Hemispherical cup body plastic part side wall through hole detection device

Abstract

The invention discloses a semispherical cup body plastic part side wall through hole detection device, and belongs to the technical field of detection equipment. Comprising a detection table, a supporting assembly and a plurality of transmission assemblies are installed on the detection table, each transmission assembly comprises a transmission mechanism and a lead screw, the transmission mechanisms are in meshing transmission through gears, one set of transmission mechanisms are connected with a driving source, and the lead screws are in sliding connection with the transmission mechanisms; an elastic piece is installed on the push rod, and a laser distance measuring sensor is installed on the extension pipe. A driving source drives a transmission mechanism to rotate, multiple sets of lead screws are controlled to rotate synchronously through meshing transmission, the lead screws drive a detection assembly to rotate and move along the axis of the detection assembly at the same time, and when a laser distance measuring sensor is inserted into a through hole in the side wall of a plastic part, movement in the axis direction of an extension pipe is limited; the laser distance measuring sensor rotates along with the extension pipe and detects the through holes in the side wall of the plastic part, and multi-hole synchronous measurement is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of detection equipment, and more specifically, to a detection device for through holes on the side wall of a hemispherical cup plastic part. Background Art

[0002] Due to different uses of plastic parts, the precision requirements for holes are also different. For high-precision holes such as through holes, their size and straightness are key performance indicators to ensure the normal use of plastic parts, so strict detection is required. However, the traditional detection method of detecting multiple side wall through holes one by one not only has a large workload and low efficiency, but also is difficult to ensure the consistency and accuracy of detection, seriously affecting the quality control of mass production. Therefore, improving the detection efficiency and accuracy of multi-hole plastic parts is of great significance for ensuring product quality and meeting market demands. In view of this, we propose a detection device for through holes on the side wall of a hemispherical cup plastic part. Summary of the Invention

[0003] The purpose of the present invention is to provide a detection device for through holes on the side wall of a hemispherical cup plastic part, which is used to solve the technical problems of difficult detection and low efficiency of through holes on the side wall of plastic parts in the prior art.

[0004] An embodiment of the present invention provides a detection device for through holes on the side wall of a hemispherical cup plastic part, including a detection table, on which a support assembly and a number of transmission assemblies are installed. The transmission assembly includes a transmission mechanism rotatably connected to the support assembly and a lead screw threadedly engaged with the support assembly. A number of transmission mechanisms are driven by gear meshing. One set of transmission mechanisms is connected to a drive source. The lead screw is slidably connected to the transmission mechanism. A detection assembly, the detection assembly includes an extension tube and a push rod slidably connected to the extension tube. The push rod is installed at the end of the lead screw. An elastic member for pulling the extension tube is installed on the push rod. Two sets of laser distance sensors for measurement are installed on the extension tube. The drive source drives one transmission mechanism to rotate, controls a number of sets of transmission mechanisms and the lead screw to rotate synchronously through gear meshing transmission. The lead screw drives the detection assembly to rotate and move along its axis through screw transmission. When the laser distance sensor is inserted into the through hole on the side wall of the plastic part, the movement of the extension tube in the axial direction is limited. The laser distance sensor rotates with the extension tube and detects the through hole on the side wall of the plastic part.

[0005] As a further description of the above technical solution, the outer diameter of the extension tube is smaller than the diameter of the through hole on the side wall of the plastic part. The axis of the extension tube is collinear with the set axis of the through hole on the side wall of the plastic part and the extension tube moves along the axis of the through hole on the side wall of the plastic part.

[0006] As a further description of the above technical solution, the two sets of laser distance sensors are located at both ends of the diameter line of the extension tube.

[0007] As a further description of the above technical solution, the support assembly includes a fixed seat installed on the detection table, and a support cover and several positioning columns for positioning plastic parts are installed on the fixed seat. Several extension pipes are movably inserted into the support cover, and a limiting plate is fixedly installed at one end of the extension pipe. Several countersunk bolts are in threaded fit with the support cover for limiting the limiting plate.

[0008] As a further description of the above technical solution, several support frames are fixedly installed in the fixed seat, a sliding frame is slidably connected to the support frames, and a limiting frame is fixedly installed at the end of the sliding frame. The limiting plate is rotatably limited on the limiting frame, and the limiting frame abuts against the end of the countersunk bolt to limit the limiting plate.

[0009] As a further description of the above technical solution, the transmission mechanism includes a support shaft and a guide pipe rotatably connected to the support frame. The support shaft and the guide pipe are driven by a universal joint, and several support shafts are meshed and driven by transmission gears. One support shaft is connected to a drive source. The lead screw is slidably connected to the guide pipe through a guide post, and the lead screw is in threaded fit with the support frame.

[0010] As a further description of the above technical solution, several of the support shafts are arranged in parallel.

[0011] As a further description of the above technical solution, the extension pipe, the push rod, the lead screw, the guide post and the guide pipe are coaxial, and the sliding direction of the sliding frame is parallel to the movement direction of the extension pipe.

[0012] As a further description of the above technical solution, the drive source includes a motor installed in the detection table. A connecting shaft is rotatably connected to the fixed seat. One end of the connecting shaft is connected to the output end of the motor, and the other end is fixedly installed with a first bevel gear. A second bevel gear meshing with the first bevel gear is fixedly installed on one support shaft.

[0013] As a further description of the above technical solution, a telescopic cylinder is installed on the detection table. The output shaft of the telescopic cylinder is fixedly connected with a pressing block, and the pressing block is directly above the hemispherical cup-shaped plastic part for limiting the top of the hemispherical cup-shaped plastic part.

[0014] By adopting the above scheme, the positioning holes of the aligned hemispherical cup-shaped plastic parts are inserted onto the positioning columns. The output shaft of the telescopic cylinder pushes the pressing block down to abut against the hemispherical cup-shaped plastic part to limit it. The output shaft of the motor drives the connecting shaft to rotate. The rotation of one support shaft is driven by the meshing of the first bevel gear and the second bevel gear, and then several transmission gears are meshed and driven, so as to realize the synchronous rotation of multiple groups of support shafts. When the support shaft rotates, it drives the guide tube, guide column and lead screw to rotate through the universal joint. The lead screw is in threaded transmission with the support frame, so that the lead screw rotates and moves obliquely upward along its axis to push the push rod. At this time, relative displacement occurs between the guide column and the guide tube; When the push rod moves, it drives the extension tube, limit plate, limit frame and sliding frame to move synchronously by pushing the limit ring. When the limit frame abuts against the countersunk head bolt, the laser distance sensor moves to the position of the side wall through hole of the plastic part and is limited. At this time, the extension tube only rotates following the push rod, and relative displacement occurs between the push rod and the extension tube in the axial direction, and the elastic part is gradually stretched. During the rotation of the laser distance sensor at the position of the side wall through hole, the side wall through hole of the plastic part is measured; The two groups of laser distance sensors rotate and measure to obtain the spacing values L1 and L2 between the two groups of laser distance sensors and the side wall through holes of the hemispherical cup plastic part. After the detection data is obtained, it is transmitted to the processor for processing. After the processor performs numerical processing such as noise reduction on the data, according to the formula D = L1 + L2 + d, the diameter D of the side wall through hole is obtained. By obtaining D at several moments and calculating the average value, the diameter size of the side wall through hole of the plastic part is obtained. When the measured value exceeds the set threshold range, the diameter of the through hole of the plastic part is unqualified.

[0015] To sum up, due to the adoption of the above technical solutions, the beneficial effects of the present invention are: 1. The present invention adopts the method of simultaneously detecting multiple groups of side wall through holes from the inside of the hemispherical body plastic part, which greatly improves the measurement efficiency, gets rid of the problem of the traditional one-by-one detection process being cumbersome and inefficient, and also reduces the limitation of the plastic part structure on the through hole detection.

[0016] 2. The present invention controls the extension tube to rotate and move along its axis to insert into the side wall through hole of the plastic part at the same time. After the laser distance sensor moves to the set position, the extension tube is restricted to move only along the axis direction and only rotates, so as to realize the measurement of the side wall through hole by the laser distance sensor.

[0017] 3. The present invention controls the limit position of the extension tube through the countersunk head bolt, which can be adjusted according to needs, and improves the flexibility of the laser distance sensor measurement.

[0018] 4. The present invention connects the support shaft and the guide tube through the universal joint, which can realize the angular transmission between the guide tube and the support shaft, and further improves the flexibility of the detection device. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of a hemispherical cup plastic part; Figure 2 It is a schematic diagram of the overall structure of a device for detecting side wall through holes of a hemispherical cup plastic part disclosed in a preferred embodiment of the present invention; Figure 3Schematic diagram of the distribution of positioning columns of a side wall through-hole detection device for a hemispherical cup plastic part disclosed in a preferred embodiment of the present invention; Figure 4 Internal structure schematic diagram of a support assembly of a side wall through-hole detection device for a hemispherical cup plastic part disclosed in a preferred embodiment of the present invention; Figure 5 Partial structure schematic diagram of a side wall through-hole detection device for a hemispherical cup plastic part disclosed in a preferred embodiment of the present invention; Figure 6 Connection structure schematic diagram of a transmission assembly of a side wall through-hole detection device for a hemispherical cup plastic part disclosed in a preferred embodiment of the present invention; Figure 7 For a side wall through-hole detection device for a hemispherical cup plastic part disclosed in a preferred embodiment of the present invention Figure 4 Enlarged view at position A; Figure 8 Connection structure schematic diagram of a detection assembly of a side wall through-hole detection device for a hemispherical cup plastic part disclosed in a preferred embodiment of the present invention; Figure 9 Detection principle diagram of a side wall through-hole detection device for a hemispherical cup plastic part disclosed in a preferred embodiment of the present invention.

[0020] Explanation of reference numerals in the figure: 1, detection table; 2, support assembly; 3, transmission assembly; 4, detection assembly; 6, connecting shaft; 7, first bevel gear; 8, second bevel gear; 9, telescopic cylinder; 10, fixing frame; 11, operating machine; 12, pressing block; 21, fixing seat; 22, support cover; 23, positioning column; 24, guiding hole; 25, support frame; 26, guide rail; 27, sliding frame; 28, limiting frame; 29, countersunk head bolt; 31, support shaft; 32, guiding tube; 33, universal joint; 34, transmission gear; 35, guiding column; 36, lead screw; 41, extension tube; 42, push rod; 43, elastic member; 44, limiting plate; 45, laser distance sensor; 46, wire hole; 47, slip ring; 48, limiting ring. Detailed implementation manners

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to 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 of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0022] Refer to Figures 1 to 9, This embodiment discloses a device for detecting through holes in the side wall of a hemispherical cup-shaped plastic part, comprising a detection platform 1, on which a support assembly 2 is mounted, the support assembly 2 comprising a fixed seat 21 fixedly mounted on the detection platform 1, a support cover 22 and a plurality of positioning columns 23 distributed in a circular array fixedly mounted on the fixed seat 21, during detection, the support cover 22 is located inside the hemispherical cup-shaped plastic part and does not interfere with it, the positioning columns 23 are inserted into the positioning holes of the spherical cup-shaped plastic part to position it, a plurality of guide holes 24 are opened on the support cover 22, a plurality of support frames 25 are fixedly mounted in the fixed seat 21, a guide rail 26 is mounted on the support frame 25, a sliding frame 27 is slidably connected to the guide rail 26, a limiting frame 28 is fixedly mounted on the end of the sliding frame 27, and a plurality of countersunk bolts 29 are threadedly fitted on the support cover 22 for limiting the moving position of the limiting frame 28.

[0023] Reference Figures 4 to 8 The test bench 1 is provided with a plurality of transmission assemblies 3. The transmission assemblies 3 include support shafts 31 rotatably connected to the fixed base 21 and guide tubes 32 rotatably connected to the support frame 25. The plurality of support shafts 31 are arranged in parallel. The support shafts 31 and the guide tubes 32 are driven by universal joints 33. A transmission gear 34 is fixedly mounted on the support shafts 31. Two adjacent groups of support shafts 31 are engaged and driven by the transmission gears 34. A guide column 35 is slidably connected to the guide tube 32. A screw rod 36 is fixedly mounted on the guide column 35. The screw rod 36 is threadedly engaged with the support frame 25. By connecting the support shafts 31 and the guide tubes 32 through the universal joints 33, a certain angle transmission can be achieved between the guide tubes 32 and the support shafts 31, thereby improving the flexibility of the transmission. In addition, the transmission of the plurality of support shafts 31 through the transmission gears 34 can achieve synchronous rotation of the plurality of support shafts 31.

[0024] Reference Figures 3 to 9 , a detection component 4 is installed on the screw rod 36, and the detection component 4 includes an extension tube 41 that is plugged into the guide hole 24, that is, the extension tube 41 can rotate or slide in the guide hole 24, and the outer diameter of the extension tube 41 is smaller than the diameter of the through hole on the side wall of the plastic part. The extension tube 41 moves along its axial direction and the axis of the extension tube 41 is collinear with the theoretical axis of the through hole on the side wall of the plastic part. The theoretical axis is the axis specified in the design. A push rod 42 fixedly connected to the screw rod 36 is slidably connected to the extension tube 41, and the push rod 42 is movably connected to the support frame 25, which can be rotated or slid. The extension tube 41, the push rod 42, the screw rod 36, the guide column 35 and the guide tube 32 are coaxially arranged, and the sliding direction of the sliding frame 27 is parallel to the movement direction of the extension tube 41.

[0025] An elastic member 43 is sleeved on the push rod 42. One end of the elastic member 43 is fixedly connected to the end plate of the push rod 42, and the other end is fixedly connected to the extension tube 41. The elastic member 43 is used to pull the extension tube 41 to move towards the end of the push rod 42. A limiting plate 44 is fixedly installed at one end of the extension tube 41 close to the elastic member 43. The limiting plate 44 is rotationally limited on the limiting frame 28. Two groups of laser distance sensors 45 for measuring the distance value are arranged at the end of the extension tube 41. The two groups of laser distance sensors 45 are located at both ends of the diameter line of the extension tube 41, which can reduce the range of rotation required for detection. The sum of the vertical distances from the two groups of laser distance sensors 45 to the axis of the extension tube 41 is equal to the diameter d of the extension tube 41. A wire hole 46 communicating with the extension tube 41 is formed in the push rod 42. A conductive ring 47 is installed on the push rod 42. The energized wire of the laser distance sensor 45 passes through the wire hole 46 and is electrically connected to the inner ring of the conductive ring 47. The outer ring of the conductive ring 47 is installed on the support frame 25 and is electrically connected to the corresponding input or output device, thereby realizing the power-on and signal transmission of the laser distance sensor 45 and avoiding the problem of wire twisting when the laser distance sensor 45 rotates following the extension tube 41.

[0026] A limiting ring 48 is fixedly installed inside the extension tube 41. The limiting ring 48 is located between the push rod 42 and the laser distance sensor 45 and is used to limit the push rod 42 to prevent the push rod 42 from colliding with the laser distance sensor 45. It should be noted that in order to prevent the side wall through hole position of the hemispherical body plastic part from deviating too much and colliding with the extension tube 41, a pressure sensor can be arranged at the end of the extension tube 41. When the pressure sensor detects a pressure value, the measurement is stopped.

[0027] Refer to Figure 4 and Figure 5 As shown in, a motor is fixedly installed inside the inspection table 1. A connecting shaft 6 is rotatably connected to the fixed seat 21. One end of the connecting shaft 6 is connected to the output end of the motor installed inside the inspection table 1, and the other end is fixedly installed with a first bevel gear 7. A second bevel gear 8 meshing with the first bevel gear 7 is fixedly installed on a support shaft 31. The output shaft of the motor drives the connecting shaft 6 to rotate, and the rotation of the support shaft 31 is realized through the meshing transmission of the bevel gears.

[0028] Refer to Figure 2 As shown in, an operating machine 11 and a fixed frame 10 are installed on the inspection table 1. A telescopic cylinder 9 is fixedly installed on the fixed frame 10. The output shaft of the telescopic cylinder 9 is fixedly connected with a pressing block 12. The pressing block 12 is located directly above the hemispherical cup plastic part. The output shaft of the telescopic cylinder 9 drives the pressing block 12 to abut against the top of the hemispherical cup plastic part, thereby fixing the hemispherical cup plastic part under inspection and ensuring the stability during measurement. To ensure the accuracy of the abutting position, a pressure sensor can be installed on the pressing block 12 for detection to avoid deformation of the hemispherical cup plastic part caused by over-tightening.

[0029] Working principle: Insert the positioning hole of the hemispherical cup plastic part after alignment onto the positioning post 23. The output shaft of the telescopic cylinder 9 pushes the pressing block 12 downward to abut against the hemispherical cup plastic part for limiting it. The output shaft of the motor drives the connecting shaft 6 to rotate. Through the meshing of the first bevel gear 7 and the second bevel gear 8, a support shaft 31 is driven to rotate. Through the meshing transmission of a number of transmission gears 34, synchronous rotation of multiple groups of support shafts 31 is achieved.

[0030] When the support shaft 31 rotates, it drives the guide tube 32, the guide post 35 and the lead screw 36 to rotate through the universal joint 33. The lead screw 36 is in threaded transmission with the support frame 25. Then the lead screw 36 rotates and moves obliquely upward along its axis to push the push rod 42. At this time, a relative displacement occurs between the guide post 35 and the guide tube 32. It should be noted that adjacent two groups of support shafts 31 are in meshing transmission through the transmission gear 34, and their rotation directions are opposite. In order to keep the lead screws 36 moving synchronously and obliquely upward, the helix directions of adjacent two lead screws 36 can be set in the opposite direction, so as to maintain synchronism.

[0031] When the push rod 42 moves, it drives the extension tube 41, the limit plate 44, the limit frame 28 and the sliding frame 27 to move synchronously by pushing the limit ring 48. When the limit frame 28 abuts against the countersunk head bolt 29, the laser distance sensor 45 moves to the position of the through hole on the side wall of the plastic part and is limited. At this time, the extension tube 41 only rotates following the push rod 42, and a relative displacement occurs between the push rod 42 and the extension tube 41 in the axial direction. The elastic member 43 is gradually stretched. During the rotation of the laser distance sensor 45 at the position of the through hole on the side wall, the through hole on the side wall of the plastic part is measured. In the present invention, by screwing the countersunk head bolt 29, the different limiting positions of the limit frame 28 can be controlled, and then the position of the laser distance sensor 45 relative to the through hole on the side wall can be controlled, improving the flexibility of adjustment. Therefore, the present invention can detect the through holes on the side walls of plastic parts with different distances from the end of the extension tube 41.

[0032] Two groups of laser distance sensors 45 rotate and measure to obtain the distance values L1 and L2 between the two groups of laser distance sensors 45 and the through holes on the side walls of the hemispherical cup plastic part. After the detection data is obtained, it is transmitted to the processor for processing. After the processor performs numerical processing such as noise reduction on the data, according to the formula D = L1 + L2 + d, the diameter D of the through hole on the side wall is obtained. By obtaining D at several moments and calculating the average value, the diameter size of the through hole on the side wall of the plastic part can be obtained. When the measured value exceeds the set threshold range, the diameter of the hole of the plastic part is unqualified.

[0033] The present invention can also detect the hole position offset of the through hole on the side wall of the plastic part. The axis position of the extension tube 41 of the present invention is the theoretical axis position of the through hole on the side wall of the plastic part. If at the same time, the detection value L1 + d / 2 of a group of laser distance sensors 45 is greater than the set radius of the through hole on the side wall, while the detection value L2 + d / 2 of another group of laser distance sensors 45 is less than the set radius of the through hole on the side wall, at this time, the laser distance sensors 45 capture adjacent points for measurement. If there is still one side much greater than the set through hole radius value and one side much less than the set through hole radius value, it is determined that there is a hole position offset.

[0034] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A detection device for through holes on the side wall of a hemispherical cup-shaped plastic part, characterized in that: It includes a detection table (1), on which a support assembly (2) and several transmission assemblies (3) are installed. The transmission assembly (3) includes a transmission mechanism rotatably connected to the support assembly (2) and a lead screw (36) threadedly engaged with the support assembly (2). Several transmission mechanisms are driven by gear meshing. One set of transmission mechanisms is connected to a drive source. The lead screw (36) is slidably connected to the transmission mechanism. A detection assembly (4), the detection assembly (4) includes an extension tube (41) and a push rod (42) slidably connected to the extension tube (41). The push rod (42) is installed at the end of the lead screw (36). An elastic member (43) for pulling the extension tube (41) is installed on the push rod (42). Two sets of laser distance sensors (45) for measurement are installed on the extension tube (41). The drive source drives one transmission mechanism to rotate, and controls several sets of transmission mechanisms and the lead screw (36) to rotate synchronously through gear meshing transmission. The lead screw (36) drives the detection assembly (4) to rotate and move along its axis through thread transmission. When the laser distance sensor (45) is inserted into the through hole on the side wall of the plastic part, the movement of the extension tube (41) in the axial direction is limited. The laser distance sensor (45) follows the rotation of the extension tube (41) and detects the through hole on the side wall of the plastic part.

2. The side wall through hole detection device for a hemispherical cup plastic part according to claim 1, wherein: The outer diameter of the extension tube (41) is smaller than the diameter of the through hole on the side wall of the plastic part. The axis of the extension tube (41) is collinear with the set axis of the through hole on the side wall of the plastic part, and the extension tube (41) moves along the axis of the through hole on the side wall of the plastic part.

3. The hemispherical cup plastic part side wall through hole detection device according to claim 1, characterized in that: The two sets of laser distance sensors (45) are located at both ends of the diameter line of the extension tube (41).

4. The side wall through hole detection device for a hemispherical cup plastic part according to claim 1, wherein: The support assembly (2) includes a fixed seat (21) installed on the detection table (1). A support cover (22) and several positioning columns (23) for positioning the plastic part are installed on the fixed seat (21). Several extension tubes (41) are movably inserted into the support cover (22). A limiting plate (44) is fixedly installed at one end of the extension tube (41). Several countersunk bolts (29) are threadedly engaged with the support cover (22) to limit the limiting plate (44).

5. A hemispherical cup plastic part side wall through-hole detection device according to claim 4, characterized in that: Several support frames (25) are fixedly installed inside the fixed seat (21). A sliding frame (27) is slidably connected to the support frames (25). A limiting frame (28) is fixedly installed at the end of the sliding frame (27). The limiting plate (44) is limited to rotate on the limiting frame (28). The limiting frame (28) abuts against the end of the countersunk bolt (29) to limit the limiting plate (44).

6. The side wall through-hole detection device for a hemispherical cup plastic part according to claim 5, characterized in that: The transmission mechanism includes a support shaft (31) rotatably connected to the support frame (25) and a guide tube (32). The support shaft (31) and the guide tube (32) are driven by a universal joint (33). Several support shafts (31) are driven by transmission gears (34) to mesh. One support shaft (31) is connected to the drive source. The lead screw (36) is slidably connected to the guide tube (32) through a guide post (35). The lead screw (36) is threadedly engaged with the support frame (25).

7. The side wall through-hole detection device for a hemispherical cup plastic part according to claim 6, characterized in that: Several of the support shafts (31) are arranged in parallel.

8. The side wall through hole detection device for a hemispherical cup plastic part according to claim 6, characterized in that: The extension tube (41), the push rod (42), the lead screw (36), the guide post (35) and the guide tube (32) are coaxially arranged, and the sliding direction of the sliding frame (27) is parallel to the movement direction of the extension tube (41).

9. The hemispherical cup plastic part side wall through hole detection device according to claim 6, characterized in that: The driving source includes a motor installed in the inspection table (1). A connecting shaft (6) is rotatably connected to the fixed seat (21). One end of the connecting shaft (6) is connected to the output end of the motor, and a first bevel gear (7) is fixedly installed at the other end. A second bevel gear (8) meshing with the first bevel gear (7) is fixedly installed on a support shaft (31).

10. A hemispherical cup plastic part side wall through hole detection device according to any one of claims 1-9, characterized in that: An expansion cylinder (9) is installed on the inspection table (1). The output shaft of the expansion cylinder (9) is fixedly connected with a pressing block (12). The pressing block (12) is located directly above the hemispherical cup plastic part and is used for limiting the top of the hemispherical cup plastic part.

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