Thermal forming manufacturing method

Abstract

The embodiment of the invention provides a thermal forming manufacturing method which comprises the steps that a raw material is blanked to obtain a needed blank, and the blank is set to be a thermal forming material; the blank is transferred to a feeding platform, and then the blank is moved into an induction heater so that the blank can be heated for the first time; the blank in the induction heater is transferred into a laser heater so that the blank can be heated for the second time, and the time for the second time of heating ranges from 10 s to 60 s; according to the method, in the first heating process, the blank is heated to the austenitizing temperature or above through the induction heater, in the second heating process, the blank is heated to the austenitizing temperature or above through the induction heater, the blank is heated to the austenitizing temperature or above through the induction heater, and in the second heating process, the blank is heated to the austenitizing temperature or above through the induction heater; the laser heater is used for uniformly heating the blank, so that the surface temperature of the blank is homogenized, and then the laser heater can be used for performing secondary heating on the position, with non-uniform surface temperature, of the blank subjected to primary heating.

Description

Technical Field

[0001] The present invention relates to the technical field of thermoforming, and more particularly to a thermoforming manufacturing method. Background Art

[0002] In the prior art, the most commonly used method for heating the blank in hot forming is heating in a heating furnace, which utilizes radiation and convection between the furnace and the blank to complete the heating of the blank. This method has the advantages of uniform heating of the blank and good overall temperature uniformity, but the heating rate is slow, about 6.5℃ / s, and the efficiency is low, which seriously affects the production efficiency of the hot forming process; it also occupies a large space, has poor flexibility, and has high investment and maintenance costs; and the furnace mouth is opened during the feeding and taking process, resulting in a large energy loss.

[0003] Induction heating is to arrange an induction coil around the blank, pass alternating current through the coil to generate alternating current inside the blank and heat the blank. This method has the advantages of fast heating rate and high efficiency. Its heating rate can reach 200℃ / s, and its efficiency can be twice that of a heating furnace, which shortens the heating time of hot forming and improves the production efficiency of hot forming. However, the size range of the dacho that can be heated by a single specification induction coil is limited, so a combination of coils of multiple specifications is required to complete the heating process of the blank; and when the temperature of the blank reaches the Curie point, the relative thermal conductivity drops to 1, and the heating rate and efficiency of induction heating are greatly reduced.

[0004] However, the temperature distribution of the thin plate surface at the outlet of the induction heater is still uneven. Many factors affect the temperature distribution on the strip surface, such as frequency, current density, air gap, relative width between the coil and the strip, distance from the magnetizer to the coil, etc. Both current density and frequency will have a certain impact on the uniformity of temperature, but the impact of current frequency is greater. The distance from the magnetizer to the coil and the relative width between the coil and the strip have a great influence on the temperature distribution of the strip, which may cause the edge temperature of the strip to be too high or too low.

[0005] When using lasers for heating, the first problem is the limitation of laser spot size. Ultra-high power lasers are needed, and the spot size can be larger than the laser head. However, the price of ultra-high power lasers is generally several times that of low power lasers. It is very costly to use ultra-high power lasers for all applications.

[0006] To address the above problems, no effective solution has been proposed yet.

[0007] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present invention and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because these solutions are described in the background technology section of the present invention. Summary of the invention

[0008] The purpose of this specification is to provide a thermoforming manufacturing method to solve the above problems.

[0009] A thermoforming manufacturing method provided in this specification includes:

[0010] Blanking the raw materials to obtain the required blanks, wherein the blanks are set as thermoforming materials;

[0011] Transferring the blank to a loading platform, and then moving the blank into an induction heater to heat the blank for the first time;

[0012] Transferring the blank in the induction heater to the laser heater to perform a second heating on the blank, wherein the second heating time is 10s-60s;

[0013] The blank that has completed the second heating is moved to a stamping machine for hot stamping to obtain a formed sheet, and then the sheet is taken out.

[0014] Preferably, during the first heating process, the induction heater heats the blank to 400° C.-700° C., and during the second heating process, the laser heater heats the blank to above the austenitizing temperature.

[0015] Preferably, during the first heating process, the induction heater heats the blank to above the austenitizing temperature, and during the second heating process, the laser heater uniformly heats the blank to make the surface temperature of the blank uniform.

[0016] Preferably, the heating time of the second heating is set to 10s-20s, and nitrogen protection is performed during the second heating process.

[0017] Preferably, the laser spot on the laser heater is arranged as a matrix spot, and the laser is arranged to move in a horizontal direction perpendicular to the direction in which the blank moves.

[0018] Preferably, the induction coil in the induction heater adopts transverse induction heating, and induction coils are provided near two opposite sides of the blank.

[0019] Preferably, during the movement of the blank during the first heating in the induction heater, two layers of ceramic rollers are used to clamp the blank for heating and movement.

[0020] Preferably, the blank is a thermoforming material of 1500Mpa or 2000Mpa.

[0021] Preferably, the blank is made of phosphated steel plate, and the surface of the blank is coated with light-absorbing paint.

[0022] Preferably, the blank is a laser welded plate, a patch plate or a plate of unequal thickness.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention performs a first heating by arranging an induction heater and then performs a second heating by arranging a laser heater, thereby being able to perform a stable and uniform hot forming process on the blank.

[0025] 2. The present invention heats the blank to 400°C-700°C by an induction heater during the first heating process, and heats the blank to above the austenitizing temperature by a laser heater during the second heating process, thereby avoiding the instability of blank hot forming caused by the low efficiency of induction heating during the first heating process, thereby improving the yield of blank hot forming.

[0026] 3. The present invention is arranged that during the first heating process, the induction heater heats the blank to above the austenitizing temperature, and during the second heating process, the laser heater uniformly heats the blank to make the surface temperature of the blank uniform. Then, the laser heater can be used to perform a second heating on the position where the surface temperature of the blank is uneven after the first heating, so that the heated temperature of the blank can be kept uniform, thereby making the blank hot forming process more stable.

[0027] 4. The present invention is arranged that during the first heating process, the induction coil in the induction heater adopts transverse induction heating, and induction coils are provided near the opposite sides of the blank, so that the blank can maintain a more uniform temperature during the first heating process, thereby further improving the stability of the blank hot forming.

[0028] 5. The laser spot on the laser heater of the present invention is set as a matrix spot, and the laser is set to move horizontally perpendicular to the direction of movement of the blank, so that the temperature of the blank heated by laser during the second heating process can be more uniform.

[0029] 6. The present invention is provided with nitrogen protection during the second heating process, thereby preventing the blank from being oxidized in a high temperature environment when the laser heater is heating during the second heating process. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0031] Figure 1 It is a side view of a production line of a thermoforming manufacturing method provided in an embodiment of this specification;

[0032] Figure 2 It is a top view of a production line of a thermoforming manufacturing method provided in an embodiment of this specification.

[0033] In the figure: 1, induction heating zone; 11, induction heater; 111, induction coil; 2, laser heating zone; 21, laser heater; 211, laser head; 3, nitrogen interface. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below in conjunction with the drawings in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this specification.

[0035] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "upper", "middle", "lower", "inner", "outer", "front", "back", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. The terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The following describes an implementation method of the present invention based on its overall structure.

[0036] Reference Figure 1 As shown, the embodiment of the present application provides a thermoforming manufacturing method, comprising:

[0037] Blanking the raw materials to obtain the required blanks, which are set as hot forming materials;

[0038] The blank is transferred to the loading platform, and then moved into the induction heater 11 to heat the blank for the first time;

[0039] The blank in the induction heater 11 is transferred to the laser heater 21 to perform a second heating on the blank, and the second heating time is 10s-60s;

[0040] The blank that has completed the second heating is moved to a stamping machine for hot stamping to obtain a formed sheet, and then the sheet is taken out.

[0041] In the present application, a person skilled in the art can blank the raw material, and then process it to obtain a blank of a corresponding shape. Then, the blank is heated for the first time and the second time. Then, the blank heated twice is stamped to obtain a formed sheet. The aforementioned process can complete the hot forming process of the blank completely and stably.

[0042] Specifically, those skilled in the art can set up an induction heating zone 1 and a laser heating zone 2. An induction heater 11 is set up in the induction heater 1 and a laser heater 21 is installed in the laser heating zone 2. By setting up the partitions, the first heating and second heating processes of the blank can be divided into different areas. The above-mentioned setting can further avoid mutual interference between the first heating and the second heating.

[0043] During the processing, the blank is transferred to the loading platform, and then transferred to the induction heater 11 through the loading platform. Preferably, the induction coil 11 in the induction heater adopts transverse induction heating, and the induction coils 111 are arranged near the opposite sides of the blank. The above-mentioned arrangement allows the blank to be evenly heated during the first heating process.

[0044] During the first heating process, the blank needs to be moved. Preferably, during the movement of the blank for the first heating in the induction heater 11, two layers of ceramic rollers are used to clamp the blank for heating and movement. It is understandable that during the movement of the blank, the blank is also rapidly heated. During this rapid heating process, the blank may warp and deform. In this embodiment, the blank is clamped by two layers of ceramic rollers to avoid warping and deformation.

[0045] according to Figure 1 The laser heating zone 2 is arranged in a shell, so that the laser heating zone 2 can be further separated from the induction heating zone 1. A plurality of laser heads 211 are arranged on the outer wall of the shell, so that the blank can be laser heated.

[0046] In the above-mentioned hot forming process, the heating time of the second heating is set to 10s-60s, preferably, the heating time of the second heating is set to 10s-20s, and nitrogen protection is performed during the second heating process. That is, a nitrogen interface 3 is also provided on the outer wall of the shell of the laser heating zone 2, so that nitrogen can be filled into the environment of the second heating. During the heating process, nitrogen protection is used while heating is performed simultaneously, so that oxidation of the blank during high-temperature heating can be effectively prevented.

[0047] Furthermore, in the process of heating the blank for the second time, preferably, the laser spot on the laser heater 21 is set as a matrix spot, and the laser is set to move horizontally in a direction perpendicular to the direction of movement of the blank. That is, setting the matrix spot can effectively keep the temperature of the blank uniform during laser heating. This can improve the efficiency and yield of hot forming of the blank.

[0048] In the above embodiment, the blank needs to be made of a material that can be thermoformed. Preferably, the blank is a thermoformed material of 1500Mpa or 2000Mpa. The above setting can further enable the blank to be stably heated for the first time and the second time.

[0049] In one embodiment, preferably, the blank is made of phosphated steel plate, and the surface of the blank is coated with light-absorbing paint. Preferably, the blank is a laser welded blank, a patch plate or a plate of unequal thickness.

[0050] In the above process, the blank is heated for the first time and the second time, wherein a first heating mode and a second heating mode are also provided in the first heating and the second heating process. The first heating mode and the second heating mode are introduced through two embodiments below.

[0051] Example 1

[0052] Preferably, during the first heating process, the induction heater 11 heats the blank to 400° C.-700° C., and during the second heating process, the laser heater 21 heats the blank to above the austenitizing temperature.

[0053] Specifically, a loading robot is used to take one of the neatly stacked 1.4mm thresholds and place it on the loading platform, and then transfer it to the induction heater 11. Among them, the feeding speed is set to 50mm / s, the power of the induction heater 11 is set to 600KW, and it is continuously heated to 500°C, and the heating time is 5s. The blank is continued to be transferred into the laser heater 21, and the laser heads 211 are arranged in an array. The size of the laser head 211 is set to 205*110mm, the spot size is 120*30mm, and the power of each laser head is set to 12KW. Turn on the laser heater 21 for heating, and continue heating to austenitize the blank. The laser heater 21 moves perpendicular to the forward direction of the blank, the heating temperature is heated to 950°C, and the heating time is 5s. Turn off the laser heater 21 after heating is completed. The heated austenitized blank is transferred to the stamping machine for stamping.

[0054] It can be understood that the above is the first heating mode. In the first heating mode, the induction heating has a faster heating rate at the Curie point, while the laser heating has a lower absorption coefficient in the low temperature section and a higher absorption coefficient in the high temperature section. In this embodiment, the blank can be first heated to 400°C-700°C by the induction heater 11, and then the laser heater 21 is used to quickly heat the high temperature section, which can greatly improve the heating efficiency. And the temperature rise of the blank can be made more uniform, making the thermoforming process more stable.

[0055] Example 2

[0056] Preferably, during the first heating process, the induction heater heats the blank to above the austenitizing temperature, and during the second heating process, the laser heater uniformly heats the blank to make the surface temperature of the blank uniform.

[0057] Use a loading robot to take one of the neatly stacked 1.4mm thresholds and place it on the loading platform, and then move it to the induction heater 11. Among them, the feeding speed is set to 50mm / s, the power of the induction heater is 1000KW, and it is heated to 930℃, and the heating time is set to 15s. Use thermal imaging to monitor the temperature of the induction heated blank to find the places where the temperature of the blank is uneven. In general, thermal imaging shows that the places where the temperature of the blank is uneven are at the head and tail of the material. The blank is transferred to the laser heater 21, and the laser heads 211 are arranged in an array. The size of the laser heads is 205*110mm, the spot size is 120*30mm, and the power of each laser head 211 is 3KW. Turn on the laser heater 21 corresponding to the uneven temperature of the blank, heat the blank, and make the temperature of the blank uniform. The heating setting time is 1s. The laser heater 21 can be turned off after heating is completed. Transfer the heated austenitized sheet to the stamping machine for stamping.

[0058] The above is the second heating mode. Specifically, increasing the power of the induction heater 11 can make the blank quickly heated at more than 700 degrees to reach the austenitizing temperature. However, increasing the power of the induction heating will make the temperature of the head, tail and surrounding of the blank uneven. At this time, the laser heater 21 can be used to perform a second heating on the uneven position of the blank to make the temperature of the blank uniform.

[0059] Although different specific embodiments are mentioned in the content of this application, this application is not limited to the situations described in the industry standards or embodiments, etc. Some industry standards or slightly modified implementation plans based on the implementation of the custom methods or embodiments can also achieve the same, equivalent or similar, or predictable implementation effects after deformation of the above embodiments. The embodiments of data acquisition, processing, output, judgment methods, etc. after these modifications or deformations can still fall within the scope of the optional implementation plans of this application.

[0060] Although the present application has been described through embodiments, those skilled in the art will appreciate that there are many modifications and changes to the present application without departing from the spirit of the present application. It is intended that the attached embodiments include these modifications and changes without departing from the present application.

Claims

1. A thermoforming manufacturing method, It is characterized in that include: Blanking the raw materials to obtain the required blanks, wherein the blanks are set as thermoforming materials; Transferring the blank to a loading platform, and then moving the blank into an induction heater to heat the blank for the first time; Transferring the blank in the induction heater to the laser heater to perform a second heating on the blank, wherein the second heating time is 10s-60s; The blank that has completed the second heating is moved to a stamping machine for hot stamping to obtain a formed sheet, and then the sheet is taken out.

2. The thermoforming manufacturing method according to claim 1, It is characterized in that During the first heating process, the induction heater heats the blank to 400° C.-700° C., and during the second heating process, the laser heater heats the blank to above the austenitizing temperature.

3. The thermoforming manufacturing method according to claim 1, It is characterized in that During the first heating process, the induction heater heats the blank to above the austenitizing temperature, and during the second heating process, the laser heater uniformly heats the blank to make the surface temperature of the blank uniform.

4. The thermoforming manufacturing method according to claim 1, It is characterized in that The heating time of the second heating is set to 10s-20s, and nitrogen protection is performed during the second heating process.

5. The thermoforming manufacturing method according to claim 1, It is characterized in that The laser spot on the laser heater is set as a matrix spot, and the laser is set to move in a horizontal direction perpendicular to the moving direction of the blank.

6. The thermoforming manufacturing method according to claim 1, It is characterized in that The induction coil in the induction heater adopts transverse induction heating, and the induction coils are arranged near the two opposite sides of the blank.

7. The thermoforming manufacturing method according to claim 1, It is characterized in that During the movement of the blank in the induction heater for the first heating, two layers of ceramic rollers are used to clamp the blank for heating and movement.

8. The thermoforming manufacturing method according to claim 1, It is characterized in that The blank is a thermoforming material of 1500Mpa or 2000Mpa.

9. The thermoforming manufacturing method according to claim 1, It is characterized in that The blank is made of phosphating steel plate, and the surface of the blank is coated with light absorbing paint.

10. The thermoforming manufacturing method according to claim 1, It is characterized in that The blank is configured as a laser welded plate, a patch plate or a plate of unequal thickness.

Images