JPS62235498A - Barrel plating method for electronic parts - Google Patents

Abstract

PURPOSE:To form plated layers of a uniform thickness on rough bodies by putting the rough bodies, regulators having a lower specific gravity and a larger size then the rough bodies and electron absorbing bodies made of an anionic conductive metal in a barrel, rotating the barrel and carrying out plating. CONSTITUTION:Many rough bodies 7 to be plated, many regulators (ceramic balls) 10 having a lower specific gravity and a larger size than the rough bodies 7 and many electron absorbing bodies 9 which are electrically conductive small balls smaller than the rough bodies 7 are simultaneously put in a barrel 4. The barrel 4 is immersed in a plating soln. 1 in a plating tank 2 and rotated. Electric current is then supplied between a cathode lead 3 and a metallic anode 5 to plate the rough bodies 7. At this time, the regulators 10, the rough bodies 7 and the electron absorbing bodies 9 are liable to form upper, middle and lower layers, respectively. Since the regulators 10 press down the rough bodies 7 into the layer of the electron absorbing bodies 9, the rough bodies 7 are uniformly provided with minus potential by more frequent contact with the electron absorbing bodies 9. Accordingly, plated layers of a uniform thickness can be formed on the rough bodies 7.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a barrel plating method for electronic components, and more particularly to an improved method for forming a plating layer of uniform and appropriate thickness on the surfaces of a large number of electronic components loaded into a barrel.

[Conventional technology]

Electrode plating of electronic components such as chip resistors is performed by a barrel plating method using a barrel plating device. That is, a large number of elements to be plated are placed in a barrel along with a large number of electricity absorbers made of conductive metal balls, commonly called dummies, and are rotated in a plating solution while being placed inside the barrel. This is done by energizing for a predetermined period of time between the introduced cathode lead and the metal anode placed outside the barrel. The metal melted and ionized from the metal anode is deposited on the surface of each element body to which a negative potential is applied via the cathode lead or dummy, forming a plating layer. Here, the dummy plays the role of an electrical path for uniformly applying a negative potential to all of the numerous element bodies distributed within the barrel from the point cathode lead.

[Problems to be solved by the invention]

It is generally said that plating growth occurs on the surface layer (upper layer) inside the barrel, but in the barrel plating method described above, the specific gravity of the ceramic body and the metal dummy is Even if the barrel rotates, the tendency for the dummy group and the elementary body group to separate and form a layer will not be lost. Therefore, there is a problem in that the agitation condition between the upper and lower parts of the barrel deteriorates, resulting in large variations in the thickness of the plating layer formed on the element body. Furthermore, when electrodes of a chip resistor are formed by plating, even if the plating solution concentration and current application time are the same, the thickness of the plating layer formed thereon differs due to the difference in resistance value. Therefore, in order to plate electrodes of a constant thickness on the elements of chip resistors having different resistance values, it is necessary to change the concentration of the plating solution, or change the energization time or the energization current value. However, it is extremely troublesome to make such adjustments in existing barrel plating equipment.
It also requires skill and is not suitable for automation. This invention was devised under the above circumstances, and it is possible to form a plating layer with little variation in thickness on the surfaces of a large number of element bodies that are put into the barrel, and, An object of the present invention is to provide an improved barrel plating method for electronic components so that a plating layer of uniform thickness can be formed by a simple procedure even if the resistance values of the input elements differ.

[Means to solve the problem]

In order to solve the above problem, the first invention method of the present application takes the following technical measures. In other words, in the barrel of a barrel plating device, there are a large number of elements on which plating layers are to be formed, and a material having a specific gravity equal to or less than that of the elements, and a size equal to or larger than the elements. A large number of regulators and a large number of metal current absorbers that conduct anions in the barrel are inserted. When a conductive coating is applied to the surface of the adjustment body, the effects of the present invention are further enhanced. In the second invention method of the present application, in the barrel of the barrel plating device, there are a large number of element bodies on which plating layers are to be formed, and the element bodies have a specific gravity equal to or less than that of the element bodies and have a size. It is equipped with a large number of adjustment bodies that are equal to or greater than the base body and have conductive coatings on their surfaces.

[Effect]

The adjustment body has a specific gravity equal to or smaller than the element body, and an outer shape equal to or larger than the element body, so
When the element is put into the barrel together with the element and the barrel is rotated, the adjustment layer tends to be positioned above the element layer. When the element body and adjustment body are circulated in the barrel while maintaining this tendency, the adjustment body has the effect of causing the element body to sink into the metal electric absorber layer forming a layer below it. to do. In addition, when applying a conductive coating to the above adjustment body,
Since the adjustment body itself absorbs ions, the area to be electrodeposited increases and the plating thickness of the element body is suppressed.

【effect】

Therefore, by using the adjusting body to push the element layer located in the upper part into the lower part and improving the agitation inside the barrel, it is possible to reduce the variation in plating thickness.
The thickness can be adjusted. Further, since the ion absorption effect can be changed by changing the amount of the adjusting body added, the thickness of the plating layer can be substantially adjusted by changing the amount of the adjusting body added relative to the amount of the element body. For example, in order to make the plating layer thickness uniform when the resistance value of the element body is different, it was conventionally necessary to adjust the current value or the energization time, but according to the present invention, the resistance value of the element body By adjusting the amount of regulator added to the amount of element, it is possible to control the energizing current value or energizing time without changing these.
A plating layer of uniform thickness can be formed.

[Explanation of Examples]

Embodiments of the present invention will be specifically described below with reference to the drawings. The barrel plating device 6 stores the plating solution 1 [
2 and inside this plating tank 2? + 'tR and rotates a perforated barrel 4. Usually this barrel 4
is adapted to be removably attached to an electrode saddle provided at the edge of the plating tank 2, and a cathode lead 3 electrically connected to the electrode saddle is introduced into the barrel 4. Further, the metal anode 5 is immersed in the plating solution l outside the barrel 4. The electrode saddle and metal anode 5 are connected to negative and negative terminals of a rectifier (not shown). In the plating method of the present invention, a large number of element bodies 7 on which plating layers are to be formed, and a large number of current absorbers 9 made of conductive small balls smaller than the element bodies 7 are placed in the barrel 4, A large number of adjusting bodies 10 having a smaller specific gravity and a larger external shape than the element body 7 are simultaneously introduced, and they are immersed and rotated in the plating tank 2, and electricity is applied between the cathode lead 3 and the metal anode 5. Do by doing. When plating the electrodes of a chip resistor, as shown in FIG. Or after carrying out the step of applying Cu (copper) protective plating [13], Sn/Pb
(solder) or Sn (tin) based plating N14 is applied. Therefore, a chip on which an internal electrode coating of Ag/Pd is formed, or one further coated with Ni or Sn coating, becomes the element body in the present invention. In addition, adjustment body 1
0, since the chip resistor is based on a ceramic substrate, it is preferable to use a ceramic ball. As shown in FIG. 1, when the barrel into which the element body 7, the adjustment body 10, and the electricity absorber 9 are simultaneously charged is rotated, the layer of the adjustment body 10, the bottom of the element body 7, and the electricity absorption body 9 are arranged in order from above. There is a tendency for layers to form. This is because the adjustment body 10 has a larger external shape and a smaller specific gravity than the element body 7, and the electric absorber 9 is made of a metal ball and has a larger specific gravity than the element body 7 and a smaller outer shape than the element body. When the barrel 4 is rotated, the adjustment body 10, the element body 7, and the electricity absorber 9 are each circulated and agitated while maintaining the above-mentioned tendency. 7 into the layer of the electric absorber 9, the chance of the element body 7 coming into contact with the electric absorber 9 increases, and a negative potential is applied uniformly, and as a result, the element body in various parts of the element layer Variations and unevenness in the thickness of the plating layer No. 7 can be avoided. Furthermore, the degree of ion absorption effect produced by applying a conductive coating to the regulating body 10 changes depending on the amount of the regulating body 10 added, so even if the energization time and the amount of current are constant, the amount of the regulating body 10 charged As a result, the thickness of the plating layer can be adjusted, making the plating layer uniform, and increasing the effects of the present invention. For example, in the case of a chip resistor, when plating something with a small resistance value, increase the amount of regulator used, and conversely, when plating something with a large resistance value, reduce the amount of regulator used. Accordingly, the thickness of the plating layer can be made uniform. As described above, the barrel plating method for electronic devices of the present invention not only reduces the variation in the thickness of the plating layer formed on the elements that are loaded in large numbers and maintains a constant product quality, but also improves the energizing device of the barrel plating device. The plating layer thickness can be substantially adjusted without the need for troublesome operations such as adjusting the plating layer thickness. Furthermore, when applying a conductive coating to the adjusting body 10, it is possible to omit adding the metal-based electricity absorbing body 9. That is, the adjusting body 10 itself serves as an electrical path from the cathode lead to the element body, and also improves agitation inside the barrel, thereby making it possible to form a plating layer with less variation in thickness on the element body. It is. In this case, the total weight of the contents of the barrel becomes very small, making handling convenient.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a chip resistor as an element body. 4...barrel, 6...barrel plating equipment, ? ...
Element body, 8... Plated layer, 9... Electricity absorber, 10...
Adjustment body.

Claims (3)

[Claims] (1) A method of forming a plating layer on an electronic component using a barrel plating device, in which a large number of elements on which the plating layer is to be formed are placed in the barrel of the barrel plating device, and the specific gravity of the element is equal to or higher than that of the element. It is characterized by introducing a large number of adjusting bodies having the following specific gravity and a size equal to or larger than the element body, and a large number of metal electricity absorbing bodies that conduct the anions in the barrel, Barrel plating method for electronic components. (2) The method according to claim 1, wherein a conductive coating is applied to the surface of the adjusting body. (3) A method of forming a plating layer on an electronic component using a barrel plating device, in which a large number of elements on which the plating layer is to be formed are placed in the barrel of the barrel plating device, and the specific gravity of the element is equal to or higher than that of the element. A barrel plating method characterized by introducing a large number of adjustment bodies having the following specific gravity, the size of which is equal to or larger than the base body, and whose surface is coated with a conductive coating.