Traceless spring test needle and gold surface traceless test method

Abstract

The application belongs to the technical field of circuit board detection, and discloses a traceless spring test needle and a gold surface traceless test method. The traceless spring test needle comprises a needle tube, a needle head and a first spring. A first sliding groove is formed in the inner wall of the needle tube. A sliding assembly is arranged in the first sliding groove. The sliding assembly is located between the needle head and the first spring. A helical first sliding groove is arranged on the inner wall of the needle tube. The sliding assembly is embedded in the first sliding groove. The sliding assembly obtains circumferential rotation force while moving in the axial direction, and drives the needle head to rotate synchronously. The needle head rotates in a "erasing" mode when contacting the gold surface, effectively removing the surface oxidation layer or insulating stains. Compared with the traditional vertical pressing mode, the rotation mechanism can greatly reduce the contact pressure on the unit area, reduce the damage to the small welding points and wire bonding structure, and avoid the structural damage caused by local stress concentration.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of circuit board detection, and particularly relates to a traceless spring test needle and a gold surface traceless test method. BACKGROUND

[0002] The spring test needle is an indispensable key tool in the Chip On Board test process, and its core function is to ensure the stability of current transmission and the reliability of contact, thereby effectively improving product yield. However, in the application of high-end binding electronic boards, the traditional test needle, although meeting the basic electrical performance requirements to some extent, exposes a series of problems that cannot be ignored, and further optimization and improvement are urgently needed.

[0003] Firstly, the traditional test needle usually adopts a higher spring force to match a smaller contact angle in the design to achieve good current conduction performance. However, in the actual test pressure process, this design is prone to leave obvious pressure marks or indentations on the gold contact surface of the device under test. In high-end COB packaging structures, chips are usually connected to the substrate through extremely thin gold wires or copper wires. These wire bonding points are not only small in size, precise in process, but also relatively fragile in structure. Once the pressure applied by the test needle is too large or the contact is too concentrated, it may cause wire offset, breakage, and even weld peeling, which seriously affects the yield and long-term reliability of the product.

[0004] Secondly, to alleviate the above problems, some manufacturers try to use test needles with large-angle contact design. This type of probe has lower pressure on the gold surface during contact, which can to some extent avoid the generation of surface pressure marks, thereby protecting the weld structure from damage. However, due to its large contact area and wide pressure distribution, it is often difficult to effectively break through the oxide layer or other insulating layer that may exist on the metal surface. If these insulating layers cannot be completely destroyed, it will lead to an increase in contact resistance, resulting in transient open circuit, signal misjudgment and other problems, thereby affecting the accuracy and consistency of the test results. SUMMARY

[0005] Therefore, the present application aims to provide a traceless spring test needle and a gold surface traceless test method to solve the problems existing in the background art.

[0006] To solve the above technical problems, the technical scheme one of the present application is a traceless spring test needle, which comprises a needle tube, a needle head and a first spring, a first sliding groove is formed on the inner wall of the needle tube, a sliding assembly is arranged in the first sliding groove, and the sliding assembly is located between the needle head and the first spring; the first sliding groove extends spirally along the axial direction of the needle tube; when the needle head contacts a test surface, the needle tube is pressed downward, the sliding assembly relatively slides along the spiral first sliding groove, and the needle head is driven to rotate under the guidance of the first sliding groove; the needle head obtains circumferential rotation force while obtaining axial pressure, so that the surface layer of the test surface is effectively damaged, and the needle head can accurately contact the base of the test surface, so that the accuracy and consistency of the test result are realized; the needle tube is divided into a rotating part and a pressing part by the top end of the first sliding groove; when the sliding assembly is located in the rotating part, the needle head obtains circumferential rotation force while obtaining axial pressure, so that the surface layer of the test surface is effectively damaged; when the sliding assembly is located in the pressing part, the needle head obtains axial pressure, so that stable contact with the test surface is ensured.

[0007] Preferably, the sliding assembly comprises a limiting piece, a rotating piece and a second spring, the limiting piece is located at the joint of the rotating part and the pressing part, the rotating piece is slidably arranged in the first sliding groove, the second spring is arranged between the limiting piece and the rotating piece, and the connecting end of the second spring and the rotating piece adopts rotating connection; when the sliding assembly is located in the rotating part, the second spring provides axial pressure for the rotating piece.

[0008] Further, the limiting piece and the rotating piece are both provided with a guide slope surface; the guide slope surfaces are matched with each other in structure design, so that the needle head obtains more stable circumferential rotation force when being located in the rotating part; the second spring adopts a conical spring design; the conical spring can provide good axial pressure and radial support for the movement of the needle head in the rotating part; meanwhile, by virtue of the characteristic that the elastic force of the conical spring nonlinearly changes, excessive damage to the surface layer of the test surface is avoided.

[0009] Further, a second sliding groove and a third sliding groove are formed on the inner wall of the needle tube, the bottom ends of the second sliding groove and the third sliding groove are located at the joint of the rotating part and the pressing part, and the second sliding groove and the third sliding groove are arranged in parallel with the axial direction of the needle tube; the second sliding groove is connected with the first sliding groove, and the second sliding groove is used for limiting the movement of the rotating piece on the pressing part; the limiting piece is fixed at the bottom end of the third sliding groove before the rotating piece contacts the limiting piece; after the rotating piece contacts the limiting piece, the limiting piece is pushed to move on the third sliding groove by the rotating piece.

[0010] Further, the limiting piece and the rotating piece are provided with mutually adapted clamping grooves and buckles; before the rotating piece and the limiting piece contact, only the elastic force of the second spring is transmitted to the needle through the rotating piece; after the rotating piece and the limiting piece contact, the clamping grooves and the buckles are buckled, and only the elastic force of the first spring is transmitted to the needle through the sliding assembly.

[0011] Further, the side wall of the needle tube is provided with a pushing piece, the pushing piece penetrates the inside and outside of the needle tube, the pushing piece can move in the radial direction of the needle tube, a third spring is arranged between the pushing piece and the needle tube, the third spring makes the pushing piece protrude outside the needle tube, and the pushing piece acts on the clamping groove and the buckle; after the clamping groove and the buckle are buckled, the pushing piece is pushed inward to make the pushing piece act on the clamping groove and the buckle, so that the clamping groove and the buckle are in an unbuckled state, and the rotating piece and the limiting piece are separated.

[0012] Further, the third sliding groove is provided with a fixing piece for restricting the movement of the limiting piece, the first sliding groove is provided with a control piece connected with the fixing piece, and the fixing piece and the control piece can slide in the radial direction of the needle tube; the fixing piece only limits the upward movement of the limiting piece; when the rotating piece slides in the first sliding groove, the control piece is pushed to move in the radial direction of the needle tube, and the fixing piece is driven to move; after the rotating piece and the limiting piece contact, the control piece and the fixing piece are moved to a position, and the fixing piece releases the restriction on the upward movement of the limiting piece.

[0013] Further, the traceless spring test needle can be switched between a rotating operation state and a normal operation state; before the rotating piece and the limiting piece contact, only the elastic force of the second spring is transmitted to the needle through the rotating piece, and the traceless spring test needle is in the normal operation state; after the rotating piece and the limiting piece contact, the clamping groove and the buckle are buckled, and only the elastic force of the first spring is transmitted to the needle through the sliding assembly, and the traceless spring test needle is in the rotating operation state; before operation, the traceless spring test needle is in the rotating operation state, during operation, the needle damages the surface layer of the test surface through circumferential rotation force, and then the traceless spring test needle is switched from the rotating operation state to the normal operation state, and after operation, the traceless spring test needle is still in the normal operation state, so as to avoid that the needle damages the surface layer of the test surface through circumferential rotation force again.

[0014] In order to solve the above technical problems, the technical scheme two of the present application is a gold surface traceless test method applying the traceless spring test needle in the technical scheme one.

[0015] The technical effects of the present application mainly embody in the following aspects:

[0016] By setting a helical first sliding groove on the inner wall of the needle tube and embedding the sliding assembly therein, the sliding assembly obtains a circumferential rotating force while moving axially, driving the needle to rotate synchronously. The needle performs "erasing type" rotating contact when contacting the gold surface, effectively removing the surface oxidation layer or insulating stains; compared with the traditional vertical pressing method, the rotating mechanism can greatly reduce the contact pressure per unit area; reduces damage to the tiny solder joints and wire bonding structure, and avoids structural damage caused by local stress concentration.

[0017] The conical spring is used as the main elastic force source of the sliding assembly during the rotating stage, and its nonlinear stiffness characteristic is used to provide progressive elastic force output during compression. A smaller pressure is provided at the initial stage of rotating cleaning to prevent excessive friction or scratches on the gold surface; as the pressing depth increases, the spring stiffness gradually increases to provide sufficient cleaning force; the conical structure also has good radial support capability, enhancing the stability of the rotating part during rotation; reducing abnormal conditions such as deflection and jamming of the sliding assembly, and improving the overall structural reliability. At the same time, a matching guide slope is provided between the limiting member and the rotating member to optimize the stress direction and rotation path through structural cooperation.

[0018] A clamping groove and a clamping buckle structure are provided between the limiting member and the rotating member, which are automatically locked when they are in contact, changing the elastic force transmission path. The second spring provides the required elastic force for cleaning at the initial stage; after entering the stable contact stage, the first spring becomes the main source of elastic force; realizing automatic switching from small pressure cleaning to large pressure conduction; preventing poor contact caused by external vibration or pressure fluctuation; improving test stability and electrical connection reliability. At the same time, the rotating member is locked by the clamping buckle structure after reset to prevent the rotating member from being forced to rotate in the opposite direction; such unexpected rotating action may cause the needle to rub the gold surface again during separation from the test surface, causing unnecessary damage or residual marks. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a structural diagram of the present application;

[0020] Figure 2 is a structural sectional view of the present application;

[0021] Figure 3 is Figure 2 is a sectional view of the needle tube structure;

[0022] Figure 4 is Figure 2 is a structural diagram of the sliding assembly;

[0023] Figure 5 isFigure 2 Structure sectional view of the middle sliding assembly;

[0024] Figure 6 For Figure 2 Cooperation schematic view of the middle sliding assembly and the pushing piece;

[0025] Figure 7 For Figure 2 Cooperation schematic view of the middle needle tube and the sliding assembly;

[0026] In the figure: 1, needle tube, 13, first sliding groove, 14, second sliding groove, 15, third sliding groove, 16, fixing piece, 17, control piece; 2, needle head; 3, first spring; 4, sliding assembly, 41, limiting piece, 42, rotating piece, 43, second spring, 44, guide slope, 45, clamping groove, 46, buckle, 47, pushing piece. DETAILED DESCRIPTION

[0027] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings, so that the technical scheme of the present application is easier to understand and master. In the embodiments, it should be understood that the terms "intermediate", "upper", "lower", "top", "right side", "left end", "upper", "back", "middle" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, in the present specific embodiments, if the connection or fixing method between the components is not specifically stated, the connection or fixing method can be through the commonly used bolt fixing or pin fixing in the prior art, or pin shaft connection, etc., therefore, in the present embodiment, it will not be described in detail.

[0028] Example one

[0029] The present embodiment provides a traceless spring test needle, which aims to solve the problems of solder damage, wire offset fracture and difficulty in breaking through the surface oxidation layer caused by excessive contact pressure or improper contact mode of the traditional test needle in high-end COB (Chip On Board) packaging structure.

[0030] Participation Figure 1 ,、 Figure 2 The traceless spring test needle comprises a needle tube 1, a needle head 2 and a first spring 3, wherein:

[0031] The inner wall of the needle tube 1 is provided with a first sliding groove 13, and the first sliding groove 13 is provided with a sliding assembly 4, and the sliding assembly 4 is located between the needle head 2 and the first spring 3; the front end of the needle head 2 is designed as a circular arc end face with a certain taper, so as to avoid local stress concentration caused by sharp contact; the first sliding groove 13 extends spirally along the axis direction of the needle tube 1, when the needle head 2 contacts the test surface, the needle tube 1 is pressed downward, the sliding assembly 4 relatively slides along the spiral first sliding groove 13, and the needle head 2 is driven to rotate under the guidance of the first sliding groove 13; the needle head 2 obtains circumferential rotation force while obtaining axial pressure, so as to effectively damage the surface layer of the test surface, and ensure that the needle head 2 can accurately contact the base body of the test surface, and the accuracy and consistency of the test result are realized. The needle tube 1 is divided into a rotating part and a pressing part by the top end of the first sliding groove 13; when the sliding assembly 4 is located in the rotating part, the needle head 2 obtains circumferential rotation force while obtaining axial pressure, so as to ensure that the surface layer of the test surface is effectively damaged; when the sliding assembly 4 is located in the pressing part, the needle head 2 obtains axial pressure, so as to ensure stable contact with the test surface.

[0032] Specifically, in the test process:

[0033] The test needle gradually approaches the measured gold surface, and the needle head 2 first slightly contacts the test surface; at this time, the sliding assembly 4 is located in the rotating part region of the needle tube 1; with the downward pressing action, the sliding assembly 4 relatively slides along the spiral first sliding groove 13; the spiral direction of the sliding groove drives the sliding assembly 4 to rotate, and the rotation is transmitted to the needle head 2 through the connecting structure; the needle head 2 obtains a certain circumferential rotation force while obtaining axial pressure. The needle head 2 rotates and contacts the metal surface of the test surface in a “erasing” mode; this rotating friction mode can effectively damage the oxide layer, stains or other insulating layers that may exist on the gold surface; at the same time, the contact area is uniformly distributed and the pressure is dispersed, and no obvious indentation or indentation is left on the gold surface; compared with the traditional vertical pressing mode, this rotating mechanism greatly reduces the contact pressure per unit area, thereby protecting the small solder joints and wire bonding structures from damage. When the pressing continues to deepen, the sliding assembly 4 enters the pressing part region of the needle tube 1; at this time, the sliding assembly 4 no longer rotates, but only linearly displaces; the needle head 2 mainly bears the stable axial pressure provided by the first spring 3 at this time, so as to ensure that the test surface forms a stable electrical connection; in this stage, the needle head 2 and the test surface have realized reliable base body contact, so as to ensure the stability of current transmission and the accuracy of signal acquisition.

[0034] Referring to Figure 4 , Figure 5 , further, the specific structure of the sliding assembly 4 is as follows:

[0035] The sliding assembly 4 comprises a limiting piece 41, a rotating piece 42 and a second spring 43. The limiting piece 41 is located at the intersection of the rotating part and the pressing part. The rotating piece 42 is slidingly arranged in the first sliding groove 13. The second spring 43 is arranged between the limiting piece 41 and the rotating piece 42. The connecting end of the second spring 43 and the rotating piece 42 is in rotational connection, which ensures that the spring does not affect the rotational freedom of the rotating piece 42 during compression. When the sliding assembly 4 is in the rotating part, the rotating piece 42 is provided with axial pressure by the second spring 43. The limiting piece 41 and the rotating piece 42 are both provided with a guide slope 44. The guide slopes 44 are designed to cooperate with each other in structure, so that the needle 2 obtains more stable circumferential rotation force when it is in the rotating part. The guide slope 44 is used to guide the rotating piece 42 to maintain good stress direction and rotation stability during sliding. The second spring 43 is designed as a conical spring. The conical spring can provide good axial pressure and radial support when the needle 2 moves in the rotating part. At the same time, by virtue of the nonlinear change characteristic of the elastic force of the conical spring, excessive damage to the surface layer of the test surface is avoided.

[0036] The conical spring has the following significant advantages: nonlinear elastic force change characteristic: as the compression amount increases, the spring stiffness gradually increases, thereby avoiding excessive pressure in the initial stage; good radial support ability: the conical structure helps to improve the stability of the rotating piece 42 during rotation, preventing deflection or jamming; strong adaptability: during the switching of the needle 2 from rotary contact to stable pressing, the elastic force output can be smoothly transitioned, reducing impact and vibration.

[0037] Referring to Figure 3 , further, regarding the extension design of the sliding groove structure of the needle tube 1 inner wall:

[0038] The inner wall of the needle tube 1 is provided with a second sliding groove 14 and a third sliding groove 15, the bottom ends of the second sliding groove 14 and the third sliding groove 15 are located at the joint of the rotating part and the pressing part, the second sliding groove 14 and the third sliding groove 15 are arranged in parallel with the axis direction of the needle tube 1; the second sliding groove 14 is connected with the first sliding groove 13, and the second sliding groove 14 is used for the movable limiting of the rotating part 42 on the pressing part; when the sliding assembly 4 transitions from the rotating part to the pressing part, the rotating part 42 can slide linearly along the second sliding groove 14 without rotating; it is ensured that the sliding assembly 4 only moves axially after entering the pressing stage, avoiding unstable contact or signal fluctuation caused by residual rotation. The third sliding groove 15 is used for the movable limiting of the limiting part 41 on the pressing part; before the rotating part 42 and the limiting part 41 contact, the limiting part 41 is fixedly limited at the bottom end of the third sliding groove 15; after the rotating part 42 and the limiting part 41 contact, the limiting part 41 is pushed by the rotating part 42 to move on the third sliding groove 15.

[0039] Referring to Figure 6 , further, around the connection locking mechanism between the limiting part 41 and the rotating part 42:

[0040] The limiting part 41 and the rotating part 42 are provided with a clamping groove 45 and a buckle 46 matched with each other; before the rotating part 42 and the limiting part 41 contact, only the elastic force of the second spring 43 is transmitted to the needle 2 through the rotating part 42; after the rotating part 42 and the limiting part 41 contact, the clamping groove 45 and the buckle 46 are buckled to form a stable connection structure, and only the elastic force of the first spring 3 is transmitted to the needle 2 through the sliding assembly 4. The side wall of the needle tube 1 is provided with a pushing part 47, the pushing part 47 penetrates the inside and outside of the needle tube 1, the pushing part 47 can move in the radial direction of the needle tube 1, a third spring is arranged between the pushing part 47 and the needle tube 1, the third spring makes the pushing part 47 protrude outside the needle tube 1, and the pushing part 47 acts on the clamping groove 45 and the buckle 46; after the clamping groove 45 and the buckle 46 are buckled, the pushing part 47 is pushed inward to make the pushing part 47 act on the clamping groove 45 and the buckle 46, so that the clamping groove 45 and the buckle 46 are in an unbuckled state, and the rotating part 42 and the limiting part 41 are separated.

[0041] The rotating member 42 has not yet contacted the limiting member 41; the sliding assembly 4 is only provided with the elastic force of the second spring 43; the elastic force of the second spring 43 is transmitted to the needle 2 through the rotating member 42, for realizing the rotating cleaning function; at this stage, the pressure is small, avoiding damage to the gold surface. The rotating member 42 contacts the limiting member 41, and the clamping groove 45 and the buckle 46 are automatically buckled; at this time, the first spring 3 becomes the main source of elastic force; the elastic force path is the first spring 3, the rotating member 42, the limiting member 41, and the needle 2; stronger axial pressure is provided to ensure that the needle 2 and the test surface establish a stable electrical connection; at the same time, it prevents poor contact caused by external vibration or pressure fluctuation.

[0042] After the test is completed, the sliding assembly 4 is still in the “clamping groove 45-buckle 46” locked state; at this time, if you need to reset, you can press the push member 47 to push the clamping groove 45 and the buckle 46 structure at the inner end; relative displacement is generated, so that the clamping groove 45 and the buckle 46 are separated from the buckling; the rotating member 42 and the limiting member 41 are separated, and the sliding assembly 4 returns to the free state; under the joint action of the first spring 3 and the second spring 43, the needle 2 rebounds to the upper limit; after completing a complete test cycle, the device is ready for the next test.

[0043] However, after a complete test cycle is completed, in order to make the sliding assembly 4 return to the initial state, the clamping groove 45 and the buckle 46 structure between the rotating member 42 and the limiting member 41 must be unlocked, otherwise the rotating member 42 is still limited by the limiting member 41; the sliding assembly 4 cannot freely return to the upper limit position; during the resetting process, due to the spiral guide characteristics of the first sliding groove 13, the rotating member 42 may be forced to rotate in the opposite direction; this unexpected rotating action may cause the needle 2 to rub the gold surface again during the process of separating from the test surface, causing unnecessary damage or residual marks.

[0044] Referring to Figure 7 Therefore, the embodiment further introduces the fixed member 16-control member 17 linkage structure, and combines the clamping groove 45-buckle 46 locking mechanism and the push member 47 unlocking function, to realize the active control and state switching of the movement path of the sliding assembly 4.

[0045] The third sliding groove 15 is provided with a fixing part 16 for restricting the movement of the limiting part 41, the first sliding groove 13 is provided with a control part 17 connected with the fixing part 16, and the fixing part 16 and the control part 17 can slide in the radial direction of the needle tube 1; the fixing part 16 only limits the upward movement of the limiting part 41, and does not limit the downward movement or axial sliding of the limiting part 41; when the rotating part 42 slides in the first sliding groove 13, the control part 17 is pushed to move in the radial direction of the needle tube 1, and the fixing part 16 is driven to move; after the rotating part 42 contacts the limiting part 41, the control part 17 and the fixing part 16 are moved to the position, and the upward movement of the limiting part 41 is no longer limited by the fixing part 16. The fixing part 16, the control part 17 and the needle tube 1 are provided with a fourth spring for pushing the inner wall of the needle tube 1.

[0046] The traceless spring test needle can be switched between the rotating operation state and the normal operation state.

[0047] Before the rotating part 42 contacts the limiting part 41, only the elastic force of the second spring 43 is transmitted to the needle head 2 through the rotating part 42, and the elastic force of the first spring 3 acts on the third sliding groove 15 through the limiting part 41, and is not transmitted to the needle head 2, and the traceless spring test needle is in the normal operation state.

[0048] After the rotating part 42 contacts the limiting part 41, the clamping groove 45 and the buckle 46 are buckled, and only the elastic force of the first spring 3 is transmitted to the needle head 2 through the sliding assembly 4, and the elastic force of the second spring 43 is the internal force of the sliding assembly 4 and does not act on the needle head 2 after the clamping groove 45 and the buckle 46 are buckled; the traceless spring test needle is in the rotating operation state.

[0049] Before operation, the traceless spring test needle is in the rotating operation state, during operation, the needle head 2 destroys the surface layer of the test surface through the circumferential rotation force, and then the traceless spring test needle is switched from the rotating operation state to the normal operation state, and after operation, the traceless spring test needle is still in the normal operation state, so as to avoid that the needle head 2 destroys the surface layer of the test surface again through the circumferential rotation force.

[0050] Embodiment two

[0051] The embodiment discloses a gold surface traceless test method, which is realized based on the structure of the traceless spring test needle in the embodiment one, and specifically includes the following steps.

[0052] S1, initial preparation stage:

[0053] Place the electronic device to be tested on the test platform, ensuring that its test surface is level. Check if the traceless spring test needle is in the rotating state, i.e., the clamping slot 45 and the clamping buckle 46 have been buckled, and the sliding assembly 4 is locked. At this time, the first spring 3 provides the main spring force for the needle 2, ensuring that the test needle has stable initial contact ability. The front end of the needle 2 is designed in a circular arc shape to avoid local stress concentration on the gold surface.

[0054] S2, needle 2 contact and surface damage stage:

[0055] Control the test equipment to slowly approach the test needle to the gold surface to be tested until the needle 2 slightly contacts the test surface. Continue to press the needle tube 1 downward, and the sliding assembly 4 starts to slide downward along the first sliding slot 13 in the inner wall of the needle tube 1. Since the first sliding slot 13 is spirally distributed, it drives the rotating part 42 to produce a circumferential rotating motion. The rotating part 42 transmits the rotating force to the needle 2, so that it rotates slightly while obtaining axial pressure. The needle 2 contacts the gold surface in a "erasing" manner, effectively removing the oxidation layer, stains or other insulating substances that may exist on the surface. The conical second spring 43 provides auxiliary spring force in this stage to ensure that the pressure is moderate during the rotating cleaning process without damaging the gold surface and the solder structure below.

[0056] S3, sliding assembly 4 switching and stable contact stage:

[0057] When the rotating part 42 continues to press down and enters the pressure applying part area, it is separated from the spiral guide path of the first sliding slot 13. The rotating part 42 slides into the second sliding slot 14 and stops rotating, only performing linear displacement. At this time, the rotating part 42 contacts the limiting part 41, the clamping slot 45 and the clamping buckle 46 are automatically buckled to form a mechanical connection. The first spring 3 becomes the main source of spring force, and the spring force path is: first spring 3→rotating part 42→limiting part 41→needle 2. The needle 2 establishes a reliable electrical connection with the test surface with stable axial pressure. This stage ensures the stability of current transmission, accurate signal acquisition, improves test consistency and repeatability.

[0058] S4, test completion and reset stage

[0059] After the test, the test system releases the pressing force, but the sliding assembly 4 is still in the locked state; if resetting is needed, the operator or automatic equipment can push the pusher 47 arranged on the side wall of the needle tube 1 inward; the pusher 47 can move radially along the needle tube 1 under the action of the third spring, and the inner end thereof acts on the structure of the clamping groove 45 and the buckle 46; the clamping groove 45 and the buckle 46 are disengaged, the rotating part 42 and the limiting part 41 are separated, and the sliding assembly 4 returns to the free state; under the joint action of the first spring 3 and the second spring 43, the sliding assembly 4 rebounds to the upper limit position, and the needle 2 is separated from the test surface; during the resetting process, the sliding assembly 4 is no longer constrained by the limiting part 41, avoiding unintended rotation caused by the spiral sliding groove guide; ensuring that the needle 2 does not cause secondary friction or damage to the gold surface during the separation process, and truly realizing “traceless testing”.

[0060] S5, state switching and retesting preparation

[0061] After resetting is completed, the sliding assembly 4 enters the “normal operation state”, that is, only the second spring 43 provides elastic force; the fixing part 16 relocks the upward movement of the limiting part 41 under the linkage of the control part 17; and the next test is ready; ensuring that each test starts from the same initial state, improving the consistency and reliability of the test results.

[0062] Of course, the above is only a typical example of the present application, in addition to which the present application can have other various specific embodiments, and any technical solution formed by equivalent replacement or equivalent transformation falls within the scope of the present application.

Claims

1. A traceless spring test needle comprising a needle tube, a needle head and a first spring, characterized in that: a first sliding groove is formed on the inner wall of the needle tube, a sliding assembly is arranged in the first sliding groove, and the sliding assembly is located between the needle head and the first spring; the first sliding groove extends spirally along the axial direction of the needle tube; when the needle head contacts a test surface, the needle tube is pressed downward, the sliding assembly slides along the spiral first sliding groove, and the needle head is rotated under the guidance of the first sliding groove; the needle head obtains circumferential rotation force while obtaining axial pressure, thereby effectively damaging the surface layer of the test surface and ensuring that the needle head accurately contacts the substrate of the test surface, so as to realize the accuracy and consistency of the test result; the needle tube is divided into a rotating part and a pressing part by the top end of the first sliding groove; when the sliding assembly is located in the rotating part, the needle head obtains circumferential rotation force while obtaining axial pressure, thereby ensuring that the surface layer of the test surface is effectively damaged; when the sliding assembly is located in the pressing part, the needle head obtains axial pressure, thereby ensuring stable contact with the test surface; the sliding assembly comprises a limiting piece, a rotating piece and a second spring, the limiting piece is located at the junction of the rotating part and the pressing part, the rotating piece is slidably arranged in the first sliding groove, the second spring is arranged between the limiting piece and the rotating piece, and the connecting end of the second spring and the rotating piece is rotationally connected; when the sliding assembly is located in the rotating part, the second spring provides axial pressure for the rotating piece; the limiting piece and the rotating piece are both provided with guide slopes; the guide slopes are designed to cooperate with each other in structure, so that the needle head obtains more stable circumferential rotation force when it is in the rotating part; the second spring is designed as a conical spring; the conical spring can provide good axial pressure and radial support when the needle head moves in the rotating part; at the same time, the conical spring has the characteristic of nonlinear change of elastic force, thereby avoiding excessive damage to the surface layer of the test surface; a second sliding groove and a third sliding groove are formed on the inner wall of the needle tube, the bottom ends of the second sliding groove and the third sliding groove are located at the junction of the rotating part and the pressing part, and the second sliding groove and the third sliding groove are arranged in parallel with the axial direction of the needle tube; the second sliding groove is connected with the first sliding groove, and the second sliding groove is used for limiting the movement of the rotating piece on the pressing part; the third sliding groove is used for limiting the movement of the limiting piece on the pressing part; before the rotating piece and the limiting piece contact, the limiting piece is fixed at the bottom end of the third sliding groove; after the rotating piece and the limiting piece contact, the limiting piece is pushed by the rotating piece to move on the third sliding groove. 2.The traceless spring test needle according to claim 1, characterized in that: the limiting piece and the rotating piece are provided with a clamping groove and a clamping buckle that match each other; before the rotating piece and the limiting piece contact, only the elastic force of the second spring is transmitted to the needle head through the rotating piece. ​ ​ When the rotating member and the limiting member contact, the clamping groove and the clamping buckle are buckled, and only the elastic force of the first spring is transmitted to the needle through the sliding assembly.

3. The traceless spring test needle according to claim 2, characterized in that: A pusher is arranged on the sidewall of the needle tube, the pusher penetrates through the inner and outer sides of the needle tube, the pusher can move in the radial direction of the needle tube, a third spring is arranged between the pusher and the needle tube, the third spring makes the pusher protrude outside the needle tube, and the pusher acts on the clamping groove and the clamping buckle. When the clamping groove and the clamping buckle are buckled, the pusher is pushed inward, the pusher acts on the clamping groove and the clamping buckle, the clamping groove and the clamping buckle are unbuckled, and the rotating member and the limiting member are separated.

4. The traceless spring test needle according to claim 3, characterized in that: A fixing member for restricting the movement of the limiting member is arranged in the third sliding groove, a control member connected with the fixing member is arranged in the first sliding groove, and the fixing member and the control member can slide in the radial direction of the needle tube; and the fixing member only restricts the upward movement of the limiting member. When the rotating member slides in the first sliding groove, the control member is pushed to move in the radial direction of the needle tube, and the fixing member is driven to move; after the rotating member and the limiting member contact, the control member and the fixing member are moved to the position, and the fixing member releases the restriction on the upward movement of the limiting member.

5. The traceless spring test needle according to claim 4, characterized in that: The traceless spring test needle can be switched between a rotating operation state and a normal operation state; Before the rotating member and the limiting member contact, only the elastic force of the second spring is transmitted to the needle through the rotating member, and the traceless spring test needle is in the normal operation state; After the rotating member and the limiting member contact, the clamping groove and the clamping buckle are buckled, and only the elastic force of the first spring is transmitted to the needle through the sliding assembly, and the traceless spring test needle is in the rotating operation state; Before operation, the traceless spring test needle is in the rotating operation state, during operation, the needle damages the surface layer of the test surface through circumferential rotation force, then the traceless spring test needle is switched from the rotating operation state to the normal operation state, and after operation, the traceless spring test needle is still in the normal operation state, so that the needle is prevented from damaging the surface layer of the test surface through circumferential rotation force again.

6. A gold surface traceless test method using the traceless spring test needle according to any one of claims 1 to 5.

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