Machining method and machining equipment for blind hole in side wall of inner cavity of small engineering plastic part

Abstract

The small engineering plastic part inner cavity side wall blind hole machining equipment comprises a bottom plate, a driving assembly is arranged on the bottom plate, the driving assembly is installed on a fixing plate, and a limiting block is arranged on the fixing plate; the positioning machining assembly comprises two supporting plates arranged opposite to the limiting blocks, the tops of the two supporting plates are equal in height, and the side faces of the two supporting plates are flush; the gear transmission assembly comprises a main transmission shaft and a drill bit which are installed on the supporting plate, an output shaft of the driving assembly is connected with the main transmission shaft, a first gear is installed on the main transmission shaft, the drill bit is arranged on a gear chuck in a sleeving mode, the first gear is meshed with the gear chuck, and the end of the drill bit penetrates through the supporting plate. The machining equipment is assembled firstly, then the engineering plastic parts are placed on the positioning machining assembly to complete horizontal and side positioning for drilling machining, finally, the engineering plastic parts move by a set distance in a side mode and then shut down for material taking, the operation steps are simple, the cost is low, and the machining equipment is suitable for small-size and small-batch engineering plastic parts.

Description

Technical Field

[0001] The present invention relates to the technical field of local innovative design in drilling processing, and particularly relates to a method and a processing device for machining blind holes on the inner cavity side wall of small engineering plastic parts. Background Art

[0002] In a traditional three-axis numerical control machining device (CNC), the main shaft is vertically arranged above the workbench, and the drill bit is vertically installed in the drill bit clamping sleeve at the lower part of the main shaft. It can only perform horizontal movement and vertical drilling. For the operation of machining blind holes on the inner cavity side wall of a workpiece, the main shaft cannot enter the inner cavity of the workpiece and cannot turn to directly machine blind holes on the inner cavity side wall of the workpiece. It is necessary to use a forming or electric discharge machining (EDM) device to directly machine blind holes on the inner cavity side wall of the workpiece. However, such numerical control machining devices have high costs, are not applicable to EDM engineering plastic parts, and are not suitable for machining inner wall blind holes of small batches of engineering plastic workpieces.

[0003] For the machining of blind holes on the inner cavity side wall of an engineering plastic part as shown in Figure 5 , the cavity of the engineering plastic part is in the shape of an open slot, and the machining position of the blind hole is on the long side of the inner wall of the cavity. Traditional injection molding core pulling can be directly achieved, but the development cycle and time cost of the mold are relatively high, and it is only applicable to mass production and is not suitable for small batches of products. In addition, it is not suitable to adopt the traditional machining method of first clamping and fixing the engineering plastic part and then inserting the drill bit into the cavity for blind hole machining. However, due to size limitations, a conventional drilling device cannot be placed inside the cavity for work, and purchasing a special micro-drilling device is relatively expensive and uneconomical for small batch production and machining.

[0004] In the prior art, the patent with the publication number CN212857856U discloses a structure for machining blind holes on the inner cavity side wall, including a main shaft seat. The main shaft seat is provided with a main rotating shaft. A stretching bracket is fixedly connected to the lower part of the main shaft seat. The outer end of the stretching bracket horizontally extends to one side of the main rotating shaft. The stretching bracket is provided with a transmission mechanism and a drill bit clamping mechanism for installing a drill bit. The drill bit clamping mechanism is arranged outside the stretching bracket. The transmission mechanism is respectively in transmission connection with the main rotating shaft and the drill bit clamping mechanism. Compared with the prior art, this structure for machining blind holes on the inner cavity side wall can enable the drilling tool to extend from the opening of the shell workpiece to the place to be machined, directly machine blind holes in the inner cavity of the shell, with high machining accuracy of the blind holes, simple operation, and improved production efficiency.

[0005] The patent with the publication number CN115338450A discloses an inner cavity drilling device based on a gear set transmission structure and its installation method. The inner cavity drilling device includes a driving shaft, a transmission shaft, a driven gear shaft, a base, a pressing plate, a support column, a locking device, a tool clamping mechanism, etc. The transmission shaft, the left bearing of the transmission shaft, and the right bearing of the transmission shaft form a transmission shaft system, and the driven gear shaft, the upper bearing of the driven gear shaft, and the lower bearing of the driven gear shaft form a driven gear shaft system, ensuring the rotational accuracy of the shaft system. At the same time, a high-precision gear set is used to ensure the stability of rotation. The present invention adopts the gear set transmission technology to convert the driving force of the machine tool spindle into the driving force of the driven gear shaft after two reversals. The present invention has the following advantages: 1. Stable transmission and high processing accuracy; 2. Since the size of the driven gear shaft is small, it can extend into the part to be processed for processing, solving the difficulty of blind hole processing in the inner cavity of the part to be processed; 3. Different tools can be replaced according to different processing sizes, and the operation is flexible, etc.

[0006] In order to solve one of the above problems, the present application provides a method and equipment for machining blind holes on the inner cavity side wall of small engineering plastic parts. Summary of the Invention

[0007] The purpose of the present invention is to solve the problems existing in the prior art, and to propose a method and equipment for machining blind holes on the inner cavity side wall of small engineering plastic parts. By first assembling the processing equipment, then placing the engineering plastic part on the positioning and processing component to complete horizontal and edge positioning for drilling, and finally moving the engineering plastic part a set distance along the edge and then stopping the machine to take the material, the operation steps are simple and the cost is low, which is suitable for small batches of small engineering plastic parts.

[0008] In order to achieve the above purpose, the present invention adopts the following technical scheme: A method for machining blind holes on the inner cavity side wall of small engineering plastic parts, including the following steps:

[0009] S1. Assemble the processing equipment, fix the driving component and the positioning and processing component on the bottom plate, install the gear transmission component on the positioning and processing component, the driving component drives the drill bit on the gear transmission component to rotate and work, the end of the drill bit is located outside the positioning and processing component, and the top and side of the positioning and processing component respectively cooperate with the inner cavity of the engineering plastic part;

[0010] S2. Drilling processing, place the engineering plastic part on the positioning and processing component to complete horizontal and edge positioning and move away from the end of the drill bit, start the driving component to make the drill bit rotate and work, and push the engineering plastic part along the axial direction of the drill bit close to the end of the drill bit for drilling processing;

[0011] S3. Stop the machine and take the material. After the engineering plastic part moves a set distance along the edge, the driving component stops, the engineering plastic part retreats and resets, and take the engineering plastic part that has completed the blind hole processing from the positioning and processing component.

[0012] In step S1, the positioning and processing assembly is two support plates arranged side by side. The top surfaces of the two support plates are at the same height and their sides are flush.

[0013] Furthermore, the gear transmission assembly as described above includes a gear and a transmission shaft fixed with the gear. The transmission shaft is rotatably installed on the support plate.

[0014] Furthermore, a drill chuck is fixed outside the drill bit as described above. The drill chuck meshes with a second gear, and the second gear meshes with a first gear. The second gear and the first gear are respectively fixed on a driven transmission shaft and a main transmission shaft.

[0015] Furthermore, both of the two support plates are installed on a fixed seat, and the fixed seat is fixed on the bottom plate; the driving assembly is a motor and a speed reducer. The motor drives the speed reducer to work, and the output shaft of the speed reducer is connected to the main transmission shaft.

[0016] In step S2, the top of the positioning and processing assembly is in contact with the bottom surface of the inner cavity of the engineering plastic part, and at least one side of the positioning and processing assembly is in contact with the inner cavity side wall of the engineering plastic part.

[0017] In step S3, the driving assembly and the positioning and processing assembly are arranged oppositely. The driving assembly further includes a limit block and a control box. Push the engineering plastic part by hand along the axial direction of the drill bit to move to the limit block to complete the drilling process, and the control box realizes the start and stop of the motor.

[0018] A small blind hole processing device for the inner cavity side wall of an engineering plastic part includes a bottom plate. A driving assembly is arranged on the bottom plate. The driving assembly is installed on a fixing plate, and a limit block is arranged on the fixing plate;

[0019] A positioning and processing assembly, the positioning and processing assembly includes two support plates arranged oppositely to the limit block. The tops of the two support plates are at the same height and their sides are flush;

[0020] A gear transmission assembly, the gear transmission assembly includes a main transmission shaft and a drill bit respectively installed on the support plate. The output shaft of the driving assembly is connected to the main transmission shaft. A first gear is installed on the main transmission shaft. A drill chuck is installed outside the drill bit. The first gear meshes with the drill chuck, and the end of the drill bit penetrates through the outside of the support plate.

[0021] Furthermore, the gear transmission assembly as described above further includes a driven transmission shaft rotatably installed on the support plate. A second gear is installed on the driven transmission shaft. The second gear meshes with the first gear and the drill chuck respectively.

[0022] Furthermore, the driving assembly as described above includes a motor and a speed reducer installed on the fixing plate. The output shaft of the speed reducer is connected to the main transmission shaft through a coupling.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: First, assemble the processing equipment, then place the engineering plastic parts on the positioning and processing components to complete horizontal and edge positioning for drilling processing. Finally, after the engineering plastic parts move a set distance along the edge and stop, take the materials. The operation steps are simple and the cost is low, which is suitable for the processing of blind holes on the inner cavity side walls of small-sized and small-batch engineering plastic parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a perspective view of the present invention;

[0025] Figure 2 is a top view of the present invention;

[0026] Figure 3 is Figure 2 a schematic diagram after placing the engineering plastic parts in

[0027] Figure 4 is Figure 3 an exploded schematic diagram of

[0028] Figure 5 is a schematic diagram after processing the blind holes of the engineering plastic parts of the present invention.

[0029] In the figure: 11, motor; 12, fixed plate; 13, control box; 21, limit block; 22, fixed seat; 23, first support plate; 24, second support plate; 30, drill bit; 301, gear chuck; 31, driven transmission shaft; 310, second gear; 32, main transmission shaft; 320, first gear; 4, bottom plate; 5, engineering plastic part; 51, blind hole. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly defined and limited, terms such as "fixed", "installed", "connected", "set", etc. should be understood in a broad sense. For example, when an element is referred to as "fixed to" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "installed on" another element, it can be directly installed on the other element or there can also be an intermediate element. When an element is considered to be "connected" to another element, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements.

[0032] For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] 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 of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] Embodiment 1

[0035] Refer to Figures 1-4As shown in the figure, a processing device for blind holes on the inner cavity side wall of a small engineering plastic part according to the present invention includes a bottom plate 4. A driving component is arranged on the bottom plate 4 to provide power for drilling processing. The driving component is installed on a fixing plate 12, and a limiting block 21 is arranged on the fixing plate 12; a positioning and processing component, the positioning and processing component includes two supporting plates oppositely arranged with the limiting block 21. The limiting block 21 can block the movement of the engineering plastic part 5, playing a role in limiting and determining the drilling depth. The tops of the two supporting plates are at the same height and the sides are flush, so as to cooperate to support the cavity of the engineering plastic part 5, that is, the bottom of the cavity of the engineering plastic part 5 is in contact with the top surface of the supporting plate, and the side wall of the cavity of the engineering plastic part 5 is in contact with one side of the supporting plate, so that the engineering plastic part 5 can be positioned against the edge on the supporting plate, and the drilling feed is realized by manual pushing and moving; a gear transmission component, the gear transmission component includes a main transmission shaft 32 and a drill bit 30 respectively installed on the supporting plate. The output shaft of the driving component is connected to the main transmission shaft 32. A first gear 320 is installed on the main transmission shaft 32, and a gear chuck 301 is installed outside the drill bit 30. The first gear 320 meshes with the gear chuck 301. The end of the drill bit 30 penetrates through the supporting plate and is used for drilling the inner cavity side wall of the engineering plastic part 5. The length of the drill bit 30 will not interfere with the placement and movement operations of the engineering plastic part 5 on the supporting plate, and can meet the requirements of the position and size of the blind hole 51. The driving component provides power to the gear transmission component to drive the drill bit 30 to perform rotary drilling work.

[0036] Embodiment 2

[0037] Referring to Figures 1-4 As shown in the figure, on the basis of the technical solution of Embodiment 1, for the specific structural design of the gear transmission component of a processing device for blind holes on the inner cavity side wall of a small engineering plastic part, as Figure 1 and Figure 2 it can be seen that the gear transmission component further includes a driven transmission shaft 31 rotatably installed on the supporting plate. A second gear 310 is installed on the driven transmission shaft 31, and the second gear 310 meshes with the first gear 320 and the gear chuck 301 respectively. Further, the two supporting plates are respectively the first supporting plate 23 and the second supporting plate 24. The main transmission shaft 32, the driven transmission shaft 31 and the drill bit 30 are respectively assembled and connected to the two supporting plates through bearings. The installation and selection of the bearings are conventional technical means and will not be elaborated here. The first supporting plate 23 is oppositely arranged with the limiting block 21, and the limiting block 21 plays a role in limiting and blocking. The drill bit 30 penetrates through the second supporting plate 24 and the end of the drill bit 30 is located outside the second supporting plate 24 to determine the installation position and direction of the drill bit 30.

[0038] For the specific structural design of the driving component, as Figure 2 and Figure 4It can be known that the driving component includes a motor 11 and a speed reducer installed on the fixed plate 12. The output shaft of the speed reducer is connected to the main transmission shaft 32 through a coupling. Usually, the motor 11 and the speed reducer are assembled together and installed on the fixed plate 12. In addition, the driving component further includes a control box 13, which is electrically connected to the motor 11. The control box 13 is installed on the bottom plate 4 to start and stop the motor 11.

[0039] Embodiment III

[0040] Referring to Figures 1-4 As shown, on the basis of the technical solution of the above embodiment, a method for machining blind holes on the inner cavity side wall of a small engineering plastic part includes the following steps:

[0041] S1. Assemble the processing equipment. Fix the driving component and the positioning and processing component on the bottom plate 4. Install a gear transmission component on the positioning and processing component. The driving component drives the drill bit 30 on the gear transmission component to rotate and work. The end of the drill bit 30 is located outside the positioning and processing component. The top and side parts of the positioning and processing component respectively cooperate with the inner cavity of the engineering plastic part 5.

[0042] S2. Drilling process. Place the engineering plastic part 5 on the positioning and processing component to complete horizontal and edge positioning and move it away from the end of the drill bit 30. Start the driving component to make the drill bit 30 rotate and work. Push the engineering plastic part 5 along the axial direction of the drill bit 30 close to the end of the drill bit 30 for drilling process.

[0043] S3. Stop the machine and take the material. After the engineering plastic part 5 moves to the side by a set distance, the driving component stops. The engineering plastic part 5 retreats and resets. Take the engineering plastic part 5 that has completed the machining of the blind hole 51 from the positioning and processing component.

[0044] In step S1, the positioning and processing component is two support plates arranged side by side. The top surfaces of the two support plates are at the same height and the side parts are flush, that is, the top and side parts of the support plates are machined into positioning reference surfaces. The cavity of the engineering plastic part 5 is on the top and side parts of the support plates. Its top is used as the horizontal positioning reference surface, and one of its side parts is used as the side edge positioning reference surface. In addition, the gear transmission component includes a gear and a transmission shaft fixed with the gear. The transmission shaft is rotatably installed on the support plate. The number of gears can be selected as two or more according to needs. It has two functions. One is to partially replace the speed reducer to provide the function of reducing the speed; the other is to meet the requirement of flexible installation position of the drill bit 30.

[0045] There are three gears in the processing equipment of this application. A gear chuck 301 is fixed outside the drill bit 30. The gear chuck 301 meshes with the second gear 310, and the second gear 310 meshes with the first gear 320. The second gear 310 and the first gear 320 are respectively fixed on the driven transmission shaft 31 and the main transmission shaft 32. Generally, the second gear 310, the first gear 320 and the gear chuck 301 are all located between the first support plate 23 and the second support plate 24. The distance between the two support plates can meet the cavity size requirements of the engineering plastic part 5. In the actual production process, if the cavity size of the engineering plastic part 5 does not match the distance between the two support plates, the second gear 310, the first gear 320 and the gear chuck 301 can also be arranged outside the two support plates. In addition, both of the two support plates are installed on the fixed seat 22, and the fixed seat 22 is fixed on the bottom plate 4; the driving component is a motor 11 and a speed reducer. The motor 11 drives the speed reducer to work, and the output shaft of the speed reducer is connected to the main transmission shaft 32.

[0046] In step S2, the top of the positioning and processing component is in contact with the inner cavity bottom surface of the engineering plastic part 5, and at least one side of the positioning and processing component is in contact with the inner cavity side wall of the engineering plastic part 5. In fact, the same step positions with the same position and size are processed on the support plates to match the inner cavity of the engineering plastic part 5. The design of the step positions is to determine the co-planar side dimensions of the two support plates. Combining the distance parameters of the two support plates to match the cavity size of the engineering plastic part 5. The top surface and side dimensions of the fixed seat 22 do not exceed the top surface and step position dimensions of the support plates to prevent the fixed seat 22 from interfering.

[0047] In step S3, the driving component and the positioning and processing component are arranged oppositely. The driving component further includes a limit block 21 and a control box 13. Push the engineering plastic part 5 along the axial direction of the drill bit 30 to the limit block 21 to complete the drilling process. The control box 13 realizes the start and stop of the motor 11.

[0048] The innovative design of the present invention is that the position of the drill bit remains fixed. The engineering plastic part 5 is placed on the support plate where the drill bit is installed and is moved manually in the axial direction of the drill bit, which is equivalent to the feed machining of the drill bit. Specifically, the transmission mode of the drill bit 30 is changed. The top and side parts of the support plate are machined into positioning reference surfaces. The cavity of the engineering plastic part 5 is on the top and side parts of the support plate. Using its top as the horizontal positioning reference surface and one of its side parts as the side positioning reference surface, the engineering plastic part 5 is pressed down and placed horizontally on the support plate and positioned against the side. After the engineering plastic part 5 is placed in place (the inner wall of the cavity will not touch the drill bit), the motor 11 is started, and the engineering plastic part 5 is manually pushed along the side of the support plate to realize the drilling operation of the drill bit until it touches the limit block 21 and stops moving. Then the drill bit stops working, and the engineering plastic part 5 retreats and resets, and the engineering plastic part 5 with the blind hole 51 processed is taken out.

[0049] In the present invention, the assembly and mating relationships of various components are involved. Each gear, bearing, motor 11, reducer, and control box 13 and their control software, etc. are of the prior art or materials. Those skilled in the art can directly purchase or customize them according to the required product models and specifications from the market.

[0050] The electrical components mentioned in the text are all electrically connected to the external main controller and 220V mains or industrial electricity, and the main controller can be a conventional known device such as a computer that plays a control role.

[0051] The above are only the preferred specific embodiments of the present invention. Common knowledge such as the specific structures and characteristics known to the public in the solutions is not described in detail here. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. 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, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A method for processing blind holes on the inner wall of a small engineering plastic part, characterized in that: The steps include: S1. Assemble the processing equipment, fix the drive assembly and the positioning processing assembly on the bottom plate (4), install the gear transmission assembly on the positioning processing assembly, the drive assembly drives the drill bit (30) on the gear transmission assembly to rotate, the end of the drill bit (30) is located outside the positioning processing assembly, and the top and side of the positioning processing assembly are respectively matched with the inner cavity of the engineering plastic part (5); S2. Drilling processing, placing the engineering plastic part (5) on the positioning processing assembly to complete horizontal and side positioning and away from the end of the drill bit (30), starting the drive assembly to rotate the drill bit (30), and manually pushing the engineering plastic part (5) along the axial direction of the drill bit (30) close to the end of the drill bit (30) for drilling processing; S3. Stop the machine to take the material. After the engineering plastic part (5) moves to the side by a set distance, the drive assembly stops, the engineering plastic part (5) moves back and resets, and the engineering plastic part (5) with the blind hole (51) processed is taken from the positioning processing assembly.

2. A method for processing blind holes on the inner wall of a small engineering plastic part according to claim 1, characterized in that: In step S1, the positioning processing assembly is two support plates arranged side by side, and the top surfaces of the two support plates are at the same height and the sides are arranged flush.

3. A method for processing blind holes on the inner cavity side wall of a small engineering plastic part according to claim 2, characterized in that: The gear transmission assembly comprises a gear and a transmission shaft fixed with the gear, and the transmission shaft is rotatably mounted on the support plate.

4. A method for processing blind holes on the inner wall of a small engineering plastic part according to claim 3, characterized in that: A gear chuck (301) is fixed outside the drill bit (30), the gear chuck (301) meshes with the second gear (310), the second gear (310) meshes with the first gear (320), and the second gear (310) and the first gear (320) are respectively fixed on the driven transmission shaft (31) and the main transmission shaft (32).

5. A method for processing blind holes on the inner cavity side wall of a small engineering plastic part according to claim 4, characterized in that: The two support plates are both mounted on a fixing seat (22), and the fixing seat (22) is fixed on the base plate (4); the driving assembly is a motor (11) and a reducer, the motor (11) drives the reducer to work, and the output shaft of the reducer is connected to the main transmission shaft (32).

6. The method for processing blind holes on the inner wall of a small engineering plastic part according to claim 1, characterized in that: In step S2, the top of the positioning processing component is fitted with the bottom surface of the inner cavity of the engineering plastic part (5), and at least one side of the positioning processing component is fitted with the side wall of the inner cavity of the engineering plastic part (5).

7. The method for processing blind holes on the inner wall of a small engineering plastic part according to claim 1, characterized in that: In step S3, the driving assembly and the positioning processing assembly are arranged relative to each other, and the driving assembly also includes a limit block (21) and a control box (13). The engineering plastic part (5) is manually pushed along the axial direction of the drill bit (30) to the limit block (21) to complete the drilling process, and the control box (13) realizes the start and stop of the motor (11).

8. A blind hole processing device for the inner cavity side wall of a small engineering plastic part, comprising a bottom plate (4), characterized in that: A driving assembly is arranged on the bottom plate (4), and the driving assembly is mounted on a fixing plate (12), and a limiting block (21) is arranged on the fixing plate (12); A positioning processing assembly, the positioning processing assembly comprising two support plates arranged opposite to the limit block (21), the tops of the two support plates being at the same height and the sides being arranged flush; A gear transmission assembly, the gear transmission assembly comprising a main transmission shaft (32) and a drill bit (30) respectively mounted on a support plate, the output shaft of the drive assembly being connected to the main transmission shaft (32), a first gear (320) being mounted on the main transmission shaft (32), a gear chuck (301) being mounted outside the drill bit (30), the first gear (320) being engaged with the gear chuck (301), and an end of the drill bit (30) being arranged to penetrate outside the support plate.

9. The blind hole processing equipment for the inner cavity side wall of a small engineering plastic part according to claim 8 is characterized in that: The gear transmission assembly further comprises a driven transmission shaft (31) rotatably mounted on the support plate, a second gear (310) being mounted on the driven transmission shaft (31), and the second gear (310) respectively meshes with the first gear (320) and the gear chuck (301).

10. The blind hole processing equipment for the inner cavity side wall of a small engineering plastic part according to claim 9, characterized in that: The driving assembly comprises a motor (11) and a reducer mounted on a fixed plate (12); an output shaft of the reducer is connected to a main transmission shaft (32) via a coupling.

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