JPS5911698A - Method of drying to measure heat resistant and flux resistant characteristics of printed circuit board part - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drying method for measuring the heat resistance and flux resistance characteristics of a printed wiring board, and more specifically, to a drying method for measuring the heat resistance and flux resistance characteristics of a printed wiring board. Relates to a forced drying method for quickly making properties measurable.

As is well known, printed wiring boards (hereinafter abbreviated as PC boards) are often used in electrical equipment, and in order to complete such PC boards, automatic semi-
] The characteristics of the mounted electronic components may change. Must be used. More specifically, in the automatic semi-Il1 cutting work, which is a single culm with a semi-Ill, not only PC boards but also
Electronic components such as transistors mounted thereon are also exposed to high temperatures close to 300° C. for a short period of time, causing changes in their characteristics and, in severe cases, thermal damage.

Therefore, it was actually completed and used as an fCP C board product4.
Before soldering, the characteristics of a PC board product for measurement that has been soldered with a single solder in the same strip f1 as in the automatic soldering work are measured, but the measurements are performed especially when the flux is completely dry. Therefore, the soldering must be done after the soldering process has been completed.For this reason, the soldering is left to stand for about 4 to 5 days. If the flux is not sufficiently dried and hardened, it is in liquid form, so even if flux enters the contact parts of switches, volume controls, etc., one river movement will avoid moving the flux, resulting in poor contact. However, after drying, the flux becomes hard and causes problems such as poor contact. therefore,
Due to the influence of adding 1', it took at least 4[1.-5 days or more to know whether the result was lζ or old, making it an extremely inefficient process.

The conventional PC base product for special +'l measurement is the first one.
As shown in the figure, a special I11 is pre-installed on the PC board 1.
The measured electronic component 2 is mounted, flux applied, and preheated in an environment of 80°C to 100°C. Then automatic? Soldering is done using a device similar to I'III, and sometimes the copper foil part is soldered at a temperature of 250 mm.
℃ to reach 260℃. Cliff I11a J1) After completion, natural cooling I41 and 411 until the flux is completely hardened.
Leave to stand for ~5 days, and then measure various characteristics.

Therefore, this invention shortens the time of natural/l placement after half fJ] (E+ 4:J) so that the characteristic measurement results can be obtained after 0 hours. For this purpose, various experiments have shown that the flux should be kept in a warm and humid environment in which drying progresses most efficiently and that does not affect the 1-1 properties of electronic components, as well as the length of time it is left in that environment. , the upper limit is the heat-resistant temperature of 1 to transistor, which is the most sensitive to heat as an electronic component;
℃, so there is no humidity in this temperature range.

The time difference was set to 40%, 50%, and 20 to 30 hours.

Examples of this invention are shown in FIGS. 3 and 4 below. l-
1) Side view of the C board product and “1 hour of work progress”
This will be explained along the progression chart. First, an electric component with a terminal of 1Φ for a circuit formed of copper foil has a temperature of 25%.
First light measurement was carried out in an environment with humidity (Rl-1) of 65%, and 7 lux was applied to the copper foil surface 11 of the substrate 10. Maintaining the temperature at 85°C, apply flux to the copper foil surface 11,
The temperature of the copper foil surface 11 of the substrate 10 is roughly maintained at 85° C. and covered.

Then, the terminals 13 of the electronic component 12 are soldered to the circuit 14 made of copper foil using an automatic semi-automatic device.

Nowadays, the copper foil surface 11 of the board 10 has reached 260°C, but? VIll (=I immediately naturally cooled 7J1
Once cooled, at a temperature of 50° C. to 65° C., under the influence of 50% to 40% Rl-1, for 20 hours or more, preferably 3 hours, Leave the matter unattended for at least 24 hours or 30 hours.

Thereafter, it is cooled to room temperature and the electrical characteristics of the electronic component 12 fixed to the substrate (fIio) are measured.

As is clear from the following explanation, the pudding 1 of this invention
~The drying method used to measure the heat resistance and anti-Norax properties of circuit board products does not damage electronic components due to heat, and since the PC board products are left in an environment where flux dries in the shortest time, it is easy to measure the properties. time can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a side view of a PC board product, Fig. 2 is a progress explanatory diagram showing a series of operations involved in a conventional drying method, and Fig. 33 is a side view of a C board product to which this invention is applied. , FIG. 4 is a progress explanatory diagram showing a series of 11 operations in the drying method according to the present invention. 5-

Claims (1)

[Claims] Electronic components are mounted on the board of the printer 1 and soldered t'J'
L. In the drying method used to measure the heat resistance and flux resistance characteristics of electronic components, after soldering, a natural cooling sill is used.
ζPrinted wiring board products at a temperature of 50℃ to 65℃, and
J: A drying method in which the electrical characteristics of the mounted electronic components can be measured after being left in an atmosphere with a humidity of 50% to 40% for approximately 20 hours or more.