all extend in one direction from an upper edge to a lower edge or from a right edge to a left edge.

[0029] In one embodiment, the length (L1) of the wide section 74 of the channel 70 can be from 5 to 500 mm or within a partial range therefrom. For example, the length L1 of the wide section 74 can be 10 to 250 mm, 25 to 250 mm, 25 to 150 mm, 10 to 100 mm, 25 to 75 mm, 40 to 60 mm, or approximately 50 mm (e.g., ± 5 mm). Although lengths within these ranges may be advantageous for securing a TC wire 64, 66 (described in more detail below), the length L1 of the wide section 74 can be less than or greater than these ranges. In one embodiment, the width (W1) of the wide section 74 of the channel 70 can be from 0.5 to 10 mm or within a partial range therefrom. For example, the width of the wide section 74 can be 1 to 8 mm, 1 to 6 mm, 1 to 5 mm, 2 to 5 mm, 1 to 4 mm, 2 to 4 mm or about 3 mm (e.g. ± 0.5 mm).Although widths within these ranges may be advantageous for securing a TC wire 64, 66 (described in more detail below), the width of the wide section 74 may be smaller than or larger than these ranges. In one embodiment, the depth (D1) of the wide section 74 of the channel 70 may be from 0.25 to 5 mm or within a partial range therefrom. For example, the depth D1 of the wide section 74 may be 0.5 to 3 mm, 0.5 to 2 mm, 0.5 to 1.5 mm, 0.75 to 1.5 mm, 0.75 to 1.25 mm, or approximately 1 mm (e.g., ± 0.1 mm). In other words, the depth D1 of the wide section 74 may be from 5% to 95% of the thickness of the blank 12 or within a partial range therefrom. For example, the depth D1 can be 10 to 90%, 20 to 80% or 25 to 75% of the thickness of the cut 12, or lie within other sub-ranges.Although depths D1 within these ranges may be advantageous for securing a TC wire 64, 66 (described in more detail below), the depth D1 of the wide section 74 may be less than or greater than these ranges. In one embodiment, the spacing between the wide sections 74 in a pair 80 of channels may be from 0.5 to 1000 mm or within a partial range therein. For example, the spacing may be 1 to 500 mm, 1 to 250 mm, 1 to 100 mm, 5 to 75 mm, 5 to 50 mm, 10 to 45 mm, 15 to 40 mm, 20 to 35 mm, 20 to 30 mm, or approximately 25 mm (e.g., ± 3 mm). The spacing may be determined from a centerline of the channels 70.

[0030] In one embodiment, the width (W2) of the narrow section 72 of the channel 70 can be from 0.25 to 3 mm or within a partial range therefrom. For example, the width of the narrow section 72 can be 0.3 to 1.5 mm, 0.3 to 1.25 mm, 0.3 to 1 mm, 0.4 to 1 mm, 0.4 to 0.8 mm, 0.5 to 0.7 mm, or approximately 0.6 mm (e.g., ± 0.1 mm). The width of the narrow section 72 can also be determined based on the size or diameter of a TC wire 64, 66 to be inserted therein. In one embodiment, the narrow section 72 can have a width that is slightly larger (e.g., about 0.1 mm) than the diameter of the TC wire 64, 66. In another embodiment, the width of the narrow section 72 can be 1.05 to 1.3 times the diameter of the TC wire 64, 66, or lie within a partial range thereof.For example, the narrow section 72 can be 1.1 to 1.25 times, 1.15 to 1.2 times, or approximately 1.18 times (e.g., ± 0.02) the diameter of the TC wire 64, 66. In one embodiment, the diameter of the TC wire 64, 66 is measured with the casing. In another embodiment, the diameter of the TC wire 64, 66 is measured without the casing (e.g., bare wire 64, 66). Although widths within these ranges may be advantageous for securing a TC wire 64, 66 (described in more detail below), the width of the narrow section 72 can be smaller or larger than these ranges.

[0031] The length L1 of the narrow section 72 of the channel 70 can vary based on the size of the blank 12 in which it is formed and / or the position of the wide section 74 within the blank 12. Generally, the wide section 74 can have a length L1 as described above, regardless of the size of the blank 12. The narrow section 72 can extend from the wide section 74 to an edge 76 of the blank 12. Therefore, the length L1 of the narrow section 72 can increase or decrease depending on the size of the blank 12 and / or the position of the wide section 74. If the blank 12 is very large and / or if the wide section 74 is centered within the blank 12, then the narrow section 72 can be relatively long, whereas if the blank 12 is small and / or the wide section 74 is located close to an edge 76 of the blank 12, the narrow section 72 can be relatively short.Accordingly, the narrow section 72 can have any suitable length L1 connecting the wide section 74 of the channel 70 to an edge 76 of the blank 12. The depth (D2) of the narrow section 72 of the channel 70 can be within the same values ​​as those described above for the wide section 74. In one embodiment, the narrow section 72 and the wide section 74 can have the same depth. However, in another embodiment, the narrow section 72 and the wide section 74 can have different depths. The depths of the sections 72 and / or 74 can also vary along their lengths L1—either in absolute terms or as a percentage of the thickness of the blank 12.For example, cut 12 may have a non-uniform thickness, which means that if sections 72 and / or 74 have a uniform depth, then the depth as a percentage of the cut thickness cannot be uniform. However, if sections 72 and / or 74 maintain a constant depth as a percentage of the cut thickness, then the absolute depths of the sections cannot be uniform.

[0032] The channels 70 and the narrow sections 72 and wide sections 74 thereof can be formed in the blank 12 by any suitable method. In one embodiment, the channel 70 can be machined into the blank 12. For example, the channel 70 can be formed by milling, engraving, or grinding. The channels 70 can be formed manually or automatically, such as by computer numerical control (CNC). Other methods known in the prior art for machining a groove or channel 70 can also be used, such as cutting or chiseling (e.g., manually or mechanically). Methods other than machining can also be used to form the channel 70. For example, the channel 70 can be formed in the blank 12 as part of the blank forming process, such as by embossing, casting, or molding.Channel 70 can be formed by electrical discharge machining (EDM). EDM generally involves creating an electrode with a faceted shape corresponding to channel 70 and then burning the channel 70 to a desired depth D1. Channels 70 can have a transverse cross-section (e.g., perpendicular to a longitudinal axis) that is rectangular in shape. In a top view (such as in . Fig. (as shown in Figure 4), the wide section 74 may have rounded ends, but the ends may also be essentially flat or have other configurations. One end 82 may be adjacent to the narrow section 72, so that a transition area or region 86 exists between the wide section 74 and the narrow section 72. The other end 84 may be opposite the end 82, and the transition area 86 opposite the narrow section 72.

[0033] With reference to Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. Figure 8 shows embodiments of a blank 12 having a temperature measuring device 60 attached to it, depicted in various forming stages. Although the device 60 is shown and described with a pair 62 of TC wires 64, 66 secured in a pair 80 of channels 70, it is understood that by repeating the disclosed steps, several pairs 62 of wires 64, 66 can be secured in several channels. For example, three pairs 62 of TC wires 64, 66 and three pairs 80 of channels 70 can be present, with one pair arranged in the center and on opposite sides of the blank 12.

[0034] The TC wires 64 and 66 can each have tips 68 at one end. In one embodiment, the tips 68 of each wire 64, 66 can be attached to the blank 12 in a channel 70 at a fastening point 88. A pair 62 of TC wires can be attached to a pair 80 of channels 70 (e.g., one wire 64, 66 in each channel 70). In one embodiment, each tip 68 can be attached to, near, or adjacent to the end 84 of the channel 70 opposite the narrow section 72. The tips 68 can be attached to the channels 70 with an electrically and thermally conductive connection to form a separate junction. In one embodiment, the tips 68 are welded to the channels 70. However, other fastening methods can be used, such as an electrically conductive adhesive, brazing, soldering (for applications at relatively low temperatures) or other methods known in the prior art.For example, the tips 68 can be fastened by means of fasteners such as screws or bolts. Alternatively, the tips 68 can be secured in a second narrow section 72 extending from an opposite side of the first narrow section 72 in a manner similar to that described below (e.g., in paragraph 0054). The tips 68 of the TC wires 64, 66 can be fastened such that a portion of each wire 64, 66 extends to the end 82 adjacent to the narrow section 72. Accordingly, a portion of each wire 64, 66 can extend within the wide section 74 of the channel 70 between the end 84 and the transition area 86 (as, e.g., in paragraph 0054). Fig. 5 shown). Although a single attachment point 88 has been described, the tips 68 on the channels 70 can be attached at a plurality of attachment points 88 or by a continuous attachment segment.

[0035] After the TC wires 64, 66 have been attached to the blank 12 in the wide sections 74 of the channels 70, the wires can be further secured in the wide sections 74 by an adhesive or bonding material 90. The adhesive material 90 can be introduced into the wide section 74 of each channel 70 to secure the sections of wires 64, 66 located in the wide section 74 to the blank 12. The adhesive material 90 can be any suitable material that bonds, adheres to, or is attached to the materials that the wires 64, 66 and the blank 12 (e.g., metals) form. The adhesive material 90 can be selected according to the temperatures, forces, or other conditions to which the blank 12 is subjected during use.For example, an adhesive material 90 for an aluminum hot stamping process (as described above) must be able to withstand temperatures of 490 °C without melting, burning, cracking, or other failure. The adhesive material 90 must also be able to withstand the forces of the die set 18 and / or rapid quenching to the temperature of the die set 18 (e.g., approximately 1 to 30 °C).

[0036] In one embodiment, the adhesive material 90 contains a composite adhesive. The composite adhesive can be a metal-based or metallic composite adhesive. In one embodiment, the metal composite adhesive can contain a metal or metal alloy and a refractory oxide. The metal or metal alloy can contain aluminum (or Al alloy), nickel (or Ni alloy), or steel (e.g., stainless steel such as 316). The metal composite can be a multi-component adhesive containing, for example, a base and a binder. The base can contain the metal / metal alloy and a refractory oxide, and the binder can contain water and one or more of aluminum oxide, phosphate, silicon dioxide, and a silicate. Suitable examples of a metal composite adhesive include those provided by Cotronics under the name Durabond™. For example, Durabond™ 950, 952, and 954, which are based on aluminum, nickel, and 954, respectively.stainless steel based. Further information regarding Durabond™ adhesives can be found in the Safety Data Sheet (SDS), revised October 2004, the disclosure of which is hereby incorporated in its entirety by reference.

[0037] After application, the adhesive material 90 can completely or substantially fill (e.g., fill at least 95%) the wide section 74 of the channel 70. The adhesive material 90 can be flush with or slightly below an upper surface 92 of the blank 12. This can avoid or reduce a direct effect of the adhesive material 90 during a subsequent embossing process. The adhesive material 90 (e.g., a metal composite adhesive) can be applied as a liquid or a paste and then cured or dried to exhibit the above properties. The adhesive material 90 can dry or cure over time at room temperature, or heat or a curing agent / additive can be applied to accelerate the drying / curing time. In at least one embodiment, the narrow section 72 of the channel 70 may not contain any adhesive material 90 or may contain substantially no adhesive material 90 (e.g.,less than 1% of the volume of the narrow section).

[0038] The adhesive material 90 (e.g., a metal composite adhesive) can provide additional adhesion between the wires 64, 66 and the blank 12 in the wide section 74. This additional adhesion can ensure that the tips 68 of the wires 64, 66 remain in (physical and electrical) contact with the blank 12. Electrical contact of the wires with the blank may be necessary for the thermocouple to function properly, and physical contact may be necessary so that heat is effectively transferred from the blank to the wires. In one embodiment, the tips 68 of the wires 64, 66 are welded together in the wide section 74 of the channel 70, and a metal composite adhesive is introduced to fill the remaining space in the wide section 74 of the channel 70 and secure the wires in the wide section of the channel 70.Welding the wires 64, 66 to the channel 70 can provide very good electrical and physical contact between the wires and the blank 12. However, the weld may be relatively weak and / or brittle and may not withstand the temperatures or forces exerted during a hot stamping process and / or handling. Accordingly, the welding alone may be insufficient to maintain contact between the wires 64, 66 and the channel 70. The metal composite adhesive (or other adhesive material) provides additional security and adhesion between the blank 12 and the wires 64, 66. Since the tips 68 are welded into the channel 70, the adhesive can be electrically and thermally insulating, as the welds provide conductivity (thermal and electrical) between the blank 12 and the wires 64, 66.

[0039] After the adhesive material 90 has dried or cured, a section 94 of each of the wires 64, 66, extending away from the transition area 86 and to an edge 76 of the blank 12, can be secured in the narrow section 72 of each channel 70. As described above, the narrow section 72 can have a width W2 that is slightly larger than a size or diameter of the wires 64, 66. The TC wires 64, 66 can have varying diameters depending on the application. In one embodiment, the TC wires 64, 66 can have a diameter (e.g., outside diameter) of 0.2 to 2 mm or within any partial range thereto. For example, the wires 64, 66 can have a diameter of 0.3 to 1.5 mm, 0.3 to 1 mm, 0.3 to 0.8 mm, 0.4 to 0.7 mm, 0.4 to 0.6 mm or about 0.5 mm (e.g. ± 0.05 mm).

[0040] The sections 94 of the wires 64, 66 can be secured in the narrow sections 72 by any suitable method. In one embodiment, the narrow section 72 of the channel 70 can be crimped at one or more positions, such that the channel 70 is deformed to secure or lock the wire 64, 66. An example of a crimping method is chiseling or spot chiseling the narrow section 72 of the channel 70 at one or more positions. During the chiseling process, a chisel tip can strike the channel 70 while in contact with it, causing the walls of the channel 70 to deform and securing the wire 64, 66 therein. Each wire 64, 66 can be spot chiseled at several positions 96 along a length of the narrow section 72 of the channel 70 to secure the wire 64, 66 in the channel 70.Securing wires 64 and 66 within channel 70 prevents them from being directly struck during processes such as stamping. If a thin wire 64 or 66 is exposed during a stamping process, it is likely to be crushed, severed, broken, or otherwise damaged, causing the thermocouple to stop working. Furthermore, this would interfere with the stamping and quenching process and could leave a mark on the stamp surface.

[0041] The sections 94 of the wires 64, 66 secured in the narrow sections 72 can be bare wire 64, 66 or can have a housing / coating 98. Bare wire 64, 66 can refer to the fact that the wire 64, 66 has no insulating coating or housing 98 on it, so that the wire 64, 66 is purely metal. In some embodiments, the sections 94 of the wires 64, 66 can have a housing 98 or coating 98 surrounding the metal wire. The housing 98 can surround the wire 64, 66 along the entire length of the narrow section 72. The housing 98 can terminate at or near the transition region 86, so that it does not extend substantially into the wide section 74. In another embodiment, the housing 98 can extend into the wide section 74, for example to just in front of the tip 68 (to allow electrical and thermal conductivity).The housing 98 can be made of any suitable material that is electrically insulating and can withstand the temperatures at which the thermocouple is used. Examples of suitable housing materials include glass or silicon dioxide braiding or wrapping, ceramic fibers or wrapping, cotton braiding, or a polymer (e.g., polyvinyl, nylon, PVC). For the relatively high temperatures of hot stamping, a glass- or ceramic-based housing 98 can be used. Enclosing the wires 64, 66 in a housing 98 can provide insulation and / or protection of the wires from contact with materials or components that are not intended to be measured by the thermocouple. For example, in system 10, the blank 12 can rest between dies 20 and 22 in a die set 18 prior to the stamping process. The blank 12 can be held by one or more staging devices 26.Accordingly, the exposed sections of wires 64, 66 (e.g., not covered by the adhesive material 90 or insulation) can (intentionally or unintentionally) make contact with other materials or components during the measurement process. The housing 98 can prevent the temperature of these other components from affecting the measurements and can electrically insulate wires 64, 66 from the components. The use of bare wire 64, 66 in the narrow section 72 can allow electrical contact with the blank 12, which could enable current flow through a shorter circuit, thus shifting the temperature sensing / measuring position of the thermocouple. In embodiments where this may be undesirable, housingd thermocouple wires can be used in the narrow section of the channel 70.

[0042] The wires 64, 66 can extend from the narrow section 72 and finally be connected to a voltmeter (not shown) or other electronics known to the average person skilled in the art for providing the reference junction and determining the voltage between the TC wires 64, 66 (e.g., the wires can be connected to a temperature sensing device). The voltmeter or other electronics can determine a temperature of the blank 12 in the area containing the tips 68 of the wire pair 62. As described above, several wire pairs 62 can be present, secured in pairs 80 of channels 70 in the blank 12. Accordingly, multiple temperature readings can be generated at different locations in the blank 12. These temperature readings can be used to monitor the performance of a blank forming process (e.g.,to calibrate, analyze, evaluate, or otherwise test / improve processes such as heat treatment, embossing, quenching, hot stamping, or others. For example, the blank 12, which incorporates the device 60, can be used to calibrate or analyze the performance of a hot stamping process such as the one described above. The temperature readings can be used to ensure that an aluminum blank is solution annealed at the correct temperature and that the entire blank is solution annealed properly. The readings can also be used to ensure that, during the quenching of the aluminum blank in the stamping process, the entire blank is cooled at the correct rate and to the correct temperature.

[0043] Accordingly, a cutout 12 with 70 channels defined therein is provided. The channels can accommodate thermocouple wires 64, 66 (one per channel 70). Each channel 70 can have a narrow section 72 and a wide section 74 with a transition area 86, where the two sections meet (e.g., the sections can run continuously towards each other). The wide section 74 can be located in an interior space 78 of the blank 12 (e.g., spaced from the edges), and the narrow section 72 can extend from the transition area 86 to an edge 76 of the blank 12. The tips 68 of each wire 64 / 66 can be attached or fixed to the blank 12 within the wide section 74 of the channel 70, for example, by welding. The tips 68 can be attached to an end of the wide section 74 opposite the transition area 86 and the narrow section 72.An adhesive material 90, such as a metal composite adhesive, can then be introduced into the wide section 74 to fill or substantially seal it. The adhesive material 90 further secures the wire 64 / 66 in the wide section 74 to complement the initial fastening (e.g., weld). The section 74 of the wire 64, 66 extending from the wide section 74 can be inserted into the narrow section 72 of the channel 70 and out into the edge 76. The wire 64, 66 can be secured in the narrow section 72, for example, by crimping the channel 70 (e.g., spot chiseling). The section 74 of the wire 64, 66 extending beyond the edge 76 can then extend to a voltmeter or other electronics to determine the temperature of the blank 12 near the fastening point 88.

[0044] A flowchart 100, which is in Fig. Figure 9 discloses an embodiment for forming the blank 12 with an integrated temperature sensing device 60. In step 102, channels 70 are formed in the blank 12. The channels 70 can be formed in pairs 80, with one or more pairs 80 of channels 70 being present. The channels 70 can have a narrow section 72 and a wide section 74, the narrow section 72 extending from an edge of the blank 12 to an interior of the blank 12 and terminating in a transition region 86. The wide section 74 can extend from the transition region 86 at one end to an opposite end. The channels 70 can be formed by any suitable method, such as machining.

[0045] In step 104, a thermocouple (TC) wire 64, 66 can be attached to each channel 70. The wires 64, 66 can be attached to the opposite ends of the wide sections 74 of the channels 70. The wires 64, 66 can be attached by means of any suitable electrically and thermally conductive connection. In one embodiment, the wires 64, 66 can be welded to the channels 70. The wires 64, 66 can extend from the opposite end and through the transition area 86 within the wide section 74 of the channel 70.

[0046] In step 106, an adhesive material 90 can be introduced into the wide sections 74 of the channels 70. The adhesive material 90 can fill or substantially fill the wide sections 74 of the channels 70. After drying or curing, the adhesive material 90 can be flush with an upper surface of the blank 12 or it can have an upper surface that is below the upper surface of the blank 12. The narrow sections 72 of the channels 70 can be free or substantially free of the adhesive material 90 (e.g., filled to less than 1%). In one embodiment, the adhesive material 90 can be a metal composite adhesive.

[0047] In step 108, the sections 74 of the wires 64, 66, extending from the wide sections 74 of the channels 70, can be inserted into the narrow sections 72 of the channel 70. In step 110, the wires 64, 66 can be secured in the narrow sections 72 of the channels 70. The wires 64, 66 can be secured by deforming the channels 70 so that the wires 64, 66 are held in the channels 70. In one embodiment, the channels 70 can be deformed by chiseling (e.g., spot chiseling) several points along the narrow section 72 of each channel 70. After step 110, the blank 12 is formed with a temperature sensing device 60.

[0048] In step 112, the blank 12, equipped with an integrated temperature sensing device 60, can be used to perform a calibration, inspection, or other analytical process. The blank 12 can be used in a heat treatment, quenching, stamping, or any other process where the temperature of the blank 12 is important. In one embodiment, the blank 12 can be used in a hot stamping process, wherein the blank 12 is heated and inserted into a cooled stamping die and stamped. The hot stamping process can be suitable for an aluminum blank, wherein the blank 12 is heated to a solution annealing temperature and then stamped in a cooled die set to form the blank 12, and subsequently quenched.

[0049] Although the channels 70 have been described as having a wide section 74 and a narrow section 72, the blank 12 can also be formed with channels 70 having a uniform or substantially uniform width. The channels 70 can extend from an edge 76 of the blank 12 to an interior 78 of the blank 12. The tips 68 of the wires 64 / 66 can be attached to one end of each channel 70, for example, by welding, similar to the above. In one embodiment, the adhesive material 90 can be applied / introduced into the entire channel 70 from the edge 76 to the attachment point 88. In this embodiment, the amount of adhesive material 90 used is increased compared to the embodiments with a wide section 74 and a narrow section 72.In another embodiment, the adhesive material 90 can be applied to / introduced into a second section 74, wherein a first section 72 is substantially free of adhesive material 90. This is similar to the embodiments described above, except that sections 72 and 74 have the same or substantially the same width. Applying the adhesive material 90 may be more difficult, costly, and / or time-consuming than securing a wire 64, 66 in a narrow channel 70 (e.g., by crimping). Therefore, the embodiments described above with a wide section 74 and a narrow section 72 may be more time- and cost-efficient, as well as easier to manufacture.

[0050] Although the blank 12, which includes a temperature measuring device 60, has been described above with separate channels 70 for each wire 64 / 66, in another embodiment the pair of wires can also share a channel 70. In this embodiment, the wires 64, 66 can have a connection point at or near their tips 68, which can be attached to one end 84 of the wide section 74 similarly to the above (e.g., by welding). The pair of wires can be secured by means of an adhesive material 90 and can be secured in a narrow section 72 similarly to the above. The dimensions of the narrow section 72 can be adjusted to accommodate two wires 64, 66 instead of one.Alternatively, the channel 70 can have a uniform or substantially uniform width as described above, and the pair of wires 64, 66 can be applied to / inserted into the entire channel 70 by means of adhesive material 90. Other modifications to the blank 12 and / or the wires 64, 66 to form a common channel configuration can be made and are apparent to the person skilled in the art based on the present disclosure.

[0051] With reference to Fig. 10, Fig. 11, Fig. 12 to Fig. Figure 13 shows images of several test specimens as well as data from several heating and quenching tests. Fig. Figure 10 shows three different test specimens. On the left is a baseline specimen 12 (sample 1) in which the TC wires were screwed through holes drilled into the specimen 12. In the middle and on the right are specimens 12 in which the TC wires were welded to the end of the wide section 74 of the channel 70 (e.g., as in Fig. (11 shown). In both blanks 12, the wide section 74 was filled with a metal composite adhesive to further secure the wire 64, 66 in the channel 70. In the middle sample (sample 2), the TC wires were stripped to the bare metal from the welded tip just beyond the edge of the blanks 12. In the right-hand sample (sample 3), the TC wires were left with an insulating casing up to the section 74 that extends into the wide section 74 of the channel 70.

[0052] With reference to Fig. Figure 12 shows temperature versus time data for the three samples during a center point heating test. During the center point heating test, the entire blank was positioned on the hot plate. As shown in Fig. As can be seen in Figure 12, the baseline sample 1 showed a significant delay in the measurement of the elevated temperature and reached a lower temperature (350 °C) than the other samples. Samples 2 and 3 performed similarly and showed a reduced delay compared to sample 1. The two samples reached similar temperatures of 370 °C and 375 °C, respectively.

[0053] The results of heat treatment and quenching are in Fig. Figure 13 shows the temperatures to which a blank is exposed during a hot stamping process for high-strength aluminum (e.g., 7xxx series). The samples were heated in a convection oven set to 480 °C and then quenched in water at room temperature. As shown in Fig. As can be seen in Figure 13, all three samples reached a temperature close to the oven temperature (474 ​​°C, 474 °C, and 476 °C, respectively). As shown in the enlarged section of the graph, sample 3 performed slightly better, reaching a higher temperature in less time. Accordingly, the results in Fig. 12 to Fig.13, that the blanks with the TC wires welded in a wide section of a channel 70 and cemented therein by an adhesive provide an accurate temperature measurement of their area of ​​the blank with low delay. The time-to-temperature ratio of a component can be an important property of a heating or cooling process, which is why a low temperature delay can be extremely advantageous.

[0054] Although exemplary embodiments have been described above, these embodiments are not intended to describe all possible forms of the disclosed device and method. Rather, the terms used in the specification are descriptive and not limiting, and it is understood that various modifications may be made without deviating from the spirit and scope of the disclosure as claimed. The features of the different embodiments can be combined to form further embodiments of the disclosed concepts.

Claims

[1] Metal cutting (12), comprising: a metal sheet with a surface having at least one pair (80) of channels (70) defined therein, each channel (70) having a first section (72) extending from an edge (76) of the blank (12) and a second section (74) in an interior (78) of the blank (12); at least one pair (62) of thermocouple wires (64, 66), wherein one wire (64, 66) is attached to every second section (74); and the wires (64, 66) are welded to every second section (74); characterized by , that the second section (74) is wider than the first section (72); and the metal blank (12) comprises an adhesive material (90) arranged in every second section (74). [2] Metal blank (12) according to claim 1, wherein the first section (72) of each channel (70) extends continuously into the second section (74) of the channel (70) and the sections (72, 74) meet at a transition area (86). [3] Metal blank (12) according to claim 1, wherein the wires (64, 66) are attached at each second section (74) at one end (84) of the second section (74) opposite the first section (72). [4] Metal blank (12) according to claim 1, wherein a section of each wire (64, 66) is secured in each first section (72). [5] Metal blank (12) according to claim 1, wherein each first section (72) is deformed in at least one area to secure the wire (64, 66) therein. [6] Metal blank (12) according to claim 1, wherein every second section (74) has a length (L1) of 5 to 500 mm, a width (W1) of 0.5 to 10 mm and a depth (D2) of 0.25 to 5 mm and every first section (72) has a width (W2) of 0.25 to 3 mm and a depth of 0.25 to 5 mm. [7] Metal blank (12) according to claim 1, wherein each first section (72) is substantially free of adhesive material (90), i.e., is filled with adhesive material (90) to less than 1 volume %. [8] Metal blank (12) according to claim 1, wherein every second section (74) is substantially filled with the adhesive material (90), i.e. to at least 95 volume %. [9] Metal blank (12) according to claim 1, wherein each wire (64, 66) extends from a fastening point (88) in the second section (74) of the channel (70) through the first section (72) of the channel (70) and beyond the edge (76) of the blank (12). [10] Hot stamping system (10), comprising: an oven (14); a coolable stamp set (18); a metal blank (12) defining at least two channels (70) extending to an edge (76), each channel (70) having a first section (72) and a second section (74); a pair (80) of thermocouple wires (64, 66), wherein one wire (64, 66) is fixed in the second section (74) of each channel (70) and extends through the first section (72) outwards past the edge (76); wherein each wire (64, 66) is connected to a temperature measuring device (60); and wherein the wires (64, 66) are welded to every second section (74); characterized by , that the second section (74) is wider than the first section (72); the hot stamping system (10) further comprises an adhesive material (90) arranged in every second section (74); and the adhesive material (90) contains a metal composite adhesive. [11] Hot stamping system (10) according to claim 10, wherein the first section (72) and the second section (74) meet at a transition area (86) and the wires (64, 66) on each second section (74) are attached at an end (84) of the second section (74) opposite the transition area (86). [12] Hot stamping system (10) according to claim 10, wherein every second section (74) has a length (L1) of 5 to 500 mm, a width (W1) of 0.5 to 10 mm and a depth (D2) of 0.25 to 5 mm and every first section (72) has a width (W2) of 0.25 to 3 mm and a depth (D2) of 0.25 to 5 mm. [13] Method for producing a temperature-sensing metal blank (12), comprising: Forms of at least one pair (80) of channels (70) in a surface of a metal sheet, each channel (70) having a first section (72) and a second section (74); Securing a thermocouple wire (64, 66) in the second section (74) of each channel (70); wherein the securing step includes welding the thermocouple wires (64, 66) in the second section (74) of each channel (70); and Securing at least one section of each wire (64, 66) in the first section (72) of each channel (70); characterized by , that the forming step includes forming each channel (70) with a first, narrower section (72) and a second, wider section (74); the procedure further includes introducing an adhesive material (90) into every second section (74); and the adhesive material (90) in the introduction step contains a metal composite adhesive. [14] Method according to claim 13, wherein each second section (74) is formed in an interior (78) of the metal sheet, wherein each first section (72) extends from an edge (76) of the metal sheet and meets the second section (74) at a transition area (86) and the thermocouple wires (64, 66) are attached to an end (84) of the second section (74) opposite the transition area (86).

Images