METHOD FOR DETERMINING THE WAVE HEIGHT OF A SOLDERING WAVE, DEVICE FOR DETERMINING THE WAVE HEIGHT OF A SOLDERING WAVE AND WAVE SOLDERING SYSTEM

Abstract

A device (16) and method for determining the wave height (H) of a solder wave (42) formed from liquid solder (41) and conveyed by a solder nozzle assembly (12) is provided. The device includes a resiliently flexible film body (18) for floating placement on the solder wave (42) and a measuring unit (38) for determining the position of the surface of the film body (18) floating on the solder wave relative to a reference point (39). The device has an evaluation unit (44) for determining the wave height (H) depending on the position of the film body (18). A wave soldering machine is also provided.

Claims

1. A method for determining the wave height (H) of a solder wave (42), wherein liquid solder (41) is conveyed through a solder nozzle assembly (12) to form the solder wave (42), the method comprising: placing an elastically flexible film body (18) on the solder wave (42) such that the film body (18) floats on the solder wave (42), determining the position of the surface of the film body (18) floating on the solder wave relative to a reference point (39), and determining the wave height (H) depending on the position of the film body (18).

2. The method according to claim 1, wherein, for determining the relative position of the surface of the film body (18), a reference distance (A.sub.1) between the reference point (39) and a measuring unit (38) is measured, and that a wave distance (A.sub.2) between the surface of the film body (18) floating on the solder wave and the measuring unit (38) is measured.

3. The method according to claim 1, wherein the surface of the film body (18) resting on an edge (36) of the solder nozzle assembly (12) is used as the reference point (39).

4. The method according to claim 1, wherein an edge (36) of the solder nozzle assembly (12) is used as the reference point.

5. The method according to claim 2, wherein the distance (A.sub.1, A.sub.2) is measured by a measuring unit (38) in the form of a radar measuring unit, a laser measuring unit, an optical, inductive or capacitive measuring unit, and/or an ultrasound measuring unit.

6. A device (16) for determining the wave height (H) of a solder wave (42) formed from liquid solder (41) and conveyed by a solder nozzle assembly (12), having a resiliently flexible film body (18) for floating placement on the solder wave (42), having a measuring unit (38) for determining the position of the surface of the film body (18) floating on the solder wave relative to a reference point (39), and having an evaluation unit (44) for determining the wave height (H) depending on the position of the film body (18).

7. The device (16) according to claim 6, wherein the measuring unit (38) is designed for measuring a reference distance (A.sub.1) between the reference point (39) and the measuring unit and for measuring a wave distance (A.sub.2) between the surface of the film body (18) floating on the solder wave and the measuring unit (38).

8. The device (16) according to claim 6, wherein the film body (18) and/or the measuring unit (38) are arranged on a holding device (20).

9. The device (16) according to claim 8, wherein the holding device (20) has a displacement mechanism (22) that displaces the film body (18) between a measuring position in which the film body rests in a floating manner on the solder wave (42) and a parked location in which the film body is in a parked position.

10. The device (16) according to claim 9, wherein the displacement mechanism (22) is configured as a lifting mechanism for displacing the film body (18) in the vertical direction for retraction and extension.

11. The device (16) according to claim 9, wherein the displacement mechanism is configured as a pivot mechanism for pivoting the film body (18) about a pivot axis into the measuring position and for pivoting the film body out into the parked position.

12. The device (16) according to claim 6, wherein the holding device (20) has an adapter element (28) which encloses an acute angle (w) with a vertical plane (30) and on which the film body (18) is arranged.

13. The device (16) according to claim 6, wherein the film body (18) is formed by a metal sheet.

14. The device (16) according to claim 6, wherein the film body (18) has a rectangular shape in plan view having two longitudinal sides (32) and two narrow sides (34).

15. The device (16) according to claim 6, wherein the film body (18) has a base surface and edge regions (46) having free edges, wherein the edge regions (46) enclose an angle in the range of 30-150.

16. A wave soldering machine (10) having a solder nozzle assembly (12), having a pump (14) for conveying liquid solder (41) through the solder nozzle assembly (12) to form a solder wave (42), and having a device (16) according to claim 6.

17. The wave soldering machine (10) according to claim 16, having a displacement unit (40) movable along an x-direction and/or y-direction, wherein the device (16) is arranged on the displacement unit (40).

18. The wave soldering machine (10) according to claim 16, wherein a protective screen (48) is provided between the film body (18) and the measuring unit (38).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] FIG. 1 shows a wave soldering machine having a device for determining the wave height in a reference state;

[0041] FIG. 2 shows the wave soldering machine according to FIG. 1 in a measuring state; and

[0042] FIG. 3 shows a film body for a device for determining the wave height with an adapter.

DETAILED DESCRIPTION

[0043] FIG. 1 shows a wave soldering machine 10 which provides a solder nozzle assembly 12 and a pump 14 for pumping liquid solder through the solder nozzle assembly 12. In FIG. 1, no liquid solder is conveyed by the pump 14 through the solder nozzle assembly 12.

[0044] FIG. 1 further shows a device 16 for determining the wave height of a solder wave, the device 16 having a resiliently flexible film body 18 which is arranged on a holding device 20. The holding device 20 in turn has a displacement mechanism 22 which is designed as a lifting mechanism for displacing the film body 18 in the direction of a vertically extending z-axis. The displacement mechanism 22 is formed by a base body 24 having actuating elements 26 movable therein in the direction of the z-axis. The actuating elements 26 can thus be retracted and extended in the direction of the z-axis. An adapter element 28, on which the film body 18 is ultimately fastened, is provided at the free ends of the actuating elements 26. The adapter element 28 is arranged in such a way that it encloses an acute angle w with a horizontal 30 so that the film element 18 is ultimately likewise arranged extending obliquely to the horizontal 30.

[0045] The film element 18 is in turn designed in particular as a spring steel sheet and has a rectangular basic shape having two longitudinal sides 32 and two narrow sides 34. In this case, one narrow side 34 is fixedly arranged on the adapter element 28. The other narrow side 34 is a free narrow side, which in FIG. 1 rests against a tear-off edge 36 of the solder nozzle assembly 12. The film body 18 has in particular a thickness of 0.1 mm to 0.2 mm. In particular, the wave height H can be detected with a tolerance of/0.1 mm to 0.25 mm. In this case, the resiliency of the film body 18 is designed in such a way that it is ensured that it is deflected by a solder wave 42 and reliably floats on the latter.

[0046] In order to ensure that the free narrow side 34 comes to rest against the tear-off edge 36, the adapter element 28 together with the film body 18 can be moved in the z-direction via the displacement mechanism 22 until the film body 18, or its free narrow side 34, comes to rest against the tear-off edge 36.

[0047] The device 16 further has a measuring unit 38 in the form of a laser measuring unit, which measures the distance A.sub.1 between a reference point 39, which lies on the surface of the film body 18 resting on the tear-off edge 36, and the measuring unit 38. Distance A.sub.1 is a reference distance since it is measured without taking into account the solder wave forming during operation of the machine.

[0048] The surface of the film body 18 is in particular painted or coated in order to enable precise measurement of the distance A by the measuring unit 38.

[0049] The device 16 can be arranged on a displacement unit 40, which is only schematically indicated in FIG. 1, so as to be displaceable in a y-direction extending transversely to the z-direction.

[0050] During operation of the wave soldering machine 10, i.e., when printed circuit boards are soldered, the device 16 is in a parked position (not shown).

[0051] If the wave height H of a solder wave 42, consisting of liquid solder 41, which is shown in FIG. 2, is by the pump 14 and passes through the solder nozzle assembly 12, is intended to be determined, the device 16 is moved from the parked position (not shown in the figures) into the measuring position shown in FIG. 2. In this case, the device 16 is located in the same position as in FIG. 1. Due to the presence of the solder wave 42 and the placement of the flexible film body 18 on the solder wave 42, the film body 18 floats on the solder wave 42 and thus is deflected upward due to the presence of the solder wave 42.

[0052] This results in a wave distance A.sub.2 between the measuring unit 38 and the surface of the film body 18 floating on the solder wave 42.

[0053] Thus, if the distance between the measuring unit 38 and the surface of the film body 18 is measured in the measuring location shown in FIG. 2, and this distance A.sub.2 is compared with reference distance A.sub.1, the wave height H can ultimately be determined by means of an evaluation unit 44 indicated schematically in FIGS. 1 and 2. The wave height H can be determined in the embodiment shown in the figures by the difference of the reference distance A.sub.1 and the wave distance A.sub.2: H=A.sub.1A.sub.2. In this case, the evaluation unit 44 can be integrated into the measuring unit 38.

[0054] The measurement of the distances A.sub.1 and A.sub.2 in this case preferably takes place in the region of the surface of the film body 18, the underside of which is located in the liquid solder of the solder wave.

[0055] However, according to the disclosure it is conceivable that the reference point 39, as shown in FIG. 1, does not lie on the surface of the joint body, but is formed, for example, by the tear-off edge 36. In this case, geometric conditions such as the thickness of the film body 18 must be taken into account when determining the wave height H.

[0056] The wave height H determined by means of the device 16 can in particular be displayed to a user or communicated to a superordinate controller. Depending on the wave height H, signals can then be generated and/or measures can be taken.

[0057] In order to protect the measuring unit 38 from heat and solder splashes, a protective screen 48, indicated in FIG. 2, is advantageously provided between the measuring unit 38 and the film body 18.

[0058] Even if the distance A.sub.2 between the measuring unit 38 and the surface of the film body 18 is measured at only one point in the figures, it is conceivable that the measurement takes place at multiple points so that a more accurate, possibly averaged, measurement result is achieved.

[0059] An alternative embodiment of a film body 18 on an adapter element 28 is shown in FIG. 3. In the region of its free narrow side 34 and in the region of the portions of the longitudinal sides 32 facing the narrow side 34, the film body 18 has edge regions 46 which are folded upward perpendicularly to the plane of the film body 18. The folded regions are connected to one another in a water-tight manner, in the corners. This achieves a better floating behavior of the film body 18 on the solder wave 42. Furthermore, liquid solder 41 is prevented from flooding the upper side of the film body 18, which would ultimately falsify the measurement result. Instead of or in addition to the upwardly folded edge regions 46, it is conceivable that further and/or additional elements or means are provided on the upper side of the film body 18, which elements or means prevent the film body from dipping into the solder wave.