JPS608904B2 - Printed circuit board soldering method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic soldering apparatus, particularly to a method and apparatus for soldering printed circuit boards in an automatic soldering apparatus using static soldering.

Generally, in an automatic soldering device using a stationary solder plate, a carrier is guided directly above the stationary solder plate by a compare chain or a running rail with a fixed running track, and the printed circuit board held by the carrier is guided to the stationary solder plate. Soldering is performed by soaking.

When soldering with such a solder rating, conditions such as the angle of entry of the printed circuit board into the static solder bath, the depth of soldering, the soaking time, and the exit angle have a great influence on the quality of the soldering. .

Therefore, when soldering using a static solder, it is necessary to quickly adjust the conditions and select the optimal one in response to changes in the size of the printed circuit board, the activity of the flux, the soldering temperature, the running speed of the carrier, etc. No. These adjustments cannot be easily made with conventional automatic soldering equipment using static soldering brackets.

In other words, in the conventional devices, although the immersion time can be adjusted, the entrance and exit angles cannot be adjusted, or even if these conditions are set at the beginning, they can be adjusted at all. In addition, with conventional automatic soldering equipment, the travel trajectory of the carrier is determined, so if the transport device malfunctions and stops while the printed circuit board is being soldered statically, the printed circuit board will be exposed to high temperatures for a long period of time. In some cases, the large number of components mounted on the printed circuit board are left immersed in the molten solder and are all thermally damaged, making them unusable. The purpose of the present invention is to easily adjust all the conditions for soldering the printed circuit board, and to quickly pull up the printed circuit board immersed in molten solder even if a failure occurs in the transport device, thereby protecting the mounted components from heat damage. An object of the present invention is to provide a method and apparatus for soldering a printed circuit board.

Thus, the gist of the present invention is to provide a method for soldering a printed circuit board by supporting a printed circuit board on a compare chain running on a stationary solder plate and immersing the printed circuit board in the stationary solder as the compare chain runs. The vertical distance between the stationary case and the compare chain is independently adjusted by moving the compare chain at two points, an entry side and an exit side of the compare chain with respect to the stationary solder. This is a continuous printed circuit board soldering method in which the angle of entry and exit of the printed circuit board into the stationary solder plate, the immersion depth, and the immersion time are adjustable.

According to another feature of the present invention, a stationary solder chain; a compare chain that supports a printed circuit board and immerses and solders the printed circuit board in the stationary solder while running on the stationary solder layer; a mechanism for applying a constant tension to the compare chain; and a mechanism installed at two points on the input side and the output side of the compare chain with respect to the stationary solder,
The vertical distance between the stationary solder and the compare chain is
This is a printed circuit board continuous soldering device consisting of two compare chain lifting mechanisms that can be adjusted independently at two points on the entry side and the exit side. The compare chain preferably consists of two pairs of compare chains, and the printed circuit board is suspended and supported by a carrier held between the compare chains.

The constant tension applying mechanism preferably comprises at least one idle sprocket installed on the compare chain, and further, the compare chain lifting mechanism comprises a sprocket that is engaged with the compare chain and can be raised and lowered, Furthermore, the support shaft of the movable sprocket is connected to a air cylinder, so that the vertical distance between the stationary solder frame and the comparison chain can be adjusted.

Further, the present invention is characterized in that two compare chains are lowered in the direction of a static solder bath using two sets of movable sprockets, and printed circuit boards are placed in a static solder bath while adjusting the descending state. This is a method of soldering by submerging the solder into the solder, and the device is equipped with two sets of movable sprockets for lowering the two compare chains in the direction of the stationary solder layer.

Note that the side where the printed circuit board supported by the compare chain begins to be immersed in the static solder bath is the "input side" of the compare chain into the static solder bath, and the side where the printed circuit board supported by the compare chain starts to be immersed in the static solder bath is the "input side" and the side that ends the immersion and exits from the static solder bath. is called the "outside".

Generally speaking, it refers to the two sides facing each other around the center of a stationary solder. The present invention will be explained below based on the drawings.

Fig. 1 is a plan view of a soldering device according to an embodiment of the present invention, Fig. 2 is a sectional view taken along the line D-B in Fig. 1, and Figs. 3a to 3e illustrate the lowered state of the compare chain in the present invention. It is something.

The automatic soldering device has two compare chains 3, 3 that run while suspending a carrier 2 holding a printed circuit board 1.
runs in the direction of arrow A, and two sets of movable sprockets 5a, 5a, 5b, and 5b are installed to lower the comparison chain in four directions.

A pair of elevating sprockets 5a, 5a installed at the rear in the running direction are connected by an axle 6, and the axle 6 is connected to the air via a plunger 8 which also serves as a support shaft for the elevating sprockets. It is connected to cylinder 7. Similarly, another set of elevating and lowering sprockets 5b, 5b installed at the front in the running direction are also connected by a sea bream 6, which is also connected to a plunger 8 of an air cylinder 7. Further behind the movable sprockets 5a, 5a and in front of the movable sprockets 5b, 5b are fixed sprockets 9, 9.
, 9, 9 are installed, and idle sprockets 10, 10 for adjusting the expansion and contraction of the compare chain as the movable sprocket goes up and down are installed behind the stationary soldering rack. Next, a soldering method using the above printed circuit board soldering apparatus will be explained.

The movable sprockets 5a, 5a, 5b, and 5b are connected to each air cylinder via each plunger that also serves as a support shaft, and the air cylinder is connected to an appropriate switch such as a limit switch or a timer (not shown). The descending speed, stopping time, timing, etc. are adjusted according to commands such as these. This vertically movable sprocket lowers the compare chains 3, 3 in the four directions of the stationary solder plate, and the printed circuit board of the carrier suspended by the compare chain is submerged into the stationary solder plate and soldered. By adjusting the operation of the two air cylinders, the angle at which the printed circuit board enters and exits the stationary solder, the bonding depth, and the bonding time can be optimized. Next, the lowering state of the compare chain in the present invention will be explained with reference to FIG.

First, before the carrier 2 holding the printed circuit board 1 approaches the stationary solder, the movable sprockets 5a and 5b are at the top as shown in Figure a, and the comparison chain 3 is parallel to the molten solder S. It becomes.

{b) When the carrier approaches a stationary solder and is placed in the middle of the running track or the mitt switch is turned ON', the vertically movable sprockets 5a and 5b begin to descend.

At this time, if you set the entry angle Q that is most suitable for soldering the printed circuit board, the movable sprocket 5b on the entry side will be 5
a, and the compare chain descends to a position where the angle Q is reached. {c} When the printed circuit board starts to sink in the state shown in Figure b, the vertically movable sprocket 5a further descends, and the printed circuit board runs parallel to the molten solder s as shown in Figure c.

[d- When the printed circuit board is removed from the molten solder, the elevating and lowering sprocket 5b on the exit side rises first as shown in Figure d, and the compare chain is set at an appropriate angle of 8 to remove the printed circuit board. Immediately after 'e' soldering, it is desirable to quickly return the printed circuit board to a horizontal position in order to eliminate unevenness of the molten solder adhering to the printed circuit board.

Therefore, as shown in Figure e, the sprockets 5a and 5 can be raised and lowered.
As in the case of figure a, b becomes the top level and makes the compare chain horizontal. The descending state of the compare chain mentioned above can be selected in any way by adjusting the descending speed, stopping time, and timing of the air cylinder.Also, in the event of an emergency stop due to a failure of the conveyor, this can be sensed and the air cylinder Since it can also raise the temperature, it can protect components mounted on printed circuit boards from heat damage.

The advantages of the present invention are listed below.

■ The angle at which the printed circuit board enters the static solder and exits from the static solder can be arbitrarily selected. ■ The immersion time for static soldering of printed circuit boards can be easily adjusted.

■ By linking the contact state between the carrier and the molten solder with the operation of the air cylinder, stable soldering can be achieved with a constant penetration depth regardless of the amount of molten solder.

■ Even if the conveyance device makes an emergency stop, the air cylinder is raised so that the parts will not be damaged by heat.

As explained above, the present invention can always optimize the soldering conditions of the printed circuit board, so there is no soldering defect.
Moreover, it has an unprecedented and excellent effect of completely eliminating the loss of mounted components due to accidents.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a soldering apparatus according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the low D shown in FIG. 1...Printed circuit board, 2...Carrier, 3...・Compare chain, 4...Stationary soldering, 5a, 5b...Elevating and lowering sprocket,
7...Air cylinder. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A method for soldering by supporting a printed circuit board on a conveyor chain running above a static solder bath and immersing the printed circuit board in the static solder bath as the conveyor chain runs, By moving the conveyor chain and independently adjusting the vertical distance between the static solder bath and the conveyor chain at two points, one on the entrance side and one on the exit side of the conveyor chain with respect to the static solder bath, the printed circuit board is A method for continuous soldering of printed circuit boards in which the entrance/exit angle, immersion depth, and immersion time into the static solder bath are freely adjustable. 2. Stationary solder bath; A conveyor chain that supports a printed circuit board and immerses and solders the printed circuit board in the stationary solder bath while running on the stationary solder bath; A mechanism that applies a constant tension to the conveyor chain; and The conveyor chain is installed at two points on the entrance side and the exit side with respect to the static solder bath, and the vertical distance between the static solder bath and the conveyor chain is set at the two points on the entrance side and the exit side, respectively. independently adjustable,
A continuous printed circuit board soldering device consisting of two conveyor chain lifting and lowering mechanisms. 3. The conveyor chain is composed of a pair of two conveyor chains, and the printed circuit board is suspended and supported by a carrier held between the conveyor chains.
An apparatus according to claim 2. 4. The apparatus of claim 2 or 3, wherein said constant tensioning mechanism comprises at least one idler sprocket engaged with said conveyor chain. 5. The apparatus according to any one of claims 2 to 4, wherein the conveyor chain elevating mechanism comprises a movable sprocket engaged with the conveyor chain.
6. The apparatus according to claim 5, wherein the support shaft of the movable sprocket is connected to an air cylinder, and the vertical distance from the stationary solder bath can be adjusted.