Laser welding device for noble metal plates

Abstract

The present application relates to a kind of laser welding devices of noble metal plate, including mould unit, heavy down pressure unit and laser unit;Mould unit is used to support noble metal plate, heavy down pressure unit is used to press the welding portion of noble metal plate, laser unit is used to carry out laser welding to the welding portion of noble metal plate;Heavy down pressure unit includes: first heavy down pressure unit, for the first end of the noble metal plate is positioned on the mould unit;Second heavy down pressure unit is used to position the second end of the noble metal plate in the form of being stacked above the first end of the noble metal plate on the mould unit;And third heavy down pressure unit is used to beat the noble metal plate;Wherein, the first heavy down pressure plate of first heavy down pressure unit and the second heavy down pressure plate of second heavy down pressure unit are located on the side of preset weld position when down pressure, the third heavy down pressure plate of third heavy down pressure unit covers preset weld position when down pressure and can be dragged to the other side of preset weld position.

Description

TECHNICAL FIELD

[0001] The present application relates to a laser welding device and a laser welding method for a precious metal plate, in particular, a laser welding device and a laser welding method for a precious metal crucible, and belongs to the field of mechanical processing. BACKGROUND

[0002] As a crucible used for a crystal growing device, a metal-made crucible is generally used. In particular, in the crystal growth of a high-melting-point material such as sapphire (single-crystal aluminum oxide), a precious metal crucible such as a platinum crucible formed of a precious metal such as platinum, iridium, molybdenum, tungsten, and an alloy mainly composed of these is known.

[0003] At present, a common processing method for a precious metal crucible is to use a die stamping process for the bottom and a welding process for the outer part of the crucible (for example, refer to JP 2006-205200). This method has small processing difficulty and high processing efficiency. However, a large and thin platinum plate is extremely easy to have a welding defect when welded, and the welding seam is easy to crack and easy to have a leakage phenomenon in use. Therefore, a double-layer platinum crucible is often used in actual use, and the service life of the crucible is short. However, on the one hand, the precious metal such as platinum is expensive, and on the other hand, based on the demand for the efficiency of the crystal growth at present, it is also required to make the crucible large. These all require that the platinum crucible made has a long service life and can withstand repeated use. SUMMARY

[0004] The present application provides a laser welding device for a precious metal plate, the laser welding device comprising a die unit, a multiple pressing unit, and a laser unit; the die unit is used to support the precious metal plate, the multiple pressing unit is used to press the welding part of the precious metal plate, and the laser unit is used to laser weld the welding part of the precious metal plate; wherein the multiple pressing unit comprises: a first pressing unit, which is used to position the first end of the precious metal plate on the die unit; a second pressing unit, which is used to position the second end of the precious metal plate on the die unit in a manner of being stacked above the first end of the precious metal plate; and a third pressing unit, which is used to press the precious metal plate; wherein the first pressing plate of the first pressing unit and the second pressing plate of the second pressing unit are located on one side of a preset welding seam position when pressed, and the third pressing plate of the third pressing unit covers the preset welding seam position when pressed and can be dragged to the other side of the preset welding seam position.

[0005] Preferably, the first pressing plate of the first pressing unit and the second pressing plate of the second pressing unit are respectively driven by a first pressing power mechanism and a second common pressing power mechanism, and are supported by a first-second common pressing support.

[0006] Preferably, the third heavy down-pressing plate of the third heavy down-pressing unit is driven by a third heavy down-pressing mechanism and supported by a third heavy down-pressing support.

[0007] Preferably, the third heavy down-pressing unit further comprises a horizontal moving mechanism for horizontally moving the third heavy down-pressing support supporting the third heavy down-pressing plate.

[0008] Preferably, the third heavy down-pressing unit further comprises a horizontal moving guide rail for guiding the horizontal movement of the third heavy down-pressing support supporting the third heavy down-pressing plate, and the lower end of the third heavy down-pressing support is arranged on the horizontal moving guide rail.

[0009] Preferably, the lower end of the third heavy down-pressing support is provided with a spring.

[0010] Preferably, the third heavy down-pressing support comprises a plurality of fan-shaped ring pieces.

[0011] Preferably, the first heavy down-pressing plate, the second heavy down-pressing plate and / or the third heavy down-pressing plate are composed of a plurality of serially connected pressing blocks.

[0012] Preferably, the mold unit comprises a mold and a mold fixed top clamp.

[0013] Beneficial effects: The present application adds a set of straight-line pressing plate units on the basis of conventional straight-line pressing plate units. The added straight-line pressing plate units can not only perform down-pressing actions, but also perform dragging actions. The precious metal plate to be welded (pre-set weld position) can be further compacted by stamping and pressing, and can be dragged to the other side of the pre-set weld position after stamping and pressing, so as to ensure that both sides of the pre-set weld position are in a compacted state. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the laser welding device of the present application.

[0015] Figure 2 It is a structural schematic diagram of the first heavy down-pressing unit and the second heavy down-pressing unit.

[0016] Figure 3 It is a structural schematic diagram of the third heavy down-pressing unit.

[0017] Figure 4 It is a down-pressing schematic diagram of the heavy down-pressing unit in the laser welding device of the present application.

[0018] Figure 5 It is a welding schematic diagram of the heavy down-pressing unit in the laser welding device of the present application.

[0019] Figure 6 It is a schematic diagram of an example welding pattern (straight-line type, and the light spot is a solid circle).

[0020] Figure 7 An example welding pattern schematic is shown (straight line, light spot is a hollow ring).

[0021] Figure 8 An example welding pattern schematic is shown (Z zigzag line, light spot is a solid dot).

[0022] Figure 9 An example welding pattern schematic is shown (wavy line, light spot is a solid dot).

[0023] Figure 10 An example welding pattern schematic is shown (spiral, light spot is a solid dot). DETAILED DESCRIPTION

[0024] The present invention provides a laser welding device for precious metal plates, which can include a mold unit, a multiple pressing unit, and a laser unit. The mold unit is used to support the precious metal plates. For example, it includes a mold that supports the precious metal plates and determines the shape of the crucible, and a mold fixing top clamp that fixes the mold with the precious metal plates wound around to the machine tool. The multiple pressing unit is used to press the welding part of the precious metal plates. The laser unit is used to laser weld the welding part of the precious metal plates.

[0025] The multiple pressing unit can include two sets of linear pressing plate units. Specifically, the first and second pressing units are basic pressing plate units, and the third pressing unit is an enhanced pressing plate unit. The first pressing unit is used to position the first end of the precious metal plate on the mold unit; the second pressing unit is used to position the second end of the precious metal plate on the mold unit in a manner of being stacked above the first end of the precious metal plate; and the third pressing unit is used to press the precious metal plate.

[0026] The first pressing plate of the first pressing unit and the second pressing plate of the second pressing unit are located on one side of the preset weld position when pressed, and the third pressing plate of the third pressing unit covers the preset weld position when pressed and can be dragged to the other side of the preset weld position.

[0027] In one embodiment, the first, second, and third pressing units each include a linear pressing plate for pressing the precious metal plate, a pressing power mechanism for driving the linear pressing plate, and a pressing support for supporting the linear pressing plate and the pressing power mechanism.

[0028] In one embodiment, the first pressing plate of the first pressing unit and the second pressing plate of the second pressing unit are respectively driven by the first pressing power mechanism and the second common pressing power mechanism, and are supported by the first and second common pressing supports.

[0029] In one embodiment, the third heavy down-pressing plate of the third heavy down-pressing unit is driven by a third heavy down-pressing mechanism and supported by a third heavy down-pressing support.

[0030] In a preferred embodiment, the third heavy down-pressing unit further comprises a horizontal moving mechanism for horizontally moving the third heavy down-pressing support supporting the third heavy down-pressing plate.

[0031] In a more preferred embodiment, the third heavy down-pressing unit further comprises a horizontal moving guide rail for guiding the horizontal movement of the third heavy down-pressing support supporting the third heavy down-pressing plate, and the lower end of the third heavy down-pressing support is movably arranged on the horizontal moving guide rail.

[0032] In a preferred embodiment, the lower end of the third heavy down-pressing support is provided with a spring.

[0033] In a preferred embodiment, the third heavy down-pressing support comprises a plurality of fan-shaped ring pieces.

[0034] In a preferred embodiment, the first heavy down-pressing plate, the second heavy down-pressing plate and / or the third heavy down-pressing plate are composed of a plurality of serially connected pressing blocks.

[0035] The present application also provides a laser welding method for a precious metal plate, comprising: positioning a first end of the precious metal plate on a mold by down-pressing a first heavy down-pressing plate to form an inner layer of a welding overlap surface; positioning a second end of the precious metal plate on the mold by down-pressing a second heavy down-pressing plate next to the first heavy down-pressing plate and above the first end of the precious metal plate in a form of being overlaid on the first end of the precious metal plate to form an outer layer of the welding overlap surface, wherein the first heavy down-pressing plate and the second heavy down-pressing plate are both located on the same side of a preset welding position when being down-pressed; positioning a third heavy down-pressing plate next to the second heavy down-pressing plate and covering the preset welding position; tapping the precious metal plate by using the third heavy down-pressing plate; moving the third heavy down-pressing plate away from the second heavy down-pressing plate and to the other side of the preset welding position; and welding at the preset welding position according to a preset welding route by using a laser unit.

[0036] In a preferred embodiment, the left edge of the first heavy down-pressing plate is 3.0-4.0 mm away from the preset welding position.

[0037] In a preferred embodiment, the right edge of the third heavy down-pressing plate is 0.1-3 mm away from the preset welding position after the third heavy down-pressing plate is moved.

[0038] In a preferred embodiment, the down-pressing pressure of the first heavy down-pressing plate is 190-300 N.

[0039] In a preferred embodiment, the down-pressing pressure of the second heavy down-pressing plate is 200-350 N.

[0040] In a preferred embodiment, the pressing force of the third pressing plate is 100-180 N.

[0041] In a preferred embodiment, the tapping force of the third pressing plate is 290-500 N.

[0042] In a preferred embodiment, the tapping force of the third pressing plate is greater than the pressing force of the third pressing plate. Preferably, the tapping force of the third pressing plate is 2-4 times the pressing force of the third pressing plate.

[0043] In a preferred embodiment, the laser welding spot is a hollow ring.

[0044] In a preferred embodiment, the laser welding path is linear, zigzag, wavy or spiral.

[0045] The present application also provides a multiple pressing unit, comprising a first pressing unit, a second pressing unit and a third pressing unit; the first pressing unit and the second pressing unit each comprise a first pressing plate and a second pressing plate capable of pressing action, and the first pressing plate and the second pressing plate are located on one side of a preset welding position when pressing; the third pressing unit comprises a third pressing plate capable of pressing action and dragging action, a third pressing support supporting the third pressing plate, a third pressing power mechanism enabling the third pressing plate to perform pressing action, and a horizontal movement mechanism enabling the third pressing plate to perform dragging action; the third pressing plate covers the preset welding position when pressing, and can be dragged to the other side of the preset welding position; the third pressing support comprises a plurality of fan-shaped ring pieces.

[0046] The present application also provides a mold fixed top clamp, comprising a clamp base fixed on a machine tool, and a stud telescoping towards a mold, the stud comprising a first stud and a second stud connected by threads, the clamp base being provided with an inner cavity with internal threads at the upper end for accommodating the first stud; the first stud being provided with a first adjusting nut for adjusting the depth of the first stud screwed into the inner cavity of the clamp base, and a second adjusting nut for adjusting the length of the threaded connection part of the first stud and the second stud.

[0047] In a preferred embodiment, the second stud is provided with a side end face matching the outer surface of the mold.

[0048] The specific embodiments of the present application are described in detail below with reference to the accompanying drawings and examples. It should be understood that the following drawings and examples are used to illustrate the present application, but not to limit the present application.

[0049] Reference is made to Figure 1Fig. 1 shows a schematic view of a laser welding device according to the present application, comprising a mold unit, a pressing unit (linear pressing plate unit) and a laser unit arranged on a machine tool.

[0050] Referring to Figure 1 and Figure 2 The mold unit has a mold 1 for supporting a noble metal plate, and a mold fixing clamp 2 for fixing the mold to the machine tool. The length direction of the mold 1 is defined as the front-rear direction, wherein the direction toward the outside of the paper is the front direction, and the direction toward the inside of the paper is the rear direction. The direction perpendicular to the horizontal plane of the machine tool is defined as the up-down direction, and the left side of the mold (the direction to the left side of the paper) is defined as the left direction, and the right side of the mold (the direction to the right side of the paper) is defined as the right direction.

[0051] The mold 1, as a mold for determining the shape of the crucible, can be a hollow cylindrical shape, or a columnar shape with a rectangular cross section, etc. Before welding, the noble metal plate is bent along the outer surface of the mold 1 and adheres to the outer surface of the mold 1. Then the mold 1 wrapped with the noble metal plate is placed in the work station and fixed by the mold fixing clamp 2. The noble metal plate is, for example, a platinum plate (hereinafter, platinum crucibles are prepared by using platinum plates (platinum sheets) as an example, but it should be understood that other noble metal plates can be used, such as iridium, molybdenum, tungsten, etc. The thickness of the platinum plate (platinum sheet) can be 0.06-0.50 mm, and preferably rectangular, and the appropriate size of the platinum sheet can be selected according to the size of the desired crucible, for example, the width can be 10-600 mm to form the depth of the crucible, and the length can be 30-600 mm to form the circumference of the outer circumferential surface of the crucible.

[0052] The mold fixing clamp 2 can be a retractable clamp arranged in pairs on the left and right sides of the mold, for example, comprising a clamp base fixed on the machine tool, and a threaded stud retractable toward the mold 1. In one example, the threaded stud comprises a first threaded stud and a second threaded stud screw-connected, and the clamp base upper end is provided with an inner cavity with internal threads for accommodating the first threaded stud; the first threaded stud can be screwed into the inner cavity of the clamp base upper end, and the first threaded stud is provided with a first adjusting nut for adjusting the depth of the first threaded stud screwed into the inner cavity of the clamp base, and a second adjusting nut for adjusting the length of the screwing part of the first threaded stud and the second threaded stud. For example, after the mold is placed in the work station, the first adjusting nut is first adjusted to make the first threaded stud retract toward the mold until it contacts the outer surface of the mold for rough adjustment, and then the first adjusting nut is adjusted to further make the second threaded stud press the mold. With the help of two-step adjustment, the mold can be clamped more reliably. In addition, the side end surface of the preferred second threaded stud facing the mold is matched with the outer surface of the mold.

[0053] In one example, a pair of screws is retracted towards the outside of the machine tool (in the direction of the fixture base), the fixture is opened, the mold wrapped with platinum sheet is put in, the pair of screws is extended towards the inside of the machine tool (in the direction of the mold), the mold 1 is clamped, and the mold 1 is fixed. It should be understood that the mold fixing top clamp 2 can be provided with multiple pairs along the length direction of the mold. For example, one pair is provided at each end of the mold, or additionally one pair is provided at the center of the mold.

[0054] The multiple pressing units include a first pressing unit, a second pressing unit and a third pressing unit, each of which can include a power mechanism, a pressing plate and a support. The first pressing unit is used to position one end of the platinum sheet on the mold to form the inner layer of the welding portion (welding overlap surface). The second pressing unit is used to position the other end of the platinum sheet on the mold to form the outer layer of the welding portion (welding overlap surface), so as to ensure that the platinum sheet surrounds and wraps the outer surface of the mold to determine the peripheral surface of the crucible. The first pressing unit includes a first pressing plate 3, and the second pressing unit includes a second pressing plate 4. The first pressing plate 3 and the second pressing plate 4 can use a common pressing power mechanism to perform pressing, beating, pressing and other actions, for example, the first and second pressing pneumatic mechanisms 5 shown in FIG. 6. Figure 2 It should be understood that the first pressing plate 3 and the second pressing plate 4 can also be operated by independent pressing power mechanisms respectively. A common pressing support can also be used to support the first pressing plate 3 and the second pressing plate 4 and their power mechanisms, for example, the first and second pressing supports 6 shown in FIG. 7. Figure 2 Similarly, it should be understood that multiple pressing supports can also be used to support the first pressing plate 3 and the second pressing plate 4 and their power mechanisms respectively.

[0055] The welding position is preset, which is preferably arranged along the length direction of the mold and located in the central plane parallel to the longitudinal axis of the mold but perpendicular to the horizontal plane of the machine tool. The mold 1 wrapped with the platinum sheet (platinum metal plate) is fixed on the work station, and the first end surface (the inner layer of the welding overlap surface) of the platinum sheet is attached to the mold directly above and across the preset welding position by a specified distance, for example, 0.1-1 mm across the preset welding position, so as to ensure that the inner layer of the welding portion after welding is controlled within 0.1-1 mm. In this way, the airtightness of the crucible can be ensured while the platinum loss is minimized.

[0056] The mold fixing top clamp 2 fixes the mold 1, and then the first and second lower pressing support 6 is operated to position the first lower pressing plate 3 directly above the mold. The first lower pressing plate 3 is pressed down to press the first end surface (the inner layer 15 of the welding overlap) of the platinum sheet. At this time, the left edge (the edge close to the welding seam) of the first lower pressing plate 3 is about 3.0-4.0 mm away from the welding seam position, to ensure that the second lower pressing plate 4 can be placed between the welding seam position and the first lower pressing plate 3. The other end surface (the second end surface) of the platinum sheet is wound around the mold to press on the first end surface of the platinum sheet to form the outer layer of the welding overlap. Similarly, the second end surface (the outer layer 16 of the welding overlap) of the platinum sheet is placed directly above the mold and across the welding seam position 17 at a specified distance, for example, 3.0-4.0 mm beyond the welding seam position, to ensure that the outer layer excess edge is controlled at 3.0-4.0 mm after welding. In this way, the airtightness of the crucible can be ensured while minimizing the loss of platinum. Then the first and second lower pressing support 6 is operated to position the second lower pressing plate 4 directly above the mold. The second lower pressing plate 4 is pressed down to press the second end surface (the outer layer of the welding overlap) of the platinum sheet. At this time, the right edge of the second lower pressing plate 4 is close to (preferably next to) the left edge of the first lower pressing plate (see Figure 4 ), and the left edge of the second lower pressing plate 4 is about 1.0-3.0 mm away from the welding seam position. It should be understood that the positions of the first lower pressing plate 3 and the second lower pressing plate 4 can be adjusted in advance to be next to a certain distance above the mold 1, and then the first end surface and the second end surface of the platinum sheet are inserted into the positions of the mold 1 and the first lower pressing plate 3 and the second lower pressing plate 4 in turn, and the first lower pressing plate 3 and the second lower pressing plate 4 are pressed down respectively.

[0057] The first lower pressing plate 3 and the second lower pressing plate 4 can press the end surfaces of the platinum sheet against the outer circumferential surface of the mold to determine the circumference of the crucible, but both the first lower pressing plate 3 and the second lower pressing plate 4 are located on the same side of the welding seam, and can only compact the platinum sheet on one side (the right side in the figure) of the welding seam position. Here, the combination of the first lower pressing unit and the second lower pressing unit is referred to as the basic lower pressing unit.

[0058] Thus, the present application adds a set of straight pressing plate mechanism, i.e. the third pressing unit, also called the enhanced pressing unit, on the other side (left side) of the weld position. The third pressing unit comprises a third pressing plate 7, a third pressing power mechanism (e.g. a third pressing pneumatic mechanism 8), a third pressing support 9, a horizontal moving guide 10 and a horizontal moving mechanism 11. The horizontal moving guide 10 can be fixed on the machine tool and arranged perpendicularly to the length direction of the mold. The third pressing support 9 is used to support the third pressing plate 7 and the third pressing power mechanism and can move horizontally along the horizontal moving guide 10. The horizontal moving mechanism 11 can be a manual moving knob or a manual push-pull rod, etc. to move the third pressing support 9 supporting the third pressing plate 7 and the third pressing power mechanism horizontally (left and right) on the horizontal moving guide 10. It should be understood that the horizontal moving mechanism can also be an electric mechanism.

[0059] As shown in Figure 1 and Figure 3 , the third pressing support 9 can be formed as a fan-shaped ring piece with an inner diameter greater than the outer diameter of the mold, preferably 2.0-3.0 times the outer diameter of the mold, so that the third pressing support 9 and the components supported thereby can approach or move away from the mold 1 without obstacles.

[0060] In one example, the third pressing support 9 is moved right to approach the mold 1 and the third pressing plate 7 is located above the mold by means of the horizontal moving mechanism 11, the third pressing pneumatic mechanism 9 is operated to press the third pressing plate 7, and the third pressing plate 7 completely covers the preset weld position next to the second pressing plate 3 (at this time), the third pressing pneumatic mechanism 9 is operated to press 2-4 times (the third pressing plate 7 repeats the pressing and releasing action). Then, the third pressing support 9 is moved left by a specified distance by means of the horizontal moving mechanism 11 to expose the position of the preset weld for laser welding, preferably, the right end of the third pressing plate is 0.1-3 mm, preferably 0.1-1 mm away from the weld (see Figure 5 ).

[0061] Preferably, the lower end of the fan-shaped ring piece of the third pressing support 9 can be provided with a spring, so that the third pressing support 9 can be kept on the horizontal moving guide 10 during pressing or releasing. In addition, the third pressing support 9 can be composed of 3-6 fan-shaped ring pieces arranged at equal intervals.

[0062] In one example, the first, second and third lower pressing plates 3, 4 and 7 are long strips parallel to each other and to the length direction of the mold 1. The first, second and third lower pressing plates 3, 4 and 7 can be formed by a plurality of small blocks, so that the damaged parts can be replaced without replacing the whole. The pressing force of the first lower pressing plate 3 can be 190-300 N, the pressing force of the second lower pressing plate 4 can be 200-350 N, and the pressing force of the third lower pressing plate 7 can be 100-180 N. The beating pressure of the third lower pressing plate 7 is 290-500 N. The beating pressure of the third lower pressing plate 7 is greater than the pressing force of the third lower pressing plate 7, for example, the former can be 2-4 times the latter. It should be understood that the above shows that the pneumatic mechanism is used to operate the pressing or beating action of the first, second and third lower pressing plates 3, 4 and 7, but the power mechanism of the first, second and third lower pressing plates 3, 4 and 7 is not limited to this, for example, a magnetic power mechanism (such as an electrophoretic magnet) can be used.

[0063] Then laser welding is performed. The laser unit includes a laser bracket 12, a laser guide rail 13, and a laser 14. The laser bracket 12 serves to mount the laser 14 and its associated components (such as the laser guide rail 13, the laser motion lead screw, the laser motor, etc.) to the machine tool and support these components. The laser motion lead screw is mounted inside the laser guide rail 13, and under the program instructions of laser welding, the motor drives the motion lead screw to make the laser 13 travel along the direction of the laser guide rail 13 to perform the welding action. The laser 14 outputs a laser beam with a given power according to the program instructions, melts the upper platinum sheet and the lower platinum sheet 40-80% in thickness to achieve the purpose of welding the platinum sheet. The welded cylindrical crucible wall is formed.

[0064] The laser can use IPG's QCw150W (spot diameter is 200um) or single-mode laser (focal spot 28um) for example, but is not limited to this. Beam mode is a major indicator of beam quality. The lower the beam mode order, the better the beam focusing performance, the smaller the spot, and the higher the power density under the same laser power. As shown in Figures 6-10 The welding path (pattern) can be straight, zigzag, wavy, spiral, etc. The spot can be a solid dot or a hollow ring.

[0065] The crucible wall prepared by the present application is welded with the stamping formed crucible bottom to form a platinum-gold crucible.

[0066] The following examples are further illustrated in detail to explain the present application. It should be understood that the following examples are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Some non-essential improvements and adjustments made by those skilled in the art according to the above content of the present application are within the scope of protection of the present application. The specific process parameters in the following examples are only one example in the appropriate range, i.e. those skilled in the art can make appropriate selection within the range according to the description herein, and are not limited to the specific values in the following examples.

[0067] Example 1

[0068] Cut the platinum plate (thickness: 0.16 mm, width: 550 mm, length: 150 mm), bend the platinum plate and insert the right end surface (forming the inner layer of the welding surface) between the mold and the first heavy pressing plate, the right side of the inner layer of the welding surface across the weld and 1 mm away from the preset weld position (weld), press down the first heavy pressing plate (pressing pressure: 220 N), and the right side of the first heavy pressing plate is 4.0 mm away from the weld. The platinum plate is bent around the mold and the left end surface of the platinum plate (forming the inner layer of the welding surface) is covered on the right end surface (forming the outer layer of the welding surface), the outer layer of the welding surface across the weld and 3.0-3.5 mm away from the weld, press down the second heavy pressing plate (pressing pressure: 260 N), at this time the right side of the second heavy pressing plate is next to the left side of the first heavy pressing plate, and the left side of the second heavy pressing plate is 2.0 mm away from the weld. Push the third heavy pressing support to make the third heavy pressing plate above the mold, press down the third heavy pressing plate (pressing pressure: 140 N) to make it next to the second heavy pressing plate, and press the third heavy pressing plate 3 times (pressing pressure: 420 N). Pull the third heavy pressing support to expose the weld position and then perform laser welding, the process parameters of laser welding are: power 150 W, welding pattern (Fig. 1), solid spot, spot diameter 28 μm, and welding speed 60 mm / S. Figure 6

[0069] Example 2

[0070] Except that the welding pattern (Fig. 2) is different from that of Example 1, the other parameters are the same as those of Example 1. Figure 7

[0071] Example 3

[0072] Except that the welding pattern (Fig. 3) is different from that of Example 1, the other parameters are the same as those of Example 1. Figure 8

[0073] Example 4

[0074] Except that the welding pattern (Fig. 4) is different from that of Example 1, the other parameters are the same as those of Example 1. Figure 9 ​​​, wavy broken line type, solid spot, spot diameter 28 μm) different from Example 1, other parameters same as Example 1.

[0075] Example 5

[0076] Except for the welding pattern Figure 10 , spiral type, solid spot, spot diameter 28 μm) different from Example 1, other parameters same as Example 1.

[0077] Comparative Example 1

[0078] No third heavy down plate is set, other parameters same as Example 1.

[0079] Comparative Example 2

[0080] The third heavy down plate does not perform tapping, other parameters same as Example 1.

[0081] The crucible wall formed by the above examples and comparative examples is welded with the stamping formed crucible bottom to form a platinum crucible, the loss rate is calculated, and the water tightness test is performed.

[0082] The entrusted sample is strictly tested according to the platinum laser welding inspection procedure:

[0083] I. Test conditions:

[0084] 1. The weld inspection should be performed under a certain intensity of light;

[0085] 2. The platinum crucible has a bottom (bottom, no bottom plus bottom or edge sealing).

[0086] II. Test method:

[0087] 1. Add room temperature water to the crucible mouth by 10 mm in the platinum crucible, and stand for 5 min;

[0088] 2. Carefully observe the weld for leakage with the naked eye;

[0089] 3. Add hydrochloric acid to the room temperature water in the platinum crucible at a proportion of 0.1%, and stand for 5 min.

[0090] 4. Wipe the weld with PH test paper, and carefully observe whether the PH test paper changes color.

[0091] III. Judgment standard:

[0092] If there is no leakage observed with the naked eye and the PH test paper does not change color, it is judged to be qualified. The formed crucible is used for crucible crystal growth at 600-1500°C. The loss rate and leakage after 7 days, 15 days and 30 days of service are observed. The test results are shown in Table 1.

[0093] Table 1

[0094]

Claims

1. A laser welding apparatus for precious metal plates, characterized in that, The laser welding device comprises a mold unit, a multiple pressing unit and a laser unit; the mold unit is used for supporting a noble metal plate, the multiple pressing unit is used for pressing a welding part of the noble metal plate, and the laser unit is used for laser welding the welding part of the noble metal plate; wherein the multiple pressing unit comprises: a first multiple pressing unit, which is used for positioning a first end of the noble metal plate on the mold unit; a second multiple pressing unit, which is used for positioning a second end of the noble metal plate on the mold unit in a form of being stacked above the first end of the noble metal plate; a third multiple pressing unit, which is used for pressing the noble metal plate; wherein a first multiple pressing plate of the first multiple pressing unit and a second multiple pressing plate of the second multiple pressing unit are located on one side of a preset welding seam position when being pressed, and a third multiple pressing plate of the third multiple pressing unit covers the preset welding seam position when being pressed and can be dragged to the other side of the preset welding seam position; the first multiple pressing plate of the first multiple pressing unit and the second multiple pressing plate of the second multiple pressing unit are respectively driven by a first multiple pressing power mechanism and a second multiple pressing power mechanism and are supported by a first-second multiple pressing common support; the third multiple pressing plate of the third multiple pressing unit is driven by a third multiple pressing mechanism and is supported by a third multiple pressing support; the third multiple pressing unit further comprises a horizontal movement mechanism for horizontally moving the third multiple pressing support supporting the third multiple pressing plate.

2. The laser welding apparatus of claim 1, wherein, the third multiple pressing unit further comprises a horizontal movement guide rail for guiding the horizontal movement of the third multiple pressing support supporting the third multiple pressing plate, and the lower end of the third multiple pressing support is placed on the horizontal movement guide rail.

3. The laser welding apparatus of claim 1, wherein, the lower end of the third multiple pressing support is provided with a spring.

4. The laser welding apparatus of claim 1, wherein, the third multiple pressing support comprises a plurality of fan-shaped ring-shaped pieces.

5. The laser welding apparatus of claim 1, wherein, the first multiple pressing plate, the second multiple pressing plate and / or the third multiple pressing plate are composed of a plurality of series pressing blocks.

6. The laser welding apparatus of claim 1, wherein, the mold unit comprises a mold and a mold fixed top clamp.

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