Wiping device for a stencil printer

Abstract

The present disclosure provides a squeegee device 700 for a stencil printer, comprising a squeegee holder 710, a squeegee 720 having a movement path for squeegeeing a material discharged onto a stencil 130, the squeegee 720 being disposed obliquely with respect to the stencil 130 and rearward of the movement path, and a mounting assembly 730 configured to attach the squeegee 720 to the squeegee holder 710. The mounting assembly 730 is further configured to adjust an inclination angle of the squeegee 720 with respect to the stencil 130 and maintain the squeegee 720 at the adjusted angular position.

Description

Technical Field

[0001] The present disclosure generally relates to a squeegee assembly in a stencil printer for printing a viscous material, such as solder paste, onto a substrate, such as a printed circuit board.

Background Art

[0002] In a typical circuit board manufacturing process, a stencil printer is used to print solder paste onto a printed circuit board. A circuit board, also referred to broadly as an electronic substrate, has a pattern of solder pads or some other conductive surfaces onto which solder paste can be deposited, and the circuit board is automatically fed into a stencil printer. Before printing the solder paste onto the circuit board, a particular hole or marking on the circuit board, referred to as a fiducial point, is used to align the circuit board with the stencil or mesh board of the stencil printer. The fiducial point is used as a reference point for aligning the circuit board with the stencil. When the circuit board is aligned with the printer's stencil, the circuit board is raised up to the stencil by a substrate support and fixed relative to the stencil. The stencil support may be, for example, a platform having pins or other article supports. Thereafter, the solder paste is ejected by moving a squeegee or squeezer over the stencil, whereby the solder paste lands on the circuit board through the holes of the stencil. The solder paste is typically ejected onto the stencil from a standard solder paste supply cartridge. When the printing operation is complete, the circuit board is released, lowered, and after being detemplated from the template, is conveyed to another location within the printed circuit board manufacturing line. As the squeegee moves across the stencil, the solder paste spreads in front of the squeegee, thereby helping the solder paste to be mixed as needed to achieve the desired viscosity and fill the holes of the mesh board or stencil.

Summary of the Invention

[0003] According to a first aspect of the present disclosure, the present disclosure provides a scraping device for a stencil printer, comprising a scraper holder, a scraper having a moving path for scraping the material discharged onto the stencil, the scraper being disposed obliquely with respect to the stencil and obliquely with respect to the rear of the moving path, and a mounting assembly configured to attach the scraper to the scraper holder. The mounting assembly is configured to adjust the inclination angle of the scraper with respect to the stencil and to maintain the scraper at the adjusted angular position.

[0004] According to the above-described scraping device, the mounting assembly includes a support column having a rotation axis and connected to the scraper holder. The scraper is connected to the support column, the scraper has a lateral length direction with respect to the moving path, and the length direction of the scraper coincides with the direction of the rotation axis. The inclination angle of the scraper with respect to the stencil is adjusted by rotating the support column about its rotation axis.

[0005] According to the above-described scraping device, the mounting assembly further includes a pair of connection blocks that respectively connect two axial ends of the support column to the scraper holder. The connection block has a locked state and an unlocked state. When the connection block is in the unlocked state, the support column can adjust the inclination angle of the scraper with respect to the stencil by rotating about its rotation axis. When the connection block is in the locked state, the connection block restricts the support column from rotating about its rotation axis so as to maintain the scraper at the adjusted angular position.

[0006] According to the above-mentioned scraping device, the connection block includes a hole and an opening communicating with the hole. The opening is disposed on one side of the hole. The hole is used to receive the axial end of the support column, and the opening divides the connection block into a first part and a second part, and the first part and the second part can be opened and contracted relative to each other to increase or decrease the size of the hole. The mounting assembly further includes a fastener for detachably fastening the first part and the second part at the opening so that the connection block has a locked state and an unlocked state.

[0007] According to the above-mentioned scraping device, the scraping device further includes an angle marking device. The angle marking device is fixedly connected to the support column and is configured to indicate the inclination angle of the scraper relative to the stencil based on its relative position with respect to the connection block.

[0008] According to the above-mentioned scraping device, the angle marking device is a marking plate. The marking plate is connected to one axial end of the support column and is configured to rotate with the support column.

[0009] According to the above-mentioned scraping device, the marking plate has a reference edge. The reference edge is arranged parallel to the scraper. An angular scale is provided on the connection block, and the scale pointed to by the reference edge represents the inclination angle of the scraper relative to the stencil.

[0010] According to the above-mentioned scraping device, the marking plate is located on the opposite side of the scraper in the connection block.

[0011] According to the above-mentioned scraping device, a limiting groove is provided on the marking plate. The limiting groove extends in the circumferential direction and receives a limiting pin disposed on the connection block.

[0012] According to the above-mentioned scraping device, the support column includes a generally flat support surface located on its first side.

[0013] According to the above-mentioned scraping device, the mounting assembly further includes a support plate. The support plate is clamped between the support surface of the support column and the scraper. The scraper can flex around the bottom edge of the support plate.

[0014] According to a second aspect of the present disclosure, the present disclosure provides a stencil printer including the scraping device according to the first aspect described above.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2A

Figure 2B

Figure 3A

Figure 3B

Figure 4A

Figure 4B

Figure 5

Figure 6A

Figure 6B

Figure 7A

Figure 7B

Figure 8A

Figure 8B

Figure 9A

Figure 9B

[0016] Various specific embodiments of the present disclosure will be described below with reference to the accompanying drawings, which form a part of this specification. Terms indicating directions such as "front", "rear", "upper", "lower", "left", "right", "top", "bottom", etc. are used in this disclosure to describe various exemplary structural components and elements of the present disclosure. It should be understood that these terms are used herein merely for the convenience of illustration and are determined based on the exemplary directions shown in the accompanying drawings. Since the examples disclosed in the present disclosure can be arranged in different directions, these terms indicating directions are for illustrative purposes only and should not be regarded as limiting.

[0017] FIG. 1 is a perspective view of a stencil printer 100 according to an example of the present disclosure. As shown in FIG. 1, the stencil printer 100 includes a rack 110 that supports various components of the stencil printer. The components of the stencil printer 100 include a controller 120, a display 125, a stencil 130, and a print head assembly or print head 140 for applying a material to be ejected (e.g., solder paste). The stencil 130 and the print head 140 can preferably be combined with or connected to the rack 110. In one example, the print head 140 can be attached to a print head bracket 150, and the print head bracket 150 can be attached to the rack 110. Under the control of the controller 140, the bracket 150 can move the print head 140 in the Y-axis direction perpendicular to the X-axis and the Z-axis. The print head 140 can be disposed above the stencil 130, and the front scraper or the rear scraper of the print head 140 can be lowered in the Z-axis direction to contact the stencil 130. Thereafter, via the bracket 150, the scraper of the print head 140 can move so as to pass through the stencil 130, enabling the solder paste to be printed onto the circuit board.

[0018] The stencil printer 100 can also include a conveyance system that includes a track 160 used to transfer a printed circuit board (which may also be referred to as a "printed wiring board", a "substrate", or an "electronic substrate") to a printing position inside the stencil printer 100. The track 160, also referred to herein as a "feeding mechanism", is configured to provide, load, or transfer a circuit board to the working area of the stencil printer 100 and to remove the circuit board from the working area. The stencil printer 100 has a support assembly 170 for supporting the circuit board.

[0019] In some examples, the print head 140 can be arranged to obtain solder material from a source such as a dispenser (e.g., a solder paste cartridge) that provides solder paste to the print head during the printing operation. Instead of a solder paste cartridge, other methods of supplying solder paste may be used. For example, the solder paste may be manually deposited between the scrapers, or the solder paste may be from an external source. Further, in some examples, the controller 120 may be set to control the operation of the stencil printer 100 using a personal computer having a Microsoft DOS or Windows® XP operating system with application-specific software. The controller 120 may be network-connected to a host controller used to control a production line for manufacturing circuit boards.

[0020] In some examples, the stencil printer 100 operates as follows. The circuit board is fed into the stencil printer 100 in the X-axis direction by the transport track 160. The support assembly 170 raises the circuit board and fixes it in the printing position. Next, the print head 140 lowers the desired print head squeegee in the Z-axis direction until the print head squeegee contacts the stencil 130 with the desired pressure. Then, the print head 140 moves in the Y-axis direction through the stencil 130 by the print head bracket 150. The print head 140 deposits the solder paste so that it falls onto the circuit board through the holes in the stencil 130. When the print head 140 completely crosses the stencil 130, the squeegee rises away from the stencil 130 and the circuit board lowers to return to the transport track 160. Thereafter, the circuit board is released and discharged from the stencil printer 100 to allow a second circuit board to be loaded into the stencil printer 100. To print on the second circuit board, a different squeegee contacts the stencil along the Z-axis and the print head 140 moves through the stencil 130 in a direction opposite to the direction used for the first circuit board.

[0021] Referring further to FIG. 1, an imaging system 180 can be provided to align the stencil 130 with the circuit board before printing and to inspect the circuit board after printing. In one example, the imaging system 180 can be disposed between the stencil 130 and a support assembly 170 that supports the circuit board. The imaging system 180 is connected to an imaging bracket 185 that moves the imaging system. In the scraper assembly, the imaging bracket 185 can be connected to the rack 110, and the imaging bracket 185 includes a beam extending between the side rails of the rack 110 such that the imaging system 180 can move back and forth in the Y-axis direction above the circuit board. Also, the imaging bracket 185 can include a transfer device that surrounds the imaging system 180 from the outside and is arranged to move in the X-axis direction along the length of the beam. The structure of the imaging bracket 185 for moving the imaging system 180 is well known in the technical field of solder paste printing. The method is as follows. The imaging system 180 can be disposed at an arbitrary position below the stencil 130 above the circuit board to obtain images of a predetermined area of the circuit board or the stencil, respectively.

[0022] In the scraper assembly, the print head 140 includes a frame member 145 that forms part of the bracket 150. The frame member 145 is configured to move along a printing direction such as the Y-axis direction. In particular, the frame member 145 is configured to slide along a linear track (not shown in FIG. 1) of the rack 110 of the stencil printer 100 at both ends thereof. With this structure, the print head bracket 150 can move in the Y-axis direction. In the scraper assembly, the frame member 145 supports a scraping device having a front scraper and a rear scraper, and a moving mechanism configured to move the scraper independently. Under the control of each moving mechanism, each scraper is configured to move along the Z-axis direction from a high position having a certain distance from the stencil 130 to a low position where it engages with the stencil 130 and applies pressure to the stencil 130.

[0023] Figures 2A and 2B show the overall structure of the scraping device 200 by the scraper assembly of the present disclosure. Figure 2A is a perspective view of the scraping device 200 from a certain perspective, and Figure 2B is a perspective view of the scraping device 200 from another perspective of Figure 2A. As shown in Figures 2A and 2B, the scraping device 200 includes a scraper holder 210, a scraper 220, and an attachment assembly 230 for attaching the scraper 220 to the scraper holder 210. The scraper holder 210 is connected to a moving mechanism of the scraper (not shown in the figure). The scraper 220 is, for example, a front scraper. For the sake of easy illustration, in the scraping device 200 shown in Figures 2A to 2C, only the front scraper and its attachment elements are shown, and the rear scraper and its attachment elements are removed. Further, the scraping device 200 can also include other components not shown in the figure.

[0024] The scraper 220 has a moving path for scraping the material (solder paste) discharged onto the stencil 130, and the moving path extends along the Y-axis direction. The scraper 220 is generally rectangular with a long side 221 and a short side 223. The length direction of the scraper 220 coincides with the X-axis direction and is a direction transverse to the moving path. The scraper 220 is arranged obliquely with respect to the stencil 130 and obliquely with respect to the rear of the moving path so as to apply pressure to the material discharged onto the stencil 130 through the scraper 220 and cause the discharged material to fall onto the electronic substrate under the stencil 130 through the holes of the stencil 130. In addition to being able to attach the scraper 220 to the scraper holder 210, the attachment assembly 230 can adjust the inclination angle of the scraper 220 with respect to the stencil 130. Also, the attachment assembly 230 can maintain the scraper 220 at the adjusted angular position so that the scraper 220 can perform the scraping operation at the adjusted inclination angle.

[0025] Figures 3A and 3B show specific components of the mounting assembly 230. Figure 3A is an exploded view of the scraping device 200, and Figure 3B is an exploded view of some components of the scraping device 200. As shown in Figures 3A and 3B, the mounting assembly 230 includes a support column 310 for supporting and holding the scraper 220, and a pair of connection blocks 320 for connecting the support column 310 to the scraper holder 210. The mounting assembly 230 further includes a support plate 330 and a back plate 340 for better connecting and holding the scraper 220 at the support column 310.

[0026] The support column 310 is generally cylindrical with a rotation axis X, and a pair of connection blocks 320 respectively connect two axial ends 312 of the support column 310 to the scraper holder 210. The longitudinal direction of the scraper 220 coincides with the direction of the rotation axis X, and the inclination angle of the scraper 220 with respect to the stencil 130 is adjusted by rotating the support column 3i0 about its rotation axis X. The support column 310 has a generally flat support surface 315 disposed on its first side. The support surface 315 is formed, for example, by cutting off a part of the support column 310 extending along the rotation axis X beyond the long side 221 of the scraper 220. The support plate 330 is generally rectangular, is clamped between the support surface 315 and the scraper 220, and the support surface 315, the support plate 330, and the scraper 220 are generally parallel. The support plate 330 has a bottom edge 335, and the scraper 220 can bend rearward along its movement path around the bottom edge 335 of the support plate 330 to perform the scraping operation better. Using the support plate 330, the area of the surface supporting the scraper 220 is enlarged. Of course, depending on the scraper assembly, the support surface 315 on the support column 310 may be set to a sufficient size such that the mounting assembly 230 does not include the support plate 330.

[0027] To connect the scraper 220, the support plate 330, and the support column 310, two sets of fasteners, namely, a first set of fasteners 350 and a second set of fasteners 370, are arranged in the scraper assembly of the present disclosure. The first set of fasteners 350 first connects the scraper 220 as a sub-assembly to the support plate 330, and then the second set of fasteners 370 connects the sub-assembly of the scraper 220 and the support plate 330 to the support column 310. In particular, the first set of fasteners 350 connects the scraper 220 to the support plate 330 from the first side of the support column 310 (i.e., the side where the support surface 315 is arranged), and the second set of fasteners 370 connects the support plate 330 to the support column 310 from the second side, which is opposite to the first side of the support column 310. The first set of fasteners 350 includes a plurality of fasteners such as bolts. The second set of fasteners 370 also includes a plurality of fasteners such as bolts. When the scraper 220 is connected to the support column 310, the rotational position about the rotation axis X of the support column 310 can be adjusted, that is, the inclination angle of the scraper 220 with respect to the stencil 130 can be adjusted.

[0028] A pair of connection blocks 320 are respectively connected to the scraper holder 210 by a plurality of fasteners (e.g., bolts) 360.

[0029] FIGS. 4A and 4B show the specific structure of one of the pair of connection blocks 320 of the mounting assembly 230. The structures of the pair of connection blocks 320 are the same. FIG. 4A is a perspective view of the connection block 320, and FIG. 4B is a side view of the connection block 320. As shown in FIGS. 4A and 4B, the connection block 320 is generally square and is connected to the scraper holder 210 at its top 425.

[0030] The connection block 320 includes a hole 421 that penetrates through a first side surface 432 and a second side surface 434 facing each other, an opening 423 that communicates with the hole 421, is disposed at the bottom 427 of the connection block 320, and also penetrates through the first side surface 432 and the second side surface 434 of the connection block 320. The opening 423 divides the connection block 320 into a first portion 426 and a second portion 428 that can be deflected relative to each other. The first portion 426 and the second portion 328 are connected at the top 425 of the connection block 320 and separated by the opening 423 at the bottom 427 of the connection block 320. Therefore, the first portion 426 and the second portion 428 can be opened and contracted relative to each other. The hole 421 is formed by the inner walls of the first portion 426 and the second portion 428 together, whereby the radial dimension (e.g., cross-section) of the hole 421 can be increased and reduced by opening and contracting the first portion 426 and the second portion 428 relative to each other. The hole 421 is used to receive the axial end 312 of the support column 310. The axial end 312 of the support column 310 can be clamped by the connection block 320 when the radial dimension of the hole 421 is reduced, and the axial end 312 of the support column 310 can be disengaged by the connection block 320 when the radial dimension of the hole 421 is increased.

[0031] The mounting assembly 230 further includes a fastener 390 that detachably fastens the first portion 426 and the second portion 428 to each other by passing through the opening 423. By the fastener 390, the connection block 320 can have a locked state and an unlocked state. When the fastener 390 is loosened so that the first portion 426 and the second portion 328 [as in the original text: 428] of the connection block 320 open with respect to each other, the connection block 320 is in the unlocked state, and the axial end 312 of the support post 310 is disengaged by the connection block 320. Accordingly, the support post 310 can adjust the tilt angle of the scraper 220 with respect to the stencil 130 by rotating about its rotation axis X. When the fastener 390 is fastened so that the first portion 426 and the second portion 328 [as in the original text: 428] of the connection block 320 cannot open with respect to each other, the connection block 320 is in the locked state, and the axial end 312 of the support post 310 is clamped by the connection block 320. Accordingly, the connection block 320 restricts the rotation of the support post 310 about its rotation axis X, thereby maintaining the scraper 220 at the adjusted angular position.

[0032] Slots 429 are provided in both the first portion 426 and the second portion 428 of the connection block 320, and the slots 429 also penetrate the first side surface 432 and the second side surface 434 of the connection block 320, but the slots 429 do not communicate with the holes 421. The slots 429 divide the first portion 426 / second portion 428 of the connection block 320 into two sections connected to each other such that their connection part becomes very thin, thereby improving the deformability (i.e., weakening its rigidity) of the first portion 426 and the second portion 428 and enabling the first portion 426 and the second portion 328 [as in the original text: 428] to more easily open and contract with respect to each other.

[0033] FIG. 5 shows the specific structure of the support post 310 in the mounting assembly 230. As shown in FIG. 5, the axial end 312 of the support post 310 is still cylindrical, and the support surface 315 is located between the axial ends 312.

[0034] Figures 6A and 6B show side views of the scraper 220 with respect to the stencil 130 at a first tilt angle position and a second tilt angle position, respectively. In Figure 6A, the interior angle between the scraper 220 and the stencil 130 is θ1, and in Figure 6B, the interior angle between the scraper 220 and the stencil 130 is θ2, and θ1 is greater than θ2. The interior angle between the scraper 220 and the stencil 130 (i.e., the tilt angle of the scraper 220 with respect to the stencil 130) is achieved by rotating the support post 310 about its rotation axis X. By rotating the support post 310, the scraper 220 connected thereto rotates together, thereby adjusting the tilt angle of the scraper 220 with respect to the stencil 130. When it is necessary to adjust the tilt angle of the scraper 220 with respect to the stencil 130, the connecting block 320 can be released from the locked state by loosening the fastener 390 (Figure 3A), that is, by rotating the support post 310 about its rotation axis X. When the tilt angle of the scraper 220 with respect to the stencil 130 is adjusted to a desired angle, the connecting block 320 can be locked from the released state by tightening the fastener 390 (Figure 3A), that is, by restricting the rotation of the support post 310 about its rotation axis X, thereby maintaining the scraper 220 at the adjusted angular position.

[0035] Figures 7A and 7B show a scraping device 700 by another scraper assembly of the present disclosure. Figure 7A is a perspective view of a certain perspective of the scraping device 700, and Figure 7B is a perspective view of another perspective of the scraping device 700. The scraping device 700 shown in Figures 7A and 7B is similar to the scraping device 200 shown in Figures 2A and 2B, and also includes a scraper holder 710, a scraper 720, and a mounting assembly 730 for attaching the scraper 720 to the scraper holder 710. The mounting assembly 730 can adjust the inclination angle of the scraper 720 with respect to the stencil 130. The scraping device 700 is different from the scraping device 200 in that the scraping device 700 further includes an angle indication device for indicating the inclination angle of the scraper 720 with respect to the stencil 130. Furthermore, the scraping device 700 further includes a pair of vertically movable baffles 780 disposed on both sides of the movement path of the scraper 720, and a pair of elastic plates 790 for resetting the pair of baffles 780 respectively.

[0036] Figures 8A and 8B show the specific structure of the scraping device 700. Figure 8A is a partial exploded view of the scraping device 700, and Figure 8B is another partial exploded view of the scraping device 700. Figure 8B shows the perspective from the rear side of Figure 8A. As shown in Figures 8A and 8B, the mounting assembly 730 includes a support column 810 and a pair of connection blocks 820. The support column 810 and the pair of connection blocks 820 are respectively connected to the scraper holder 710 by a plurality of fasteners (e.g., bolts) 860. The mounting assembly 730 further includes a support plate 830 and a back plate 840 for better connecting and holding the scraper 720 at the support column 810. The support column 810, the support plate 830, and the back plate 840 have the same structure as the support column 310, the support plate 330, and the back plate 340 of the scraping device 200, respectively. Therefore, they will not be described herein. The connection block 820 is structurally similar to the connection block 320 of the scraping device 200, but is different in that a slot 429 is arranged in the connection block 320 while it is not arranged in the connection block 820. The connection block 820 includes a hole 821 and an opening 823 that is arranged on one side of the hole 821 and communicates with the hole 821. The opening 823 divides the connection block 820 into a first part 826 and a second part 828. The first part 826 and the second part 828 can be opened and contracted relative to each other to increase or decrease the size of the hole 821. The first part 826 and the second part 828 are detachably fastened at the opening 823 by a fastener 890 so that the connection block 820 has a locked state and an unlocked state. When the connection block 820 is in the unlocked state, the support column 310 can rotate to adjust the inclination angle of the scraper 720 with respect to the stencil 130. When the connection block 820 is in the locked state, the support column 310 cannot rotate, thereby maintaining the scraper 720 at the adjusted angular position.

[0037] Unlike the scraping device 200 that connects the support column 310, the support plate 330, the scraper 220, and the back plate 340 by two sets of fasteners, the scraping device 700 connects the support column 810, the support plate 830, the scraper 720, and the back plate 840 by the positioning pin 817 disposed on the support column 810 and a set of fasteners 850. In particular, first, the support plate 830 is positioned relative to the support column 810 by the positioning pin 817, and then the support plate 830, the scraper 720, and the back plate 840 are fastened to the support column 810 by the fastener assembly 850. In this way, the scraper 720 is clamped between the support plate 830 and the back plate 840 and can bend around the bottom edge 835 of the support plate 830. The support plate 830 abuts against the support surface 815 of the support column 310. The rotational position of the support column 810 about its rotation axis X can be adjusted, that is, the inclination angle of the scraper 720 relative to the stencil 130 can be adjusted.

[0038] Furthermore, as shown in FIGS. 8A and 8B, the scraper assembly 700 further includes an angle indicating device fixedly connected to the support column 810. The position of the angle indicating device relative to the connection block 820 can indicate the inclination angle of the scraper 720 relative to the stencil 130. The angle indicating device is, for example, an indicating plate 750 fastened by a fastener 756 to one axial end of the support column 810 and configured to rotate with the support column 810. The indicating plate 750 is positioned on the side of the connection block 820 opposite to the support column 810. As can be seen from FIGS. 8A and 8B, the support column 810 is positioned inside the connection block 820, while the indicating plate 750 is positioned outside the connection block 820. The indicating plate 750 is generally fan-shaped and has a reference edge 752 disposed parallel to the scraper 720 (see FIGS. 9A and 9B). The connection block 820 is provided with an angular scale 822, and the scale indicated by the reference edge 752 represents the inclination angle of the scraper 720 relative to the stencil 130.

[0039] In addition, a limiting groove 753 is also provided on the indicator plate 750, and the limiting groove 753 extends in the circumferential direction. A limiting pin 757 is provided on the connection block 820 and is received in the limiting groove 753, and can move along the limiting groove 753 as the indicator plate 750 rotates. The limiting groove 753 engages with the limiting pin 757 to limit the rotation range of the indicator plate 750 so as to facilitate the angle adjustment of the scraper 720.

[0040] Furthermore, as shown in FIGS. 8A and 8B, a pair of baffles 780 of the scraper assembly 700 are used to hold the solder paste in the moving path of the scraper 720 during the squeegeeing of the material (solder paste) applied by the scraper 720. The baffle 780 is movably connected to the connection block 820 vertically by a fastener 783. The baffle 780 is disposed on the side connected to the support post 810 of the connection block 820. The baffle 780 is generally U-shaped and thus has a space for avoiding the support post 810 so that the baffle 780 does not interfere with the support post 810 during vertical movement. A pair of chutes 785 are provided on the baffle 780, and the fastener 783 disposed on the connection block 820 is received in the chute 785 and can move along the chute 785, thereby enabling the movement of the baffle 780 relative to the connection block 820.

[0041] When squeegeeing the solder paste with the squeegee 720, it is necessary to apply a certain amount of pressure to the stencil 130. Therefore, the squeegee assembly 700 descends with respect to the stencil 130 and deforms the squeegee 720 to apply pressure. In order to hold the solder paste in the movement path of the squeegee 720, it is necessary that when operating, the lowermost ends of the pair of baffles 780 and the lowermost end of the squeegee 720 are all in contact with the stencil 130. Therefore, in order to hold the solder paste in the movement path of the squeegee 720 without affecting the operation of the squeegee 720, the baffle 780 needs to be able to move up and down with respect to the connection block 820 and the squeegee holder 710. That is, the baffle 780 needs to move upward when pressure is applied to the stencil by the squeegee 720 and the stencil deforms, and the baffle 780 needs to move downward when the pressure applied to the stencil by the squeegee 729 is removed or the applied pressure decreases in order to return the stencil to its original state. In this way, the lowermost end of the baffle 780 is always on the same plane as the lowermost end of the squeegee 720 (that is, both are in contact with the stencil 130), and the baffle 780 always holds the solder paste in the movement path of the squeegee 720 without affecting the operation of the squeegee 720. In order to enable the baffle 780 to move up and down with respect to the mounting block 820 along with the deformation of the squeegee 720, the squeegee assembly 700 further includes a pair of elastic plates 790 that are connected to the squeegee holder 710 and extend to above the position of the pair of baffles 780 respectively. Furthermore, the pair of elastic plates 790 are configured to be elastically deformed by the thrust of the baffle 780 when the pair of baffles 780 move upward and to enable the pair of baffles 780 to move downward by the restoring force.

[0042] Figures 9A and 9B are side views of the scraper 720 in the wiper device 700 with respect to the stencil 130 at the first tilt angle position and the second tilt angle position, respectively, and the baffle 780 is not shown to clarify the scraper 720. In FIG. 9A, the interior angle between the scraper 720 and the stencil 130 is θ3, and in FIG. 9B, the interior angle between the scraper 220 and the stencil 130 is θ4. As shown in FIG. 9A, the reference edge 752 of the indicator plate 750 is aligned at a 65-degree scale, which indicates that the interior angle θ3 between the scraper 720 and the stencil 130 is 65 degrees. As shown in FIG. 9B, the reference edge 752 of the indicator plate 750 is aligned at a 40-degree scale, which indicates that the interior angle θ4 between the scraper 720 and the stencil 130 is 40 degrees. Through the angle indicated by the reference edge 752 of the indicator plate 750, the operator can easily identify and adjust the tilt angle of the scraper 720 with respect to the stencil.

[0043] Through long-term observation, the inventors of the present disclosure found that the inclination angle of the scraper of the existing stencil printer with respect to the stencil cannot be adjusted. That is, regardless of the viscosity of the material to be ejected, the size of the holes in the stencil, etc., the inclination angle of the scraper with respect to the stencil is the same. Therefore, the same pressure is always applied to the stencil by the scraper, whereby the falling speed of the material ejected from the stencil printer from the stencil onto the electronic substrate below the stencil often does not reach the desired speed. For this purpose, the present disclosure provides a scraper assembly and a stencil printer using the scraper assembly. In the scraper assembly of the present disclosure, the angle of the scraper with respect to the stencil can be adjusted as required, and a mounting assembly is arranged so that the stencil can be maintained at the adjusted angular position. More specifically, when used on-site, various influencing factors such as the viscosity of the material to be ejected and the size of the holes in the stencil are also considered in order to adjust the angle of the scraper with respect to the stencil so that the material to be ejected, which is squeegeed by the scraper, falls from the holes of the stencil onto the electronic substrate below the stencil at a desired speed. Furthermore, the mounting assembly of the scraper assembly of the present disclosure for adjusting the angle of the scraper with respect to the stencil not only has a simple structure but also is easy to operate, whereby the on-site operation operator can easily adjust the angle of the scraper with respect to the stencil.

[0044] Although the present disclosure has been described in conjunction with the example of the scraper assembly outlined above, various alternative, modified, changed, improved, and / or substantial equivalents may be apparent to at least those of ordinary skill in the art, whether now known or foreseeable in the present or near future. Additionally, the technical effects and / or technical problems described herein are exemplary and not limiting. Thus, the disclosure herein may be used to solve other technical problems, may have other technical effects, and / or may solve other technical problems. Therefore, the example of the scraper assembly of the present disclosure described above is exemplary and not intended to be limiting. Various changes can be made without departing from the spirit or scope of the present disclosure. Accordingly, the present disclosure is intended to include all known or previously developed alternative, modified, changed, improved, and / or substantial equivalents.

Claims

1. A scraping device (200, 700) for a stencil printer, comprising: a scraper holder (210, 710); a scraper (220, 720) having a movement path for squeegeeing a material discharged onto a stencil (130), the scraper (220, 720) being disposed obliquely with respect to the stencil (130) and obliquely with respect to the rear of the movement path; a mounting assembly (230, 730) configured to attach the scraper (220, 720) to the scraper holder (210, 710); wherein the mounting assembly (230, 730) is configured to be able to adjust an inclination angle of the scraper (220, 720) with respect to the stencil (130) and to be able to maintain the scraper (220, 720) at an adjusted angular position; the scraping device (200, 700).

2. The mounting assembly (230, 730) comprises: a support column (310, 810) having a rotation axis X, the support column (310, 810) being connected to the scraper holder (210, 710); wherein the scraper (220, 720) is connected to the support column (310, 810), the scraper (220, 720) has a longitudinal direction transverse to the movement path, and the longitudinal direction of the scraper (220, 720) coincides with the direction of the rotation axis X; the inclination angle of the scraper (220, 720) with respect to the stencil (130) is adjusted by rotating the support column (310, 810) about its rotation axis X; the scraping device (200, 700) according to Claim 1.

3. The mounting assembly (230, 730) further comprises: a pair of connection blocks (320, 820) that respectively connect two axial ends of the support column (310, 810) to the scraper holder (210, 710); wherein The connection blocks (320, 820) have a locked state and an unlocked state. When the connection blocks (320, 820) are in the unlocked state, the support columns (310, 810) can adjust the tilt angle of the scraper (220, 720) with respect to the stencil (130) by rotating about the rotation axis X thereof. When the connection blocks (320, 820) are in the locked state, the connection blocks (320, 820) limit the support columns (310, 810) from rotating about the rotation axis X thereof so as to maintain the scraper (220, 720) at the adjusted angular position. The scraping device (200, 700) according to claim 2.

4. The connection blocks (320, 820) include holes (421, 821) and openings (423, 823) communicating with the holes (421, 821). The openings (423, 823) are arranged on one side of the holes (421, 821) so as to receive the axial end portions of the support columns (310, 810). The openings (423, 823) divide the connection blocks (320, 820) into a first portion (426, 826) and a second portion (428, 828), and the first portion (426, 826) and the second portion (428, 828) can be opened and contracted relative to each other so as to increase or reduce the size of the holes (421, 821). The mounting assembly (230, 820) further includes a fastener (390, 890) that detachably fastens the first portion (426, 826) and the second portion (428, 828) in the opening (423, 823) so that the connection block (320, 820) has the locked state and the unlocked state. The scraping device (200, 700) according to claim 3.

5. Furthermore, an angle indicating device fixedly connected to the support column (810), configured to indicate the tilt angle of the scraper (720) with respect to the stencil (130) based on its relative position with respect to the connection block (820). The scraping device (700) according to claim 3, comprising the above.

6. The angle indicating device is an indicating plate (750) connected to one axial end of the support column (810), and the indicating plate (750) is configured to rotate together with the support column (810). The scraping device (700) according to claim 5.

7. The indicating plate (750) has a reference edge (752) arranged parallel to the scraper (720). An angular scale is provided on the connection block (820), and the scale pointing to the reference edge (752) represents the inclination angle of the scraper (720) with respect to the stencil (130). The scraping device (700) according to claim 6.

8. The indicating plate (750) is located on the opposite side of the scraper (720) in the connection block (820). The scraping device (700) according to claim 6.

9. A limiting groove (753) is provided on the indicating plate (750), and the limiting groove (753) extends in the circumferential direction and receives a limiting pin (757) arranged on the connection block (320). The scraping device (700) according to claim 6.

10. The support columns (310, 810) are provided with generally flat support surfaces (315, 815) positioned on their first sides. The scraping devices (200, 700) according to claim 2.

11. The mounting assembly (230, 730) Support plates (330, 830) clamped between the support surfaces (315, 815) of the support columns (310, 810) and the scrapers (220, 720). further comprises The scrapers (220, 720) can flex around the bottom edges (335, 835) of the support plates (330, 830). The scraping devices (200, 700) according to claim 10.

12. A stencil printer comprising the scraping device (200, 700) according to any one of claims 1 to 11.

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