JPH0157992B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for measuring the soldering time of an object to be soldered that is immersed in molten solder.

[Technical background of the invention and its problems]

Conventionally, a glass plate was mounted on a soldering transport holder, and a stopwatch was manually started by looking through the glass plate at the moment when the molten solder spewing out from the jet solder bath began to come into contact with the glass plate. The stopwatch is stopped by observing the moment when the molten solder completely separates from the glass plate, and the stopwatch measures the time that the object to be soldered is immersed in the molten solder, that is, the soldering time. However, since it is a manual measurement based on visual observation, it is difficult to measure with high precision.

[Purpose of the invention]

The present invention seeks to provide a method for measuring with high accuracy the soldering time of an object to be soldered that is immersed in molten solder.

[Summary of the invention]

In the soldering time measuring method of the present invention, a pair of electrodes is attached to a holder for holding an object to be soldered which is conveyed by a soldering conveyor, and the pair of electrodes is conveyed by the conveyor. Then, the lower ends of the pair of electrodes are immersed in the molten solder in the solder bath as objects to be soldered, and the counter is controlled by a measuring circuit that operates with the molten solder as a contact between the pair of electrodes, and the solder of the pair of electrodes is immersed. This configuration is characterized in that the soldering time of the object to be soldered is measured by measuring the soldering time.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail with reference to embodiments shown in the drawings.

As shown in FIG. 1 or 2, by attaching a measuring plate 3 to a holder 2 for holding objects to be soldered, which is conveyed by a conveyor 1 for soldering, A pair of electrodes 4 inserted and fixed in flat positions with no difference are attached to the holder 2 via the measurement plate 3. As the measurement plate 3, a printed circuit board or the like may be used.

The conveyor 1 holds the holder 2 by means of a pair of rails 5 and 6 disposed along the soldering line.
A pin 9 protruding from a chain 8 supporting the wheels 7 on both sides of the holder and movably disposed along the rail 6 on one side is inserted into the engagement plate 10 on one side of the holder 2 so as to be movable up and down. By forcibly transferring the chain 8, the pin 9 pulls the engagement plate 10 and transfers the holder 2 along the rails 5 and 6. The holder 2 has claws 11 and 1 for gripping the printed circuit board.
2, 13, and 14, and the measuring plate 3 is gripped by these claws. The claws 11 and 13 can be moved to adjust the distance between them and the other party.

Next, as shown in FIG. 3, the pair of electrodes 4 attached to the holder 2 via the measuring plate 3 are conveyed above the jet solder tank 15 by the conveyor 1, and the pair of electrodes 4 are solder bath 15
It is immersed as an object to be soldered into the molten solder 17 jetted from the nozzle 16 of the solder. The actual objects to be soldered are lead components inserted into a printed circuit board or chip components bonded to the bottom surface of a printed circuit board.

Then, as shown in FIG. 5, the counter 18 is controlled on and off by a digital measuring circuit that operates the molten solder 17 as a contact point 17a between the pair of electrodes 4, and the soldering time of the pair of electrodes 4 is controlled. By measuring, the soldering time of the object to be soldered can be measured. The measurement circuit includes NOT circuits 19, 20, 21, delay circuits 22, 23, and NAND circuits 24, 25. The power supply is L...0V, H...+5V. Also
The output of the NAND circuit is reversed by the counter 18.

Next, the function of the digital measurement circuit described above will be explained.
Note that the symbols used in this explanation correspond to those shown in FIG.

(a) Before soldering = Contact 17a open A = 0, B = 1, X = 1, = 0 C = 1, D = 0, Y = 1, = 0 (b) At the start of soldering = Contact 17a closed Immediately after A = 1, B = 1 (by delay circuit 22), X = 0, = 1 (counting starts) C = 0, D = 0 (by delay circuit 23), Y = 1, = 0 (c) Soldering Middle = Contact 17a closed A = 1, B = 0, X = 1, = 0 C = 0, D = 1, Y = 1, = 0 (d) At the end of soldering = Immediately after contact 17a opens A = 0, B = 0 (by delay circuit 22), X = 1, = 0 C = 1, D = 1 (by delay circuit 23), Y = 0, = 1 (count completed) (e) After soldering = contact 17a open A=0, B=1, X=1, =0 C=1, D=0, Y=1, =0 The counter 18 starts counting by =1 in the above (b), ), the count ends with =1, so the soldering time during that time can be measured.

FIG. 4 shows the relationship between the contact 17a and the counter 18, and the symbols in this figure correspond to the symbols in the above description.

Note that the present invention is not limited to the jet soldering bath 15, but may be used in a vertically moving solder bath or a vertically moving soldering device for objects to be soldered. In addition, the objects to be soldered are not limited to parts mounted on printed circuit boards, such as
When attaching a solder film to an IC lead frame, a jig may be used to hold a large number of ICs alone. Further, the pair of electrodes 4 may be directly fixed to the holder 2 via an insulating material without using the measurement plate 3. Furthermore, the pair of electrodes 4
A plurality of sets may be provided on one printed circuit board, and for example, multi-point measurements may be performed over the entire surface of the printed circuit board.

〔Effect of the invention〕

According to the present invention, a pair of electrodes is attached to a holder for holding an object to be soldered that is conveyed by a conveyor for soldering, and the pair of electrodes is used as an object to be soldered, and molten solder is applied to the holder for holding an object to be soldered. is the contact point between this pair of electrodes, and the soldering time is measured using a measuring circuit and a counter under the same conditions as the soldering object, so the soldering time of the soldering object can be measured with high precision. This information can be used as a reference for adjusting the conveyance speed of the conveyor and the operation status of the solder bath, thereby ensuring the optimum soldering time.

[Brief explanation of drawings]

FIG. 1 is a plan view of a holder used in carrying out the present invention, FIG. 2 is a sectional view of the holder and a conveyor, and FIG. 3 is a sectional view showing an embodiment of the soldering time measuring method of the present invention. FIG. 4 is a timing chart of the measuring circuit, and FIG. 5 is a circuit diagram of the measuring circuit. DESCRIPTION OF SYMBOLS 1... Soldering conveyor, 2... Holder, 4... Electrode, 15... Solder bath, 17... Melting solder, 17a... Contact, 18... Counter.

Claims (1)

[Claims] 1. A pair of electrodes is mounted on a holder for holding objects to be soldered that is transported by a soldering conveyor, without any difference in the front and back, and this pair of electrodes is transported by the conveyor, and the lower ends of this pair of electrodes are The object to be soldered is immersed in molten solder in a solder bath, and the counter is controlled by a measuring circuit that operates with the molten solder as a contact between the pair of electrodes, and the soldering time of the pair of electrodes is measured. A soldering time measuring method characterized by measuring the soldering time of an object to be soldered.