JPH01118365A - Device for controlling preheater in automatic soldering device - Google Patents

Abstract

PURPOSE:To preheat a printed circuit board at optimum temp. and to feed it to a soldering device by measuring the temp. of the board of after its preheating, driving a temp. controller by the comparison with a set temp. and controlling the temp. of a preheater in case of executing molten soldering by preheating the printed board. CONSTITUTION:In case of soldering the back face of a printed circuit board PC by bringing it into contact with the jet face of a molten solder it is preheated by a preheater PH after coating a flux on the soldering face and fed to a jet soldering device by drying the flux. In this case the arrival of the board PC at the outlet port side of the downstream side preheater PH is detected by a timing sensor 12 and the temp. of the board PC is observed by a temp. sensor 11 by driving a measuring means 22. The temp. of both preheaters PH is adjusted to the optimum set temp. PX1, PX2 respectively by the temp. controller 31 attached to the power source AC for heater 33 by driving a setting means 25 after operating this observed value by an arithmetic means 23, the printed board PC is preheated to a proper temp. and fed to the jet soldering device and the soldering is executed on the board with high yield.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an automatic soldering device that automatically performs soldering processing on a printed circuit board while it is being transported. The present invention relates to a preheater control device in an automatic soldering apparatus for preheating a printed circuit board to a predetermined temperature.

Conventional technology A device that continuously solders a large amount of printed circuit boards by bringing the printed circuit boards conveyed in a substantially horizontal direction by a conveying device into contact with a jet surface of molten solder in a solder tank is called automatic soldering. It is well known as an attachment device.

In such automatic soldering equipment, the printed circuit board is transported from the flux coating process at the most upstream side, through the preheating process at the middle area, and to the final soldering process. This is to dry the flux and preheat the printed circuit board and electronic components attached to its top surface, thereby mitigating the thermal shock to these components when they come into contact with the solder jet. is.

Therefore, the preheater in conventional automatic soldering equipment is
This is a box-shaped electric heater with a large opening at the top, and is capable of preheating printed circuit boards when they are transported over a short distance above the heater. I found one that detects the air temperature at an appropriate location and controls the power supplied to the heater based on this.

Problems to be Solved by the Invention According to the prior art, the air temperature at the location where the temperature sensor 9 on the repeater is installed is as follows:
Even if it was possible to maintain the temperature at a predetermined target temperature, there was no control over the actual temperature of the printed circuit board that passed over the preheater, so the appropriate temperature of the printed circuit board itself was 1q. There was a problem in that there was no guarantee whatsoever as to whether or not this was done. Therefore, each time the shape, size, etc. of the 71 non-standard board is changed, it is necessary to conduct a test run for a large number of sheets and then determine the preheater temperature setting, which requires extremely complicated operations. Met.

Therefore, in view of the actual state of the prior art, an object of the present invention is to directly measure the temperature of a printed circuit board that has passed over a preheater, and use this result to adjust the temperature setting value of a temperature controller. As a result, the temperature of the preheater can be adjusted in response to excess or deficiency of the temperature of the printed circuit board, so the preheating temperature of the printed circuit board can always be maintained at an appropriate value, and therefore, a large number of test runs can be performed. It is an object of the present invention to provide a preheater control device for an automatic soldering device, which is unnecessary and therefore convenient for operation.

Means for Solving the Problems The structure of the present invention to achieve the above object is that in an automatic soldering apparatus that includes a preheater and a temperature controller that controls the temperature of the preheater, a printed circuit board is placed at the outlet of the preheater. a temperature sensor that measures the temperature of the printed circuit board at the outlet of the preheater, a measuring means, a calculating means, and a setting means, the measuring means detecting the temperature detected by the output of the timing sensor. The temperature sensor is activated at the measurement timing of the sensor, its output is read, and the calculation means performs predetermined calculation processing on the measurement result of the measurement means.
The gist of the setting means is that the temperature setting value of the temperature controller is adjusted and set based on the calculation result of the calculation means.

With this configuration, the presence of the printed circuit board that has passed through the top surface of the printer and reached its exit is detected via the output of the timing sensor, and accordingly, The measuring means can read the actual temperature of the printed circuit board by activating the temperature sensor. Therefore, the calculation means takes, for example, the average value of a large number of measurement results for the measurement results obtained by the measurement means, and
Alternatively, since it is possible to perform calculation processing such as comparing the magnitude with the preheating temperature setting value of the printed circuit board, the setting means uses the calculation result to adjust the temperature setting value of the temperature controller. can be done.

In this way, the temperature controller can continue to control the temperature of the preheater based on the temperature set value set in the temperature controller, so that the printed circuit board is eventually controlled to the appropriate preheating temperature. be able to.

It works as described above.

Example Examples will be described below with reference to the drawings.

The preheater control device in the automatic soldering apparatus has a main component (first figure).

The automatic soldering apparatus transports the printed circuit board PC by a transport device (not shown), and preheats the printed circuit board PC during transport by two series of preheaters PH1PH arranged cascaded along the transport path CR. ing. In addition, for each printer PH, temperature sensor 1
A temperature control system is constructed by a temperature controller 32, a temperature controller 31, and a heater 33, and the heater 33 is supplied with power from a power source AC via the temperature controller 31.

The control device main body 20 includes a measurement timing detection means 21,
It includes a measuring means 22, a calculating means 23, an initial setting value calculating means 24, and a setting means 25.

Each output of the temperature sensor 11 and timing sensor 12 is
Measuring means 22 and measurement timing detecting means 21, respectively.
The measurement timing detection means 21, the measurement means 22, the calculation means 23, and the setting means 25 are connected in cascade in this order. Roughly, the output from the setting means 25 is connected to each temperature controller 31.31, and the temperature sensor 32.
Each output of 32 is branched and inputted to the initial setting value calculating means 24, and the output thereof is inputted to the setting means 25.

Here, the timing sensor 12 is, for example, an optical sensor equipped with a light emitter/receiver, and detects the presence of the printed circuit board PC that has passed through the upper surface of the preheaters PH and reached the outlet of the downstream preheater PH. It is something that can be done. Further, the temperature sensor 11 is, for example, a radiation thermometer, and is a printed circuit board P located at the outlet of the preheater PH.
It is assumed that the temperature of the back surface of C can be measured without contact. The temperature sensor 32 may be, for example, a well-known thermocouple type sensor, and it is sufficient that it can measure the ambient temperature δ1 at a predetermined location within the preheater PH.

The operation of the preheater control device in the automatic soldering device having such a configuration is as follows.

The printed circuit board PC transported along the transport route CR is
When preheated by the preheaters PH and PH reaches the outlet side of the downstream preheater PH, the timing sensor] 2 detects this and informs the measurement timing detection means 21 of the control device main body 20 of the measurement timing. A signal 12a is sent out. The measurement timing detection means 21 is
In response to this, the measuring means 22 is activated, so that the measuring means 22 activates the temperature sensor 11 and reads the temperature signal 11a from now on. However, here, it is assumed that the temperature sensor 11 outputs the surface temperature of a part of the back surface of the printed circuit board PC that the temperature sensor 11 is aimed at as a temperature signal 11a.

The calculation means 23 performs appropriate processing on the temperature measurement value read by the measurement means 22, and then calculates the temperature value read by the measurement means 22.
5, the setting means 25 sets appropriate temperature set values PXI, Px2 to the temperature controller 31.31.
can be given. However, the calculation processing performed by the calculation means 23 includes calculation for calculating the deviation between the current temperature of the printed circuit board PC and its target value. In addition, here, since the preheaters PH, PH and the temperature controllers 31.31 attached thereto are each in two series, the temperature setting values pxl, Px2 given to each humidity controller 31.31 are relative to the printed circuit board PC. in an appropriate ratio to avoid excessive heat shock.
It is assumed that this can be used as an allocated value. For example, when the temperature set values given to the temperature controllers 31.31 of the upstream and downstream preheaters PH and PH are PXl and Px2, respectively, PX1=PX2-δ
(However, δ is preferably a positive temperature difference).

In addition, the initial setting value calculating means 24 sets the initial values of the optimum temperature setting values Pxl and px2, which are necessarily determined depending on the type of printed circuit board PC, in the temperature controller 31, 31 via the setting means 25. The initial value at this time may be manually input by referring to past driving results, or may be data stored in advance in a memory (not shown). It is also good. However, the initial setting value calculation means 24
Since the outputs 32a, 32a of the temperature sensor 32.32 indicating the current temperature of the preheaters PH, PH are input to the
However, it is possible to detect that the temperature has been raised to the initial values of the temperature set values pxl and PX2, and in response, a switching operation is also performed to shift the overall operation to the above-mentioned steady control state. It is assumed that this is being done.

Each function of the control device main body 20 can also be realized as software built into a microcomputer (FIG. 2).

First, the temperature controller 31 of the preheaters PH and PH.
Give the initial values of temperature set values Pxl and Px2 to 31 (step (1) in the figure, hereinafter simply referred to as (1)), and wait for the temperature of preheaters PH and PI- to rise (2) .

Next, the timing sensor 12 detects that the printed circuit board PC is at the outlet of the preheaters PH and PH (3), and when the presence of the printed circuit board PC is detected, after an appropriate time delay ( 4), temperature sensor 1
1 and read the back surface temperature XN, which is the current preheating temperature of the printed circuit board PC (5). timing sensor 1
By repeating this reading operation a predetermined number of times while 2 is detecting the presence of the printed circuit board PC ((4) or 7)), the average value of the back surface temperature XN during that time X = ΣXN Obtained (8).

Therefore, by comparing the average value and the preheating temperature setting value Px of the printed circuit board PC ((9), (10)), new temperature setting values P×1, px2 were obtained ((11) or 13
)) By setting this in the temperature controller 31.31 (14), the temperature of the preheaters PH, PH can be set and adjusted to the optimum value for properly preheating the printed circuit board PC. be. Note that step 13 is for, when a new preheating temperature setting value px is obtained, distributing it to the two temperature controllers 31, 31 in an appropriate ratio and then setting it. It is assumed that the equations herein can be changed to any other equations.

For example, by adding corrections that take into consideration conditions such as the size of the printed circuit board PC and the conveyance speed, it is possible to expect better controllability.

Now, if we compare the control device main body 20 in FIG. 1 with the flowchart in FIG. 2, it is clear that the measurement timing detection means 21 in the former corresponds to steps (3) and (6) in the latter. , hereafter, the measuring means 22 performs step (5)
In step (7) to 13), the calculation means 23 performs the steps (7) to 13).
The setting means 25 corresponds to steps (1) and (14), and the initial setting value calculation means 24 corresponds to steps (1) and (2), respectively.

In addition, in the above explanation, the preheater PI7PH is
It goes without saying that this can be made into only one system, or three or more systems, if necessary.

DETAILED DESCRIPTION OF THE INVENTION As described in detail, the present invention includes a timing sensor that detects the presence of a printed circuit board at the outlet of a preheater, a temperature sensor that measures the temperature of the printed circuit board at the outlet of the preheater, and a sub-measuring means. By including a calculation means and a setting means, the temperature of the printed circuit board conveyed to the outlet of the preheater can be directly measured, and the temperature setting value of the temperature controller of the preheater can be optimally adjusted and set using the result. This is an advantage in that it is possible to reliably achieve the appropriate preheating temperature for printed circuit boards, and it is therefore possible to effectively eliminate the operational inconvenience and waste of conducting test runs for a large number of boards. It has a positive effect.

[Brief explanation of the drawing]

1 and 2 show an embodiment, FIG. 1 is an overall configuration system diagram, and FIG. 2 is a flowchart of the main body of the control device. PC...Printed board PH...Preheater Pxl, Px2...Temperature setting value 11...Temperature sensor 12...Timing sensor 22...Measuring means 23...Calculating means 25...Setting means 31...Temperature controller

Claims (1)

[Claims] 1) In an automatic soldering apparatus that includes a preheater that preheats a printed circuit board being transported and a temperature controller that controls the temperature of the preheater, detecting that a printed circuit board is present at the outlet of the preheater. a timing sensor that measures the temperature of the printed circuit board at the outlet of the preheater; and a temperature sensor that measures the temperature of the printed circuit board at the outlet of the preheater, and activates the temperature sensor at the measurement timing detected by the output of the timing sensor. Automatic soldering comprising a measuring means for reading, a calculating means for calculating the measurement results by the measuring means, and a setting means for adjusting and setting the temperature set value of the temperature controller based on the calculation results of the calculating means. Preheater control device in equipment. 2) The preheater control device in an automatic soldering apparatus according to claim 1, wherein the temperature sensor is a radiation thermometer. 3) The preheater is comprised of a plurality of series arranged in series along the conveyance path of the printed circuit board, and the temperature controller is provided corresponding to each of the plurality of series. A preheater control device in the automatic soldering apparatus according to item 1 or 2.