A method for connecting leads of a surface mount device

Abstract

The present application relates to a kind of leg connection methods, in particular to a kind of straight insertion type device leg connection method, solve the problems of high cost, connection quality non-quantitative evaluation standard of prior art.The method includes steps: step 1: crimping pliers is adjusted to preset gear;Step 2: leg is connected with needle terminal;Step 3: pull-off force test;Qualified execution step 7;Unqualified compare △F and △F0;△F<△F0 execution step 4;△F≥△F0 take same batch straight insertion type device and needle terminal again, return step 1 and adjust preset gear;Step 4: take same batch straight insertion type device and needle terminal again, after cleaning, it is connected using the crimping pliers with adjusted gear;Step 5: pull-off force test;Qualified execution step 7;Unqualified execution step 6;Step 6: take same batch straight insertion type device and needle terminal again, after being connected using the crimping pliers with adjusted preset gear, return step 5;Step 7: needle hole terminal is inserted;Step 8: package heat shrink protection sleeve.

Description

TECHNICAL FIELD

[0001] The present application relates to a leg connection method, in particular to a straight insertion type device leg connection method. BACKGROUND

[0002] The straight insertion type package is a commonly used outer shape structure of electronic devices. When assembling, the electrical interconnection of the leg and the circuit is generally realized by direct through-hole welding or wire connection welding. However, in some special application fields, for example, application fields requiring the straight insertion type device to have a special spectrum band light emitting function, the material of the leg of the straight insertion type device in this application field is usually a special metal material with poor solder wettability. It is difficult to form and has poor plasticity, and the electrical interconnection of the leg and the circuit cannot be realized by direct through-hole welding or wire connection welding. For the electrical interconnection of the straight insertion type device in this application field, the traditional way is to realize the electrical interconnection by screwing and extruding the leg with a TC type terminal screw. Although this method can realize electrical interconnection, the connection contact surface is narrow, which belongs to point connection and is easy to be loosened by external force. Moreover, it has poor high-voltage electrical performance, large contact resistance, complex assembly process, large volume of connecting components, poor transportation and assembly, poor plug-in and plug-out substitution interchangeability, and no quantitative evaluation standard for connection quality and lack of connection stability.

[0003] To solve the above problems and meet the high reliability requirements of aerospace products, the existing solutions are as follows: one is to replate a solderable layer on the leg of the straight insertion type device made of special metal material, and then realize the electrical interconnection of the leg and the circuit by direct through-hole welding or wire connection welding. Although this solution fundamentally solves the problem, the cost is very high, and the cost of plating materials and processes even exceeds the value of the straight insertion type device itself. Another solution is to prevent the screw from loosening, to reinforce the joint by potting, and to fix the wire, so as to enhance the connection firmness of the electrical interconnection realized by screwing and extruding the leg with a TC type terminal screw. This solution is a traditional method for aerospace technology and can be applied within a certain range, but it has high cost, strict space requirements and complex process route, and cannot be applied on a large scale. In addition, a closed point extrusion method is also used to connect the leg of the straight insertion type device with the closed point extrusion end of the needle terminal in the closed pit extrusion terminal, and then connect the plug-in connection end of the needle terminal connected with the leg with the plug-in connection end of the hole terminal connected with the wire in the closed pit extrusion terminal, so as to realize the external electrical interconnection through the wire connected with the hole terminal. However, when the closed point extrusion connection is performed by using a pressure clamp, the gear position of the pressure clamp is generally adjusted by experience, and then the extrusion force of the pressure clamp is controlled. It is difficult to make the extrusion force appropriate, which may cause the connection to be not firm due to insufficient extrusion force, or the extrusion points of the leg and the needle terminal to be damaged due to excessive extrusion force, thereby causing the leg and the needle terminal to be separated or damaged and broken during use. SUMMARY

[0004] The purpose of the present application is to solve the problem of high reliability electrical interconnection between the lead of a straight insertion type device and the circuit when the material of the lead is a special metal material with poor welding wettability, and to provide a straight insertion type device lead connection method.

[0005] To solve the above technical problems, the technical solution adopted by the present application is:

[0006] A straight insertion type device lead connection method for connecting the lead of a straight insertion type device with a length greater than or equal to 10 mm, characterized in that it comprises the following steps:

[0007] Step 1: Adjust the gear position of the crimping pliers to a preset gear position;

[0008] Step 2: Using the crimping pliers with the gear position adjusted in step 1, connect the lead of the straight insertion type device to the closed point extrusion end of the needle terminal in the closed pit compression terminal through a closed point extrusion method;

[0009] Step 3: Test the pull-off force of the lead and the needle terminal connected in step 2;

[0010] If the pull-off force test value F reaches the preset pull-off force value F0, and the connection between the lead and the needle terminal is not broken, it is judged as test qualified, and step 7 is executed;

[0011] If the pull-off force test value F does not reach the preset pull-off force value F0, and the connection between the lead and the needle terminal is broken, it is judged as test unqualified, and the pull-off force test value F1 at the time of breakage is recorded, then the difference value AF between F0 and F1 is compared with the preset pull-off force difference threshold value AF0: if AF < AF0, step 4 is executed; if AF ≥ AF0, the needle terminal of the closed pit compression terminal and the straight insertion type device with the lead not yet connected are taken again, then step 1 is returned, and the preset gear position of the crimping pliers is adjusted larger;

[0012] Step 4: Take the needle terminal of the closed pit compression terminal and the straight insertion type device with the lead not yet connected again, and clean the dirt of the lead of the straight insertion type device and the needle terminal first, then connect the lead of the straight insertion type device to the closed point extrusion end of the needle terminal through a closed point extrusion method using the crimping pliers with the gear position adjusted in step 1;

[0013] Step 5: Test the pull-off force of the lead and the needle terminal connected in step 4;

[0014] If the pull-off force test value F reaches the preset pull-off force value F0, and the connection between the lead and the needle terminal is not broken, it is judged as test qualified, and step 7 is executed;

[0015] If the pull-off force test value F does not reach the preset pull-off force value F0, the leg and the needle terminal connection have been broken, and it is judged that the test is unqualified, and step 6 is performed;

[0016] Step 6: Reconnect the needle terminal of the closed pit compression terminal of the same batch of straight insertion type devices whose legs have not been connected, and increase the preset gear of the compression clamp, connect the legs of the straight insertion type device to the closed pit compression end of the needle terminal by the closed pit compression mode, and then return to step 5;

[0017] Step 7: The plug-in connection end of the needle terminal connected with the leg is connected with the plug-in connection end of the hole terminal of the closed pit compression terminal connected with the wire, and a matching point is formed;

[0018] Step 8: The needle terminal and the hole terminal connected in step 7 are sleeved with a heat shrink protective sleeve, and the heat shrink protective sleeve is blown and shrunk by a heat gun to be adhered to the outer surface of the needle terminal and the hole terminal, and after the whole is wrapped, it is placed for 10-20 minutes, and the connection of the legs of the straight insertion type device and the wire is completed.

[0019] Further, in order to make the compression degree suitable when connecting the legs of the same batch of straight insertion type devices to the outside electrical interconnection, and save test time and test cost, the straight insertion type device leg connection method of the present application preferably further comprises step 9, the connection of the legs of other straight insertion type devices of the same batch whose legs have not been connected and the corresponding wires, specifically:

[0020] Step 9.1: The legs of other straight insertion type devices of the same batch whose legs have not been connected are connected to the closed pit compression end of the needle terminal in the corresponding closed pit compression terminal by the closed pit compression mode using the compression clamp whose gear has been adjusted for the last time;

[0021] Step 9.2: The connection of the legs of other straight insertion type devices of the same batch whose legs have not been connected and the corresponding wires is completed by the method of steps 7 to 8.

[0022] Further, in order to connect more firmly under the condition of the same gear of the compression clamp, the specific operation method of the closed pit compression mode is:

[0023] Step A: Put the needle terminal in the closed pit compression terminal into the compression clamp jaw, and make the needle terminal top to the bottom end of the positioner on the compression clamp, so that the needle terminal and the positioner cooperate well;

[0024] Step B: The leg of the straight insertion type device is inserted into the compression hole of the needle terminal cooperating well with the positioner in step A until the bottom is touched, ensuring that the leg of the straight insertion type device can be seen from the observation port of the needle terminal;

[0025] Step C: Operate the crimping pliers to perform a closed point squeezing operation to form a squeezing point and complete the operation.

[0026] Furthermore, in order to find out the reason why the pull-off force test fails as quickly as possible, the preset pull-off force difference threshold ΔF0 is set to (20% to 25%)F0.

[0027] Furthermore, in order to ensure reliable connection, convenient procurement and low cost, the closed pit pressure terminal uses the J599 type closed terminal 22D#.

[0028] Furthermore, in order to achieve good contact resistance and excellent electrical performance, the pin terminal and the hole terminal in the J599 type closed terminal 22D# are both made of copper material as the inner base and gold-plated outer covering layer.

[0029] Furthermore, the model of the crimping pliers is M22520 / 2-01, and the model of the positioner installed on the crimping pliers is K42.

[0030] Furthermore, when performing the pull-off force test, a pull-off force tester is used to perform the pull-off force test;

[0031] When the preset pull-off force value F0 is within the range of 34N to 40N, the initial value of the preset gear in step 1 is gear 2, and the preset pull-off force difference threshold ΔF0 is 8N.

[0032] In this way, when the preset pull-off force value F0 is within the range of 34N to 40N, the gear position of the crimping pliers is initially adjusted to gear 2 in step 1. This will not cause damage to the pins of the through-hole device, and will ensure that the pull-off force that can be sustained after the connection is as close as possible to or meets the requirements of the preset pull-off force value F0. By setting the preset pull-off force difference threshold △F0 to 8N, the reason for the failure of the pull-off force test can be found as soon as possible, reducing the number of attempts required to determine the appropriate gear position of the crimping pliers.

[0033] Furthermore, in order to ensure that the heat shrink protective sleeve is firmly adhered to the outer surface of the pin terminal and the hole terminal after heat shrinkage, and can wrap the pin terminal and the hole terminal as a whole, protect the entire structure from external force and meet the requirements of moisture resistance, salt spray resistance, and mildew resistance, in step 8, the heat shrink protective sleeve is a transparent heat shrink protective sleeve with a diameter of 2 mm to 3 mm;

[0034] After the heat shrink protective sleeve is put on the outer part of the pin terminal and the socket terminal after the plug connection, the two ends of the heat shrink protective sleeve protrude 2mm to 4mm from the outer parts of the pin terminal and the socket terminal after the plug connection;

[0035] When using a hot air blower to shrink the heat shrink protective sleeve, the heat shrink temperature is 120℃±5℃, and the heat shrink time is 10S~15S.

[0036] Further, in order to be able to quickly shrink after being heated, the material of the transparent heat-shrinkable protective sleeve is polyolefin.

[0037] The beneficial effects of the present application are:

[0038] (1) The straight insertion type device leg connecting method of the present application connects the leg of the straight insertion type device with the closed point extrusion end of the needle terminal in the closed pit compression terminal through the closed point extrusion mode, and then tests the pull-off force of the integrated leg and needle terminal; when the test is unqualified, according to the size relationship between the difference value AF obtained by subtracting the pull-off force test value F1 at the time of fracture from the preset pull-off force value F0 and the preset pull-off force difference threshold AF0, it is determined whether to use the way of first cleaning, still unqualified after cleaning, and then adjusting the position of the pressure contact pliers, or directly adjusting the position of the pressure contact pliers, to overcome the unqualified pull-off force test, until the pull-off force test is qualified; then the plug-in connection end of the needle terminal connected with the leg is connected with the plug-in connection end of the hole terminal in the closed pit compression terminal connected with the wire; finally, a heat-shrinkable protective sleeve is sleeved on the outside of the integrated needle terminal and hole terminal after plug-in connection, and the electrical interconnection of the leg of the straight insertion type device to the outside is realized through the wire connected with the hole terminal;

[0039] When the straight insertion type device leg connecting method of the present application is used to solve the problem of high-reliability electrical interconnection of the leg of the straight insertion type device with poor special metal material in welding wettability and the circuit, it does not need to plate a weldable layer on the leg, nor does it need to use a TC type terminal screw to tighten and extrude the leg to realize electrical interconnection, thus avoiding the problem of very high cost caused by plating a weldable layer on the leg, and avoiding a series of problems caused by the need for anti-loosening treatment of the screw, the need for potting and reinforcement of the joint point, and the need for fixing the wire to increase the connection firmness. At the same time, compared with the traditional closed point extrusion method for realizing the electrical interconnection of the leg of the straight insertion type device to the outside, the present application first adjusts the position of the pressure contact pliers to the preset position, and the initial value of the preset position of the pressure contact pliers is given according to experience, which is usually low, and will not damage the extrusion points of the leg and the needle terminal due to excessive extrusion force. Then, when the pull-off force test is unqualified, according to the size relationship between the difference value AF obtained by subtracting the pull-off force test value F1 at the time of fracture from the preset pull-off force value F0 and the preset pull-off force difference threshold AF0, different ways are used to overcome the unqualified pull-off force test until the pull-off force test is qualified. Therefore, by using the straight insertion type device leg connecting method of the present application, the problem of the leg and the needle terminal being disconnected or damaged due to insufficient extrusion force or damage to the extrusion points of the leg and the needle terminal can be avoided.

[0040] In summary, the straight insertion type device leg connection method of the present application gets rid of the traditional complex assembly process and its components, can realize fast connection, and improves the connection efficiency; when connecting, the closed pit compression terminal is used, which is several times smaller than the traditional TC type terminal, and has a good space advantage; in addition, when connecting, the connection is reliable and the high-voltage electrical performance is good through the ring extrusion connection of the compression pliers; moreover, the closed pit compression terminal used in the connection is maturely applied in aerospace, which fully utilizes the characteristics of the needle and hole of the terminal, can freely select the terminal type, realizes free plugging, has good terminal interchangeability, and has low cost; in addition, during the connection process, the connection reliability can be detected through the pull-off force test, and the firmness of the connection can be quantitatively evaluated; therefore, the present application solves the technical problems of high cost, large size of the connecting piece, complex process route, poor electrical performance and interchangeability, and lack of connection stability in the prior art when solving the high-reliability electrical interconnection problem of the straight insertion type device leg and the circuit of the special metal material with poor welding wetness of the leg material. The straight insertion type device leg connection method of the present application can realize the high-reliability and high-stability electrical interconnection of the straight insertion type device leg and the circuit of the special metal material with poor welding wetness of the leg material.

[0041] (2) The straight insertion type device leg connection method of the present application preferably further comprises step 9, connecting the legs of other straight insertion type devices in the same batch with the corresponding wires. In this way, when the legs of the straight insertion type devices in the same batch are electrically interconnected, the legs of the first straight insertion type device in the same batch are connected with the needle terminal, and then the pull-off force test is performed to determine whether the gear position of the compression pliers needs to be adjusted; after the gear position of the compression pliers is adjusted, the electrical interconnection of the legs of other straight insertion type devices in the same batch is performed without the need for the pull-off force test; therefore, when the electrical interconnection of the legs of the straight insertion type device is realized by using the straight insertion type device leg connection method of the present application, on the one hand, for a single leg, whether the connection is reliable can be quantitatively evaluated by the pull-off force test; on the other hand, for the straight insertion type devices in the same batch, the pull-off force test does not need to be performed on each leg connected with the needle terminal, which saves the test time and cost.

[0042] (3) The closed pit compression terminal in the present application is preferably J599 type closed terminal 22D#, and the needle terminal and the hole terminal are preferably made of copper material with gold material coated on the outer wrapping layer, which adopts gold plating process, has good contact resistance, and excellent electrical performance.

[0043] (4) In the present application, for the external electrical interconnection of the lead of the direct insertion type device with the preset pull-off force value F0 in the range of 34N-40N, the preferred model and gear of the crimping pliers, the model of the positioner, and the preferred preset pull-off force difference threshold value AF0 for quickly finding out the reason for the pull-off force test failure and reducing the number of attempts required to determine the appropriate gear of the crimping pliers are provided, which is convenient to apply. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 is the structure diagram of the external electrical interconnection of the lead on the direct insertion type package lamp in step 8 of the embodiment of the direct insertion type device lead connection method of the present application.

[0045] The explanation of each number in the figure is as follows:

[0046] 1 - direct insertion type package lamp, 2 - lead, 3 - extrusion point, 4 - pin terminal, 5 - fitting point, 6 - hole terminal, 7 - heat shrink protective sleeve, 8 - wire, 9 - observation port of the pin terminal, 10 - observation port of the hole terminal. DETAILED DESCRIPTION

[0047] The present application will be described in detail below in combination with the drawings and specific embodiments.

[0048] Referring to Figure 1 , the direct insertion type device lead connection method of the present application is used for the connection of the lead of the direct insertion type device with a length greater than or equal to 10mm. In the embodiment, the direct insertion type device is a direct insertion type package lamp 1, the lead part of which is packaged in a glass body, and part of which is outside the glass body. The lead 2 outside the glass body is responsible for electrical interconnection with the outside world, and the material of the lead 2 is iron-cobalt-nickel. When the direct insertion type device lead connection method of the present application is applied to electrical interconnection with the outside world, it is required that the length of the lead 2 on the direct insertion type package lamp 1 cannot be less than 10mm, because of the length requirement of the closed point extrusion process and the stress release requirement. In the embodiment, the length of the lead 2 on the direct insertion type package lamp 1 is 20mm, which ensures the requirement of at least 5mm for the length of the closed point extrusion process and more than 5mm for stress release, so that the lead 2 on the direct insertion type package lamp 1 after connection will not cause stress damage to the glass package body. In the embodiment, the minimum pull-off force value required to be met after the electrical connection of the lead 2 with the pin terminal 4 is 34N.

[0049] When the direct insertion type device lead connection method of the present application is applied to the external electrical interconnection of the lead 2 on the direct insertion type package lamp 1, it includes the following steps:

[0050] Step 1: adjust the gear of the crimping pliers to the preset gear; in this embodiment, the model of the crimping pliers is preferably M22520 / 2-01, the model of the positioner installed on the crimping pliers is preferably K42, and the initial value of the preset gear of the crimping pliers is 2 gears, i.e., when the external electrical interconnection of the first leg of the same batch of direct insertion type packaging lamps 1 is performed, the gear of the crimping pliers is first adjusted to 2 gears.

[0051] Step 2: connect the leg 2 of the direct insertion type device to the closed point extrusion end of the needle terminal 4 in the closed pit pressing terminal by the closed point extrusion method using the crimping pliers with the gear adjusted in step 1; in order to be reliable in connection and low in cost, in this embodiment, the closed pit pressing terminal is preferably selected as a J599 type closed terminal 22D#, which has a cylindrical shape with a diameter of 0.8 mm and a length of 8 mm. In order to have good contact resistance and excellent electrical performance, the needle terminal 4 and the hole terminal 6 in the above-mentioned J599 type closed terminal 22D# are both made of copper material as the inner base and gold material as the outer coating. In this embodiment, in order to be more firmly connected under the condition of the same gear of the crimping pliers, the specific operation method of the closed point extrusion method is as follows:

[0052] Step A: place the needle terminal 4 in the closed pit pressing terminal into the jaws of the crimping pliers and make the needle terminal 4 top the bottom end of the positioner on the crimping pliers so that the needle terminal 4 is well matched with the positioner;

[0053] Step B: extend the leg 2 of the direct insertion type device into the pressing hole of the needle terminal 4 well matched with the positioner in step A until the bottom is touched, and ensure that the leg 2 of the direct insertion type device can be seen from the observation port 9 of the needle terminal;

[0054] Step C: operate the crimping pliers to perform the closed point extrusion operation to form the extrusion point 3 and complete the operation.

[0055] Step 3: test the pull-off force of the leg 2 and the needle terminal 4 connected as a whole in step 2; in this embodiment, the pull-off force tester is used to test the pull-off force when the pull-off force test is performed;

[0056] If the pull-off force test value F reaches the preset pull-off force value F0 and the connection between the leg 2 and the needle terminal 4 is not broken, it is determined that the test is qualified, and step 7 is performed; the preset pull-off force value F0 is determined according to the requirements in the actual use environment;

[0057] If the pull-off force test value F does not reach the preset pull-off force value F0, the connection between the leg 2 and the needle terminal 4 is broken, it is judged that the test is unqualified, the pull-off force test value F1 at the time of breaking is recorded, and then the difference value AF between F0-F1 is compared with the preset pull-off force difference threshold value AF0: if AF<AF0, step 4 is executed; if AF≥AF0, the needle terminal 4 in the closed pit compression terminal of the same batch of straight plug-in devices whose legs 2 have not been connected is taken again, then step 1 is returned, and the preset gear of the compression clamp is adjusted to be larger;

[0058] The preset pull-off force difference threshold value AF0 is determined according to experience, and is usually (20%-25%) F0. When the preset pull-off force value F0 is in the range of 34N-40N, the initial value of the preset gear in step 1 is preferably 2 gears, and the preset pull-off force difference threshold value AF0 is preferably 8N, and the embodiment takes 8N; in this way, the reason for the unqualified pull-off force test can be found out as soon as possible, and the number of attempts required to determine the appropriate gear of the compression clamp is reduced.

[0059] Step 4: The needle terminal 4 in the closed pit compression terminal of the same batch of straight plug-in devices whose legs 2 have not been connected is taken again, the leg 2 of the straight plug-in device and the needle terminal 4 are first cleaned, and then the leg 2 of the straight plug-in device is connected to the closed point extrusion end of the needle terminal 4 by the closed point extrusion method using the compression clamp with the gear adjusted in step 1.

[0060] Step 5: The pull-off force test is performed on the connected leg 2 and needle terminal 4.

[0061] If the pull-off force test value F reaches the preset pull-off force value F0, the connection between the leg 2 and the needle terminal 4 is not broken, it is judged that the test is qualified, and step 7 is executed.

[0062] If the pull-off force test value F does not reach the preset pull-off force value F0, the connection between the leg 2 and the needle terminal 4 is broken, it is judged that the test is unqualified, and step 6 is executed.

[0063] Step 6: The needle terminal 4 in the closed pit compression terminal of the same batch of straight plug-in devices whose legs 2 have not been connected is taken again, and the preset gear of the compression clamp is adjusted to be larger, the leg 2 of the straight plug-in device is connected to the closed point extrusion end of the needle terminal 4 by the closed point extrusion method, and then step 5 is returned.

[0064] Step 7: connect the plug-in connection end of the needle terminal 4 connected with the leg 2 with the plug-in connection end of the hole terminal 6 of the closed pit compression terminal connected with the wire 8 to form a matching point 5; in the embodiment, when the wire 8 is connected with the hole terminal 6 of the closed pit compression terminal, the operation method is similar to the closed point compression method when the straight insertion type device leg 2 is connected with the needle terminal 4 of the closed pit compression terminal, that is, the hole terminal 6 is replaced by the needle terminal 4, the wire 8 is replaced by the straight insertion type device leg 2, and the observation port 10 of the hole terminal is replaced by the observation port 9 of the needle terminal, and then the same method is used for operation.

[0065] Step 8: wrap the heat shrinkable protective sleeve 7 on the whole outside of the needle terminal 4 and the hole terminal 6 connected in step 7, and blow the heat shrinkable protective sleeve 7 with a heat gun to make it shrink and adhere to the outer surface of the needle terminal 4 and the hole terminal 6, and then stand for 10-20 minutes after the whole is wrapped to complete the connection of the straight insertion type device leg 2 with the wire 8. In order to ensure that the heat shrinkable protective sleeve 7 is firmly adhered to the outer surface of the needle terminal 4 and the hole terminal 6 after shrinking and can wrap the whole needle terminal 4 and hole terminal 6 to protect the whole structure from external impact and meet the requirements of moisture-proof, salt mist-proof and mold-proof, the heat shrinkable protective sleeve 7 adopts a transparent heat shrinkable protective sleeve, the diameter thereof is preferably 2-3 mm, and the two ends of the heat shrinkable protective sleeve 7 after being wrapped on the whole outside of the needle terminal 4 and the hole terminal 6 connected in step 7 preferably protrude 2-4 mm from the two ends of the whole outside of the needle terminal 4 and the hole terminal 6. When the heat shrinkable protective sleeve 7 is blown with a heat gun, the heat shrinkage temperature is preferably 120±5℃, and the heat shrinkage time is preferably 10-15 seconds. In the embodiment, in order to quickly shrink after being heated, the material of the transparent heat shrinkable protective sleeve is polyolefin, the diameter of the heat shrinkable protective sleeve 7 is 3 mm, the two ends of the heat shrinkable protective sleeve 7 protrude 2 mm from the two ends of the whole outside of the needle terminal 4 and the hole terminal 6 connected in step 7, the heat shrinkage temperature is 120℃, and the heat shrinkage time is 10 seconds, and the heat shrinkable protective sleeve 7 is stood for 20 minutes after heat shrinkage.

[0066] In order to make the compression degree suitable when connecting the legs of the same batch of straight insertion type devices with external electrical interconnection and save test time and cost, the straight insertion type device leg connection method of the application preferably further comprises step 9, which is the connection of the legs 2 of other straight insertion type devices of the same batch with the corresponding wires 8, and the specific steps are as follows:

[0067] Step 9.1: connect the legs 2 of other straight insertion type devices of the same batch with the corresponding closed point compression ends of the needle terminals 4 of the closed pit compression terminals by the closed point compression method using the crimping pliers with the last adjusted gear position.

[0068] Step 9.2: complete the connection of the legs 2 of other straight insertion type devices of the same batch with the corresponding wires 8 by the method of steps 7-8.

[0069] The wire 8 is used for electrical interconnection with the outside. As can be known from the above connection process, in the straight insertion type device lead connection method of the present application, the lead for electrical interconnection with the outside of the first straight insertion type device in the same batch is connected with the needle terminal, and after the connection is completed, a pull-off force test is performed to determine whether the stop position of the crimping pliers needs to be adjusted; after the stop position of the crimping pliers is adjusted to be appropriate, the leads of other straight insertion type devices in the same batch are connected for electrical interconnection with the outside, and the pull-off force test is not needed; therefore, in the straight insertion type device lead connection method of the present application, when the leads of the straight insertion type device are connected for electrical interconnection with the outside, on the one hand, for a single lead, whether the connection is reliable can be quantitatively evaluated by the pull-off force test; on the other hand, for the straight insertion type devices in the same batch, the pull-off force test does not need to be performed on each lead connected with the needle terminal, and the test time and cost are saved.

[0070] The straight insertion type device lead connection method of the present application is applied in the design of a certain type of high-voltage power supply, and after electrical performance tests and temperature cycle and random vibration tests, the appearance of the extrusion point is good, and the electrical connection is reliable, which shows that the method can meet the requirements of high-voltage characteristics and connection characteristics.

[0071] In summary, the straight insertion type device lead connection method of the present application not only has reliable connection quality, small size, excellent electrical performance, but also has good interchangeability, high production efficiency, low cost, and the firmness of the connection can be quantitatively evaluated.

Claims

1. A method for connecting the lead of a surface mount device, for the connection of the lead of a surface mount device having a length of 10 mm or more, characterized in that, The method comprises the following steps: Step 1: adjust the gear position of the crimping pliers to a preset gear position; Step 2: connect the lead leg (2) of the straight insertion type device to the closed point extrusion end of the needle terminal (4) in the closed pit compression terminal by the closed point extrusion mode using the crimping pliers with the gear position adjusted in step 1; Step 3: test the pull-off force of the lead leg (2) and the needle terminal (4) connected as a whole in step 2; If the pull-off force test value F reaches the preset pull-off force value F0, and the connection between the lead leg (2) and the needle terminal (4) is not broken, it is judged that the test is qualified, and step 7 is performed; If the pull-off force test value F does not reach the preset pull-off force value F0, and the connection between the lead leg (2) and the needle terminal (4) is broken, it is judged that the test is unqualified, the pull-off force test value F1 at the time of breakage is recorded, and then the difference value AF of F0-F1 is compared with the preset pull-off force difference threshold AF0: if AF<AF0, step 4 is performed; if AF≥AF0, the lead leg (2) of the straight insertion type device and the needle terminal (4) in the closed pit compression terminal of the same batch which have not been connected are taken again, then step 1 is returned, and the preset gear position of the crimping pliers is adjusted to be larger; Step 4: the lead leg (2) of the straight insertion type device and the needle terminal (4) in the closed pit compression terminal of the same batch which have not been connected are taken again, the lead leg (2) of the straight insertion type device is cleaned first, then the lead leg (2) of the straight insertion type device is connected to the closed point extrusion end of the needle terminal (4) by the closed point extrusion mode using the crimping pliers with the gear position adjusted in step 1; Step 5: test the pull-off force of the lead leg (2) and the needle terminal (4) connected as a whole; If the pull-off force test value F reaches the preset pull-off force value F0, and the connection between the lead leg (2) and the needle terminal (4) is not broken, it is judged that the test is qualified, and step 7 is performed; If the pull-off force test value F does not reach the preset pull-off force value F0, and the connection between the lead leg (2) and the needle terminal (4) is broken, it is judged that the test is unqualified, and step 6 is performed; Step 6: the lead leg (2) of the straight insertion type device and the needle terminal (4) in the closed pit compression terminal of the same batch which have not been connected are taken again, the preset gear position of the crimping pliers is adjusted to be larger, the lead leg (2) of the straight insertion type device is connected to the closed point extrusion end of the needle terminal (4) by the closed point extrusion mode, and then step 5 is returned; Step 7: the plug-in connection end of the needle terminal (4) connected with the lead leg (2) is connected to the plug-in connection end of the hole terminal (6) connected with the wire (8) in the closed pit compression terminal, and a matching point (5) is formed; Step 8: the plug-in connection end of the needle terminal (4) connected with the lead leg (2) is connected to the plug-in connection end of the hole terminal (6) connected with the wire (8) in the closed pit compression terminal, and a matching point (5) is formed; 2. The method of claim 1, wherein Step 9: the lead leg (2) of the straight insertion type device and the corresponding wire (8) are connected, and the lead leg (2) of the straight insertion type device and the corresponding wire (8) are connected. Step 9.1: the legs (2) of the same batch of other straight plug-in type devices which have not been connected are connected with the closed point extrusion end of the corresponding closed pit pressure terminal through the closed point extrusion method by using the last adjusted pressure clamp; Step 9.2: the connection between the legs (2) of the same batch of other straight plug-in type devices which have not been connected and the corresponding wires (8) is completed by using the method of steps 7 to 8.

3. The method of claim 1, wherein The specific operation method of the closed point extrusion method is: Step A: put the needle terminal (4) in the closed pit pressure terminal into the pressure clamp jaw, and make the needle terminal (4) top to the bottom end of the positioner on the pressure clamp, so that the needle terminal (4) is well matched with the positioner; Step B: insert the leg (2) of the straight plug-in type device into the pressing hole of the needle terminal (4) matched with the positioner in step A until it touches the bottom, and ensure that the leg (2) of the straight plug-in type device can be seen from the observation port (9) of the needle terminal (4); Step C: operate the pressure clamp to implement the closed point extrusion operation to form the extrusion point (3), and complete the operation.

4. The straight plug-in type device leg connection method according to claim 1, wherein: The preset pull-off force difference threshold value △F0 is (20%-25%)F0.

5. The straight plug-in type device leg connection method according to claim 1, wherein: The closed pit pressure terminal selects J599 type closed terminal 22D#.

6. The straight plug-in type device leg connection method according to claim 5, wherein: The needle terminal (4) and hole terminal (6) in the J599 type closed terminal 22D# are made of copper material as the internal base and gold material as the outer wrapping layer.

7. The straight plug-in type device leg connection method according to claim 5, wherein: The model of the pressure clamp is M22520 / 2-01, and the model of the positioner installed on the pressure clamp is K42.

8. The straight plug-in type device leg connection method according to claim 7, wherein: When the preset pull-off force test is performed, a pull-off force tester is used to test the pull-off force; When the preset pull-off force value F0 is in the range of 34N-40N, the initial value of the preset gear in step 1 is 2 gears at the beginning, and the preset pull-off force difference threshold value △F0 is 8N.

9. The straight plug-in type device leg connection method according to claim 5, wherein: In step 8, the heat shrink protective sleeve (7) is a transparent heat shrink protective sleeve with a diameter of 2mm-3mm; After the heat shrink protective sleeve (7) is sleeved on the outside of the whole needle terminal (4) and hole terminal (6) after the plug connection, the two ends of the heat shrink protective sleeve (7) each protrude 2mm-4mm from the two ends of the whole needle terminal (4) and hole terminal (6) outside; When the heat shrink protective sleeve (7) is blown and shrunk by using a heat blower, the heat shrink temperature is 120℃±5℃, and the heat shrink time is 10S-15S.

10. The straight plug-in type device leg connection method according to claim 9, wherein: The material of the transparent heat shrink protective sleeve is polyolefin.

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