JPH02307204A - Sheathing method for electronic component - Google Patents

Abstract

PURPOSE:To make the thickness of a sheath resin substantially uniform and to improve solderability of a lead terminal by preheating an electronic component element, dipping it in powdered resin, removing resin adhered to the marginal part of the terminal without thermally melting it, and then thermally curing it, etc. CONSTITUTION:When an electronic component element 1 is preheated, dipped in powderlike thermosetting resin 4, the resin is adhered, then thermally cured and the component is sheathed, the element 1 is excessively heated and dipped repeatedly to adhere resins 4, 6 to a position not to protrude from the root of its lead terminal 3, the element 1 is then excessively heated, dipped in the resin 4 in predetermined length l3 of the element 1 and the terminal 3, then pulled up, resin 7 adhered to the marginal part of the terminal 3 without thermally melting it, and then thermally cured. For example, the resin 4 is powderlike epoxy resin having 50-70 deg.C of softening temperature. The resin layer 7 adhered to the marginal part of the terminal 3 is formed with a cutting line by bringing it in contact with a jig tooth 8, then pressing, and further brushing to remove it.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a method for packaging electronic components.

Conventional technology Conventionally, the methods for packaging electronic component elements with resin include methods such as immersing them in liquid resin and heat curing them, immersing them in powdered resin and heat curing them, storing them in resin cases, and molding them. Among these methods, the method of packaging with powdered resin has been used relatively often.

In this case, since lead terminals are drawn out from the electronic component, resin adheres to the lead terminals, and a process for removing the resin is added. For example, as in JP-A-50-16857, electronic component elements and lead wires are preheated, immersed in powdered resin, pulled up, excess resin layered, and heated to harden; As in Publication No. 55-15306, after preheating electronic component elements and lead terminals, they are immersed in powdered resin and pulled up, heated and melted, cooled, and then the resin adhering to excess parts is removed and heated to harden. The exterior packaging methods were being considered.

Problems to be Solved by the Invention In the method of packaging using powdered resin as described above, preheating and dipping are required several times in order to form a resin layer of uniform thickness around the outer periphery of the electronic component element. This has to be done repeatedly, and as a result, it is not easy to remove the grease that has adhered to the lead terminals several times, and the polishing time becomes long, causing scratches on the plated parts of the lead terminals, resulting in poor soldering properties. There were other problems.

Means for Solving the Problems The present invention solves the above-mentioned problems, and provides an electronic component in which an electronic component element is preheated and immersed in a powdered thermosetting resin, and after the resin is attached, the electronic component is heated and cured. In the packaging method, the electronic component element is repeatedly preheated and immersed to adhere the resin to a position that does not protrude from the base of the lead terminal, and the electronic component element is preheated to a predetermined length of the entire element and the lead terminal. This is a method for packaging an electronic component, which is characterized in that the lead terminal is immersed in the resin and pulled up, and then the resin adhering to the excess portion of the lead terminal is removed without being heated and melted, and then heated and hardened.

Effect: By the above-mentioned packaging method, only the electronic component element is repeatedly preheated and immersed in resin, so a resin layer of almost uniform thickness is formed around the outer periphery of the element, and the resin attached to the excess portion of the lead terminal is heated. Since the resin is transferred to the removal process without being melted, the resin is easily peeled off, the polishing time is shortened, and the plated parts of the lead terminals are not damaged, resulting in significantly improved soldering properties.

EXAMPLES The present invention will be explained below with reference to examples of film capacitors shown in FIGS. 1 to 5.

First, as shown in Fig. 4, a plurality of film capacitor elements 1 fixed to a jig 3 are preheated at 100 to 120°C, and then the viscosity is 300 to 500 cps and the surface tension is 24 dyn.
immersed in liquid epoxy resin of e/cm at a temperature of 100 to 1
After curing by heating at 25°C for 40 to 60 minutes, the capacitor element 1 heated at the temperature is immersed in powdered epoxy resin 4 with a softening temperature of 50 to 70°C as shown in FIG. 1(a). and pull it up as shown in Figure 1 (b). 3 is a lead terminal, and 5 is a resin layer that has been immersed and melted. Next, after preheating in the same manner, it is immersed in powdered epoxy resin 4 as shown in FIG. 1(c) and pulled up as shown in FIG. 1(d). In FIGS. 1(a) and 1(c), the immersion depth J, j22 is the same as or smaller than 12, where the immersion depth J22 is the same as or smaller than 12, and the resin layer 6 is pulled up. Form. After further preheating the film capacitor element, the entire element and lead terminals 3 are placed in a powdered epoxy resin 4 as shown in FIG.
It is immersed to a distance including a predetermined length i3 of , and then pulled up.

At this time, a resin layer 7 is formed on the outer surface of the lead terminal 3 of the film capacitor element, as shown in FIG. 2, which is adhered and melted for the first time due to the preheating temperature in the final stage. Next, without heating and melting the element, as shown in Fig. 2, jig teeth 8 are brought into contact with the resin layer 7 adhering to the excess portion of the lead terminal 3 to make cuts, followed by pressing, and further brushing. Remove the excess resin layer and heat in a heating furnace at a temperature of 110°C.
The resin layer is heated for 20 minutes to melt and flow and harden to form a glossy and beautiful surface layer as shown in FIG.

Then, the rating is indicated on the surface layer using ultraviolet curable ink to complete the process. In addition, the above immersion depth j21 and 1
By setting the position 2 depending on the shape and size of the film capacitor element, the thickness of the resin layer on the completed surface can be made almost uniform.

The table shows a comparison example between a film capacitor manufactured by the method of the present invention based on the above-mentioned example and one manufactured by the conventional method.

The defective rate of resin adhesion to lead terminals in the table is the defective rate of products in which unnecessary resin remains on the lead terminal 3 in the external appearance inspection after the resin coating, and the solder wettability of the lead wire is the defective rate of products mentioned above. Preheat the lead terminals to a temperature of 60°C and a humidity of 90 to 9.
The results of a solder graph test using a molten solder rod at a temperature of 230° C. after being left in a 5% thermostatic bath for 72 hours, left at room temperature for 1 hour, and immersed in flux are shown. And the time in the table is the immersion depth of 2mm in the solder graph test.
, the immersion time is 4 seconds, and in the solder graph curve shown in FIG.
4 is the value obtained by examining how many seconds have elapsed since the start of solder wetting. In Figure 5, tl is the start of immersion in the solder bath, t2 is the stop of rising of the solder bath, t3 is the start of solder wetting, th is the progress of wetting and the displacement is 0, t4 is the solder wetting equilibrium point, t5 is the descent of the solder bath, and t6 is the solder bath. This is the point where it leaves the surface.

As is clear from the table, the products manufactured by the method of the present invention have fewer defects in appearance, and the soldering properties of the lead wires are significantly improved. Although the above-described embodiments have been described with respect to film capacitors, it goes without saying that similar effects can be achieved with other electronic components such as tantalum capacitors and resistors.

Effects of the Invention As described above, according to the method of the present invention, the thickness of the exterior resin can be made almost uniform, and the soldering properties of the lead terminals are significantly improved. It is also advantageous in terms of production management, as it makes it easier to remove the resin by brushing, increases wear life, and lengthens replacement, inspection and maintenance periods.

[Brief explanation of drawings]

FIGS. 1 to 4 are explanatory diagrams of the manufacturing process of a film capacitor manufactured by the electronic component packaging method of the present invention. FIG. 5 is a solder graph curve diagram for evaluating solder leakage of lead terminals. 1: Film capacitor element 2: Lead terminal 3: Powdered epoxy resin

Claims (1)

[Claims] In an electronic component packaging method in which an electronic component element is preheated and immersed in a powdered thermosetting resin, and the resin is adhered and then heated and cured, the electronic component element is repeatedly preheated and dipped, and then the base of the lead terminal is removed. A process of attaching the resin to a position where it does not protrude, and preheating the electronic component element, immersing the entire element and the lead terminal in the resin to a predetermined length, and pulling it up, and removing the excess portion of the lead terminal without heating and melting it. A method for packaging electronic parts, which comprises removing resin attached to the parts and then curing them by heating.