JPS58101488A - Method of drying printed resistor - 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 method for drying a printed resistor formed by printing a resistor on a substrate made of a synthetic resin laminate. Resin 81 having
After stamping all the resistors on the I-layer board with resistive paint, and applying a solder resist film to the designated areas, place the resistor in a drying oven to dry the resistor paint and dry the resistor resist film. produced by doing). The drying process is very important in the production of printed resistors, and the quality of this drying will affect the load life characteristics, high temperature storage characteristics, etc. Conventionally, printed resistors are dried using a drying oven whose heating means is a hot air heater consisting of a sheathed heater and a fan. A method of passing through the interior was used. However, when only a hot air heater is used as a heating means, the heat is transferred through the air, resulting in poor thermal efficiency and the drawback that it takes a long time to dry.

SUMMARY OF THE INVENTION An object of the present invention is to propose a method for drying a printed resistor that can be dried evenly in a short period of time, thereby making it possible to efficiently manufacture high-quality printed resistors.

The drying method of the present invention uses a drying oven equipped with a far-infrared heater in an area near the entrance and a hot-air type dryer in other areas.
The substrate is rapidly raised to a predetermined temperature [1], and the board is heated by the fireworks heater to a temperature within a predetermined range that matches the firing conditions of the resistor paint, etc., for drying and aging.

Ninth, in order to efficiently dry the printed resistor, it is preferable to quickly raise the temperature of the substrate to near the upper limit of the temperature suitable for drying and aging, and then maintain it within a predetermined range. In the case of using only the conventional hot air heater and using the method, the change in IIt of the substrate from the time the substrate is carried into the oven until it is cooled is 9 as shown in Figure j@1, and the substrate carried into the drying oven is The temperature gradually rises from the inlet to the outlet, reaching a maximum of 111 degrees near the outlet, and after being taken out of the furnace, it is cooled by a cooling fan. In this way, the traditional method
It takes a very long time to complete the rounding, drying and aging of the printed resistor because the temperature of the substrate cannot be raised quickly, usually about 50 minutes. On the other hand, if the substrate is first heated using a far-infrared heater as in the present invention, the substrate can be uniformly and quickly heated from inside by the radiant heat from the heater. Suitable for drying in nine temperatures can be raised in the tube. It is necessary to dry the resistor within a predetermined temperature range, and it is necessary to avoid drying it at an unnecessarily high temperature. However, if a far-infrared heater is used as the only heating means in the drying oven, it is possible to maintain the substrate temperature in a straight line. This will cause the temperature to rise above the allowable temperature. Therefore, in the present invention, heating by a far-infrared heater and heating by a hot-air heater are used together, and the far-infrared heater
After the temperature reaches a predetermined value and the body dies, the heating is switched to hot air heating and heating is performed within a temperature range suitable for drying and aging the resistor. It is better to adopt such a method,
It has become clear that the time required to transport printed resistors into a furnace and then take them out in a trench can be reduced to at least 6 minutes and 11 degrees.

Figures 2 (4) and (8) schematically show an example of an apparatus used for carrying out the method of the present invention, and in these figures, 1 is a drying oven, and 2 is an apparatus on which a resistor is printed. A circulating conveyor 4 conveys the dried substrates to the entrance of the drying oven 1. A circulating conveyor 4 receives the substrates carried out from the drying oven 1 by a conveyor 6 and passes them under a cooling fan 5. A far-infrared heater 6 is disposed in a first region t near the entrance of the drying oven 1, and a terminal end K11II of the first region is provided.
A hot air type heater consisting of a sheathed heater 7 and an air blower 7 is disposed in a second area t extending from the position where the drying oven is opened to the outlet K of the drying oven. The conveyor 6 consists of nine reticular belts so that the substrates placed on it can be heated from below, and the far-infrared heater 6 is placed above and below the conveyor ink to maintain a predetermined distance between it and the conveyor. Electricity is distributed. The number of far-infrared heaters 6 placed above and below the conveyor 6 is determined by the width of the conveyor and the distance between each heater and the conveyor so as to always give uniform heat radiation to the printed resistor on the conveyor. Alternatively, it is appropriately set depending on the heat radiation area of each far-infrared heater. And a region t of $1 where the far infrared heater 6 is arranged.

By appropriately setting the length of the infrared rays, the capacity of each far-infrared heater, and the conveyance speed of the conveyor 6, the board can dry and age the resistor at a predetermined heating rate (IZ''/56C). Make sure it gets heated close to the appropriate temperature.

The hot air heater placed in the second region 4 in the drying oven 1 may have a structure similar to that conventionally used.
This hot air type heater is heated by a far-infrared heater to maintain the temperature of the nine substrates within a constant range. ? As long as it provides the required amount of heat, it is possible to use one with a smaller capacity than in the past. The length of the area tt of 11 to 2 where the hot air heater is arranged is determined by considering the moving speed of the conveyor so that the substrate temperature of the resistor can be maintained for the time required to dry and age the resistor. ◇ In addition, the cooling fan 6 is installed adjacent to the outlet of the drying oven.
The length of the IAS area 1.0 is determined by considering the speed of the conveyor 4 so that the printed resistor is exposed to the heat from the cooling fan for an appropriate time to slowly cool the printed resistor after being carried out from the drying oven to a temperature close to room temperature. In carrying out the present invention, we conducted a series of experiments to find an appropriate value for the ratio of the lengths of the first region t and the region @2 in the drying oven. . In this experiment, the total length of the furnace was 12 m (
(constant), the length of the cooling zone t is 2 degrees, and the lengths of the zones t and t are varied to dry and age the printed resistor using nine furnaces. The obtained printed resistor K (area resistance: 10Ω/hole) was subjected to a load life test, a high temperature storage test, and a moisture resistance storage test, and the results were evaluated into five grades: good, fair, and poor. Also, the adhesion and II degree characteristics of the resistor are similarly evaluated on a five-point scale. In addition, in the load life test, the rated power was 100 at 7oc.
0 hours, and in the high temperature storage test, the temperature was 100℃.
I left it for IOGO time. The nine humidity resistant storage tests were carried out at a temperature of 40
cS Can be left in an atmosphere with humidity of 90 to 95 degrees for 1000 hours. The results of this experiment are shown in Table 1.1II41 From the above results, it is clear that good results can be obtained when using a drying oven of 9 to 9. A similar experiment was conducted on a printed resistor using a far-infrared heater at various heating rates. You can get the same results as the cost. Here experiment number 1-
FIG. 4 shows the change in substrate temperature versus time for each case of 1'V. The drying oven that can be used in this case is one with a total length of 12 m, a length of 4 tp+, and a length of 4 6 lin, and the length of the cooling area t is 2 sets.
From the above results, the temperature increase rate is in the range t5~t14U/la! It's clear that it's a rash. The big 4th
It is clear from the figure that 4 minutes is sufficient for the heat treatment time in the drying oven, and it is clear that the time required for drying can be significantly shortened compared to the conventional method.

As described above, according to the present invention, a far-infrared heater is disposed in the area near the entrance of the drying oven, the far-infrared heater quickly raises the temperature of the substrate, and after the drying process, the heating is switched to the hot-air heater. It keeps the heating at the right temperature for a long time, so it dries! ! This method has the advantage that the manufacturing time for printed resistors can be significantly shortened compared to the conventional method, and the production efficiency of printed resistors can be significantly improved.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the temporal change of one substrate in the conventional method, Fig. 2 (2) and Fig. 2) shows the apparatus used in the ninth embodiment of the present invention, and the figure shows a schematic longitudinal section. Side view, −
Figure (6) is a schematic cross-sectional view of the far-infrared heating section, Figure 3 is a diagram showing an example of the temperature change of the substrate when using the method of the present invention, and Figure 4 is a diagram showing the experimental results. be.

Claims (1)

[Claims] A method for drying a printed resistor in which a printed resistor is dried by printing a resistor on a substrate made of a composite #MIi+ laminate and passing it through a drying oven using a conveyor, in which a far-infrared heater is installed in an area near the entrance of the drying oven. (9) A hot air heater is provided in each of the other areas, and the resistor is first heated by the far infrared heater to quickly raise the temperature of the substrate by 10 degrees, and then the hot air heater is used to heat the substrate. A method for drying an illumination resistor, which involves heating and drying within a predetermined humidity range.