PCB micro drill bit coating loading device

Abstract

This invention discloses a PCB micro-drill bit coating loading device, including a drive shaft sleeve, a bearing, a fixing ring, a fixing tray, a stop bar, and at least one micro-drill positioning plate. The drive shaft sleeve is used for transmission connection with an external drive shaft and is rotatably mounted on the inner ring of the bearing. The fixing ring is fixedly mounted on the outer ring of the bearing. The fixing tray is fixedly mounted on the top of the fixing ring and has a sloped upper surface. The stop bar is fixedly mounted on the outside of the fixing ring and is used for abutting against an external limiting shaft. The micro-drill positioning plate is located above the fixing tray and is fixedly mounted on the drive shaft sleeve. The micro-drill positioning plate has multiple placement holes for placing micro-drills. This invention keeps the fixing tray stationary by cooperating with the stop bar and the limiting shaft. The relative motion between the tail of the micro-drill and the stationary sloped surface during its revolution generates friction to drive the micro-drill to rotate. The rotation is stable and reliable. At the same time, the double-layer positioning plate and the staggered hole layout significantly increase the loading capacity.

Description

Technical Field

[0001] This invention relates to the field of coating fixture technology, and more specifically to a PCB micro-drill bit coating loading device. Background Technology

[0002] Coating processes such as physical vapor deposition (PVD) or chemical vapor deposition (CVD) are key methods for improving the lifespan and cutting performance of PCB micro-drill bits. In these processes, to achieve uniform coating on complex structures such as drill bit edges and helical grooves, specialized fixtures are usually required to make the micro-drill rotate and revolve during the coating process. US Patent Application US20220282364A1 discloses a PVD fixture for slender cylindrical workpieces. By tilting the rotation axis of the workpiece (rotating sleeve) at a certain angle γ relative to the center of the retaining plate, the workpiece passively rotates due to its tilted posture when the entire fixture system revolves, thereby achieving uniform coating deposition. However, this existing technology still has shortcomings in practical applications: on the one hand, the workpiece relies on a single tilt angle to generate passive rotation during revolution, and its rotational driving force comes from a single source. The rotational stability is easily affected by fluctuations in process parameters, making it difficult to ensure that each micro-drill maintains a stable and controllable rotational state throughout the entire revolution, resulting in the need to improve the consistency of coating thickness; on the other hand, the workpiece loading structure design of this fixture is relatively simple, and the number of micro-drills that can be loaded in a single process is limited, making it difficult to meet the demand for high efficiency and low cost in large-scale production. Summary of the Invention

[0003] This invention proposes a PCB micro-drill bit coating loading device, which solves the problem of low production efficiency caused by unstable self-rotation driving force of micro-drills in the prior art.

[0004] The technical solution of this invention is implemented as follows:

[0005] A PCB micro-drill bit coating loading device includes:

[0006] A drive shaft sleeve, which is used for transmission connection with an external drive shaft;

[0007] The bearing, wherein the drive shaft sleeve is rotatably mounted on the inner ring of the bearing;

[0008] A retaining ring, which is fixedly assembled to the outer ring of the bearing;

[0009] A fixed tray is fixedly assembled to the top of the fixed ring, and the upper surface of the fixed tray has a slope.

[0010] A stop bar is fixedly assembled to the outside of the fixed ring, and the stop bar is used to abut against the external limiting shaft;

[0011] At least one micro-drill positioning disk is located above the fixed tray and is fixedly mounted on the drive shaft sleeve. The micro-drill positioning disk has multiple placement holes for placing micro-drills.

[0012] Furthermore, the axial direction of the stop rod is perpendicular to the radial direction of the fixed ring, one end of the stop rod is fixedly connected to the fixed ring, and the other end of the stop rod is used to abut against the external limiting shaft.

[0013] Furthermore, the micro-drill positioning disk includes a first positioning disk and a second positioning disk arranged at an upper and lower interval. The first positioning disk and the second positioning disk are both provided with the placement hole, and the placement hole of the first positioning disk corresponds vertically to the placement hole of the second positioning disk.

[0014] Furthermore, the placement holes on both the first and second positioning disks are distributed in two concentric circles, and the placement holes in the inner and outer circles are staggered in the circumferential direction.

[0015] Furthermore, it also includes a connecting sleeve, which is sleeved and fixed to the outside of the drive shaft sleeve, and the micro-drill positioning disk is fixedly assembled to the connecting sleeve.

[0016] Furthermore, the bottom of the connecting sleeve has a radially outwardly extending convex ring, and the micro-drill positioning disk includes a first positioning disk and a second positioning disk arranged at an upper and lower interval. The second positioning disk is supported on the top of the convex ring, and the first positioning disk is fixed to the top of the connecting sleeve.

[0017] Furthermore, the upper surface of the fixed tray is a conical surface, and the angle between the generatrix of the conical surface and the horizontal plane is 25° to 35°.

[0018] Furthermore, the placement hole is a through hole, the micro drill is inserted through the placement hole, and the bottom of the micro drill abuts against the slope of the fixed tray.

[0019] Furthermore, it also includes an annular cover, which is fixedly assembled to the outer edge of at least one of the micro-drill positioning disks, and the annular cover covers the periphery of the micro-drill positioning disk.

[0020] Furthermore, the rolling elements of the bearing are alumina ceramic balls.

[0021] The beneficial effects of the technical solution provided in this application are as follows:

[0022] 1. In this application, the micro-drill positioning disk, which is fixedly mounted on the drive shaft sleeve, is driven to revolve by the drive shaft sleeve. At the same time, the stop bar fixedly mounted on the outside of the fixed ring abuts against the external limit shaft, keeping the fixed ring and the fixed tray fixedly mounted on its top stationary. Thus, during the revolution of the micro-drill positioning disk, the bottom of the micro-drill placed in the placement hole and the slope of the fixed tray generate relative movement. The slope applies friction to the bottom of the micro-drill and generates a driving torque, causing the micro-drill to generate a stable and controllable rotation in the placement hole.

[0023] 2. This application, by setting the micro-drill positioning disk as a first positioning disk and a second positioning disk with vertical spacing and corresponding placement holes, achieves double-layer loading of micro-drills within a limited space, significantly increasing the number of micro-drills processed in a single process, effectively improving production efficiency and reducing production costs. Furthermore, the placement holes on the first and second positioning disks are distributed in two concentric circles, staggered circumferentially, forming a triangular layout. This ensures the number of hole positions while preventing interference between micro-drills during their revolution and rotation, further optimizing space utilization. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the cross-sectional structure of the present invention;

[0027] Figure 3 This is a partially enlarged cross-sectional structural diagram of the present invention.

[0028] In the diagram: 1-Bearing; 2-Fixing ring; 3-Stop bar; 4-Drive shaft sleeve; 5-Connecting sleeve; 51-Convex ring; 6-Micro-drill positioning plate; 61-First positioning plate; 62-Second positioning plate; 7-Placement hole; 8-Annular cover; 9-Fixing tray. Detailed Implementation

[0029] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] like Figures 1 to 3 As shown, this embodiment provides a PCB micro-drill bit coating loading device, which is mounted on a planetary carrier of the coating equipment. This planetary carrier typically has a rotatable chassis with multiple upward-extending drive shafts distributed circumferentially on the chassis, and multiple limiting shafts positioned at corresponding locations. This device achieves stable operation during the coating process through cooperation with the drive shafts and limiting shafts.

[0031] See Figure 1 and Figure 2 The core transmission component of this device is the drive shaft sleeve 4, which has a hollow tubular structure with an inner hole for fitting onto an external drive shaft. The top of the drive shaft sleeve 4 has a polygonal collar, such as a hexagonal or square structure, which mates with the polygonal shaft segment at the top of the drive shaft to achieve circumferential fixation, ensuring that the rotational torque of the drive shaft can be smoothly transmitted to the drive shaft sleeve 4 and preventing relative slippage. The lower part of the drive shaft sleeve 4 is rotatably mounted on the inner ring of a bearing 1. The bearing 1 is a deep groove ball bearing or angular contact bearing capable of withstanding high-temperature vacuum environments, and its inner and outer rings can rotate freely relative to each other.

[0032] A fixing ring 2 is fitted around the outer ring of bearing 1. The fixing ring 2 is a circular ring structure, and its inner wall is interference-fitted with the outer ring of bearing 1 or fixed by fasteners to ensure that there is no relative movement between the two. A fixing tray 9 is fixedly connected to the top of the fixing ring 2 by screws or welding. The fixing tray 9 is generally disc-shaped, and its upper surface is a slope 10 structure. In this embodiment, the slope 10 is specifically a conical surface. The generatrix of the conical surface forms an angle with the horizontal plane. The value of this angle is in the range of 25° to 35°, preferably 30°. This angle design ensures that sufficient friction is generated when the bottom of the micro-drill contacts the slope 10, without excessively compressing the distance between the upper and lower positioning plates due to an excessively large angle.

[0033] A stop bar 3 is fixedly connected to the outer side wall of the fixed ring 2. The axis of the stop bar 3 extends radially along the fixed ring 2. One end of the stop bar 3 is welded to or threaded to the fixed ring 2, and the other end extends outward. The function of the stop bar 3 is to abut against the limiting shaft on the planetary carrier. When the planetary carrier chassis rotates, the stop bar 3 abuts against the stationary limiting shaft, thereby preventing the fixed ring 2 and the fixed tray 9 connected above it from rotating together with the drive shaft sleeve 4, so that the fixed tray 9 always remains stationary.

[0034] A connecting sleeve 5 is fitted around the outside of the drive shaft sleeve 4. The connecting sleeve 5 has a cylindrical structure, and its inner wall is connected to the outer wall of the drive shaft sleeve 4 by a key or a set screw to ensure that the two rotate synchronously. The bottom of the connecting sleeve 5 is integrally formed or welded with a radially outwardly extending protruding ring 51, the upper surface of which is a horizontal support surface. The top of the connecting sleeve 5 is also provided with a connecting structure.

[0035] This device includes two micro-drill positioning discs, a first positioning disc 61 and a second positioning disc 62, arranged vertically at an interval. The second positioning disc 62 is located below, its central hole fitting onto the outside of the connecting sleeve 5, and its lower surface rests on the top plane of the convex ring 51, which provides axial positioning. The first positioning disc 61 is located above, its central hole also fitting onto the outside of the connecting sleeve 5, and it is axially fixed by a fastening nut or retaining ring at the top of the connecting sleeve 5. Thus, both the first positioning disc 61 and the second positioning disc 62 rotate synchronously with the connecting sleeve 5 and the drive bushing 4. Both the first and second positioning discs 61 and 62 have multiple through holes 7 for placing the micro-drill. The placement holes on the first positioning disc 61 correspond vertically to those on the second positioning disc 62, ensuring the micro-drill remains vertical after insertion. The drill bit of the micro-drill faces upwards, and the shank passes through the placement hole 7, with its bottom end abutting against the slope 10 of the fixed tray 9.

[0036] like Figure 3 As shown, to further increase the loading capacity of a single coating, the placement holes 7 on both the first positioning disk 61 and the second positioning disk 62 are distributed in two concentric rings. The inner ring placement holes are evenly distributed along the circumference, and the outer ring placement holes are also evenly distributed along the circumference. The placement holes in the inner and outer rings are staggered in the circumferential direction, forming a triangular layout. This layout maximizes the number of holes within a limited disk area, while ensuring sufficient clearance between adjacent micro-drills to avoid collisions and interference during revolution and rotation.

[0037] An annular cover 8 is also fixedly fitted to the outer edge of the first positioning disk 61. The annular cover 8 is a thin-walled circular structure that extends downward and covers the periphery of the first positioning disk 61 and the second positioning disk 62. The function of the annular cover 8 is to shield the uncoated area of ​​the micro drill, especially to protect the markings on the drill shank from being contaminated by the coating material, ensuring that the markings are clear and readable.

[0038] The rolling elements of bearing 1 are made of alumina ceramic balls, which have the characteristics of high temperature resistance, self-lubrication, and non-magnetic properties. They can operate stably for a long time in a vacuum coating environment of 250℃ to 550℃, and will not cause contamination to the coating due to the release of ferromagnetic elements by the material itself. The main body materials of drive bushing 4, fixed ring 2, fixed tray 9, connecting sleeve 5, first positioning plate 61, second positioning plate 62, and annular cover 8 are all made of 304 stainless steel. This material has good vacuum compatibility, high temperature resistance, and low outgassing rate, meeting the special requirements of PVD / CVD coating processes for fixture materials.

[0039] The working process and principle of this device are as follows: In the initial state, micro-drills are inserted one by one into the placement holes 7 of the first positioning plate 61 and the second positioning plate 62. After the tail of the micro-drill passes through the placement hole, its bottom end face naturally abuts against the slope 10 of the fixed tray 9. The entire device is hoisted onto the planetary carrier, so that the drive shaft sleeve 4 is fitted onto the drive shaft. The polygonal shaft segment on the drive shaft cooperates with the polygonal collar at the top of the drive shaft sleeve 4, while the stop rod 3 abuts against one side of the limit shaft.

[0040] After the coating equipment is started, the planetary carrier chassis begins to rotate, driving multiple drive shafts on it to revolve around the center of the equipment. Simultaneously, the drive shafts themselves rotate under the drive of a motor. The rotational torque of the drive shafts is transmitted to the drive shaft sleeve 4 through a polygonal mating mechanism. The drive shaft sleeve 4 then drives the connecting sleeve 5, the first positioning plate 61, and the second positioning plate 62 to rotate together around the drive shaft axis; this is the revolution motion of the micro-drill. Meanwhile, because the stop lever 3 abuts against the stationary limit shaft, the fixed ring 2 and the fixed tray 9 cannot rotate and remain stationary.

[0041] As the micro-drill revolves with the first positioning disk 61 and the second positioning disk 62, its tail remains in contact with the stationary fixed tray 9's slope 10. Due to the inclination of the slope 10, the micro-drill's tail experiences an oblique thrust as it slides on it. This thrust can be decomposed into horizontal and vertical components. Under the action of the horizontal component, the micro-drill generates a torque about its own axis. When this torque overcomes the static friction between the micro-drill's tail and the slope 10, as well as the rolling friction between the micro-drill and the wall of the placement hole 7, the micro-drill begins to rotate within the placement hole 7. This rotation is entirely passively generated by the relative motion between the revolving motion and the stationary slope 10, requiring no additional gears, levers, or other active drive components.

[0042] During this process, the micro-drill revolves around the drive shaft axis along with the first positioning disk 61 and the second positioning disk 62, while also rotating on its own axis, forming a three-dimensional motion. The coating material emitted by the coating source can be uniformly deposited on all surfaces of the micro-drill, including complex structural areas such as the cutting edge and spiral grooves, effectively avoiding the shadowing effect. Due to the stable and reliable rotation, the coating thickness is uniform, the film layer is dense, and the adhesion is strong.

[0043] The dual-layer structure design of the first positioning disk 61 and the second positioning disk 62 significantly increases the number of micro-drills that can be loaded in a single process, improving upon traditional single-layer paddle-type fixtures by more than 95%. The staggered triangular hole layout of the inner and outer rings achieves a high-density arrangement of 130 loading holes within a limited space, while ensuring sufficient movement space for each micro-drill.

[0044] The slope 10 of the fixed tray 9 is designed with an angle of 25° to 35°, preferably 30°. Practical verification has shown that this angle range allows for a stable and moderate frictional force between the micro-drill tail and the slope 10. If the angle is less than 25°, the contact area between the micro-drill tail and the slope 10 increases, resulting in excessive friction. This can cause the micro-drill to become unstable, alternating between sliding and rolling, or even jamming. If the angle is greater than 35°, the distance between the upper and lower positioning plates is compressed, affecting the loading density and the micro-drill's movement space. Simultaneously, the reduced friction may lead to insufficient self-rotation driving force.

[0045] The annular cover 8 effectively shields the drill shank area, ensuring that the coating material is deposited only on the drill bit portion requiring coating. This keeps the markings on the drill shank clear, facilitating subsequent traceability and management. The bearing 1 uses alumina ceramic balls as rolling elements, avoiding the ferromagnetic contamination that can occur with traditional steel bearings at high temperatures, ensuring coating purity. Simultaneously, the self-lubricating properties of the ceramic material reduce operating resistance at high temperatures, extending the device's service life.

[0046] It should be noted that this specific embodiment is merely a detailed example of the technical solution of the present invention and is not intended to limit the scope of protection. For those skilled in the art, based on the technical solution disclosed in this invention, adaptive adjustments can be made to the shape, size, and connection method of each component. For example, the slope 10 of the fixed tray 9 can be set as multiple segmented inclined surfaces or curved surfaces, or the first positioning plate 61 and the second positioning plate 62 can be increased to three or more positioning plates. These equivalent transformations all fall within the scope of protection of this invention.

Claims

1. A PCB micro-drill bit coating loading device, characterized in that, include: Drive shaft sleeve (4), the drive shaft sleeve (4) is used for transmission connection with an external drive shaft; The bearing (1) and the drive bushing (4) are rotatably mounted on the inner ring of the bearing (1); A retaining ring (2) is fixedly assembled to the outer ring of the bearing (1); Fixed tray (9), the fixed tray (9) is fixedly assembled on the top of the fixed ring (2), and the upper surface of the fixed tray (9) has a slope (10). The stop bar (3) is fixedly assembled to the outside of the fixed ring (2), and the stop bar (3) is used to abut against the external limiting shaft; At least one micro-drill positioning disk (6) is located above the fixed tray (9) and is fixedly mounted on the drive shaft sleeve (4). The micro-drill positioning disk (6) has multiple placement holes (7) for placing micro-drills.

2. The PCB micro-drill bit coating loading device according to claim 1, characterized in that, The axial direction of the stop rod (3) is perpendicular to the radial direction of the fixed ring (2). One end of the stop rod (3) is fixedly connected to the fixed ring (2), and the other end of the stop rod (3) is used to abut against the external limiting shaft.

3. The PCB micro-drill bit coating loading device according to claim 1, characterized in that, The micro-drill positioning disk (6) includes a first positioning disk (61) and a second positioning disk (62) arranged at an upper and lower interval. The first positioning disk (61) and the second positioning disk (62) are both provided with the placement hole (7), and the placement hole (7) of the first positioning disk (61) corresponds to the placement hole (7) of the second positioning disk (62) vertically.

4. The PCB micro-drill bit coating loading device according to claim 3, characterized in that, The placement holes (7) on the first positioning disk (61) and the second positioning disk (62) are distributed in two concentric circles, and the placement holes (7) in the inner and outer circles are staggered in the circumferential direction.

5. The PCB micro-drill bit coating loading device according to claim 1, characterized in that, It also includes a connecting sleeve (5), which is sleeved and fixed to the outside of the drive shaft sleeve (4), and the micro-drill positioning disk (6) is fixedly assembled to the connecting sleeve (5).

6. The PCB micro-drill bit coating loading device according to claim 5, characterized in that, The bottom of the connecting sleeve (5) has a radially outwardly extending convex ring (51). The micro-drill positioning disk (6) includes a first positioning disk (61) and a second positioning disk (62) arranged at an upper and lower interval. The second positioning disk (62) is supported on the top of the convex ring (51), and the first positioning disk (61) is fixed to the top of the connecting sleeve (5).

7. The PCB micro-drill bit coating loading device according to claim 1, characterized in that, The upper surface of the fixed tray (9) is a conical surface, and the angle between the generatrix of the conical surface and the horizontal plane is 25° to 35°.

8. The PCB micro-drill bit coating loading device according to claim 1, characterized in that, The placement hole (7) is a through hole, the micro drill is inserted through the placement hole (7), and the bottom of the micro drill abuts against the slope (10) of the fixed tray (9).

9. The PCB micro-drill bit coating loading device according to claim 1, characterized in that, It also includes an annular cover (8), which is fixedly assembled to the outer edge of at least one of the micro-drill positioning disks (6) and covers the periphery of the micro-drill positioning disk (6).

10. The PCB micro-drill bit coating loading device according to any one of claims 1 to 9, characterized in that, The rolling element of the bearing (1) is an alumina ceramic ball.

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