DE3001852B1

DE3001852B1 - Method for recording the preheating temperature, the soldering medium temperature and the soldering time in a wave soldering system

Info

Publication number: DE3001852B1
Application number: DE19803001852
Authority: DE
Inventors: Wolfgang Gielisch; Ekhard Ing Pieper
Original assignee: Licentia Patent Verwaltungs GmbH
Current assignee: Bosch Telecom GmbH
Priority date: 1980-01-19
Filing date: 1980-01-19
Publication date: 1980-11-27
Also published as: DE3001852C2

Description

Durch die vorliegende Erfindung wird zur Lösung der erwähnten Aufgabe außerdem eine Anordnung zur Durchführung dieses Verfahrens angegeben, die dadurch gekennzeichnet ist, daß die Meßstation aus einer Leiterplatte besteht, auf deren Oberseite in einem Gehäuse die Schaltungsanordnungen für die Meßwertaufnahme und -speicherung und eine digitale Anzeigevorrichtung angeordnet sind, und auf deren Unterseite sich ein Thermoelement, drei in Laufrichtung der Leiterplatte hintereinander angeordnete Kontaktpunkte und ein sich längs der Kontaktpunkte erstreckender Kontaktstreifen, der auf Betriebspotential liegt, befinden. Eine vorteilhafte Ausführung dieser Anordnung besteht darin, daß zwischen dem Gehäuse der Meßstation und der Leiterplatte eine Wärmeisolationsschicht angeordnet ist und daß das Thermoelement so an der Unterseite der Leiterplatte angeordnet ist, daß es gerade noch mit der Lötmittelwelle in Berührung ist, wenn diese den dritten Kontaktpunkt verläßt. The present invention achieves the aforementioned object also specified an arrangement for carrying out this method, which thereby is characterized in that the measuring station consists of a circuit board on which Top in one Housing the circuit arrangements for the recording of measured values and storage and a digital display device are arranged, and on the On the underside there is a thermocouple, three in a row in the direction of travel of the circuit board arranged contact points and a contact strip extending along the contact points, which is at the operating potential. An advantageous embodiment of this arrangement is that between the housing of the measuring station and the circuit board a Thermal insulation layer is arranged and that the thermocouple is so on the bottom of the circuit board is arranged so that it is barely in contact with the solder wave is when it leaves the third contact point.

Anhand eines in der Zeichnung dargestellten Ausführungsbeispiels soll nun die Erfindung näher erläutert werden. Es zeigt F i g. 1 eine über einer Lötmittelwelle befindliche Meßstation, F i g. 2 die Unterseite der Meßstation und F i g. 3 ein Blockschaltbild, welches die Funktionsweise der Meßstation wiedergibt. Using an exemplary embodiment shown in the drawing the invention will now be explained in more detail. It shows F i g. 1 one over one Solder wave measurement station, FIG. 2 the underside of the measuring station and F i g. 3 is a block diagram showing the mode of operation of the measuring station.

Um die tatsächlichen Verhältnisse, wie sie an den durch eine Wellenlötanlage laufenden Leiterplatten vorherrschen, kennen zu lernen, wird eine Meßstation in gleicher Weise wie übliche Leiterplatten durch die Wellenlötanlage geschickt. Bereits oben wurde bemerkt, daß eine optimale Lötung im wesentlichen von der Vorheiztemperatur, der Lötmitteltemperatur und der Lötzeit, also davon, wie lange jeder Punkt auf der Unterseite der Leiterplatte in die Lötmittelwelle eingetaucht ist, abhängt. Ist es nämlich möglich, diese drei Größen genau zu erfassen, wie mit Hilfe der erfindungsgemäßen Meßstation, so läßt sich die Wellenlötanlage sehr präzise einstellen. Die Meßstation, welche über die Lötmittelwelle AL hinwegläuft, ist in F i g. 1 dargestellt. Sie besteht aus einer Leiterplatte 2, auf deren Oberseite in einem Gehäuse 3 Schaltungsanordnungen zur Erfassung und Speicherung der drei Größen, Vorheiztemperatur, Lötmitteltemperatur und Lötzeit, untergebracht sind. Die prinzipielle Funktionsweise der Schaltungsanordnungen wird weiter unten näher beschrieben. An dem Gehäuse 3 ist eine Anzeigevorrichtung 4-so angebracht, daß man, während die Meßstation die Wellenlötanlage durchfährt, die angezeigten Meßwerte ablesen kann. Zwischen der Leiterplatte 2 und dem Gehäuse 3 ist noch eine Wärmeisolationsschicht 5 angeordnet, die die Schaltungsanordnungen im Gehäuse gegen zu starkes Erwärmen durch die heiße Lötmittelwelle schützen soll. To the actual conditions, as presented by a wave soldering machine current printed circuit boards predominate, get to know a measuring station in sent through the wave soldering machine in the same way as conventional printed circuit boards. Already It was noted above that an optimal soldering depends essentially on the preheating temperature, the solder temperature and the soldering time, i.e. how long each point on the The bottom of the circuit board is immersed in the solder wave. is namely, it is possible to detect these three variables exactly, as with the aid of the invention Measuring station, so the wave soldering system can be set very precisely. The measuring station, which passes over the solder wave AL is shown in FIG. 1 shown. she consists of a printed circuit board 2, on the top of which in a housing 3 circuit arrangements for recording and storing the three variables, preheating temperature, solder temperature and soldering time. The basic functionality of the circuit arrangements is described in more detail below. On the housing 3 is a display device 4-attached so that one drives through the wave soldering system while the measuring station is can read the displayed measured values. Between the circuit board 2 and the housing 3 a heat insulation layer 5 is also arranged, which the circuit arrangements in the housing to protect against excessive heating from the hot solder wave.

An der Unterseite der Leiterplatte 2 befinden sich drei Kontaktpunkte 6, 7 und 8, die jeweils einen Pol der drei Prüfkontakte PK I, PK II und PK 111 darstellen, deren Bedeutung im Zusammenhang mit F i g. 3 noch erläutert wird. Die drei Kontaktpunkte 6, 7 und 8 sind, wie F i g. 2 zeigt, in Laufrichtung der Leiterplatte hintereinander angeordnet. Den zweiten Pol der drei Prüfkontakte bildet ein Kontaktstreifen 9, der sich parallel zu den Kontaktpunkten in Laufrichtung auf der Unterseite der Leiterplatte erstreckt. Der Kontaktstreifen 9 liegt auf Betriebspotential UB. Gleitet nun die Meßstation mit der Unterseite der Leiterplatte über die Lötmittelwelle t, so schließt diese nacheinander die Kontaktpunkte 6, 7 und 8 mit dem Kontaktstreifen 9 kurz, d. h. die Prüfkontakte PKI, PKII, PKIII werden geschlossen.There are three contact points on the underside of the circuit board 2 6, 7 and 8, each representing a pole of the three test contacts PK I, PK II and PK 111, their meaning in connection with F i g. 3 will be explained. The three points of contact 6, 7 and 8 are as in FIG. 2 shows one behind the other in the running direction of the circuit board arranged. The second pole of the three test contacts is formed by a contact strip 9, which is parallel to the contact points in the running direction on the underside of the circuit board extends. The contact strip 9 is at operating potential UB. Now slide the Measure station with the bottom of the circuit board over the solder wave t so closes this one after the other the contact points 6, 7 and 8 with the contact strip 9 short, d. H. the test contacts PKI, PKII, PKIII are closed.

Es wird also damit das Betriebspotential UB an entsprechende Schaltungseinheiten gelegt, die dadurch in Funktion treten. Verläßt die Lötmittelwelle die Kontaktpunkte, so sind die Prüfkontakte wieder geöffnet. Auf gleicher Höhe wie der Kontaktpunkt 8 ragt ein Thermoelement 10 durch die Leiterplatte 2.It is thus the operating potential UB to corresponding circuit units that come into operation. If the solder wave leaves the contact points, so the test contacts are opened again. At the same height as the contact point 8, a thermocouple 10 protrudes through the circuit board 2.

Dieses Thermoelement dient sowohl zur Messung der Vorheiztemperatur als auch der Lötmitteltemperatur.This thermocouple is used to measure the preheating temperature as well as the solder temperature.

In F i g. 3 ist ein Blockschaltbild dargestellt, anhand dessen nun der Ablauf der Meßwerterfassung beschrieben werden soll. Bei Schließen des ersten Prüfkontaktes PK I wird über eine Steuereinheit STeine erste Adresse im Speicher S- einem RAM - angesteuert. Wird der zweite Prüfkontakt PKII geschlossen, so findet eine Übernahme des Meßwertes der Vorheiztemperatur in die erste Adresse des Speichers S statt. Die am Thermoelement auftretende Temperatur wird in einer Temperaturmeßeinrichtung o in ein proportionales analoges elektrisches Signal umgewandelt und einem Analog-Digital-Umsetzer A/D zugeführt, dessen digitales Ausgangssignal schließlich in den Speicher geschrieben wird. Durch das Schließen des Prüfkontaktes PK II wird ebenfalls eine Zeitmeßeinrichtung Tgestartet, mit welcher die Lötzeit gemessen werden soll. Die Zeitmeßeinrichtung, z. B. ein Integrator, erzeugt auch ein analoges der Zeit proportionales elektrisches Signal. In Fig. 3 shows a block diagram, based on which now the process of data acquisition is to be described. When closing the first Test contact PK I is a control unit STeine's first address in the memory S- a RAM - controlled. If the second test contact PKII is closed, then a transfer of the measured value of the preheating temperature to the first address of the memory S instead. The temperature occurring at the thermocouple is measured in a temperature measuring device o converted into a proportional analog electrical signal and an analog-to-digital converter A / D, whose digital output signal is finally written into the memory will. Closing the test contact PK II also becomes a timing device Tstarted, with which the soldering time is to be measured. The timing device, z. B. an integrator, also generates an analog electrical proportional to time Signal.

Sobald der Schreibzyklus für die Übernahme des ersten Meßwertes in den Speicher beendet ist, wird über die Steuereinheit ST die zweite Adresse im Speicher angesteuert. Hat nun der zweite Prüfkontakt PK II die Lötmittelwelle durchlaufen und ist dadurch geöffnet worden, stoppt die Zeitmeßeinrichtung Tund das der Zeit zwischen Schließen und Öffnen des Prüfkontaktes PKII proportionale Ausgangssignal der Zeitmeßeinrichtung wird auf den Analog-Digital-Umsetzer A/D gegeben und als digitalisiertes Signal in die zweite Adresse des Speichers geschrieben. Nach Beendigung des Schreibzyklus erfolgt über die Steuereinheit ST die Ansteuerung der dritten Adresse im Speicher. Die Lötmittelwelle hat inzwischen den dritten Prüfkontakt PK III geschlossen. Sobald sie ihn wieder öffnet, wird der Meßwert der Lötmitteltemperatur wiederum in der Temperaturmeßeinrichtung o in ein proportionales analoges elektrisches Signal umgewandelt und dem Analog-Digital-Umsetzer A/D zugeführt, dessen digitales Ausgangssignal in die dritte Adresse des Speichers geschrieben wird. Dadurch, daß das Thermoelement 10 auf gleicher Höhe wie der dritte Kontaktpunkt 8 angeordnet ist, befindet sich das Thermoelement gerade noch in der Lötmittelwelle, wenn diese den Kontaktpunkt 8 verläßt. Somit ist ausgeschlossen, daß durch Auftauchen des Thermoelements aus dem Lötmittel, bevor der Meßwert erfaßt ist, Temperaturmeßfehler auftreten.As soon as the write cycle for the acceptance of the first measured value in the memory is finished, the second address in the memory is via the control unit ST controlled. The second test contact PK II has now passed through the solder wave and has thereby been opened, the timer stops T and that of the time Output signal proportional between closing and opening of the test contact PKII the timing device is given to the analog-to-digital converter A / D and as digitized signal is written to the second address of the memory. After completion of the write cycle, the control unit ST controls the third Address in memory. The solder wave now has the third test contact PK III closed. As soon as she opens it again, the reading will be the solder temperature again in the temperature measuring device o into a proportional analog electrical Signal converted and fed to the analog-to-digital converter A / D, its digital Output signal is written to the third address of the memory. As a result of that the thermocouple 10 is arranged at the same height as the third contact point 8 the thermocouple is barely in the solder wave if it is the contact point 8 leaves. This rules out the possibility of the thermocouple appearing temperature measurement errors occur from the solder before the reading is taken.

Die in den Speicher S aufgenommenen Meßwerte können sofort auf einer Anzeigevorrichtung A dargestellt oder auch später über einen manuellen Meßwertabruf MA angezeig. werden. The measured values recorded in the memory S can immediately be transferred to a Display device A shown or later via a manual readout of measured values MA displayed. will.

Claims

Claims: 1. Method for acquiring the measured values of the following sizes to be controlled in a wave soldering system, in which the circuit boards with predetermined speed first over a flux wave, then over a Preheater and finally transported over a solder wave: the preheat temperature, the solder temperature and the soldering time that each spot required on the circuit boards to traverse the solder wave, characterized that a measuring station like the circuit boards to be soldered by the wave soldering system the preheating temperature, the soldering time and the soldering temperature in sequence measures, stores and displays the measured values.

2. The method according to claim 1, characterized in that the solder wave (1) on the underside of the measurement station as it slides over the solder wave, a first test contact (PK 1) closes, creating a first address in the memory (5) is controlled so that the solder wave then a second test contact (PK II) closes, whereby the value measured in a temperature measuring device (o) of the Preheating temperature transferred to the first address in the memory, a timer circuit (T) started to measure the soldering time and after taking over the measured value of the preheating temperature in the first memory address a second address in the memory is controlled that when opening the second test contact (PK II), when the solder wave has this test contact leaves, the measured value of the soldering time is transferred to the second address in the memory and thereafter a third address in memory is driven that after the solder wave ran over a third test contact (PK 111) and opened it has taken the measured value of the solder temperature into the third address in the memory will.

3. Arrangement for carrying out the method according to one of the preceding Claims, characterized in that the measuring station consists of a printed circuit board (2) consists, on the top in a housing (3) the circuit arrangements for the recording and storage of measured values, as well as a digital display device (4) are arranged, and on the underside of which there is a thermocouple (10), three in the direction of travel the circuit board arranged one behind the other contact points (6, 75 8), as well as a contact strips (9) extending along the contact points and at operating potential is located.

4. Arrangement according to claim 3, characterized in that between the housing (3) of the measuring station and the circuit board (2) a thermal insulation layer (5) is arranged.

5. Arrangement according to claim 3, characterized in that the thermocouple (10) is arranged on the underside of the circuit board (2) that it is barely is in contact with the solder wave when it reaches the third contact point (8) leaves.

The invention relates to a method for acquiring the measured values of the following sizes to be controlled in a wave soldering machine, in which the circuit boards with predetermined speed first over a flux wave, then over a Preheater and finally transported over a solder wave: the preheat temperature, the solder temperature and the soldering time that each spot needed on the circuit boards to go through the solder wave.

Printed circuit boards with components are becoming common today soldered in wave soldering machines. The circuit boards are z. B. used in soldering trolleys and with an adjustable speed via a fluxer, via a subsequent one Heating device that dries and preheats the underside of the circuit board, and thereafter passed over a solder wave.

To adjust the wave soldering system for an optimal soldering process too can, it is necessary to the actual proportions that appear on the circuit boards occur to recognize. These are above all the preheating temperature, the soldering temperature and the soldering time. The soldering time is the time it takes for each point on the circuit board needed to go through the solder wave. Previous measurement methods for this Sizes are very inaccurate because the real proportions on the circuit boards are not can be detected. The temperatures are measured by means of a temperature sensor, which is held into the wave soldering system from the outside, and the soldering time by hand measured with a stopwatch.

The invention is now based on the object of a method as well to specify an arrangement whereby the readings of the preheat temperature, the solder temperature and the soldering time directly from the perspective of the transported through the wave soldering system Printed circuit boards can be retrieved at any time, so that after knowledge These measured values can be used to set the wave soldering system to an optimal soldering process can.

According to the invention, this object is achieved by a method which is characterized in that a measuring station such as the circuit boards to be soldered is sent through the wave soldering system, which successively adjusts the preheating temperature, measures soldering time and solder temperature, stores and displays the measured values.

One convenient process flow is that the solder wave at the bottom of the measurement station as it slides over the solder wave, a first test contact closes, thereby driving a first address in the memory is that the solder wave then closes a second test contact, whereby the value of the preheating temperature measured in a temperature measuring device in the first Address taken over in memory, started a timing circuit to measure the soldering time and after taking over the measured value of the preheating temperature in the first memory address a second address in the memory is controlled so that when the second test contact is opened, when the solder wave leaves this test contact, the measured value of the soldering time into the second address in memory and then a third address in memory is controlled that after the solder wave via a third test contact ran away and opened it, the measured value of the solder temperature is transferred to the third address in the memory.