A rotary polisher for processing an elongated core for a medical mold
By designing a rotary grinding machine specifically for machining slender cores, the problems of poor rigidity and unstable precision in machining slender cores have been solved, achieving efficient and precise core machining, which is suitable for mass production of medical molds.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- PUNCH IND DALIAN
- Filing Date
- 2025-08-20
- Publication Date
- 2026-07-28
AI Technical Summary
Existing technologies suffer from poor rigidity, easy deformation, and unstable processing accuracy when processing slender cores, which affects the accuracy and service life of the mold.
A rotary grinding tool for machining slender cores for medical molds was designed. The structure was optimized through finite element analysis. It includes a base sine component, a guide wheel rotation component, a support component, a clamping swing arm structure component, and a transmission component to achieve stable clamping and high-precision machining of the core.
It achieves high-precision machining of the core, is easy to operate and quick to clamp, and is suitable for mass production and products of different specifications, thus improving the processing efficiency and accuracy of the mold.
Smart Images
Figure CN224560871U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of machining technology, and in particular to a rotary grinding tool for machining slender cores for medical molds. Background Technology
[0002] In the medical mold industry, molds such as pipettes and syringes all require cores. However, the shape, size and length of the cores vary. In particular, the processing of small cores is very difficult. The tolerance of the diameter, roundness and coaxiality of the tip ends of the product is required to be within 0.005mm. The positioning rods are generally between 2.0mm and 0.6mm. Therefore, the processing and clamping accuracy requirements are high.
[0003] Traditional machining methods typically involve mounting a fixture on a tool grinder. The product's positioning rod is clamped onto the fixture for positioning and rotational machining of the stepped rod's dimensions. Because the fixture's guide wheel has annular grooves, and the pressure roller is above these grooves, pressing against the positioning rod, the poor rigidity of the positioning rod makes it prone to slight bending when machining small rod diameters, resulting in inconsistent dimensional accuracy. Figure 16 As shown, the tip of the slender core product consists of two stepped rods connected at an angle, with an angled transition at the tip face. The diameter of the first tip is Ф0.12mm, and its length is 5.6mm, with a 30° transition angle. Due to the slender and rigid nature of the first rod, the 5.6mm length cannot be directly machined to the Ф0.12mm size. The poor rigidity during machining would result in two problems: firstly, a tapered undercut would occur, making it impossible to guarantee tolerances; secondly, breakage would occur. Figure 11 As shown in Figure 1. Therefore, in summary, the existing method is inefficient, and its large aspect ratio, poor rigidity, unstable shape retention, and susceptibility to bending and deformation all affect the mold's accuracy and service life. Utility Model Content
[0004] The purpose of this invention is to provide a rotary grinding tool specifically designed for machining slender cores for medical molds. The grinding tool structure has been optimized through finite element analysis, solving the problem of machining the stepped rods at the tips of slender cores and shaft-type parts. This grinding tool is convenient, quick, and easy to learn for clamping and operating shaft-type parts, with accurate positioning and high roundness precision.
[0005] The technical solution adopted by this utility model to achieve the above objectives is as follows: A rotary grinding tool for machining slender cores for medical molds includes a base sine wave assembly, a guide wheel rotation assembly, a support assembly, a transmission assembly, and a clamping swing arm structure assembly. The base sine wave assembly is used for positioning and fixing the entire grinding tool on the machine tool and for determining its rotation angle. The guide wheel rotation assembly, support assembly, transmission assembly, and clamping swing arm structure assembly are respectively connected to the base sine wave assembly. The guide wheel rotation assembly is used to drive the core product to rotate in place during core machining. The support assembly and clamping swing arm structure assembly are used for support and workpiece positioning, keeping the axial and radial directions of the workpiece stable during the grinding process. The transmission assembly transmits power to the product through the guide wheel, causing the product to rotate and thus machining the core product. The base sine assembly includes a base plate, a positioning shaft seat, an A positioning shaft, a B positioning shaft, a sine base, and a sine angle adjustment seat. The positioning shaft seat is fixed on the base plate, the A positioning shaft is installed at the front end of the sine base, the sine base is connected to the base plate through the A positioning shaft and the positioning shaft seat, the sine angle adjustment seat is installed on the B positioning shaft, and the B positioning shaft is fixed at the rear end of the sine base. The guide wheel rotation assembly includes a front bearing housing, a rubber roller, and a rear bearing housing connected in sequence. The front bearing housing is connected to a synchronous pulley shaft and a front bearing shaft at the front and rear, respectively. The synchronous pulley shaft is connected to a synchronous pulley key, a synchronous pulley end cover, a bearing, and a front bearing shaft key. The front bearing shaft is connected to a front bearing end cover. The rear bearing housing is connected to a rear bearing shaft and a rear bearing end cover at the front and rear, respectively. A rubber roller is connected between the front bearing shaft and the rear bearing shaft. The support assembly includes a support frame, a carbide support plate, a workpiece positioning ejector pin, an ejector pin frame, and an ejector pin frame pad. The support frame is located behind the rubber roller and is connected to the sine base via a bracket positioning column. The carbide support plate is connected to the support frame. The upper end of the ejector pin frame is connected to the workpiece positioning ejector pin, and the lower end is connected to the ejector pin frame pad. The ejector pin frame pad is located on one side of the rubber roller and is connected to the sine base. The pressure swing arm structure assembly includes a pressure roller, a small pressure roller swing arm, and a large pressure roller swing arm. The pressure roller is connected to the large pressure roller swing arm via the small pressure roller swing arm. The large pressure roller swing arm is connected to the swing arm shaft via a swing arm seat. One end of the swing arm shaft is connected to the sine base via a swing arm limiting block, and the other end is connected to the sine base via a torsion spring assembly. The torsion spring assembly includes a torsion spring pressure pad, a torsion spring rotating pad, and a torsion spring. The torsion spring is sleeved on the swing arm shaft, and its end is connected to the torsion spring rotating pad. The root of the torsion spring is connected to the torsion spring pressure pad, and the torsion spring pressure pad is connected to the sine base. The transmission assembly includes a secondary synchronous pulley, a main synchronous pulley, and a drive motor. The drive motor is connected to the main synchronous pulley, and the main synchronous pulley is connected to the secondary synchronous pulley via a synchronous belt. The main synchronous pulley is connected to the main synchronous pulley key.
[0006] The A positioning shaft is installed at the front end of the sine base and locked in place by an internal hexagon head screw. The positioning shaft seat is installed on the base plate and locked in place by an internal hexagon head screw. The B positioning shaft is fixed to the rear end of the sine base by a locking screw M5.
[0007] The front bearing housing is connected to TC oil seal one and TC oil seal two at the front and rear respectively. The front bearing oil seal washer is connected to TC oil seal one. The rear bearing housing is connected to TC oil seal three and TC oil seal four at the front and rear respectively. The timing pulley end cover is fixedly connected by 90° countersunk screws M5*10. The front bearing housing is fixedly connected by bolts M6*75. The front bearing end cover is fixedly connected by 90° countersunk screws M4*12. The rear bearing housing is fixedly connected by bolts M6*65 and 90° countersunk screws M4*15. The rear bearing end cover is fixedly connected by bolts M10*165.
[0008] The support frame is fixedly connected by bracket locking bolts M6*10 and connected to the diamond pen by diamond pen locking bolts M6*10. The hard alloy support plate is connected to the support frame by support plate locking bolts M6*15 and support plate gaskets. The lower end of the ejector pin frame is connected to the ejector pin frame pad by ejector pin frame locking bolts M6*20. The ejector pin frame pad is connected to the sine base by ejector pin frame pad bolts M6*35.
[0009] The pressure roller large swing arm is connected to a swing arm handle for controlling direction. The pressure roller is connected to the pressure roller small swing arm through the pressure roller eccentric shaft. The pressure roller small swing arm is connected to the pressure roller large swing arm through the swing arm bolt. The pressure roller large swing arm is connected to the swing arm seat through the swing arm seat locking bolt M6*20. The swing arm limit block is connected to the sine base through the swing arm limit bolt M6*10. The end of the torsion spring is connected to the torsion spring rotating pad through the torsion spring rotating pad bolt M4*10. The torsion spring pressure pad is connected to the sine base through the torsion spring pad bolt M5*10.
[0010] The auxiliary synchronous pulley is connected to the auxiliary synchronous pulley pad by bolts M8*35, and the main synchronous pulley is connected to the main synchronous pulley pad by bolts M5*10. The synchronous belt and the two pulleys are externally connected to the inner waterproof cover of the synchronous belt and pulleys and the outer waterproof cover of the synchronous belt. A spring fixing plate is connected to the inner waterproof cover of the synchronous belt and pulleys. The drive motor is connected to the base plate of the fixing seat through the motor fixing seat. The motor fixing seat is connected to the base plate of the fixing seat by fixing seat bolts M5*40. The base plate of the fixing seat is connected to the sine base by the base plate bolts M6*15. The drive motor is externally connected to the motor waterproof cover by the motor cover bolts M5*6.
[0011] This utility model utilizes a specialized rotary grinding machine whose structure has been optimized through finite element analysis. This solves the problem of machining the stepped tips of slender core and shaft parts. The grinding machine device is convenient, quick, and easy to learn for clamping and operating shaft parts. It offers accurate positioning, high roundness precision, and can machine slender stepped shaft parts. It is easy to operate, highly practical, and quick and easy to clamp and disassemble, making it widely applicable. It can be used for batch production or products of different specifications, with significant application effects. Attached Figure Description
[0012] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the sinusoidal component structure of the base of this utility model. Figure 1 ; Figure 3 This is a schematic diagram of the sinusoidal component structure of the base of this utility model. Figure 2 ; Figure 4 This is a schematic diagram of the guide wheel rotation assembly structure of this utility model. Figure 1 ; Figure 5 This is a schematic diagram of the guide wheel rotation assembly structure of this utility model. Figure 2 ; Figure 6 A schematic diagram of the front bearing housing structure of the guide wheel rotation assembly; Figure 7 A schematic diagram of the rear bearing housing structure of the guide wheel rotation assembly; Figure 8 Schematic diagram of the structure after the guide wheel rotation assembly is installed on the sine base. Figure 1 ; Figure 9 Schematic diagram of the structure after the guide wheel rotation assembly is installed on the sine base. Figure 2 ; Figure 10 This is a schematic diagram of the support component structure of this utility model; Figure 11 This is a schematic diagram of the structure after the support components are installed on the sine base; Figure 12 This is a schematic diagram of the clamping swing arm structure assembly of this utility model; Figure 13 A schematic diagram of the structure after the clamping swing arm assembly is installed onto the sine base; Figure 14 This is a schematic diagram of the transmission component structure of this utility model. Figure 1 ; Figure 15 This is a schematic diagram of the transmission component structure of this utility model. Figure 2 ; Figure 16 This is a schematic diagram of the core product structure; Figure 17 for Figure 16 Enlarged view of section A in the middle; Figures 18.1 to 18.8 This is a diagram showing the processing sequence of each step in the core molding process.
[0013] In the diagram: 1-Base plate, 2-Positioning shaft seat, 3-A positioning shaft, 4-B positioning shaft, 5-Sine base, 6-Sine angle adjustment seat, 7-M6 locking screw, 8-M5 locking screw, 9-Hex socket head cap screw, 10-Synchronous belt pulley key, 11-Synchronous belt pulley shaft, 12-TC oil seal 1, 13-Front bearing seat, 14-Rubber roller, 15-Rear bearing shaft, 16-Rear bearing seat, 17-90° countersunk screw M5*10, 18-Synchronous belt pulley end cover, 19-Bearing, 20-M6*75 bolt, 21-Front bearing shaft key, 22-Front bearing oil seal gasket 23 - Front bearing shaft; 24 - Bolt M6*65; 25 - Front bearing end cap; 26 - 90° countersunk screw M4*12; 27 - TC oil seal II; 28 - TC oil seal III; 29 - 90° countersunk screw M4*15; 30 - Rear bearing end cap; 31 - TC oil seal IV; 32 - Bolt M10*165; 33 - Bracket positioning post; 34 - Bracket locking bolt M6*10; 35 - Diamond pen locking bolt M6*10; 36 - Support frame; 37 - Pallet locking bolt M6*15; 38 - Pallet gasket; 39 - Carbide pallet; 40 - Workpiece positioning. Ejector pin, 41-Ejector pin holder, 42-Ejector pin holder locking bolt M6*20, 43-Ejector pin holder pad bolt M6*35, 44-Ejector pin holder pad, 45-Pressure roller, 46-Pressure roller eccentric shaft, 47-Pressure roller small swing arm, 48-Swing arm bolt, 49-Torsion spring pressure washer, 50-Torsion spring washer bolt M5*10, 51-Torsion spring rotating washer bolt M4*10, 52-Torsion spring rotating washer, 53-Torsion spring, 54-Swing arm seat, 55-Swing arm seat locking bolt M6*20, 56-Swing arm shaft, 57-Swing arm limit block, 58-Swing arm limit bolt M6*10, 59-Swing arm handle, 6 0-Pressure roller swing arm, 61-Secondary synchronous belt pulley, 62-Secondary synchronous pulley pad, 63-M8*35 bolt, 64-Synchronous belt, 65-Main synchronous belt pulley, 66-Main synchronous pulley pad, 67-M5*10 bolt, 68-Main synchronous pulley key, 69-Inner waterproof cover for synchronous belt and pulley, 70-Motor mounting base, 71-Base plate of mounting base, 72-M6*15 bolt of base plate, 73-M5*40 bolt of mounting base, 74-Drive motor, 75-Spring fixing plate, 76-M5*6 bolt of motor cover, 77-Motor waterproof cover, 78-Outer waterproof cover of synchronous belt, 79-Core. Detailed Implementation
[0014] The present invention will now be described in detail with reference to the accompanying drawings and embodiments, but the present invention is not limited to the specific embodiments.
[0015] Example 1
[0016] like Figure 1 As shown, a special rotary grinding machine used in a method for processing slender cores for medical molds includes a base sine wave assembly, a guide wheel rotation assembly, a support assembly, a transmission assembly, and a clamping swing arm structure assembly. The base sine wave assembly is used for positioning, fixing, and rotating the entire grinding machine on the machine tool. The guide wheel rotation assembly, support assembly, transmission assembly, and clamping swing arm structure assembly are respectively connected to the base sine wave assembly. The guide wheel rotation assembly is used to drive the core product to rotate in place during core processing. The support assembly and clamping swing arm structure assembly are used for support and workpiece positioning, keeping the axial and radial directions of the workpiece stable during the grinding process. The transmission assembly transmits power to the product through the guide wheel, causing the product to rotate and thus realizing the processing of the core product. like Figures 2-3 As shown, the base sine assembly includes a base plate 1, a positioning shaft seat 2, an A positioning shaft 3, a B positioning shaft 4, a sine base 5, and a sine angle adjustment seat 6. The positioning shaft seat 2 is fixedly mounted on the base plate 1. The A positioning shaft 3 is mounted on the front end of the sine base 5. The sine base 5 is connected to the base plate 1 through the A positioning shaft 3 and the positioning shaft seat 2. The sine angle adjustment seat 6 is mounted on the B positioning shaft 4, and the B positioning shaft 4 is fixed to the rear end of the sine base 5. The positioning shaft seat 2 is installed and fixed on the base plate 1 by the hexagon socket head cap screw 9, the A positioning shaft 3 is installed on the front end of the sine base 5 by the hexagon socket head cap screw 9, and the B positioning shaft 4 is fixed to the rear end of the sine base 5 by the locking screw M5 8.
[0017] like Figures 4-5 , Figures 8-9 As shown, the guide wheel rotation assembly includes a front bearing housing 13, a rubber roller 14, and a rear bearing housing 16 connected in sequence. The front bearing housing 13 is connected to a synchronous pulley shaft 11 and a front bearing shaft 23 at the front and rear, respectively. The synchronous pulley shaft 11 is connected to a synchronous pulley key 10, a synchronous pulley end cover 18, a bearing 19, and a front bearing shaft key 21. The front bearing shaft 23 is connected to a front bearing end cover 25. The rear bearing housing 16 is connected to a rear bearing shaft 15 and a rear bearing end cover 30 at the front and rear, respectively. The rubber roller 14 is connected between the front bearing shaft 23 and the rear bearing shaft 15. like Figures 6-7As shown, the front bearing housing 13 is connected to TC oil seal 12 and TC oil seal 27 at the front and rear respectively. The front bearing oil seal washer 22 is connected to the TC oil seal 12. The rear bearing housing 16 is connected to TC oil seal 38 and TC oil seal 4 at the front and rear respectively. The synchronous pulley end cover 18 is fixedly connected by 90° countersunk screw M5*10 17. The front bearing housing 13 is fixedly connected by bolt M6*75 20. The front bearing end cover 25 is fixedly connected by 90° countersunk screw M4*12 26. The rear bearing housing 16 is fixedly connected by bolt M6*65 24 and 90° countersunk screw M4*15 29. The rear bearing end cover 30 is fixedly connected by bolt M10*165 32.
[0018] like Figures 10-11 As shown, the support assembly includes a support frame 36, a carbide support plate 39, a workpiece positioning ejector pin 40, an ejector pin frame 41, and an ejector pin frame pad 44. The support frame 36 is located behind the rubber roller 14 and is connected to the sinusoidal base 5 via a bracket positioning column 33. The carbide support plate 39 is connected to the support frame 36. The upper end of the ejector pin frame 41 is connected to the workpiece positioning ejector pin 40, and the lower end is connected to the ejector pin frame pad 44. The ejector pin frame pad 44 is located on one side of the rubber roller 14 and is connected to the sinusoidal base 5. The support frame 36 is fixedly connected by bracket locking bolts M6*10 34 and connected to the diamond pen by diamond pen locking bolts M6*10 35. The hard alloy support plate 39 is connected to the support frame 36 by support plate locking bolts M6*15 37 and support plate gasket 38. The lower end of the ejector pin frame 41 is connected to the ejector pin frame pad 44 by ejector pin frame locking bolts M6*20 42. The ejector pin frame pad 44 is connected to the sine base 5 by ejector pin frame pad bolts M6*35 43.
[0019] like Figures 12-13 As shown, the pressure swing arm structure assembly includes a pressure roller 45, a small pressure roller swing arm 47, and a large pressure roller swing arm 60. The pressure roller 45 is connected to the large pressure roller swing arm 60 via the small pressure roller swing arm 47. The large pressure roller swing arm 60 is connected to the swing arm shaft 56 via the swing arm seat 54. One end of the swing arm shaft 56 is connected to the sine base 5 via the swing arm limiting block 57, and the other end is connected to the sine base 5 via the torsion spring assembly. The torsion spring assembly includes a torsion spring pressure pad 49, a torsion spring rotating pad 52, and a torsion spring 53. The torsion spring 53 is sleeved on the swing arm shaft 56, and its end is connected to the torsion spring rotating pad 52. The root of the torsion spring 53 is connected to the torsion spring pressure pad 49, and the torsion spring pressure pad 49 is connected to the sine base 5. The pressure roller large swing arm 60 is connected to a swing arm handle 59 for controlling direction. The pressure roller 45 is connected to the pressure roller small swing arm 47 through the pressure roller eccentric shaft 46. The pressure roller small swing arm 47 is connected to the pressure roller large swing arm 60 through the swing arm bolt 48. The pressure roller large swing arm 60 is connected to the swing arm seat 54 through the swing arm seat locking bolt M6*20 55. The swing arm limiting block 57 is connected to the sine base 5 through the swing arm limiting bolt M6*10 58. The end of the torsion spring 53 is connected to the torsion spring rotating pad 52 through the torsion spring rotating pad bolt M4*10 51. The torsion spring pressure pad 49 is connected to the sine base 5 through the torsion spring pad bolt M5*10 50.
[0020] like Figures 14-15 As shown, the transmission assembly includes a secondary synchronous pulley 61, a main synchronous pulley 65, and a drive motor 74. The drive motor 74 is connected to the main synchronous pulley 65, and the main synchronous pulley 65 is connected to the secondary synchronous pulley 61 via a synchronous belt. The main synchronous pulley 65 is connected to the main synchronous pulley key 68. The auxiliary synchronous pulley 61 is connected to the auxiliary synchronous pulley pad 62 by bolts M8*35 63. The main synchronous pulley 65 is connected to the main synchronous pulley pad 66 by bolts M5*10 67. The synchronous belt 64 and the two pulleys are externally connected to the inner waterproof cover 69 of the synchronous belt and pulleys and the outer waterproof cover 78 of the synchronous belt. The inner waterproof cover 69 of the synchronous belt and pulleys is connected to the spring fixing plate 75. The drive motor 74 is connected to the fixing base plate 71 through the motor fixing seat 70. The motor fixing seat 70 is connected to the fixing base plate 71 through fixing seat bolts M5*40 73. The fixing base plate 71 is connected to the sine base 5 through the base plate bolts M6*15 72. The drive motor 74 is externally connected to the motor waterproof cover 77 through the motor cover bolts M5*6 76.
[0021] Example 2
[0022] like Figures 16-17 As shown, in this embodiment, the slender core is connected to its positioning rod and first-stage step rod via an angle transition. The portion of the positioning rod near the first-stage step rod plays a molding role, while the section near the head mounting plate serves a positioning function. The first-stage and second-stage step rods are also connected in the mold via a conical transition, participating in the molding process. The tip of the second-stage step rod at 30° connects to the outer cavity for positioning, ensuring the positional accuracy of the second-stage step rod during injection molding. The second-stage step rod is 0.12mm in diameter; its thinness indicates poor rigidity, necessitating appropriate machining steps to ensure its quality and coaxiality.
[0023] A method for processing slender cores for medical molds includes the following steps: S1. Guide Wheel Dressing: After the machine tool is equipped with the special rotary grinding machine, the guide wheel needs to be dressed to ensure its rotational accuracy. Since the guide wheel is made of a special material, it has high wear resistance, high friction, and high hardness. Ordinary corundum grinding wheels or green silicon carbide grinding wheels cannot be dressed and ground. Therefore, CBN or diamond grinding wheels are required for grinding and dressing. The grit size of the grinding wheel should be 400. If a grinding wheel with a grit size greater than 400 is selected to grind the guide wheel, the surface roughness value of the guide wheel will be small. That is, if it is too fine, the friction will be reduced. If it is too coarse, the guide wheel will not be wear-resistant and will wear out quickly. The surface will easily stick to the grinding debris, which will cause dimensional instability.
[0024] S2. Pallet Selection and Adjustment: The thickness of the pallet at the 30° tip should be determined based on the diameter of the product positioning rod. The pallet thickness should be less than the diameter of the positioning rod, with a difference of 0.1-0.5mm. When the diameter of the product positioning rod is less than 2.0mm, the difference should be 0.05-0.2mm. The pallet should be aligned on the grinder. In this embodiment, the product positioning rod is 0.7mm, so the thickness of the pallet can be between 0.5-0.65mm. The pallet is installed on the grinder for alignment. There are two alignment methods: one is to use a lever dial indicator to check the parallelism between the 30° inclined edge of the pallet tip and the Z-axis of the machine tool. The dial indicator value should be within 0.002. The other is to place the core product on the pallet, rotate the roller, and observe whether the product moves along the axis. If it moves in the Z+ direction, it means that the product axis is not parallel to the roller axis, and there is an angle phenomenon with the corner facing the Z+ direction. If the product moves in the Z- direction, it means that the angle between the product axis and the roller axis is facing the Z- direction. The pallet needs to be rotated slightly clockwise or counterclockwise until the product rotates in place, indicating that the product axis is parallel to the guide wheel axis.
[0025] S3. Adjustment of the workpiece positioning ejector pin: The core product is clamped onto the grinder, with the tip to be machined extending beyond the front face of the support plate. Ensure the grinding wheel does not grind the support plate during machining. Adjust the ejector pin until it is positioned on the head end face of the product, then tighten it with bolts. When adjusting the ejector pin, try to position it at the center of the head end face of the product. This prevents potential runout of the machined end face or angled surface due to the head end face not being perpendicular to the positioning axis.
[0026] S4. Pressure Roller Position Adjustment: In the pressure arm structure, the locking bolt of the pressure arm seat is used to adjust the position of the pressure roller on the product positioning rod in the Z-axis direction. The pressure arm handle has two functions: first, to adjust the pressure roller position of the pressure arm in the X-axis direction for positioning and locking; second, to facilitate the quick and easy removal or installation of the product during core product processing, by simply moving the handle.
[0027] S5. Processing: According to Figure 18.1As shown, the core product analysis is as follows: The tip of the product consists of two stepped rods connected at an angle, with an angle transition at the tip face. The diameter of the first tip is Ф0.12mm, and its length is 5.6mm, with a tip transition angle of 30°. Due to the slender and rigid first rod, the 5.6mm length cannot be directly machined to the Ф0.12mm size. Because of the poor rigidity during machining, two problems arise: firstly, a taper will occur, making it impossible to guarantee tolerances; secondly, a breakage point may appear. Figure 18.1 As shown. Therefore, it is necessary to process the material in segments according to the length-to-diameter ratio to eliminate stress concentration, such as... Figure 18.2 As shown. The end diameter is Ф0.3mm, and it also needs to be machined in sections while ensuring that it is not burned during the process. Burning will cause deformation and poor coaxiality.
[0028] Therefore, the first section, with a diameter of Ф0.12mm and a length of 5.6mm, is divided into five smaller sections for finishing. The grinding wheel selected is either a green silicon carbide grinding wheel from Norton Saint-Gobain (Shanghai) or a green silicon carbide grinding wheel from Noritake (Japan), with a grit size of 150. The grinding wheel grit cannot be too fine, as this can cause burns, insufficient grinding depth, or deformation during processing. Too coarse a grit will result in an unsatisfactory surface finish. The grinding wheel dressing should be adjusted according to the different processing sections to ensure dimensional accuracy and tolerances. The coarseness or fineness of the grinding wheel dressing is directly related to the age and dullness of the diamond dressing tool. Therefore, when processing such small products, a 120-degree single-point diamond dressing tool should be selected, using a new 8-point diamond dressing tool. During grinding wheel dressing, the feed rate and feed speed should be controlled to ensure the desired dressing fineness. The specific steps are as follows: (1) According to Figure 18.2 As shown, the roughing allowance for the grinding wheel end face is 0.03mm. It is not possible to first set the tool in the Z-axis direction, then move it 0.9mm to machine Ф0.12mm, then move it to 2mm to machine Ф0.24mm, and finally move it to 3.6mm to machine Ф0.4mm. This sequence is likely to cause root breakage when roughing Ф0.12mm. Therefore, the first small section should be machined from a length of 3.6mm to Ф0.4mm, then the length should be moved to 2mm to machine Ф0.24mm, and finally the length should be moved to 0.9mm to machine Ф0.12mm. This machining sequence ensures good coaxiality and also relieves stress for subsequent machining, preventing deformation. After rough machining, finish machining the Ф0.12mm dimension first. The grinding wheel should be finely dressed to ensure a smooth finish. Since the tolerance of Ф0.12mm is 0-0.003mm, which is very small, the machining should be slow to ensure coaxiality. When machining to the upper tolerance +0.002, stop the cutting and let the grinding wheel stay on the workpiece for 4-5 seconds to remove the grinding allowance. Otherwise, the straightness of the machined dimension will not meet the product accuracy requirements. Remove the workpiece and measure whether the machined dimension is within the tolerance or how much allowance is left. Clamp the workpiece on the machine tool and machine the remaining amount to the upper tolerance zero to prepare for subsequent sequential machining. Note that the dwell time when the grinding wheel is machined to the upper tolerance zero should be the same as the previous dwell time.
[0029] (2) According to Figure 18.3 As shown, the machining tip has a length of 0.19mm at 30°. The grinding wheel is dressed at 15° with a length of 0.4mm in the Z-axis direction. Due to the small size of the product, manual tool setting is not possible. The grinding wheel position is calculated using the machine tool's digital display coordinates. The bottom surface of the grinding wheel is 0.06mm from the center of the workpiece. The zero point of the grinding wheel is the zero point of the workpiece's Z-axis, which is the grinding wheel's tool zero point. The grinding wheel dressing length is 0.4mm. After the grinding wheel moves 0.4mm in the Z-axis direction, it cuts 0.05mm, which is the 30° feed tolerance. Since the grinding wheel position and feed amount are calculated, there will be deviations. Therefore, the grinding wheel in the length direction of the product is moved 0.35mm in the Z-axis direction, which is the 0.05mm allowance for the 0.19mm length. The grinding wheel cuts 0.06mm to the center of the product. The workpiece is removed, and the remaining length is measured. The workpiece is then clamped, the machine tool is started, and the machine tool feeds along the Z-axis. The feed amount is the remaining length. The angle machining is complete.
[0030] (3) According to Figures 18.4-18.7 As shown, the second small section of machining; the grinding wheel is dressed to a roughness of Ra0.6. Too fine a finish will cause burning and poor deformation. Continue machining the remaining portion, Ф0.12mm. Figure 18.4 As shown, the roughing allowance is 0.03mm in multiple stages. First, the Ф0.4mm length of 4.6mm is machined, then the Ф0.24mm length of 3.3mm is machined, and then the Ф0.12mm length of 2mm is rough machined. After roughing, the roughness value of the dressing wheel is Ra0.12. Note that after dressing the grinding wheel, it cannot be machined directly. The bottom surface of the grinding wheel needs to be ground with a bakelite rod to remove the broken abrasive material from the surface of the grinding wheel. Otherwise, the machining will not be able to connect smoothly with the Ф0.12mm section that was machined in the previous stage, and the Ф0.12mm dimension of the previous stage will be damaged or worn out.
[0031] (4) Third sub-section processing; rough processing of each section is performed again, such as Figure 18.5 As shown, the roughing process involves multiple sections with a length of 5.6mm for Ф0.4mm and 4.6mm for Ф0.24mm. After machining the length of Ф0.12mm down to 3.3mm, the finishing process for the grinding wheel is the same as above. Then, the 3.3mm length of Ф0.12mm is finished.
[0032] (5) Fourth sub-stage processing; roughing first, then finishing. Figure 18.6 As shown, the roughing process involves multiple sections with lengths of 7.1mm (Ф0.4mm) and 5.6mm (Ф0.24mm). After roughing the length from Ф0.12mm to 4.6mm, the finishing process is the same as above. Finally, the length of the Ф0.12mm wheel is finished at 46mm.
[0033] (6) The fifth sub-segment of processing; such as Figure 18.7As shown, rough machining is performed on the Ф0.32mm section with a length of 7.1mm and the Ф0.12mm section with a length of 5.6mm. After rough machining, the grinding wheel is finished. First, the Ф0.3mm section with a length of 7.1mm is finished, and then the grinding wheel angle is adjusted to 15° with a length of 0.4mm. When finishing the fifth small section of the Ф0.12mm dimension, the tolerances of the dimensions above the angle of 35.06mm and below the angle of 35.4mm must be taken into account. When machining the Ф0.12mm dimension, a length allowance of 0.05mm is required in the length direction for length measurement. Therefore, the tool is moved by 5.6 + 0.35 = 5.95mm before the cutter enters. After machining the Ф0.12mm dimension to the tolerance, the allowance of the lengths of 35.06mm and 35.4mm is measured. Then, the Z-axis of the machine tool clamped on the product is moved to the allowance value, and the machining is completed to the required amount, thus completing all dimensions of the first section.
[0034] (7) As shown in Figure 18.18, the feed speed for machining the second section of the rod Ф0.3-0.002 mm should be uniform, starting with roughing and then finishing. The roughness of the grinding wheel should be Ra0.8, so that the measured dimensions are uniform and stable. Roughing is done in two stages: the first stage leaves a margin of 0.04 mm, and the second stage leaves a margin of 0.01 mm with a roughness of Ra0.3. Finally, after finishing the grinding wheel, the bottom surface of the grinding wheel should be polished with a bakelite rod to remove any broken or unshed abrasive material. The finishing dimension Ф0.3-0.002 mm should take into account the length of the connecting angle and leave a margin. After Ф0.3 mm is reached, the lengths of 28 mm and 28.8 mm are measured to determine the margin, and then a second length machining is performed to complete the machining of the second section, i.e., the product is finished.
[0035] The above description, in conjunction with preferred technical solutions, provides a further detailed explanation of this utility model. It should not be construed that the specific implementation of the utility model is limited to these descriptions. For those skilled in the art, simple deductions and substitutions can be made without departing from the concept of this utility model, and all such modifications and substitutions should be considered within the scope of protection of this utility model.
Claims
1. A rotary grinding tool specifically for machining slender cores for medical molds, characterized in that: The device includes a base sine wave assembly, a guide wheel rotation assembly, a support assembly, a transmission assembly, and a clamping swing arm structure assembly. The base sine wave assembly is used for positioning, fixing, and rotating the entire grinder on the machine tool. The guide wheel rotation assembly, support assembly, transmission assembly, and clamping swing arm structure assembly are respectively connected to the base sine wave assembly. The guide wheel rotation assembly is used to drive the core product to rotate in place during core processing. The support assembly and clamping swing arm structure assembly are used for support and workpiece positioning, keeping the axial and radial directions of the workpiece stable during the grinding process. The transmission assembly transmits power to the product through the guide wheel, causing the product to rotate and realizing the processing of the core product. The base sine assembly includes a base plate, a positioning shaft seat, an A positioning shaft, a B positioning shaft, a sine base, and a sine angle adjustment seat. The positioning shaft seat is fixed on the base plate, the A positioning shaft is installed at the front end of the sine base, the sine base is connected to the base plate through the A positioning shaft and the positioning shaft seat, the sine angle adjustment seat is installed on the B positioning shaft, and the B positioning shaft is fixed at the rear end of the sine base. The guide wheel rotation assembly includes a front bearing housing, a rubber roller, and a rear bearing housing connected in sequence. The front bearing housing is connected to a synchronous pulley shaft and a front bearing shaft at the front and rear, respectively. The synchronous pulley shaft is connected to a synchronous pulley key, a synchronous pulley end cover, a bearing, and a front bearing shaft key. The front bearing shaft is connected to a front bearing end cover. The rear bearing housing is connected to a rear bearing shaft and a rear bearing end cover at the front and rear, respectively. A rubber roller is connected between the front bearing shaft and the rear bearing shaft. The support assembly includes a support frame, a carbide support plate, a workpiece positioning ejector pin, an ejector pin frame, and an ejector pin frame pad. The support frame is located behind the rubber roller and is connected to the sine base via a bracket positioning column. The carbide support plate is connected to the support frame. The upper end of the ejector pin frame is connected to the workpiece positioning ejector pin, and the lower end is connected to the ejector pin frame pad. The ejector pin frame pad is located on one side of the rubber roller and is connected to the sine base. The pressure swing arm structure assembly includes a pressure roller, a small pressure roller swing arm, and a large pressure roller swing arm. The pressure roller is connected to the large pressure roller swing arm via the small pressure roller swing arm. The large pressure roller swing arm is connected to the swing arm shaft via a swing arm seat. One end of the swing arm shaft is connected to the sine base via a swing arm limiting block, and the other end is connected to the sine base via a torsion spring assembly. The torsion spring assembly includes a torsion spring pressure pad, a torsion spring rotating pad, and a torsion spring. The torsion spring is sleeved on the swing arm shaft, and its end is connected to the torsion spring rotating pad. The root of the torsion spring is connected to the torsion spring pressure pad, and the torsion spring pressure pad is connected to the sine base. The transmission assembly includes a secondary synchronous pulley, a main synchronous pulley, and a drive motor. The drive motor is connected to the main synchronous pulley, and the main synchronous pulley is connected to the secondary synchronous pulley via a synchronous belt. The main synchronous pulley is connected to the main synchronous pulley key.
2. The dedicated rotary grinding mill according to claim 1, characterized in that: The A positioning shaft is installed at the front end of the sine base and locked in place by an internal hexagon head screw. The positioning shaft seat is installed on the base plate and locked in place by an internal hexagon head screw. The B positioning shaft is fixed to the rear end of the sine base by a locking screw M5.
3. The dedicated rotary grinding mill according to claim 1, characterized in that: The front bearing housing is connected to TC oil seal one and TC oil seal two at the front and rear respectively. The front bearing oil seal washer is connected to TC oil seal one. The rear bearing housing is connected to TC oil seal three and TC oil seal four at the front and rear respectively. The timing pulley end cover is fixedly connected by 90° countersunk screws M5*10. The front bearing housing is fixedly connected by bolts M6*75. The front bearing end cover is fixedly connected by 90° countersunk screws M4*12. The rear bearing housing is fixedly connected by bolts M6*65 and 90° countersunk screws M4*15. The rear bearing end cover is fixedly connected by bolts M10*165.
4. The dedicated rotary grinding mill according to claim 1, characterized in that: The support frame is fixedly connected by bracket locking bolts M6*10 and connected to the diamond pen by diamond pen locking bolts M6*10. The hard alloy support plate is connected to the support frame by support plate locking bolts M6*15 and support plate gaskets. The lower end of the ejector pin frame is connected to the ejector pin frame pad by ejector pin frame locking bolts M6*20. The ejector pin frame pad is connected to the sine base by ejector pin frame pad bolts M6*35.
5. The dedicated rotary grinding mill according to claim 1, characterized in that: The pressure roller large swing arm is connected to a swing arm handle for controlling direction. The pressure roller is connected to the pressure roller small swing arm through the pressure roller eccentric shaft. The pressure roller small swing arm is connected to the pressure roller large swing arm through the swing arm bolt. The pressure roller large swing arm is connected to the swing arm seat through the swing arm seat locking bolt M6*20. The swing arm limit block is connected to the sine base through the swing arm limit bolt M6*10. The end of the torsion spring is connected to the torsion spring rotating pad through the torsion spring rotating pad bolt M4*10. The torsion spring pressure pad is connected to the sine base through the torsion spring pad bolt M5*10.
6. The dedicated rotary grinding mill according to claim 1, characterized in that: The auxiliary synchronous pulley is connected to the auxiliary synchronous pulley pad by bolts M8*35, and the main synchronous pulley is connected to the main synchronous pulley pad by bolts M5*10. The synchronous belt and the two pulleys are externally connected to the inner waterproof cover of the synchronous belt and pulleys and the outer waterproof cover of the synchronous belt. A spring fixing plate is connected to the inner waterproof cover of the synchronous belt and pulleys. The drive motor is connected to the base plate of the fixing seat through the motor fixing seat. The motor fixing seat is connected to the base plate of the fixing seat by fixing seat bolts M5*40. The base plate of the fixing seat is connected to the sine base by the base plate bolts M6*15. The drive motor is externally connected to the motor waterproof cover by the motor cover bolts M5*6.