Automatic gold removing and tin coating method for gold-plated BTC component

Abstract

The invention discloses an automatic gold removing and tin coating method for a gold-plated BTC component. The automatic gold removing and tin coating method comprises the steps that the BTC component is placed on a tool jig through a mechanical arm module; the mechanical arm module sucks the BTC component, and the BTC component is moved to the soldering flux groove to be dipped in the soldering flux; the BTC component is moved to a cleaning tank to be cleaned, and redundant scaling powder on the surface of the BTC component is removed; moving the BTC component to a preheating tank to preheat the BTC component; the BTC component is immersed in a first tin pot for gold removal, and during gold removal, the mechanical arm module applies a first horizontal shaking action on the tin liquid level of the first tin pot to the BTC component; the BTC component is immersed in a second tin pot for tinning, and during tinning, the mechanical arm module applies a second horizontal shaking action on the tin liquid level of the second tin pot to the BTC component; and the BTC component is moved to a hot air leveling groove, and hot air leveling operation is conducted on the BTC component. The BTC component is subjected to gold removing and tin coating in an automatic gold removing and tin coating mode, and the production efficiency and the tin coating consistency can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic assembly, and particularly relates to an automatic gold removal and tinning method for gold-plated BTC components. Background Art

[0002] BTC (Bottom Termination Component) components, namely bottom terminal components, are widely used in printed circuit board assemblies, and the package forms are such as Figure 1 shown QFN (Quad Flat No-leads Package), Figure 2 shown LGA (Land Grid Array). Due to the advantages of high integration, small volume, high welding strength, etc., BTC components are increasingly applied in fields such as aerospace, ships, artificial satellites, etc. Before leaving the factory, in order to ensure that the solderable coating of the product is not oxidized, a gold plating protection treatment will be carried out on the surface of the device.

[0003] Due to problems such as solder joint embrittlement and insufficient strength caused by the phenomenon of gold embrittlement, more and more attention has been paid at home and abroad. The standard requirements for gold removal and tinning are that the gold-plated leads must be subjected to gold removal treatment before soldering to prevent solder joint gold embrittlement. Gold embrittlement refers to the rapid diffusion of gold into the tin of the solder when brazing on the surface coated with a gold coating, forming brittle AuSn 4 . In this compound, when the gold content reaches 3%, the solder joint will significantly show brittleness, lose luster, and affect reliability.

[0004] Currently, the industry generally adopts a manual gold removal and tinning method for BTC components. This method has many defects, such as poor tinning consistency, difficult operation, low efficiency, etc. Usually, the devices after manual tinning can only be manually pasted, greatly reducing the production efficiency. Summary of the Invention

[0005] The purpose of the present invention is to provide an automatic gold removal and tinning method for gold-plated BTC components. By adopting an automatic gold removal and tinning method to perform gold removal and tinning on BTC components, the production efficiency and tinning consistency can be improved.

[0006] To achieve the above purpose, one aspect of the present invention provides an automatic gold removal and tinning method for gold-plated BTC components, which uses an automatic tinning machine device to perform gold removal and tinning on gold-plated BTC components. The tinning machine device includes a tooling fixture, a robotic arm module, a flux tank, a cleaning tank, a preheating tank, a first solder pot, a second solder pot, and a hot air leveling tank. The method includes:

[0007] Step S1: Set the starting temperatures of the first tin pot and the second tin pot to melt the solidified tin in the first tin pot and the second tin pot into a liquid state, and place the BTC components on the tooling fixture.

[0008] Step S2: The robotic arm module picks up the BTC components and moves the BTC components to the flux bath to dip in the flux.

[0009] Step S3: The robotic arm module moves the BTC components to the cleaning bath for cleaning to remove the excess flux on the surface of the BTC components.

[0010] Step S4: The robotic arm module moves the BTC components to the preheating bath to preheat the BTC components.

[0011] Step S5: The robotic arm module moves the BTC components to the first tin pot and immerses the BTC components into the first tin pot for gold removal. When removing gold, the robotic arm module applies a first horizontal jitter action to the BTC components on the tin liquid surface of the first tin pot to eliminate the residual air existing between the BTC components and the tin liquid surface, wherein the jitter angle of the first horizontal jitter action is 2 - 4°, and the jitter speed is 1 - 10 mm / s.

[0012] Step S6: The robotic arm module moves the BTC components to the second tin pot and immerses the BTC components into the second tin pot for tinning. When tinning, the robotic arm module applies a second horizontal jitter action to the BTC components on the tin liquid surface of the second tin pot to eliminate the residual air existing between the BTC components and the tin liquid surface, wherein the jitter angle of the second horizontal jitter action is 2 - 4°, and the jitter speed is 1 - 10 mm / s.

[0013] Step S7: The robotic arm module moves the BTC components to the hot air leveling bath to perform hot air leveling operation on the BTC components.

[0014] Preferably, the tooling fixture includes a bottom support plate, a long partition rod, a short insertion rod, and a positioning post. A plurality of slots are provided on the bottom support plate for installing the long partition rod. A slot is provided in the middle of the long partition rod for installing the short insertion rod. Through holes corresponding to the slots on the bottom support plate are provided on the short insertion rod, and the positioning posts are inserted into the through holes of the short insertion rod.

[0015] Preferably, in Step S2, the dipping depth of the flux is 0.5 - 5 mm, the dipping time is 1 - 3 s, and the flux type is R type or RMA type.

[0016] Preferably, in Step S3, the flux is removed in the form of an air knife, the air speed of the air knife is 3 - 25 m / s, and the cleaning time is 0.5 - 2 s.

[0017] Preferably, in Step S4, the preheating temperature is 60 - 180 °C, and the preheating time is 10 - 200 s.

[0018] Preferably, in step S5, the jitter angle of the first horizontal jitter action is 2°, the jitter speed is 2 mm / s, and the number of jitter times is 2 times.

[0019] Preferably, in step S6, the jitter angle of the second horizontal jitter action is 3°, the jitter speed is 2 mm / s, and the number of jitter times is 2 times.

[0020] Preferably, in step S7, the hot air leveling speed is 1 - 50 mm / s, and the hot air leveling temperature is 120 - 380 °C.

[0021] According to the gold-plated BTC component automatic gold removal and tinning method in the above aspect of the present invention, the automatic gold removal and tinning method is used to perform gold removal and tinning on BTC components, which can improve production efficiency and tinning consistency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts:

[0023] Figure 1 is a schematic structural diagram of an existing QFN component;

[0024] Figure 2 is a schematic structural diagram of an existing LGA component;

[0025] Figure 3 is a schematic structural diagram of a tooling fixture according to an embodiment of the present invention;

[0026] Figure 4 is a schematic step diagram of the gold-plated BTC component automatic gold removal and tinning method according to an embodiment of the present invention;

[0027] Figure 5 is a schematic plan view of the horizontal jitter action according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0029] An embodiment of the present invention provides an automatic gold removal and tin soldering method for gold-plated BTC components, which uses an automatic tin soldering machine to perform gold removal and tin soldering on gold-plated BTC components. The tin soldering machine includes a tooling fixture, a robotic arm module, a flux tank, a cleaning tank, a preheating tank, a first tin pot, a second tin pot, and a hot air leveling tank.

[0030] As Figure 3 shown in the figure, the tooling fixture 10 includes a bottom support plate 11, a long partition rod 12, a short insertion rod 13, and a positioning post 14. The material of the tooling fixture 10 is transparent acrylic. Multiple (e.g., 18) slots are provided on the bottom support plate 11 for installing the long partition rod 12. A slot is provided in the middle of the long partition rod 12 for installing the short insertion rod 13. Through holes corresponding to the slots on the bottom support plate 11 are provided on the short insertion rod 13, and the positioning post 14 is inserted into the through holes of the short insertion rod 13. When the long partition rod 12 is assembled onto the bottom support plate 11, the corresponding slot on the bottom support plate 11 can be selected according to the size of the component to install the long partition rod 12. The short insertion rod 13 is installed into the slot of the long partition rod 12, and the positioning post 14 is inserted into the through hole of the short insertion rod 13 to complete the assembly of the tooling fixture 10.

[0031] The automatic gold removal and tin soldering method for gold-plated BTC components in the embodiment of the present invention includes the following steps S1 to S7.

[0032] In step S1, turn on the tin soldering machine, set the starting temperature of the first tin pot and the second tin pot to 260 °C to melt the solidified tin in the tin pots into a liquid state, and place the BTC components on the adjusted and assembled tooling fixture. When assembling the tooling fixture, first adjust the tooling fixture to a suitable size according to the length of the BTC components, install the long partition rod 12 into the slot on the bottom support plate 11, then install the short insertion rod 13 into the slot of the long partition rod 12 according to the width of the BTC components, and finally insert the positioning post 14 into the through hole of the short insertion rod 13 to complete the assembly of the tooling fixture.

[0033] In step S2, as Figure 4 shown in (a) of the figure, the robotic arm module sucks the BTC component 17 through the suction rod 15 and the suction nozzle 16, and as Figure 4 shown in (b) of the figure, moves to the flux tank 18 at the flux application station to dip the flux, and as Figure 4 shown in (c) of the figure, completes the flux dipping. The dipping depth is 0.5 - 5 mm, the immersion time is 1 - 3 s, and the flux type is R type or RMA type.

[0034] In step S3, the robotic arm module moves the BTC component 17 to the cleaning tank 19 at the flux cleaning station for cleaning, as Figure 4As shown in (d) of this station, an air knife is used to remove the liquid solder flux. The purpose of cleaning is to remove the excess solder flux on the surface after dipping the solder flux. The air speed of the air knife is 3 - 25 m / s, the cleaning time is 0.5 - 2 s, the blowing temperature is 23 °C, and the distance between the BTC component 17 and the air outlet 20 is 15 mm.

[0035] In step S4, the robotic arm module moves the BTC component 17 to the preheating tank of the preheating station to preheat the BTC component. The preheating temperature is 60 - 180 °C, and the preheating time is 10 - 200 s. Preferably, the preheating temperature is 140 °C and the preheating time is 30 s.

[0036] In step S5, as Figure 4 shown in (e) of this station, the robotic arm module moves the BTC component 17 to the first tin pot 21 at the gold removal station to perform gold removal on the BTC component. The gold removal station is a liquid molten tin pot. The BTC component 17 is immersed in the molten first tin pot 21, and the gold removal depth is 0.5 - 5 mm, and the gold removal time is 1 - 3 s. To avoid the phenomenon of residual air 23 between the BTC component 17 and the tin liquid surface during gold removal, as Figure 5 shown, a first horizontal jitter action 22 is applied to the BTC component 17 on the tin liquid surface to eliminate the residual air 23 between the BTC component 17 and the tin liquid surface, thereby solving the possible phenomenon of tin shortage at the bottom due to the residual air. The jitter angle of the first horizontal jitter action 22 is 2 - 4 °, and the jitter speed is 1 - 10 mm / s. As Figure 4 shown in (f) of this station, a first bottom solder 24 is formed on the bottom pad of the BTC component. Preferably, the temperature of the first tin pot is 260 °C, the gold removal time is 3 s, and it is kept in the tin liquid surface during gold removal. The robotic arm applies a horizontal jitter action. The jitter angle of the first horizontal jitter action 22 is 2 °, the jitter speed is 2 mm / s, and the number of jitter times is 2 times. The first tin pot 21 uses nitrogen circulation to prevent solder oxidation.

[0037] In step S6, as Figure 4 shown in (g) of this station, the robotic arm module moves the BTC component 17 to the second tin pot 26 at the tin plating station to perform tin plating on the BTC component. The tin plating station is a liquid molten tin pot. The BTC component 17 is immersed in the molten second tin pot 26, and the tin plating depth is 0.5 - 5 mm, and the tin plating time is 1 - 3 s; To avoid the phenomenon of residual air 23 between the BTC component and the tin liquid surface during tin plating, a second horizontal jitter action 27 is applied to the BTC component 17 on the tin liquid surface during tin plating to eliminate the residual air 23 between the BTC component 17 and the tin liquid surface, thereby solving the possible phenomenon of tin shortage at the bottom due to the residual air. The second horizontal jitter action 27 and Figure 5The first horizontal jitter action 22 shown is similar, with a jitter angle of 2 - 4° and a jitter speed of 1 - 10 mm / s. As Figure 4 shown in (h) of , a second bottom solder 28 is formed on the bottom pad of the BTC component 17. Preferably, the temperature of the second solder pot is 260°C, the tinning time is 3 s, and it is kept in the tin liquid level during tinning. The robotic arm applies a horizontal jitter action. The jitter angle of the second horizontal jitter action 27 is 3°, the jitter speed is 2 mm / s, and the number of jitter times is 2 times. The solder pot uses nitrogen circulation to prevent solder oxidation.

[0038] In step S7, the robotic arm module moves the BTC component 17 to the hot air leveling tank at the hot air leveling station. As Figure 4 shown in (i) of , the hot air leveling air knife 25 is used to perform hot air leveling operation on the BTC component 17. Since the BTC components are all components of the bottom pad type, in steps S5 and S6, unevenness will occur on the bottom pad. At this time, the hot air leveling air knife 25 is used to level the solder on the bottom pad to ensure the reliability of the component. When performing hot air leveling, the angle of the BTC component is 0 - 360°, the hot air leveling speed is 1 - 50 mm / s, and the hot air leveling temperature is 120 - 380°C. Preferably, the hot air leveling temperature is 280°C, the leveling angle is 90°, and the leveling speed is 10 mm / s.

[0039] In summary, the automatic gold removal and tinning method for gold-plated BTC components in the embodiments of the present invention has the following technical effects: Based on the 6 processing stations of the automatic tinning machine, the present invention can realize the automatic gold removal and tinning of gold-plated BTC components by using adjustable tooling fixtures and jitter actions during gold removal and tinning; the present invention has strong applicability and can be used for automatic gold removal and tinning operations of various BTC components with different sizes by adjusting the long partition plate of the tooling fixture; the present invention adopts the method of automatic gold removal and tinning and adjustable tooling fixtures, and can perform gold removal and tinning on gold-plated BTC components of various sizes; the present invention uses a horizontal jitter action to perform gold removal and tinning on large-size gold-plated BTC components, which can solve the problem of possible lack of tin on the bottom surface of BTC components during automatic gold removal and tinning; the present invention selects appropriate process parameters to realize the automatic gold removal and tinning of large-size gold-plated BTC, realizes the elimination of manual operations, and improves production efficiency and tinning consistency.

[0040] Only some exemplary embodiments of the present invention have been described by way of illustration above. Undoubtedly, for those of ordinary skill in the art, without departing from the spirit and scope of the present invention, the described embodiments can be modified in various different ways. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for automatically removing gold from gold-plated BTC components and tinning them, using an automatic tinning machine to remove gold from gold-plated BTC components, the tinning machine comprising a jig, a robotic arm module, a flux tank, a cleaning tank, a preheating tank, a first tin pot, a second tin pot, and a hot air leveling tank, characterized in that: The method comprises: Step S1: setting the starting temperatures of the first tin pot and the second tin pot to melt the solidified tin in the first tin pot and the second tin pot into liquid, and placing the BTC components on the tooling fixture; Step S2: The robot arm module absorbs the BTC components and moves the BTC components to the flux tank to dip in the flux; Step S3: The robot arm module moves the BTC components to the cleaning tank for cleaning to remove excess flux on the surface of the BTC components; Step S4: the robot arm module moves the BTC components to the preheating tank to preheat the BTC components; Step S5: The robot arm module moves the BTC component to the first tin pot, immerses the BTC component in the first tin pot for gold removal, and during the gold removal, the robot arm module applies a first horizontal shaking action on the tin liquid surface of the first tin pot to the BTC component to eliminate the residual air between the BTC component and the tin liquid surface, wherein the shaking angle of the first horizontal shaking action is 2-4°, and the shaking speed is 1-10 mm / s; Step S6: The robot arm module moves the BTC component to the second tin pot, immerses the BTC component in the second tin pot for tinning, and during the tinning, the robot arm module applies a second horizontal shaking action to the BTC component on the tin liquid surface of the second tin pot to eliminate the residual air between the BTC component and the tin liquid surface, wherein the shaking angle of the second horizontal shaking action is 2 to 4 degrees, and the shaking speed is 1 to 10 mm / s; Step S7: The robot arm module moves the BTC components to the hot air leveling tank and performs hot air leveling operation on the BTC components.

2. The method according to claim 1, characterized in that The tooling fixture includes a bottom support plate, a long partition rod, a short plug rod and a positioning column. The bottom support plate is provided with a plurality of slots for installing the long partition rod. A slot is provided in the middle of the long partition rod for installing the short plug rod. The short plug rod is provided with a through hole corresponding to the distance of the slot of the bottom support plate, and the positioning column is inserted into the through hole of the short plug rod.

3. The method according to claim 1 or 2, characterized in that In step S2, the soldering flux is dipped to a depth of 0.5 to 5 mm, the dipping time is 1 to 3 seconds, and the soldering flux type is R type or RMA type.

4. The method according to claim 1 or 2, characterized in that: In step S3, the flux is removed by using an air knife, the wind speed of the air knife is 3 to 25 m / s, and the cleaning time is 0.5 to 2 s.

5. The method according to claim 1 or 2, characterized in that: In step S4, the preheating temperature is 60 to 180° C., and the preheating time is 10 to 200 seconds.

6. The method according to claim 1 or 2, characterized in that: In step S5, the shaking angle of the first horizontal shaking action is 2°, the shaking speed is 2 mm / s, and the number of shaking times is 2 times.

7. The method according to claim 1 or 2, characterized in that: In step S6, the shaking angle of the second horizontal shaking action is 3°, the shaking speed is 2 mm / s, and the number of shaking times is 2 times.

8. The method according to claim 1 or 2, characterized in that: In step S7, the hot air leveling speed is 1-50 mm / s, and the hot air leveling temperature is 120-380°C.

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