JPH01282886A - Method and device for drying electronic circuit board - Google Patents

Abstract

PURPOSE:To prevent an unprinted part of a pattern from oxidation and a printed part from damage by irradiating far infrared rays on the pattern by ink of one side of an electronic circuit board for drying and similarly irradiating far infrared rays on the other side for drying. CONSTITUTION:Printing is effected with inks on the surface of an electronic circuit board by an electronic circuit printer 35 for being stored in a rack and subsequently placed on a carrier table 4 by a clamp 25 to by conveyed on a conveyer 22 by a transfer rail 26 followed by being sent to a drying furnace 20 holding a printed part upward for being dried by a far infrared ray irradiation device 21 up to a tack-free state. An electronic circuit board 11 is cooled in a cooling furnace 27 for being stored in a rack 33. Next, the board 11 is sent to a printer 35 and its rear is printed for being sent to the rack 23 holding the surface downward to be subjected for drying by the similar operation to the drying process of the board 10. Next, the board is dried by a hot wind drying furnace so that the printing parts of both surfaces are completely dried.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a drying method and a drying apparatus for drying ink printed on an electronic circuit board.

[Prior Art] Thermosetting ink is printed on an electronic circuit board to form or protect an electronic circuit. This printed ink is dried and hardened prior to the next step of etching or plating. Also.

Printing is performed on both sides of the electronic circuit board, so the process involves first printing on the front side and drying it, then printing on the back side and drying it.

However, as a method for drying this ink, hot air drying using hot air has conventionally been used.

[Problem to be Solved] However, hot air drying requires a long time to dry (for example, 20 minutes to dry one surface).

Therefore, while the ink on the second surface is drying, the back substrate (copper) surface becomes oxidized. Therefore.

Before printing the back side, it is necessary to perform intermediate surface treatment to remove the oxide film. Especially when increasing the printing thickness,
First, print on the surface, repeat drying 2 or 3 times,
Then print on the back side. Therefore, when the first surface is dried, the back surface is strongly oxidized.

The present invention was developed as a result of intensive studies regarding printing and drying in view of the above-mentioned problems, and it prevents oxidation of unprinted parts and prevents damage to the printed parts of electronic circuit boards. It is an object of the present invention to provide a method and apparatus for drying an electronic circuit board.

[Means for solving problems]

A method of drying an electronic circuit board according to the present invention is as follows.

An ink pattern is printed on one side of an electronic circuit board,
It is characterized by irradiating far infrared rays to dry this printed area until it is dry to the touch, then printing an ink pattern on the other side, and irradiating far infrared rays to dry this printed area until it is dry to the touch. There is a method for drying an electronic circuit board.

What should be noted in this method is that although the ink on the printed part of the electronic circuit board is dried using far infrared rays, this drying is done until it is dry to the touch, but not completely dry and hardened. The process involves printing and drying until it is dry to the touch.

However, here, as far infrared rays, 2 usually 4 to 400
Light in the long wavelength range of μm is used. Far-infrared rays can instantly and uniformly dry the inside of the printed area without drying the medium in the middle.

Printed areas can be dried in a short time.

In addition, the term "dry to the touch" refers to a state in which the ink is dry to the extent that when the printed portion is touched with the finger, the ink does not adhere to the finger. Furthermore, the above-described printing and drying can be performed not only 51 times on one side but also 3 times, for example, 2 to 3 times to increase the thickness of the printed portion. Also.

In the present invention, drying by far infrared rays is carried out at least once for each of the initial front and back printing until it is dry to the touch. Hot air may be used for the second and subsequent drying.

In addition to the above-mentioned far infrared rays, hot air drying can also be used in the final drying after drying one surface to the touch, that is, in the step of completely drying and curing the printed portions on both surfaces of the electronic circuit board.

Next, as an apparatus for carrying out the above drying method, a tunnel-shaped drying oven, a conveyor arranged to pass through the drying oven, and a printed electronic circuit board placed on the R and conveyed to the above-mentioned conveyor. It consists of a substrate transport platform that is transported by a.

A drying device for drying ink printed on an electronic circuit board, wherein the board carrier has an outer frame larger than the outer circumference of the electronic circuit board, and an electronic circuit board provided inside the outer frame. The support part is provided at a position where it does not come into contact with the printed part of the electronic circuit board, and the support part is located so that the printed part on the back side of the electronic circuit board does not come into contact with a conveyor, etc. There is an electronic circuit board drying apparatus characterized in that the outer frame has an insertion opening for inserting an electronic circuit board loading/unloading clamp inside the outer frame.

What should be noted about this apparatus is that the substrate transport table has the specific structure described above.

A device for irradiating the far infrared rays or a dryer such as a hot air device is disposed on the ceiling, side walls, etc. of the drying oven. Of course, the hot air can also be sent from outside the drying oven. Inside this drying oven, a conhair for moving the substrate carrier from the inlet to the outlet is disposed. The printed electronic circuit board is placed on the board transport table, and while the electronic circuit board passes through the drying oven, the printed ink is dried until it is dry to the touch.

Thus, the board conveyance table has a support portion for supporting the electronic circuit board on the conveyor. This support portion is provided inside the outer frame. In addition, this support part should be provided all around the inside of the outer frame as shown in the example (second
), or they may be provided on the upper and lower surfaces (see FIG. 7), or they may be provided at the four corners of the inner corner of the outer frame. however,
It should be noted that these supporting parts need to be provided at positions where they do not come into contact with printed parts on the electronic circuit board.

What is more important about the support part is that it is provided at a height so that the printed part on the back side of the electronic circuit board does not come into contact with the conveyor or the like. This means that the printed part on the back side that is dry to the touch (here, the surface part that was printed and dried in the previous process will be the back side on the substrate transport table in the back side drying process of this process) is transferred to the conveyor. This is to prevent the FM from being damaged by touching it.

In addition, the electronic circuit board is attached to the support part of the board transfer platform inside the outer frame. 9. An insertion opening is provided for inserting a clamp used for placing the substrate on the substrate and taking it out from the substrate transfer table. This insertion port.

The size should be at least large enough to allow insertion of the clamp claw. Further, it is preferable that two insertion openings be provided on opposing surfaces of the outer frame as shown in the embodiment. Moreover, they can also be provided on the four sides of the outer frame.

[Functions and Effects] In the drying method of the present invention, far infrared rays are used to dry the printed area, so the ink dries quickly and the drying time is shortened compared to conventional hot air drying. Furthermore, since the drying time is short, an oxide film is not formed on the other side as in the conventional method, and an intermediate surface treatment step for removing the oxide film is not required prior to printing on the other side.

In addition, in the one-line method, as described above, the printed portions on five sides are dried to a touch-dry state, and then the other side is printed, so it does not take a long time to dry one side. That is, since drying is carried out using far infrared rays until it is dry to the touch, the heating time for one side is extremely shortened due to both the short time drying brought about by far infrared rays and the short time drying to the touch dry state. , the conventional method requires 18% to dry one side.
According to the method of the present invention, what used to take 1 minute is now only 5 minutes. In addition, final drying will be performed.

The time required for this is approximately the same as the conventional method (for example, 35 minutes).

In addition, in the one-line method, both surfaces are dried to a touch-dry state at least once and then final drying is performed, so that the printed area is sufficiently dried and hardened.

Excellent coatings can be produced in subsequent etching and plating processes.

Next, according to the drying apparatus, the electronic circuit board is transported on the conveyor using the board transport table having the above structure. Therefore, the printed portion on the back side of the electronic circuit board, which is dry to the touch and may be softened again by heating, will not be damaged. In addition, when placing the electronic circuit board on the board transfer table or removing it from the board transfer table, the electronic circuit board can be easily handled by inserting the claw part of the clamp into the insertion opening provided in the outer frame of the board transfer table. can.

〔Example〕

First example Regarding the electronic circuit board drying device according to this example.

This will be explained using FIGS. 1 to 5.

As shown in FIG. 1, the drying apparatus 2 of this example includes a tunnel-shaped drying oven 20 provided with a far-infrared irradiation device 21, and a conveyor 2 disposed passing through the inside of the drying oven 20.
2, a board feeder 24 for feeding the board transport table 4 with the electronic circuit board 10 placed on the conveyor 22, and the electronic circuit board 11 that is dry to the touch and comes out of the conveyor 22.
and a substrate receiving a31 for receiving the substrate along with the substrate transfer platform 4.

It consists of a return conveyor 34 for sending the substrate transport platform 4 to the substrate loading machine 24.

In the board input field @24, there is a rank 23 for waiting the printed electronic circuit board 10.

A clamp 25 is provided for taking out the electronic circuit board 10 from the rack 23 and placing it on the board transfer table 4. The clamp 25 has a claw portion 251 for picking up the electronic circuit board IO.

Further, the board input 8g24 is provided with a transfer rail 26 for transferring the board transfer table 4 on which the electronic circuit board 10 is placed onto the conveyor 22. Further, a cooling furnace 27 is provided on the exit side of the drying furnace 20.

Further, it was provided on the exit side of the electronic circuit board 11 that had been dried to a touch-dry state. In the board receiving machine 31.

A clamp 32 is provided for taking out the electronic circuit board 11 on the board transfer table 4. The clamp 32 is attached to the electronic circuit board 1
It has a claw 321 for picking up 1.

The board receiver 3I also includes a rack 33 for storing the electronic circuit boards 11.

Next, a single dryer is used to dry the printed electronic circuit board lO
This section describes the procedure for drying.

First, ink is printed on the surface of the two-surface-treated electronic circuit board by an electronic circuit board printing machine 35, resulting in an electronic circuit board IO having a printed portion.

This electronic circuit board 10 is first stored in a rack 23.
Next, the clamp 24 places the i! and is transferred onto the conveyor 22 by the transfer rail 26. Then, it is sent to the drying oven 20 with the printed portion facing upward. In the drying oven 20, the printed part is dried to a touch-dry state by the far-infrared irradiation device 21, and the electronic circuit board 11 is cooled in the cooling oven 27, and the board receiver 8g,
31 and picked up from the substrate transfer table 4 by the clamp 32. Then, the electronic circuit board 11 is mounted on the rack 3
3 to wait for the next process. In addition, electronic circuit board 1
The substrate transfer table 4 from which the substrate 1 has been removed is transferred to the return conveyor 34.
It slides on the roller 341 and moves to M+7i thrower [24].

The electronic circuit board 11 having touch-dry printed portions on two surfaces is then sent to printing 8!35, where the back side is printed and sent to the rack 23 with the front side facing down. Then, it is subjected to drying in the same manner as the drying process of the electronic circuit board 10. At this time, in the drying oven, the surface that is dry to the touch first is on the conveyor 22 side (that is, the back side of the substrate transport table), and the printed part that is printed later is on the front side (upper side). It is then dried until it is dry to the touch.

The printed parts on both sides of the electronic circuit board are dried to the touch and then transferred to the first step, where they are dried in a hot air drying oven to completely dry and harden the printed parts on both sides.

Next, the substrate transfer table 4 will be described.

As shown in FIGS. 2 to 4, the board transfer table 4 includes an outer frame 41 having an inner circumference larger than the outer circumference of the electronic circuit board 10 and tilting downward, and an outer frame 41 provided inside the outer frame 41. It consists of a support part 42. The support portions 42 are provided on all four sides of the inner periphery of the outer frame 41. The height of the support portion 42 is
i3 electronic circuit board IO! When the electronic circuit board 10 Mama's printed part 5
There are 2. Furthermore, the outer frame 41 has two insertion openings 43 on its inner side on opposing surfaces (upper and lower surfaces in FIG. 2).

Next, in the substrate loading machine 24, on the substrate transfer table 4,
iS electronic circuit board 10! To place the electronic circuit board 10, as shown in FIG. is inserted into the insertion opening 43 of the substrate transfer table 4, and further lowered. As a result, the periphery of the electronic circuit board 10 rests on the support part 42 of the board transfer table 4. Next, the claw 251 is slightly opened and the insertion port 43 is pulled out. On the other hand, when the electronic circuit board 10 placed on the board transfer table 4 is picked up by the clamp 32 of the board receiving machine 31.

The order is the reverse of the above.

According to one example as described above, a printed portion printed on an electronic circuit board can be dried to a touch-dry state in a short period of time. In addition, the back side has a printed part that is dry to the touch.
An electronic circuit board having a printed part on the front side can be dried without damaging the surface of the printed part on the back side. Also, placing the electronic circuit board on the board transport table.

It is also easy to take out.

Furthermore, as in this example, if the ink printed on both sides of the electronic circuit board is dry to the touch, and the final drying is performed afterwards, it is important to be concerned about uneven drying due to the solvent that evaporates during drying. It is possible to finish and dry a large amount of electronic circuit boards at one time without having to do much.

Additionally, less dust accumulates between printing and drying. In addition, if the size of the substrate transfer table 4 is prepared in advance according to the size of the electronic circuit board 10, electronic circuit boards 10 of various sizes can be dried.

Second Embodiment In this embodiment, as shown in FIG.
It is installed only in certain places.

Further, the substrate transfer table 4 of the first embodiment is fixedly attached to the conhair 22 placed in the drying oven 20, and the substrate transfer table 4
An electronic circuit board 10 is placed on top.

According to this example, electronic circuit boards IO of the same workpiece size can be efficiently supplied one after another onto the conhair. Additionally, the substrate carrier of this example can be used for relatively thick electronic circuit boards. Also.

It has the same effect as the first embodiment.

3rd Embodiment As shown in FIGS. 7 and 8, in this embodiment, the substrate transfer table 4 shown in the first embodiment is provided with its support portion 42 only on the vertical plane in FIG. Circuit board holding tool 4
5.

As shown in FIG. 8, this presser 45 includes a plate 451 provided on the outer frame 41 and urged toward the support portion 42 by a spring coil 46.

An elastic pad 4 provided at the tip of the plate 451
52 and more. This presser 45 is the electronic circuit board 1
0 on the bearing part 42 i! When placing the electronic circuit board IO, it is opened upward, and after the electronic circuit board + FILO is placed, the end of the electronic circuit board IO is pressed against the support part 42 as shown in FIG.

The board transfer table of this example can fix the electronic circuit board, so
This is advantageous when transporting so-called weak electronic circuit boards. Other effects similar to those of the first embodiment can be obtained.

In addition, the said holding|pressing board can also be made to press down an electronic circuit board using a magnet.

Fourth Example Two drying methods according to the present invention were carried out using the drying apparatus shown in the first example. The process is shown in the table below.

In other words, on the surface of an electronic circuit board that has been subjected to 3 surface treatments.

Five-circuit pattern protection printing was performed using a thermosetting ink containing epoxy resin as a main component (Step A).

The printing thickness is 10 μm. This was placed on the substrate transport table shown in the first example and dried with far infrared rays with a wavelength of 4 to 400 μm for 5 minutes, so that the printed part was dry to the touch (
Step B), then on the back side.

Printing to protect the circuit pattern on the back side was carried out in the same manner as the above-mentioned front side printing (Step C).Next, place the electronic circuit board on a board carrier with the back side facing up and the front side facing down, The printed part on the back side was dried with far infrared rays for 5 minutes to make the printed part dry to the touch (Step D).

Then, in order to increase the thickness of the printed part on the surface, printing was performed in the same manner as in step A, and in the same way, far infrared rays were used to increase the thickness of the printed part on the surface.
It was dried for a minute to make it dry to the touch (Steps E and F).

Next, in order to increase the thickness of the printed portion on the back side, printing was performed in the same manner as in step C (step C), and for finishing drying, T1. Place the sub circuit board in a hot air drying oven and dry for 150 minutes.
Heated at °C for 36 minutes (Step H). As a result, the printed portions on the first and back surfaces were completely dried and hardened. The dried electronic circuit board was transported to the next process.

On the other hand, for comparison, a conventional method as shown in the table below was carried out. Printing in the conventional method is similar to the method of the present invention described above.

Then, printing on one surface is done in two steps (L and N processes).
During that time, hot air drying (150°C) was performed for 18 minutes (N
Step), after the second surface printing, the printed part of the surface is
Dry for 136 minutes at 0°C to completely dry and harden (0
process).

What should be noted is that the back surface is subjected to intermediate surface treatment in the P step. This is achieved by drying in the above M and O steps.
This is because a copper oxide film was formed on the back surface.

This is done prior to printing on the back side. This treatment was carried out by immersing the electronic circuit board in a 5-dilute sulfuric acid solution for 16 minutes.

After the intermediate surface treatment, printing for the back side was performed on the back side (Q step), and then hot air drying was performed in the same manner as above (R step).

Furthermore, printing was performed on the back side to increase the thickness (S step), and hot air drying was performed at 150° C. for 136 minutes to completely dry and harden the back side (T step).

As can be seen from the table, the method of the present invention does not require the intermediate surface treatment (P step) in the conventional method.

Furthermore, in the method of the present invention, far infrared rays are used until the final drying, and the printed area is dried to the touch, so the total drying time including the final drying is 51 minutes. In comparison, since the conventional method uses hot air drying, the total drying time is 108 minutes, which is twice the drying time of the present invention. Therefore, conventionally, drying and intermediate surface treatment totaled 124
However, the method of the present invention can dry in only 51 minutes.

Note that the upper side is printed twice on each of the three front and back sides, but this can be done once if necessary.

Alternatively, it can be done three times. In addition, for finishing drying,
Not only hot air but also far infrared rays can be used. In the case of the upper side, when finishing drying is performed using far infrared rays, the drying time is about 71 minutes.

In addition, on the upper side, before the above-mentioned H step, the printed part of the second backside printing can be dried by far infrared rays until it is dry to the touch.

[Brief explanation of the drawing]

1 to 5 show an electronic circuit board drying apparatus according to the first embodiment, FIG. 1 is a perspective view of the entire device, and FIG. 2 shows an electronic circuit board! FIG. 3 is a sectional view taken along the line A-A in FIG. 2, FIG. 4 is a sectional view taken along the line B-B in FIG. A front view showing the state in which the electronic circuit board is placed on the board transfer table, FIG. 6 is a plan view of the board transfer table of the second embodiment, and FIGS. 7 and 8 show the state in which the electronic circuit board is placed on the board transfer table. 7 is a plan view thereof, and FIG. 8 is a sectional view taken along the line CC in FIG. 7. 10.11. ,,Electronic circuit board. 21.5 Drying equipment. 20, Drying oven. 21, far infrared irradiation device. 22: Conveyor. 24,... Board loading machine. 25, Clamp. 31,, Board receiving machine. 32, Clamp. 35. Printing machine. 419. Board carrier. 41, , outer frame. 42,,, bearing part. 43. Insertion port. 51.52. ,,Printed part. 45... Holder.

Claims (2)

[Claims] (1) Print an ink pattern on one side of the electronic circuit board, irradiate it with far infrared rays and dry the printed area until it is dry to the touch, then print an ink pattern on the other side and irradiate it with far infrared rays. A method of drying an electronic circuit board, comprising: drying the printed portion until it is dry to the touch. (2) An electronic device consisting of a tunnel-shaped drying oven, a conveyor arranged to pass through the drying oven, and a substrate transport platform on which a printed electronic circuit board is placed and transported by the conveyor. This is a drying device for drying ink printed on a circuit board, and the board carrier has an outer frame larger than the outer circumference of the electronic circuit board, and an electronic circuit board provided inside the outer frame. The bearing part is located at a position where it does not come into contact with the printed part of the electronic circuit board, and the bearing part is located at a height where the printed part on the back side of the electronic circuit board does not come into contact with a conveyor, etc. 1. A drying device for electronic circuit boards, wherein the outer frame has an insertion opening for inserting a clamp for loading and unloading the electronic circuit board inside the outer frame.