SMT patch detection equipment

Abstract

The invention relates to the technical field of quality detection, in particular to SMT patch detection equipment which comprises a visual detection machine, an annular transmission line and a conveying table, detection openings for conveying of the conveying table are formed in the two sides of a shell of the visual detection machine, and the annular transmission line can drive the conveying table to do annular reciprocating motion. A camera in the visual inspection machine is located over a conveying track of the conveying table and detects the PCB located on the conveying table, the angle regulation and control assembly is installed on the conveying table, and the two sets of push-pull assemblies are installed in the visual inspection machine and are oppositely arranged. According to the invention, the annular transmission line drives the conveying table to move in a reciprocating manner, and the angle regulation and control assembly and the push-pull assembly are combined, so that multi-angle detection of PCBs in assembly line work can be realized, and compared with a traditional one-chip-one-detection manner, hardware cost is effectively reduced, detection efficiency and precision are greatly improved, large-scale production requirements are met, and large-scale popularization and application are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of quality inspection, and particularly to an SMT patch detection device. Background Art

[0002] An SMT patch detection device is a device used to detect the mounting quality of electronic components during the production process of surface mount technology (SMT). It usually involves checking the correct position of the patches, defects (such as misalignment, warping, damage, etc.), welding quality, and other related quality issues.

[0003] Most of the existing technologies use vision detection devices to convert the optical image of the object to be detected into an electrical signal or digital signal through an imaging system composed of a light source, a lens, and a camera. As a result, the camera is installed directly above the SMT patch detection location, and the camera can only capture the horizontal view of the PCB board to be detected. Although it can clearly capture the position distribution diagrams of surface-mounted components, the PCB board, and the surface of the leads, etc., and ensure accurate comparison with the reference diagram and / or data during the subsequent detection process, limited by the shooting angle, it cannot effectively ensure whether the surface-mounted components are stably connected to the PCB board and whether the solder joints at the tin soldering positions form firm solder joints with the component pins and PCB pads.

[0004] The solution of the existing technology is usually "one-piece-one-inspection". By moving the SMT to be detected to below the camera through a single clamping tooling, and by flipping the clamping tooling or adjusting the camera angle, the detection accuracy can be improved through multi-angle comparison. However, this is difficult to apply in the assembly line operation, and the detection efficiency is low. If it is to be applied in the assembly line operation, at least the clamping tooling needs to be able to be flipped on the assembly line (such as if the camera moves multi-angularly and there is a deviation in resetting, it is easy to have problems in the subsequent comparison). And installing a servo motor on each clamping tooling group for flipping results in a high detection cost, which is not conducive to the development of large-scale detection. Summary of the Invention

[0005] (I) Technical Problems to be Solved The technical problem to be solved by the present invention is to overcome the deficiencies of the existing technology and provide an SMT patch detection device, which solves the problems raised in the above background art.

[0006] (II) Technical Solutions To achieve the above object, the present invention provides an SMT patch detection device, including a vision detection machine, a circular transmission line, and a conveying table. Detection ports for the conveying table to pass through are opened on both sides of the outer shell of the vision detection machine. The circular transmission line can drive the conveying table to move reciprocally along a circular path. The camera in the vision detection machine is located directly above the conveying trajectory of the conveying table and detects the PCB board located on the conveying table. Its characteristics are as follows: An angle adjustment component installed on the conveying table. The angle adjustment component includes two oppositely arranged support plates, a support shaft rotatably connected between the two support plates, a placement table fixed on the support shaft, a gear, and a rack. One end of the support shaft protrudes from the support plate and is fixed to the gear. The rack is embedded and slides on the conveying table and meshes with the gear. Hook openings are provided at both ends of the rack. Two sets of oppositely arranged push-pull components installed inside the vision inspection machine. The push-pull component includes an electric push rod, a protective shell, a first connecting rod, a second connecting rod, a hook, a pressing member, and a spring. The two electric push rods are respectively fixed on both sides of the conveying path of the conveying table. The output ends of the two electric push rods face each other. The protective shell is fixed on the output end of the electric push rod. The first connecting rod is fixed to the protective shell. The hook is rotatably connected to the protective shell and can be hooked into the hook opening. A moving chute is provided at the tail end of the hook. One end of the second connecting rod is hinged to the first connecting rod, and the other end is embedded and slidably engaged with the moving chute. The pressing member is slidably connected to the protective shell, and the inner bottom thereof extends into the protective shell and can abut against the second connecting rod. Both ends of the spring are respectively fixed to the protective shell and the second connecting rod, and the hook is reset by rebounding. A pressing rod, which is fixed on the support plate and one end of which can abut against the pressing member. During the process of the electric push rod pushing / pulling the protective shell to move, the pressing member is gradually pressed down under the restriction of the pressing rod.

[0007] Optionally, support pieces are fixed at the included angle between the first connecting rod and the protective shell, and the support pieces are fixed to the first connecting rod and the protective shell.

[0008] Optionally, limiting pieces are fixed on both sides of the bottom of the pressing member. The second connecting rod is located between the two limiting pieces, and the gap between the bottom of the limiting piece and the inner bottom of the protective shell is adapted to the pressing depth of the pressing member.

[0009] Optionally, the pressing distance of the pressing member is greater than the width of the hook opening.

[0010] Optionally, a baffle extends around the periphery of the placement table. The height of the baffle is greater than the thickness of the PCB board, and the inclination angle of the placement table ≤ 45°.

[0011] Optionally, a rubber gasket is adhered to the surface of the placement table in contact with the PCB board, and anti-slip patterns are provided on the rubber gasket.

[0012] Optionally, a side rail is provided on one side of the support plate where the rack is located. The side rail is fixed to the conveying table, and the rack is slidably connected between the side rail and the support plate. One side of the rack is embedded and slidably engaged with the side rail.

[0013] Optionally, the length of the side rail is less than the length of the rack.

[0014] Optionally, an annular bottom rail is fixed on the annular transmission line. The conveying table is embedded and slidably connected to the bottom rail and reciprocates along the bottom rail.

[0015] Optionally, a rotating block is provided at the connection between the placement table and the support shaft, and the rotating block is fixed to the support shaft and the placement table.

[0016] (III) Advantageous Effects Compared with the prior art, the present invention provides an SMT patch detection device, which has the following advantageous effects: 1. The present invention drives the conveying table to reciprocate through the annular transmission line, and combines the angle adjustment component and the push-pull component to realize multi-angle detection of the PCB board during the operation of the assembly line, greatly improving the detection efficiency and accuracy, and meeting the requirements of large-scale production; 2. The present invention completes the angle adjustment of the PCB board through the cooperation of the adjustment component and the push-pull component, etc., effectively reducing the hardware cost and facilitating large-scale popularization and application; 3. The present invention fixes support pieces at the angles between the first connecting rod and the protective shell, and the support pieces are fixed to the first connecting rod box and the protective shell, ensuring the stable connection between the first connecting rod and the protective shell during movement, preventing movement deviation caused by loose connection, ensuring the movement accuracy of the push-pull component, and further improving the accuracy of the PCB board angle adjustment, providing strong support for the detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of the overall structure of the present invention; Figure 2 shows Figure 1 the enlarged structural schematic diagram of part A in Figure 3 shows Figure 1 the enlarged structural schematic diagram of part B in Figure 4 shows Figure 1 the side view structural schematic diagram; Figure 5 shows the partial structural schematic diagram; Figure 6 shows the structural schematic diagram of the angle adjustment component and the push-pull component; Figure 7 shows the structural schematic diagram of the push-pull component; Figure 8 shows the structural schematic diagram inside the protective shell of the push-pull component; Figure 9 shows Figure 8 the partial structural schematic diagram of Figure 10 shows the structural schematic diagram of the conveying table.

[0018] In the figure: 1. Visual inspection machine; 2. Ring transmission line; 3. Conveyor table; 4. Detection port; 5. Angle adjustment component; 501. Support plate; 502. Support shaft; 503. Placement table; 504. Gear; 505. Rack; 6. Hook port; 7. Push-pull component; 701. Electric push rod; 702. Protective shell; 703. First connecting rod; 704. Second connecting rod; 705. Hook; 706. Pressing piece; 707. Spring; 8. Moving chute; 9. Pressing rod; 10. Support piece; 11. Limiting piece; 12. Baffle; 13. Rubber gasket; 14. Side rail; 15. Bottom rail; 16. Rotating block. Detailed implementation mode

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] Embodiment: Please refer to Figures 1 to 10 , and a technical solution is provided according to an embodiment of the present invention: An SMT patch detection device includes a visual inspection machine 1, a ring transmission line 2, and a conveyor table 3. Detection ports 4 for the conveyor table 3 to convey are opened on both sides of the outer shell of the visual inspection machine 1. The ring transmission line 2 can drive the conveyor table 3 to move reciprocally along a ring. The camera in the visual inspection machine 1 is located directly above the conveying track of the conveyor table 3 and detects the PCB board located on the conveyor table 3. Its characteristics are as follows: An angle adjustment component 5 installed on the conveyor table 3. The angle adjustment component 5 includes two relatively arranged support plates 501, a support shaft 502 rotatably connected between the two support plates 501, a placement table 503 fixed on the support shaft 502, a gear 504, and a rack 505. One end of the support shaft 502 protrudes from the support plate 501 and is fixed to the gear 504. The rack 505 is embedded and slides on the conveyor table 3 and meshes with the gear 504. Hook ports 6 are opened at both ends of the rack 505; Two sets of relatively arranged push-pull components 7 installed in the vision inspection machine 1. The push-pull component 7 includes an electric push rod 701, a protective shell 702, a first connecting rod 703, a second connecting rod 704, a hook 705, a pressing member 706 and a spring 707. The two electric push rods 701 are respectively fixed on both sides of the conveying path of the conveying table 3. The output ends of the two electric push rods 701 are opposite. The protective shell 702 is fixed on the output end of the electric push rod 701. The first connecting rod 703 is fixed to the protective shell 702. The hook 705 is rotatably connected to the protective shell 702 and can be hooked into the hook opening 6. A moving chute 8 is provided at the tail end of the hook 705. One end of the second connecting rod 704 is hinged to the first connecting rod 703, and the other end is embedded and slidably engaged with the moving chute 8. The pressing member 706 is slidably connected to the protective shell 702, and its inner bottom extends into the protective shell 702 and can abut against the second connecting rod 704. The two ends of the spring 707 are respectively fixed to the protective shell 702 and the second connecting rod 704, and the hook 705 is reset by rebounding; A pressing rod 9, the pressing rod 9 is fixed on the support plate 501, and one end can abut against the pressing member 706. During the process of the electric push rod 701 pushing / pulling the protective shell 702 to move, the pressing member 706 is gradually pressed down by the restriction of the pressing rod 9.

[0021] It should be noted that the vision inspection machine 1, the annular transmission line 2 and the conveying table 3 are all prior arts.

[0022] The vision inspection machine 1 is an imaging system composed of a light source, a lens and a camera, etc., which converts the optical image of the object to be detected into an electrical signal or a digital signal. Among them, the light source is used to illuminate the object to provide sufficient contrast and brightness for the camera to obtain a clear image; the lens is responsible for imaging the object on the photosensitive element of the camera; the camera converts the optical signal into a digital image signal for subsequent processing and analysis; After that, according to the requirements of the detection task, information related to the object features, such as edges, corner points, contours, areas, perimeters, gray values, color features, texture features, etc., are extracted from the preprocessed image. These features will be used as the basis for judging whether the object meets the requirements. At the same time, the extracted features are compared, matched and analyzed with the preset standards or templates, and algorithms such as pattern recognition, machine learning, and deep learning are used to judge information such as the category, state, position, and size of the object, and to identify whether there are defects, abnormalities or non-compliance with specifications in the object.

[0023] The annular transmission line 2 converts the rotational motion output by the power source into a linear motion or a circular motion of the annular transmission mechanism through a transmission device, thereby driving the article to move on the annular track, and the track plays a role of restraint and guidance to ensure that the article moves along the predetermined annular path. At the same time, some guiding devices, such as guide wheels, guide plates, etc., can be set on the track to ensure the stability and accuracy of the article transmission and prevent the article from shifting or shaking during the transmission process; To achieve precise transmission and positioning of items on the annular transmission mechanism, corresponding positioning and control devices are usually equipped. The positioning device can be a mechanical stop block, photoelectric sensor, magnetic sensor, etc., which is used to determine the position of the item on the annular track. When the item reaches a specific position, the positioning device will send a signal to notify the control system to perform corresponding operations, such as stopping transmission, performing processing or assembly, etc. The control system usually consists of a programmable logic controller (PLC), a single-chip microcomputer or a computer, etc. It controls the power source, transmission device and other related devices according to the preset program and the signals fed back by the sensors, so as to realize the automatic operation and precise control of the annular transmission mechanism. For example, when processing an item at a certain position is required, the control system will stop the annular transmission mechanism before the item reaches this position and then start the transmission again after the processing is completed.

[0024] For the SMT patch detection device adopting the above structure, First, the annular transmission line 2 drives the conveying table 3 and the placement table 503 to move reciprocally along the ring, and the placement table 503 with the PCB board to be detected is conveyed into the vision inspection machine 1 in sequence. When the conveying table 3 enters the vision inspection machine 1, it enters the detection area through the detection ports 4 opened on both sides of the outer shell of the vision inspection machine 1; Then, the camera captures the position distribution diagrams of the surface-mounted components, the PCB board and the lead surface, etc. on the PCB board, so as to make a preliminary accurate comparison with the reference diagram and / or data, and detect problems such as patch position and component surface defects. If there are problems, the problematic PCB board will be taken out for rework; If there are no problems, the electric push rod 701 is started to push the protective shell 702 towards the conveying table 3. During the movement of the protective shell 702, when the pressing member 706 on the protective shell 702 moves to below the pressing rod 9, affected by the pressing rod 9, the pressing member 706 presses down, driving the second connecting rod 704 to move obliquely downward. Since the moving chute 8 is opened at the end of the hook 705 and the other end of the second connecting rod 704 is embedded and slidably engaged with the moving chute 8, the movement of the second connecting rod 704 causes the hook 705 to rotate around its rotation connection point with the protective shell 702, and the front end of the hook 705 gradually approaches the hook openings 6 at both ends of the rack 505, and finally the front end is hooked into the hook opening 6 at one end of the rack 505; Finally, as the electric push rod 701 continues to push forward, the gear 504 and the rack 505 are connected, causing the placement table 503 to tilt towards the direction of the electric push rod 701 that is outputting. It should be noted that the tilt angle needs to be less than 90°. If there is no clamping member on the placement table 503, the tilt angle needs to be less than 35°. As the placement table 503 gradually tilts, the camera can capture whether there are problems at the soldering points of the surface-mounted components on the surface of the PCB board in the tilting direction. If there are problems, they are removed. If there are no problems, the electric push rod 701 pulls back. At this time, the hook 705 hooks the hook opening 6 and drives the rack 505 to pull, and the placement table 503 gradually resets. When the protective shell 702 resets to the point where the pressing member 706 abuts against the pressing rod 9, the hook 705 gradually moves up. After the pressing member 706 is completely pressed down, the hook 705 disengages from the hook opening 6, and the placement table 503 resets.

[0025] It should also be noted that even if the rack 505 and the gear 504 are affected by transmission and the rack 505 slides to one side, causing the placement table 503 to tilt, at least one forward push of the electric push rod 701 can reset the rack 505. If the placement table 503 is not tilted, no reset operation is required.

[0026] This SMT patch detection device drives the conveying table 3 to reciprocate through the annular transmission line 2, and combines the angle adjustment component 5 and the push-pull component 7 to realize multi-angle detection of the PCB board during the operation of the assembly line, breaking through the limitation of "one-piece one-inspection". The multi-angle detection mechanism ensures comprehensive and accurate detection results, improves the product quality control ability, greatly improves the detection efficiency and accuracy, and meets the needs of large-scale production; Secondly, compared with the method of installing a servo motor on each clamping tooling group to achieve flipping, this device completes the angle adjustment of the PCB board through the cooperation of the adjustment component and the push-pull component 7, effectively reducing the hardware cost and facilitating large-scale popularization and application.

[0027] After combining the above embodiments, support pieces 10 are fixedly arranged at the angles between the first connecting rod 703 and the protective shell 702. The support pieces 10 are fixed to the first connecting rod 703 and the protective shell 702 to ensure the stable connection between the first connecting rod 703 and the protective shell 702 during movement, prevent movement deviation caused by loose connection, ensure the movement accuracy of the push-pull component 7, and further improve the accuracy of the angle adjustment of the PCB board, providing strong support for the detection accuracy.

[0028] Furthermore, by setting that the two sides of the bottom of the pressing member 706 are fixedly provided with limiting pieces 11, the second connecting rod 704 is located between the two limiting pieces 11, and the gap between the bottom of the limiting piece 11 and the inner bottom of the protective shell 702 is adapted to the pressing depth of the pressing member 706. The left and right movement ranges of the second connecting rod 704 are clearly defined to prevent it from shifting or shaking during movement, and ensure the transmission accuracy between the components of the push-pull component 7.

[0029] To prevent the hook 705 from not completely disengaging from the hook opening 6 after the pressing member 706 is pressed downward by the pressure rod 9, and the electric push rod 701 continues to pull, causing the rack 505 to deviate from the predetermined position, the pressure distance of the pressing member 706 needs to be greater than the width of the hook opening 6.

[0030] In this embodiment, the PCB board on the placement table 503 does not need to be flipped, but only needs to be tilted. The traditional method requires clamping and fixing the PCB board. However, due to assembly line operations, the placement efficiency needs to be improved. Therefore, a circle of baffles 12 extends around the periphery of the placement table 503 to prevent the PCB board from leaving the placement table 503. The height of the baffles 12 is greater than the thickness of the PCB board, and the tilt angle of the placement table 503 needs to be limited to ≤45° to prevent the PCB board from falling off during the tilting process. When the tilt angle is around 35°, the visual inspection machine 1 can effectively perform inspections.

[0031] In combination with the above embodiment, in order to further prevent the PCB board from sliding in the placement table 503, a rubber gasket 13 is adhered to the side of the placement table 503 that contacts the PCB board, and anti-slip grooves are provided on the rubber gasket 13 to prevent the PCB board from sliding as much as possible and affecting the normal operation of the visual inspection machine 1.

[0032] In this embodiment, the support plate 501 is provided with a side rail 14 on one side of the rack 505. The side rail 14 is fixed to the conveyor platform 3. The rack 505 is slidably connected between the side rail 14 and the support plate 501. One side of the rack 505 is embedded and slidably connected to the side rail 14. The setting of the side rail 14 effectively limits the movement direction of the rack 505, reduces its shaking during the sliding process, enhances the stability of the entire angle control assembly 5, and makes the PCB board more stable when adjusting the angle.

[0033] The length of the side rail 14 is smaller than that of the rack 505. Compared with the equal-length setting, the length of the side rail 14 is smaller than that of the rack 505. This can reduce the space occupied by the side rail 14 on the conveyor platform 3, making the internal structure of the equipment more compact, leaving more space for the installation and layout of other components, and improving the overall space utilization of the equipment.

[0034] A circular bottom rail 15 is fixed to the circular transmission line 2. The conveyor platform 3 is embedded in and slidably connected to the bottom rail 15 and reciprocates along the bottom rail 15. The circular bottom rail 15 provides all-round and continuous support and guidance for the conveyor platform 3, effectively preventing the conveyor platform 3 from shaking and deflecting during movement, ensuring the position accuracy of the PCB board during the conveying and testing process, and improving the reliability of the test results.

[0035] A rotating block 16 is provided at the connection between the placing table 503 and the support shaft 502. The rotating block 16 is fixed to the support shaft 502 and the placing table 503. For example, for the placing table 503 and the support shaft 502, it is necessary to ensure a certain height between the conveying table 3 and the placing table 503. By providing the rotating block 16, the placing table 503 and the support shaft 502 perform eccentric motion, which can make the space between the conveying table 3 and the placing table 503 more compact.

[0036] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An SMT chip detection device, comprising a vision detection machine (1), an annular transmission line (2) and a conveying table (3). Detection ports (4) for the conveying of the conveying table (3) are provided on both sides of the outer shell of the vision detection machine (1). The annular transmission line (2) can drive the conveying table (3) to move reciprocally along a circle. The camera in the vision detection machine (1) is located directly above the conveying track of the conveying table (3) and detects the PCB board located on the conveying table (3). It is characterized in that: An angle adjustment component (5) installed on the conveying table (3). The angle adjustment component (5) includes two oppositely arranged support plates (501), a support shaft (502) rotatably connected between the two support plates (501), a placement table (503) fixed on the support shaft (502), a gear (504) and a rack (505). One end of the support shaft (502) protrudes from the support plate (501) and is fixed to the gear (504). The rack (505) is embedded and slides on the conveying table (3) and meshes with the gear (504). Hook openings (6) are provided at both ends of the rack (505); Two sets of oppositely arranged push-pull components (7) installed in the vision detection machine (1). The push-pull component (7) includes an electric push rod (701), a protective shell (702), a first connecting rod (703), a second connecting rod (704), a hook (705), a pressing member (706) and a spring (707). The two electric push rods (701) are respectively fixed on both sides of the transmission path of the conveying table (3). The output ends of the two electric push rods (701) face each other. The protective shell (702) is fixed on the output end of the electric push rod (701). The first connecting rod (703) is fixed to the protective shell (702). The hook (705) is rotatably connected to the protective shell (702) and can be hooked into the hook opening (6). A moving chute (8) is provided at the tail end of the hook (705). One end of the second connecting rod (704) is hinged to the first connecting rod (703), and the other end is embedded and slidably matched with the moving chute (8). The pressing member (706) is slidably connected to the protective shell (702), and its inner bottom extends into the protective shell (702) and can abut against the second connecting rod (704). The two ends of the spring (707) are respectively fixed to the protective shell (702) and the second connecting rod (704), and the hook (705) is reset by rebounding; A pressing rod (9), the pressing rod (9) is fixed on the support plate (501), and one end can abut against the pressing member (706). During the process of the electric push rod (701) pushing / pulling the protective shell (702) to move, the pressing member (706) is gradually pressed down under the restriction of the pressing rod (9).

2. The SMT chip detection device according to claim 1, wherein: Support pieces (10) are fixed at the included angles between the first connecting rod (703) and the protective shell (702). The support pieces (10) are fixed to the first connecting rod (703) and the protective shell (702).

3. An SMT chip detection device according to claim 1, characterized in that: On both sides of the bottom of the pressing member (706), limiting pieces (11) are fixed. The second connecting rod (704) is located between the two limiting pieces (11). The gap between the bottom of the limiting piece (11) and the inner bottom of the protective case (702) is adapted to the pressing depth of the pressing member (706).

4. An SMT chip detection device according to claim 1, characterized in that: The pressed distance of the pressing member (706) is greater than the width of the hook opening (6).

5. An SMT chip detection device according to claim 1, characterized in that: A baffle (12) extends around the periphery of the placing table (503). The height of the baffle (12) is greater than the thickness of the PCB board. The inclination angle of the placing table (503) ≤ 45°.

6. The SMT chip detection device according to claim 5, wherein: A rubber gasket (13) is adhered to the surface of the placing table (503) in contact with the PCB board. Anti-slip lines are provided on the rubber gasket (13).

7. An SMT chip detection device according to claim 1, characterized in that: On one side of the rack (505), a side rail (14) is provided on the support plate (501). The side rail (14) is fixed to the conveying table (3). The rack (505) is slidably connected between the side rail (14) and the support plate (501). One side of the rack (505) is embedded and slidably connected to the side rail (14).

8. An SMT chip detection device according to claim 7, characterized in that: The length of the side rail (14) is less than the length of the rack (505).

9. An SMT chip detection device according to claim 1, characterized in that: An annular bottom rail (15) is fixed on the annular transmission line (2). The conveying table (3) is embedded and slidably connected to the bottom rail (15) and reciprocates along the bottom rail (15).

10. A kind of SMT chip detection device according to claim 1, characterized in that: A rotating block (16) is provided at the connection between the placing table (503) and the support shaft (502). The rotating block (16) is fixed to the support shaft (502) and the placing table (503).

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