Wire rod cleaning device and method and application

Abstract

The invention relates to the technical field of wire rod cleaning, in particular to a wire rod cleaning device and method and application. The invention discloses a wire rod cleaning device which comprises a charged dust collection unit. The charged dust collection unit comprises a corona wire and a tubular dust collection anode plate, and the corona wire is located at the axial center position of the tubular dust collection anode plate. According to the wire and wire cleaning device, particles on the surface of a wire and wire are charged through the charged dust collection unit by means of current assistance, the particles on the surface of the wire and wire are removed through electrostatic dust collection, and secondary pollution caused by contact of the particles and the wire and wire is avoided; moreover, the device is small and convenient, can be integrated at the rear end of wire drawing or annealing equipment, and is low in cost and small in occupied area.

Description

Technical Field

[0001] The present invention relates to the technical field of wire cleaning, and in particular to a wire cleaning device, method and application. Background Art

[0002] The surface cleanliness of the bonding wire has a great impact on the performance of the bonding wire itself and the bonding performance. The traditional preparation process of the bonding wire is to apply drawing liquid and annealing liquid during the drawing and annealing process to lubricate the wire and prevent sticking. However, the metal ions in the drawing liquid and annealing liquid and the dust in the air will remain on the surface during the wire preparation process. These surface particles will be embedded in the bonding wire or remain on the surface during further drawing or annealing and rewinding processes, deteriorating the mechanical properties and bonding performance of the bonding wire.

[0003] At present, cleaning of bonding wires usually involves installing a cleaning tank at the rear end of the bonding wire drawing equipment for bubble cleaning or an additional ultrasonic cleaning device. However, both of the above methods involve soaking the bonding wires in water, and the stains left in the water after cleaning can easily cause secondary contamination of the bonding wires. Furthermore, if ultrasonic cleaning is used after the final annealing, it can easily cause the wires to stick together, limiting their use. In addition, a dedicated ultrasonic cleaning device also requires a wire retracting and releasing system and a tension system, which are expensive and take up a large area.

[0004] In view of this, this invention is proposed. Summary of the invention

[0005] The first purpose of the present invention is to provide a wire cleaning device, which uses a charged dust collection unit to assist in charging the particles on the surface of the wire with an electric current, and removes the particles on the surface of the wire through electrostatic dust removal, thereby avoiding secondary pollution caused by contact between the particles and the wire; moreover, the device is small and convenient, can be integrated at the back end of the wire drawing or annealing equipment, has low cost and occupies a small area.

[0006] The second object of the present invention is to provide a wire cleaning method that can effectively remove particles on the surface of the wire, has high efficiency and good cleaning effect, and is particularly suitable for removing micron-sized particles.

[0007] A third object of the present invention is to provide application of the wire cleaning method in bonding wire cleaning.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0009] In a first aspect, the present invention provides a wire cleaning device, comprising a charged dust collecting unit;

[0010] The charged dust collecting unit comprises a corona wire and a tubular dust collecting anode plate, wherein the corona wire is located at the axial center of the tubular dust collecting anode plate.

[0011] The method comprises at least one of the following features (1) to (5);

[0012] (1) The diameter of the corona wire is 0.2 to 0.3 cm;

[0013] (2) The material of the corona wire includes stainless steel;

[0014] (3) The inner radius of the tubular dust collecting anode plate is 1 to 2 cm;

[0015] (4) The length of the tubular dust collecting anode plate is 100 to 300 mm;

[0016] (5) The material of the tubular dust collecting anode plate includes stainless steel or aluminum alloy.

[0017] Furthermore, in the charged dust collecting unit, the center distance between the wire and the corona wire is 0.11 to 0.45 cm;

[0018] And / or, the voltage applied to the charged dust collecting unit is 14 to 55 kV.

[0019] Furthermore, the wire cleaning device further comprises a power supply; the corona wire is connected to the negative electrode of the power supply, and the tubular dust collecting anode plate is connected to the positive electrode of the power supply;

[0020] And / or, the wire cleaning device also includes a conveying unit; the conveying unit includes a pay-off shaft, a tension rod, a first guide wheel, a second guide wheel and a take-up shaft arranged in sequence; the charged dust collection unit is arranged between the first guide wheel and the second guide wheel.

[0021] In a second aspect, the present invention further provides a wire cleaning method, using the wire cleaning device as described above, comprising the following steps:

[0022] The wire material to be cleaned moves in a direction parallel to the corona wire and passes through the charging dust collection unit. After the particles on the surface of the wire material are charged and dust is collected, the cleaned wire material is obtained.

[0023] Furthermore, the following relationship is satisfied: Wherein, U is the DC voltage applied by the power supply between the corona wire and the tubular dust collecting anode plate, in kV; M is the surface roughness coefficient of the wire; δ is the relative density of the gas; a is the radius of the corona wire, in cm; b is the inner radius of the tubular dust collecting anode plate, in cm.

[0024] Furthermore, the following relationship is satisfied: Where x is the center distance between the wire and the corona wire, in cm.

[0025] Furthermore, the following relationship is satisfied: l>v·(t c+t col );where l is the length of the tubular dust collecting anode plate, in meters; t c is the charging time, in seconds; t col is the dust collection time, in seconds; v is the moving speed of the wire, in m / s;

[0026] Where τ is the charging time constant, in seconds; A is the van der Waals Hamaker constant between the particle and the wire; d p is the equivalent diameter of the particle, in m; q s is the saturated charge of the particle, in C; Z is the distance between the particle and the surface of the wire, in m; The unit is kV / cm;

[0027] Where, μ is the air viscosity coefficient, unit is Pa·s; ε 0 is the dielectric constant of vacuum; r is the center distance between the particle and the corona line, in cm.

[0028] Furthermore, the particle size of the particles removed by the wire cleaning method satisfies the following relationship: Where A is the van der Waals Hamaker constant between the particle and the wire; Z is the distance between the particle and the wire surface, in meters; E x is the electric field strength at the wire, in kV / cm; ε 0 is the vacuum dielectric constant, ε r is the relative dielectric constant of the particles.

[0029] In a third aspect, the present invention further provides application of the wire cleaning method as described above in bonding wire cleaning.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The wire cleaning device of the present invention uses a charged dust collection unit to assist electric current to charge the particles on the surface of the wire, and removes the particles on the surface of the wire by electrostatic dust removal, thereby effectively avoiding secondary contamination caused by the contact between the particles and the wire in traditional ultrasonic cleaning.

[0032] 2. The wire cleaning device of the present invention adopts micro-electrostatic dust removal, which can effectively remove particles on the surface of the wire, has high efficiency and good cleaning effect, and is particularly suitable for removing micron-sized particles.

[0033] 3. Compared with the traditional ultrasonic cleaning device, the wire cleaning device of the present invention is more compact, low-cost, and occupies less space. It can be integrated after wire drawing or after the annealing machine. As a final cleaning method, it avoids problems such as wire sticking and abnormal wire release. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 It is a schematic structural diagram of the wire cleaning device of the present invention.

[0036] Figure 2 It is a schematic diagram of corona discharge and charging of the present invention.

[0037] Figure 3 It is the spatial electric field intensity curve of the charged dust collecting unit of the present invention.

[0038] Figure 4 This is a picture of particles adsorbed on the bonding wire surface of the present invention.

[0039] Figure 5 It is the particle dust collection driving speed curve of the present invention.

[0040] Figure 6 It is the particle dust collection time curve of the present invention.

[0041] Figure 7 This is a surface morphology of the uncleaned bonding wire of the present invention.

[0042] Figure 8 This is a surface morphology of the bonding wire after ultrasonic cleaning of the present invention.

[0043] Fig. 9 This is a surface morphology of the bonding wire after cleaning in Example 1 of the present invention.

[0044] Fig.10 This is the spatial electric field strength curve of the charged dust collecting unit of Example 2 of the present invention.

[0045] Fig.11 This is the spatial electric field strength curve of the charged dust collecting unit of Example 3 of the present invention.

[0046] Reference numerals:

[0047] 11-corona wire; 12-tubular dust collecting anode plate; 2-power supply; 3-wire; 41-pay-off shaft; 42-tension wheel; 43-first guide wheel; 44-second guide wheel; 45-take-up shaft; 46-tension rod; 47-servo motor. DETAILED DESCRIPTION

[0048] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0049] A wire cleaning device, method and application of the present invention are described in detail below.

[0050] See also Figure 1 , in some embodiments of the present invention, there is provided a wire cleaning device, comprising a charged dust collecting unit;

[0051] The charged dust collecting unit comprises a corona wire 11 and a tubular dust collecting anode plate 12 , wherein the corona wire 11 is located at the axial center of the tubular dust collecting anode plate 12 .

[0052] The wire cleaning device of the present invention charges the particles on the surface of the wire with the help of electric current, removes the particles on the surface of the wire by electrostatic dust removal, and avoids secondary pollution caused by contact between the particles and the wire. In addition, the device is small and convenient, and can be integrated at the back end of the wire drawing or annealing equipment, with low cost and small footprint.

[0053] The wire cleaning device of the present invention adopts micro-electrostatic field dust removal, which effectively avoids secondary pollution caused by the contact between particles and wires in traditional ultrasonic cleaning.

[0054] The wire cleaning device of the present invention adopts micro-electrostatic dust removal, which can effectively remove particles on the surface of the wire, has high efficiency and good cleaning effect, and is particularly suitable for removing micron-sized particles.

[0055] The wire cleaning device of the present invention is more compact, low-cost, and occupies less space than a traditional ultrasonic cleaning device. It can be integrated after wire drawing or after an annealing machine as a final cleaning method, avoiding problems such as wire sticking and abnormal wire release.

[0056] The wire cleaning device of the present invention is used to clean the wire. In the device, the particles on the surface of the wire are charged and dust is collected. In the charging stage, the gas molecules undergo corona discharge under the action of the high-voltage electric field, thereby generating a large number of free electrons and positive ions, that is, gas ionization. The positive ions are immediately attracted by the corona wire and lose their charge. The free electrons move toward the tubular dust collecting anode plate under the action of the electric field and fill the space between the two poles. When the wire containing particles enters this area, the free electrons meet the particles and attach to the particles to make the particles negatively charged. After the charging stage is over, the dust collection stage begins. During the dust collection process, the electric field force on the particles is greater than the van der Waals force. The particles break away from the adsorption of the wire and move toward the tubular dust collecting anode plate, thereby effectively removing the particles on the surface of the wire.

[0057] In some embodiments of the present invention, the corona wire 11 is coaxial with the tubular dust collecting anode plate 12 .

[0058] In some embodiments of the present invention, the diameter of the corona wire 11 is 0.2-0.3 cm; typically but not limiting, for example, the diameter of the corona wire 11 can be 0.2 cm, 0.25 cm, 0.3 cm, or a range of any two thereof. The diameter of the corona wire adopts the above size, which is small and convenient for integration into wire drawing, annealing and other equipment.

[0059] In some embodiments of the present invention, the material of the corona wire 11 includes stainless steel.

[0060] In some embodiments of the present invention, the cross-sectional shape of the corona wire 11 is circular.

[0061] In some embodiments of the present invention, the length of the corona wire 11 is greater than or equal to the length of the tubular dust collecting anode plate 12, which can ensure that the electric field strength in the length direction of the tubular dust collecting anode plate is consistent and is easy to install.

[0062] In some embodiments of the present invention, the inner radius of the tubular dust collecting anode plate 12 is 1 to 2 cm; typically but not restrictively, for example, the thickness of the tubular dust collecting anode plate 12 can be 1 cm, 1.5 cm, 2 cm or a range of any two thereof.

[0063] The inner radius of the tubular dust collecting anode plate affects the voltage to be applied, the spatial electric field strength, the dust collecting time and the length of the tubular dust collecting anode plate.

[0064] In some embodiments of the present invention, the length of the tubular dust collecting anode plate 12 is 100 to 300 mm; typically but not restrictively, for example, the length of the tubular dust collecting anode plate 12 can be 100 mm, 150 mm, 200 mm, 250 mm, 300 mm or a range of any two thereof.

[0065] The length of the tubular dust collecting anode plate adopts the above dimensions, which is conducive to ensuring the dust collecting efficiency and is convenient for installation and equipment integration.

[0066] In some embodiments of the present invention, the tubular dust collecting anode plate 12 is made of stainless steel or aluminum alloy.

[0067] In some embodiments of the present invention, in the charged dust collecting unit, the center distance between the wire and the corona wire 11 is 0.11 to 0.45 cm; typically but not restrictively, for example, in the charged dust collecting unit, the center distance between the wire and the corona wire 11 can be 0.11 cm, 0.15 cm, 0.20 cm, 0.25 cm, 0.30 cm, 0.35 cm, 0.40 cm, 0.45 cm or a range of any two thereof.

[0068] In some embodiments of the present invention, the voltage applied to the charged dust collecting unit is 14 to 55 kV; typically but not limitatively, for example, the voltage applied to the charged dust collecting unit can be 14 kV, 20 kV, 25 kV, 30 kV, 35 kV, 40 kV, 45 kV, 50 kV, 55 kV or a range of any two thereof.

[0069] In some embodiments of the present invention, the tubular dust collecting anode plate 12 is fixed to the corona wire 11 by screws and nuts; it can be easily disassembled, washed, and dried to avoid secondary pollution and reuse. In some embodiments of the present invention, the corona wire 11 is connected to the negative electrode of the power supply 2, and the tubular dust collecting anode plate 12 is connected to the positive electrode of the power supply 2.

[0070] In some embodiments of the present invention, the tubular dust collecting anode plate 12 is grounded.

[0071] The corona wire of the invention is connected to the negative electrode of the power supply, has high breakdown voltage, strong stability and higher dust removal efficiency for fine particles.

[0072] In some embodiments of the present invention, the power supply 2 includes a DC / DC direct current boost module.

[0073] The DC / DC direct current boost module outputs high-voltage direct current. Specifically, it generates low-voltage pulses through high-frequency oscillation, then boosts the voltage to a predetermined voltage value through a pulse transformer, and then obtains high-voltage direct current through pulse rectification to supply the charged dust collection unit.

[0074] In some embodiments of the present invention, the wire cleaning device also includes a conveying unit; the conveying unit includes a pay-off shaft 41, a tension wheel 42, a first guide wheel 43, a second guide wheel 44 and a take-up shaft 45 arranged in sequence; the charged dust collection unit is arranged between the first guide wheel 43 and the second guide wheel 44; preferably, a tension rod 46 is arranged on the tension wheel 42.

[0075] In some embodiments of the present invention, the conveying unit further includes a servo motor 47 , and the servo motor 47 is connected to the pay-off shaft 41 and the take-up shaft 45 , respectively.

[0076] In some embodiments of the present invention, the pay-off reel 41 and the take-up reel 45 include insulating materials.

[0077] In some embodiments of the present invention, the wire cleaning device further comprises a supporting and fixing module, and the supporting and fixing module is used to fix the charged dust collecting unit.

[0078] In some embodiments of the present invention, a wire cleaning method is provided, using the wire cleaning device described above, comprising the following steps:

[0079] The wire material to be cleaned moves in a direction parallel to the corona wire 11 and passes through the charging dust collecting unit. After the particles on the surface of the wire material are charged and dust is collected, the cleaned wire material is obtained.

[0080] In some embodiments of the present invention, the input voltage of the input end of the power supply 2 is 12-24V, which can ensure the safety of personnel.

[0081] In some embodiments of the present invention, the DC voltage U applied by the power supply 2 between the corona wire 11 and the tubular dust collecting anode plate 12 satisfies the following relationship:

[0082] Wherein, U is the DC voltage applied by the power supply between the corona wire and the tubular dust collecting anode plate, in kV; M is the surface roughness coefficient of the corona wire; δ is the relative density of the gas; a is the radius of the corona wire, in cm; b is the inner radius of the tubular dust collecting anode plate, in cm.

[0083] According to the Pico empirical formula, the electric field strength at the beginning of the corona is Among them, E c is the initial electric field strength of the corona, kV / cm; δ is the relative density of the gas; M is the surface roughness coefficient of the corona wire, and for a smooth wire M=1; a is the radius of the corona wire, cm.

[0084] For example, the radius of the corona wire is a = 0.1 cm, M is 1, and δ is 1, then E c It is 58kV / cm.

[0085] Spatial electric field strength of charged dust collection unit Among them, E ris the electric field strength in space, kV / cm; U is the DC voltage applied by the power supply between the corona wire and the tubular dust collecting anode plate, kV; r is the distance between the particle and the center of the corona wire, cm; b is the inner radius of the tubular dust collecting anode plate, cm; a is the radius of the corona wire, cm; the settings of U, b and a should ensure that the electric field strength E generated on the surface of the corona wire a Greater than E c , causing the air near the corona line to ionize; that is kV.

[0086] For example, for a=0.1 cm, b=1 cm, M=1, δ=1, U>13.4 kV can meet the corona discharge requirements.

[0087] In some embodiments of the present invention, the center distance x between the wire and the corona wire 11 satisfies the following relationship:

[0088] Wherein, x is the center distance between the wire and the corona wire, in cm; U is the DC voltage applied by the power supply between the corona wire and the tubular dust collecting anode plate, in kV; δ is the relative density of the gas; M is the surface roughness coefficient of the corona wire; b is the inner radius of the tubular dust collecting anode plate, in cm; a is the radius of the corona wire, in cm.

[0089] In order to avoid the air gap between the wire and the corona wire being punctured and burning the wire, the wire should be located outside the corona zone. In order to ensure that the particles on the surface of the wire are effectively charged, the wire should be as close to the corona wire as possible. Therefore, the center distance between the wire and the corona wire is

[0090] For example, U is 25kV, and the spatial electric field strength curve of the charged dust collection unit is as follows: Figure 3 As shown. Since the initial corona intensity is 58kV / cm, gas ionization occurs in the area where the electric field intensity is greater than this value, and the electric field intensity on the surface of the corona wire reaches the strongest, about 109kV / cm. Therefore, the corona zone is the range from the surface of the corona wire to the initial corona intensity, that is, the space range of 0.1 to 0.19cm from the center of the corona wire; the wire material can be arranged at 0.2cm to 0.3cm from the center of the corona wire, and the corresponding electric field intensity is 55 to 43kV / cm.

[0091] See also Figure 2 During the charging process, there is an electrostatic field E in the corona region that is sufficient to partially ionize the gas. rThis electric field causes the gas molecules to undergo corona discharge under the action of the high voltage electric field, thereby generating a large number of free electrons and positive ions, i.e., gas ionization. The positive ions are immediately attracted by the corona wire 11 and lose their charge, and the free electrons move toward the tubular dust collecting anode plate 12 under the action of the electric field, filling the space between the two poles. When the wire material 3 containing particles enters this area, the free electrons meet the particles, attach to the particles, and make the particles negatively charged.

[0092] In some embodiments of the present invention, the length l of the tubular dust collecting anode plate 12 satisfies the following relationship:

[0093] l>v·(t c +t col );where l is the length of the tubular dust collecting anode plate, in meters; t c is the charging time, in seconds; t col is the dust collection time, in seconds; v is the moving speed of the wire, in m / s;

[0094] Where τ is the charging time constant, in seconds; A is the van der Waals Hamaker constant between the particle and the wire; d p is the equivalent diameter of the particle, in m; q s is the saturated charge of the particle, in C; Z is the distance between the particle and the surface of the wire, in m; The unit is kV / cm;

[0095] Where, μ is the air viscosity coefficient, in Pa·s; b is the inner radius of the tubular dust collecting anode plate, in cm; a is the radius of the corona wire, in cm; ε 0 is the dielectric constant of vacuum; d p is the equivalent diameter of the particle, in m; U is the DC voltage applied by the power supply between the corona wire and the tubular dust collecting anode plate, in kV; x is the center distance between the wire and the corona wire, in cm; r is the distance between the particle and the center of the corona wire, in cm.

[0096] See also Figure 4 , the particle size of the surface of wire materials, such as bonding wires, is usually 2 to 10 μm. After the wire materials enter the charged area, the particles are charged by the electric field. On the one hand, the charged particles are adsorbed on the surface of the wire materials by the van der Waals force of the wire materials, and on the other hand, they are directed to the tubular dust collecting anode plate by the electric field force.

[0097] In some embodiments of the present invention, the particle size of the particles removed by the wire cleaning method satisfies the following relationship: Where, d pis the equivalent diameter of the particle, in m; A is the van der Waals Hamaker constant between the particle and the wire; Z is the distance between the particle and the wire surface, in m; E x is the electric field strength at the wire, in kV / cm; ε 0 is the vacuum dielectric constant, ε r is the relative dielectric constant of the particles.

[0098] For the adhesion of dust particles, van der Waals forces play a dominant role. Where A is the van der Waals Hamaker constant between the dust particles and the wire, which is on the order of 10 -20 J;d p is the equivalent diameter of the particle; Z is the distance between the particle and the surface of the wire. The van der Waals force usually works in the range of 0.4 to 10 nm. When Z = 0.4 nm, the van der Waals force is the largest and the particle is the most stable.

[0099] Electric force F e =q p E x ; Among them, E x is the electric field strength at the location of the wire, kV / cm; q p is the particle charge, q p It's about time. q s is the particle saturation charge, C; Among them, ε r is the relative dielectric constant of the particle, usually ranging from 2 to 8, and 5 is taken here; ε 0 is the vacuum dielectric constant, ε 0 =8.85×10 -12 C 2 / N·m;d p is the equivalent diameter of the particle, m; τ is the charging time constant, s; Among them, N 0 is the ion density, ions / m 3 ; e is the electron charge, e = 1.6 × 10 -19 C; K is the ion mobility, m 2 / s·V;t c is the charging time, s; when t = t c When the particle charge F e =F v , the charging phase ends, then The particle charge The minimum particle size requirement F for dust collection can be achieved e =q s E x >Fv ,Right now

[0100] For example, for x = 0.2 cm, a = 0.1 cm, b = 1 cm, U = 25 kV, Z = 0.4 nm, ε r =5,d pmin =1.9μm.

[0101] Atmospheric temperature conditions N 0 The typical value distribution of K is N 0 =5×10 14 pcs / m 3 , K = 2.2 × 10 -4 m 2 / (s·V), then the charging time constant τ=0.002s; when time t c =τ, the particle charge is half of the saturation charge.

[0102] For example, for x = 0.2 cm, a = 0.1 cm, b = 1 cm, d p =1.9μm, U=25kV, Z=0.4nm, ε r =5, when t=t c = 0.047s, the particle charge q p =1.161×10 -15 C;

[0103] For x = 0.2 cm, a = 0.1 cm, b = 1 cm, d p =3μm, U=25kV, Z=0.4nm, ε r =5, when t=t c = 0.0034s, the particle charge q p =1.833×10 -15 C, at this time F e =F v .

[0104] When t>t c , F e >F v , the particles will get rid of the adsorption of the wire material and move toward the tubular dust collecting anode plate, and the particles will enter the dust collecting stage; during the dust collecting process, the particles are affected by the drag force of the air and the electric field force.

[0105] Drag force F D =3πμd p ω; drag force prevents particles from flying toward the tubular dust collecting anode plate; where μ is the air viscosity coefficient, usually 17.9×10 -6 Pa·s; ω is the speed at which particles approach the tubular dust collecting anode plate, m / s; electric field force F e =qp E r , assuming that air is a Newtonian fluid, then Where m is the particle mass; t col is the dust collection time; in, Very small and can be ignored. In an electric field, the speed at which charged particles approach The driving speed is related to the distance r between the particle and the center of the corona wire. The particle dust collection driving speed curve is as follows: Figure 5 shown.

[0106] The time required for particles to be collected by the tubular dust collecting anode plate Particle collection time curve Figure 6 shown.

[0107] During the dust collection stage, the particles move at a certain speed v in the direction of the wire. Therefore, in order to complete the particle charging and dust collection in the charged dust collection unit, the length of the tubular dust collection anode plate l>v·(t c +t col ).

[0108] For x = 0.2 cm, a = 0.1 cm, b = 1 cm, d p =1.9μm, U=25kV, t c =47ms, t col =3.97ms, for v = 1.5m / s, l>0.0765m;

[0109] For x = 0.2 cm, a = 0.1 cm, b = 1 cm, d p =3μm, U=25kV, t col =2.45ms, for v=1.5m / s, l>0.0088m.

[0110] In some embodiments of the present invention, the radius a of the corona wire 11 is 0.1 to 0.15 cm; the inner radius b of the tubular dust collecting anode plate 12 is 1 to 2 cm; the applied voltage U is related to the values ​​of a and b, for b = 1 cm, U is 14 to 26 kV, for b = 2 cm, U is 19 to 55 kV; the values ​​of a, b, and U will also affect the value of the center distance x between the wire and the corona wire 11, and the value range of x is 0.11 to 0.45 cm; the minimum clean dust particle size d pminIt is also affected by the values ​​of the above four key parameters, with a value range of 1.9 to 7.2 μm, indicating that dust particles above this value in micrometers can be clearly seen; considering the values ​​of the above key parameters and the convenience of equipment integration and installation, the moving speed of the wire is controlled at 0.1 to 3 m / s; the length l of the tubular dust collecting anode plate 12 is 100 to 300 mm.

[0111] In some embodiments of the present invention, specific parameter settings in the wire cleaning method are shown in Table 1.

[0112] Table 1

[0113]

[0114] See also Figure 1 In some embodiments of the present invention, the wire ends are drawn out from the pay-off shaft 41, and sequentially pass through the tension wheel 42, the first guide wheel 43, the charged dust collection unit, the second guide wheel 44, and wrap around the take-up shaft 45 to stick the wire ends on the take-up shaft 45; the shafts are installed, the DC power supply is turned on, the pay-off shaft 41 and the take-up shaft 45 rotate synchronously driven by the servo motor 47, and the take-up shaft 45 also reciprocates back and forth, so that the wires pass through the charged dust collection system, the particles are charged in the system and separated from the surface of the wires under the action of the electric field force, and adsorbed on the dust collection plate, and the cleaned wires are gradually wound on the take-up shaft 45 and arranged evenly. During the winding process of the wires, the tension rod 46 provides the winding tension.

[0115] In some embodiments of the present invention, the wire is appropriately tensioned during the movement, and for a wire with a diameter of 18 to 30 μm, the wire tension is 1.2 to 3 gf.

[0116] In some embodiments of the invention, the wire material comprises a bonding wire.

[0117] In some embodiments of the present invention, application of the above-mentioned wire cleaning method in bonding wire cleaning is also provided.

[0118] Example 1

[0119] See also Figure 1 , the bonding wire cleaning device provided in this embodiment includes a charged dust collection unit, a power supply and a conveying unit;

[0120] The charged dust collecting unit comprises a corona wire 11 and a tubular dust collecting anode plate 12, wherein the corona wire 11 is located at the axial center of the tubular dust collecting anode plate 12; the corona wire 11 is coaxial with the tubular dust collecting anode plate 12; the radius a of the corona wire 11 is 0.1 cm, the length is 120 mm, and the material is stainless steel; the thickness of the tubular dust collecting anode plate 12 is 2 mm, the inner radius b is 1 cm, and the length l is 100 mm;

[0121] The corona wire 11 is connected to the negative electrode of the power source 2, and the tubular dust collecting anode plate 12 is connected to the positive electrode of the power source 2 and is grounded;

[0122] The power supply 2 includes a DC / DC direct current boost module;

[0123] The conveying unit includes a pay-off shaft 41, a tension wheel 42, a first guide wheel 43, a second guide wheel 44 and a take-up shaft 45 which are arranged in sequence; the charged dust collecting unit is arranged between the first guide wheel 43 and the second guide wheel 44; a tension rod 46 is arranged on the tension wheel 42; the pay-off shaft 41 is connected to a servo motor 47; and the take-up shaft 45 is connected to the servo motor 47.

[0124] The bonding wire cleaning method provided in this embodiment uses the bonding wire cleaning device described above and includes the following steps:

[0125] The wire ends are led out from the pay-off shaft 41, and pass through the tension wheel 42, the first guide wheel 43, the charged dust collection unit, the second guide wheel 44 in sequence, and are pasted on the take-up shaft 45 by wrapping around the take-up shaft 45. After the shafts are installed, the DC power supply is turned on, and the pay-off shaft 41 and the take-up shaft 45 rotate synchronously driven by the servo motor 47. At the same time, the take-up shaft 45 also reciprocates back and forth, so that the annealed bonding wire with a diameter of 18 to 30 μm moves at a moving speed (v) of 1.5 m / s under a wire tension of 1.2 to 3 gf in a direction parallel to the corona wire 11 and passes through the charged dust collection unit. After the particles on the surface of the bonding wire are charged and dusted, a clean bonding wire is obtained. The cleaned wire is gradually wound on the take-up shaft 45 and arranged evenly.

[0126] The DC voltage (U) supplied by the power supply 2 between the corona wire 11 and the tubular dust collecting anode plate 12 is 25 kV; in the charged dust collecting unit, the electric field strength on the surface of the corona wire 11 is 109 kV / cm, which is higher than the initial electric field strength (E c 58kV / cm), which meets the requirements of corona discharge, thereby generating a large number of free electrons and positive ions, that is, gas ionization, and the spatial electric field strength is as follows Figure 3 As shown;

[0127] In the charged dust collection unit, the bonding wire is parallel to the corona wire 11, the bonding wire is on the horizontal side of the corona wire 11, and the center distance (x) between the bonding wire and the corona wire 11 is 0.2 cm; at this time, the bonding wire is located outside the corona area to prevent the air gap between the bonding wire and the corona wire from being punctured and burning the bonding wire, while ensuring that the particles on the surface of the bonding wire are effectively charged;

[0128] In the charged dust collection unit, positive ions in the space are immediately attracted by the corona wire and lose their charge. Free electrons move toward the tubular dust collecting anode plate under the action of the electric field and fill the space between the two poles. When free electrons collide with particles on the surface of the bonding wire, they attach to the particles and make them negatively charged. Figure 3As shown; at this time, the particles are subject to van der Waals attraction and electric field repulsion; under atmospheric temperature conditions, N 0 The typical value distribution of K is N 0 =5×10 14 pcs / m 3 , K = 2.2 × 10 -4 m 2 / (s·V), then the charging time constant τ=0.002s; when time t c =τ, the particle charge is half of the saturation charge; for x = 0.2cm, a = 0.1cm, b = 1cm, d pmin =1.9μm, U=25kV, Z=0.4nm, ε r =5, when t=t c =0.047s, the charge q p =1.161×10 -15 C, the charging stage ends;

[0129] When t>t c When F e >F v , the particles will get rid of the bonding wire adsorption and move toward the tubular dust collecting anode plate. Particles with a diameter of 1.9μm or more will enter the dust collecting stage. During the dust collecting process, the particles are affected by the drag force and electric field force of the air. The particle driving speed is as follows: Figure 5 As shown; for x = 0.2cm, a = 0.1cm, b = 1cm, d pmin =1.9μm, U=25kV, t c =47ms, t col =3.97ms, for v = 1.5m / s, l>0.0765m, therefore, l = 100mm can meet the dust collection 1.9μm (d pmin ) or above particle size is required.

[0130] The bonding wire cleaning method of this embodiment can clean the bonding wire of 1.9 μm (d pmin ) and above particles can be effectively removed.

[0131] Cleaning effect:

[0132] The surface morphologies of the bonding wires that were not cleaned, the bonding wires that were ultrasonically cleaned, and the bonding wires that were cleaned in Example 1 are shown in FIG. Figure 7 , Figure 8 and Fig. 9 As shown. Figure 7 to Figure 9 It can be seen that the surface of the uncleaned bonding wire is covered with a large number of black particles with a particle size of 2 to 10 μm, the surface of the bonding wire after ultrasonic cleaning has a small amount of particles, and the surface of the bonding wire after cleaning by the bonding wire cleaning method of Example 1 has no black particles, and the cleaning effect is the best.

[0133] Example 2

[0134] The bonding wire cleaning device provided in this embodiment includes a charged dust collection unit, a power supply and a conveying unit;

[0135] The charged dust collecting unit comprises a corona wire 11 and a tubular dust collecting anode plate 12, wherein the corona wire 11 is located at the axial center of the tubular dust collecting anode plate 12; the corona wire 11 is coaxial with the tubular dust collecting anode plate 12; the radius a of the corona wire 11 is 0.15 cm, the length is 180 mm, and the material is stainless steel; the thickness of the tubular dust collecting anode plate 12 is 2 mm, the inner radius b is 2 cm, and the length l is 150 mm;

[0136] The corona wire 11 is connected to the negative electrode of the power source 2, and the tubular dust collecting anode plate 12 is connected to the positive electrode of the power source 2 and is grounded;

[0137] The power supply 2 includes a DC / DC direct current boost module;

[0138] The conveying unit includes a pay-off shaft 41, a tension wheel 42, a first guide wheel 43, a second guide wheel 44 and a take-up shaft 45 which are arranged in sequence; the charged dust collecting unit is arranged between the first guide wheel 43 and the second guide wheel 44; a tension rod 46 is arranged on the tension wheel 42; the pay-off shaft 41 is connected to a servo motor 47; and the take-up shaft 45 is connected to the servo motor 47.

[0139] The bonding wire cleaning method provided in this embodiment uses the bonding wire cleaning device described above and includes the following steps:

[0140] The wire ends are led out from the pay-off shaft 41, and pass through the tension wheel 42, the first guide wheel 43, the charged dust collection unit, the second guide wheel 44 in sequence, and are pasted on the take-up shaft 45 by wrapping around the take-up shaft 45. After the shafts are installed, the DC power supply is turned on, and the pay-off shaft 41 and the take-up shaft 45 rotate synchronously driven by the servo motor 47. At the same time, the take-up shaft 45 also reciprocates back and forth, so that the annealed bonding wire with a diameter of 18 to 30 μm moves at a moving speed (v) of 2 m / s under a wire tension of 1.2 to 3 gf in a direction parallel to the corona wire 11 and passes through the charged dust collection unit. After the particles on the surface of the bonding wire are charged and dusted, a clean bonding wire is obtained. The cleaned wire is gradually wound on the take-up shaft 45 and arranged evenly.

[0141] The DC voltage (U) supplied by the power supply 2 between the corona wire 11 and the tubular dust collecting anode plate 12 is 22 kV; in the charged dust collecting unit, the electric field strength on the surface of the corona wire 11 is 56.6 kV / cm, which is higher than the initial electric field strength (E c 53.2kV / cm), which meets the requirements of corona discharge, thereby generating a large number of free electrons and positive ions, that is, gas ionization, and the spatial electric field strength is as follows Fig.10 As shown;

[0142] In the charged dust collection unit, the bonding wire is parallel to the corona wire 11, the bonding wire is on the horizontal side of the corona wire 11, and the center distance (x) between the bonding wire and the corona wire 11 is 0.17 cm; at this time, the bonding wire is located outside the corona area, avoiding the air gap between the bonding wire and the corona wire from being broken down and burning the bonding wire, while ensuring the effective charging of particles on the surface of the bonding wire;

[0143] In the charged dust collection unit, positive ions in the space are immediately attracted by the corona wire and lose their charge. Free electrons move toward the tubular dust collecting anode plate under the action of the electric field and fill the space between the two poles. When free electrons collide with particles on the surface of the bonding wire, they attach to the particles and make them negatively charged. For x = 0.17 cm, a = 0.1 cm, b = 2 cm, d pmin =2.4μm, U=22kV, Z=0.4nm, ε r =5, when t=t c =26.6ms, the charge q p =1.594×10 -15 C, the charging stage ends; when t>t c When F e >F v , the particles will get rid of the bonding wire adsorption and move to the tubular dust collecting anode plate. The particles with a diameter of 2.4μm or more will enter the dust collecting stage. During the dust collecting process, the particles are affected by the drag force and electric field force of the air. For x = 0.17cm, a = 0.1cm, b = 2cm, d pmin =2.4μm, U=22kV, t c =26.6ms, t col =43.6ms, for v = 2m / s, l>0.1403m, therefore, l = 150mm can meet the dust collection 2.4μm (d pmin The bonding wire cleaning method of this embodiment can be used for particles with a diameter of 2.4 μm (d pmin ) and above particles can be effectively removed.

[0144] Example 3

[0145] The bonding wire cleaning device provided in this embodiment includes a charged dust collection unit, a power supply and a conveying unit;

[0146] The charged dust collecting unit includes a corona wire 11 and a tubular dust collecting anode plate 12, wherein the corona wire 11 is located at the axial center of the tubular dust collecting anode plate 12; the corona wire 11 is coaxial with the tubular dust collecting anode plate 12; the radius a of the corona wire 11 is 0.15 cm, the length is 180 mm, and the material is stainless steel; the thickness of the tubular dust collecting anode plate 12 is 2 mm, the inner radius b is 1 cm, and the length l is 150 mm;

[0147] The corona wire 11 is connected to the negative electrode of the power source 2, and the tubular dust collecting anode plate 12 is connected to the positive electrode of the power source 2 and is grounded;

[0148] The power supply 2 includes a DC / DC direct current boost module;

[0149] The conveying unit includes a pay-off shaft 41, a tension wheel 42, a first guide wheel 43, a second guide wheel 44 and a take-up shaft 45 which are arranged in sequence; the charged dust collecting unit is arranged between the first guide wheel 43 and the second guide wheel 44; a tension rod 46 is arranged on the tension wheel 42; the pay-off shaft 41 is connected to a servo motor 47; and the take-up shaft 45 is connected to the servo motor 47.

[0150] The bonding wire cleaning method provided in this embodiment uses the bonding wire cleaning device described above and includes the following steps:

[0151] The wire ends are led out from the pay-off shaft 41, and pass through the tension wheel 42, the first guide wheel 43, the charged dust collection unit, the second guide wheel 44 in sequence, and are pasted on the take-up shaft 45 by wrapping around the take-up shaft 45. After the shafts are installed, the DC power supply is turned on, and the pay-off shaft 41 and the take-up shaft 45 rotate synchronously driven by the servo motor 47. At the same time, the take-up shaft 45 also reciprocates back and forth, so that the bonding wire with a diameter of 18 to 30 μm after annealing is moved from the pay-off shaft in a direction parallel to the corona wire 11 at a moving speed (v) of 2 m / s under a wire tension of 1.2 to 3 gf and passes through the charged dust collection unit. After charging and collecting dust on the surface of the bonding wire, the cleaned bonding wire is obtained. The cleaned wire is gradually wound on the take-up shaft 45 and arranged evenly.

[0152] The DC voltage (U) supplied by the power supply 2 between the corona wire 11 and the tubular dust collecting anode plate 12 is 16 kV; in the charged dust collecting unit, the electric field strength on the surface of the corona wire 11 is 56.2 kV / cm, which is higher than the initial electric field strength (E c 53.2kV / cm), which meets the requirements of corona discharge, thereby generating a large number of free electrons and positive ions, that is, gas ionization, and the spatial electric field strength is as follows Fig.11 As shown;

[0153] In the charged dust collection unit, the bonding wire is parallel to the corona wire 11, the bonding wire is on the horizontal side of the corona wire 11, and the center distance (x) between the bonding wire and the corona wire 11 is 0.16 cm; at this time, the bonding wire is located outside the corona area, avoiding the air gap between the bonding wire and the corona wire from being broken down and burning the bonding wire, while ensuring the effective charging of particles on the surface of the bonding wire;

[0154] In the charged dust collection unit, positive ions in the space are immediately attracted by the corona wire and lose their charge. Free electrons move toward the tubular dust collecting anode plate under the action of the electric field and fill the space between the two poles. When free electrons collide with particles on the surface of the bonding wire, they attach to the particles and make them negatively charged. For x = 0.16 cm, a = 0.15 cm, b = 1 cm, d pmin =2.1μm, U=16kV, Z=0.4nm, ε r =5, when t=t c =42.2ms, the charge q p =1.322×10 -15 C, the charging stage ends; when t>t c When F e >F v , the particles will get rid of the bonding wire adsorption and move to the tubular dust collecting anode plate. Particles with a diameter of more than 2.1μm will enter the dust collecting stage. During the dust collecting process, the particles are affected by the drag force and electric field force of the air. For x = 0.16cm, a = 0.1cm, b = 2cm, d pmin =2.1μm, U=16kV, t c =42.2ms, t col =6.3ms, for v=3m / s, l>0.1456m, therefore, l=150mm can meet the dust collection of 2.1μm (d pmin The bonding wire cleaning method of this embodiment can be used for particles with a diameter of 2.1 μm (d pmin ) and above particles can be effectively removed.

[0155] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wire cleaning device, characterized in that: Including a charged dust collection unit; The charged dust collecting unit comprises a corona wire and a tubular dust collecting anode plate, wherein the corona wire is located at the axial center of the tubular dust collecting anode plate.

2. The wire cleaning device according to claim 1, characterized in that: The method comprises at least one of the following features (1) to (5); (1) The diameter of the corona wire is 0.2 to 0.3 cm; (2) The material of the corona wire includes stainless steel; (3) The inner radius of the tubular dust collecting anode plate is 1 to 2 cm; (4) The length of the tubular dust collecting anode plate is 100 to 300 mm; (5) The material of the tubular dust collecting anode plate includes stainless steel or aluminum alloy.

3. The wire cleaning device according to claim 2, characterized in that: In the charged dust collecting unit, the center distance between the wire and the corona wire is 0.11 to 0.45 cm; And / or, the voltage applied to the charged dust collecting unit is 14 to 55 kV.

4. The wire cleaning device according to claim 3, characterized in that: The wire cleaning device further comprises a power supply; the corona wire is connected to the negative electrode of the power supply, and the tubular dust collecting anode plate is connected to the positive electrode of the power supply; And / or, the wire cleaning device also includes a conveying unit; the conveying unit includes a pay-off shaft, a tension wheel, a first guide wheel, a second guide wheel and a take-up shaft arranged in sequence; the charged dust collection unit is arranged between the first guide wheel and the second guide wheel.

5. A wire cleaning method, characterized in that: The wire cleaning device according to any one of claims 1 to 4 comprises the following steps: The wire material to be cleaned moves in a direction parallel to the corona wire and passes through the charging dust collection unit. After the particles on the surface of the wire material are charged and dust is collected, the cleaned wire material is obtained.

6. The wire cleaning method according to claim 5, characterized in that: The following relationship is satisfied: Wherein, U is the DC voltage applied by the power supply between the corona wire and the tubular dust collecting anode plate, in kV; M is the surface roughness coefficient of the corona wire; δ is the relative density of the gas; a is the radius of the corona wire, in cm; b is the inner radius of the tubular dust collecting anode plate, in cm.

7. The wire cleaning method according to claim 6, characterized in that: The following relationship is satisfied: Where x is the center distance between the wire and the corona wire, in cm.

8. The wire cleaning method according to claim 7, characterized in that: Satisfies the following relationship: l>v·(t c +t col );wherein, l is the length of the tubular dust collecting anode plate, in meters; t c is the charging time, in seconds; t col is the dust collection time, in seconds; v is the moving speed of the wire, in m / s; Where τ is the charging time constant, in seconds; A is the van der Waals Hamaker constant between the particle and the wire; d p is the equivalent diameter of the particle, in m; q s is the saturated charge of the particle, in C; Z is the distance between the particle and the surface of the wire, in m; The unit is kV / cm; Where μ is the air viscosity coefficient, in Pa·s; ε0 is the vacuum dielectric constant; r is the distance between the particle and the center of the corona line, in cm.

9. The wire cleaning method according to claim 8, characterized in that: The particle size of the particles removed by the wire cleaning method satisfies the following relationship: Where A is the van der Waals Hamaker constant between the particle and the wire; Z is the distance between the particle and the wire surface, in meters; E x is the electric field strength at the wire, in kV / cm; ε0 is the vacuum dielectric constant, ε r is the relative dielectric constant of the particles.

10. Use of the wire cleaning method according to any one of claims 5 to 9 in bonding wire cleaning.

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