Technical Field

The present invention relates to an upgraded soldering unit, usable in particular in automated soldering processes.

Background Art

The need is known to perform automated or semi-automated soldering operations on printed circuits, wirings or small-size masses.

A first known soldering technique comprises the use of robotized systems for moving a laser-beam emission and focalisation device.

Such systems, though finding widespread application in the industrial field for precision soldering on electronic circuits, are not however cost-effective for all types of uses due to their high costs.

With particular reference to the realisation of soldering points on electronic boards, a second soldering technique involves the use of soldering units comprising a first device for the emission of a flow of hot air in correspondence to an area to be heated, on the lower face of the board.

Such first device is generally composed of an air-heating station to which is connected, by means of a duct, a hot air flow dispensing nozzle.

Simultaneously, a second device of the soldering unit which supports a metal material with low fusible temperature, of the type of tin, tin alloys or the like, approaches the upper face of the board until the material comes into contact with the heated area.

The heat thus conveyed by conduction leads to the fusion of the material which deposits on the heated area in correspondence to a point to be soldered.

The operation is subsequently repeated for the realisation of further soldering points.

These known soldering units are not however without drawbacks.

In particular, the presence of two separate devices, one for the emission of the flow of hot air and one for the deposit of the metal material, significantly complicates the soldering process and, at the same time, calls for the use of complicated automation technologies for the synchronisation of the two devices. Another drawback of known soldering units consists in the large overall dimensions, deriving in particular from the considerable dimensions of the heating station used.

Not the least drawback is that of the low level of precision achieved by such soldering units: the area heated by the flow of hot air dispensed by the nozzle is in fact considerably greater compared to the actual surface area to be soldered. The patent document EP 2054187 A2 describes an air soldering unit suited to overcome the above drawbacks.

In particular, such soldering unit can be associated with conventional automated movement means, of the type of a robot arm or the like, and comprises a support suited to support both an air flow heating and injection device, and dosing and positioning means of a fusible metal material.

Such soldering unit too, however, is susceptible to upgrading.

In particular, such soldering unit can be upgraded so as to perform:

better quality soldering;

- soldering of different types;

soldering of components of different types.

Description of the Invention

The main aim of the present invention is to provide an upgraded soldering unit which allows to perform better quality soldering in the best possible way.

Another object of the present invention is to provide an upgraded soldering unit which allows to perform soldering of different types in the best possible way. Another object of the present invention is to provide an upgraded soldering unit which allows to perform soldering of components of different types in the best possible way.

Another object of the present invention is to provide an upgraded soldering unit which allows to reduce the overall dimensions of the equipment and devices used.

Another object of the present invention is to provide an upgraded soldering unit which allows to increase the precision of the soldering process with respect to the known air soldering units.

Another object of the present invention is to provide an upgraded soldering unit which allows to overcome the mentioned drawbacks of the state of the art within the ambit of a simple, rational, easy and effective to use as well as low cost solution.

The above objects are achieved by the present upgraded soldering unit, comprising dosing and positioning means for dosing and positioning a fusible metal material in correspondence to an area to be soldered and at least a heating and injection device of a fluid in correspondence to said area to be soldered, characterized by the fact that it comprises selection means of said fluid suited to select at least one between compressed air and inert gas.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will become more evident from the description of a preferred, but not sole, embodiment of an upgraded soldering unit, illustrated purely as an example but not limited to the annexed drawings in which:

figures 1 and 2 are axonometric views of the upgraded soldering unit according to the invention;

figure 3 is a side view of the upgraded soldering unit according to the invention; figures 4 and 5 are partial section views from above of the heating and injection device of the upgraded soldering unit according to the invention.

Embodiments of the Invention

With particular reference to such figures, globally indicated by 1 is an upgraded soldering unit, particularly used for soldering components of printed circuits, for soldering wirings and for soldering small-size masses.

The soldering unit 1 comprises a substantially plate-shaped support element 2, having a fastening plate 3 associable with automated movement means, of the type of a robotized arm or the like.

The support element 2 supports a heating and injection device 4 suited to heat and inject a fluid in correspondence to an area to be soldered.

Furthermore, the support element 2 supports dosing and positioning means 5 of a material of metal type and fusible in correspondence to the area to be soldered. In particular, the heating and injection device 4 comprises a body 6 of substantially tubular shape, hollow, elongated and opened at the extremity, which houses a heating element 7 and which has a fluid dispensing mouth 8. Advantageously, the heating element 7 can be composed of an incandescent glow plug of the type commonly used during the starting process of diesel engines.

Advantageously, the soldering unit 1 comprises selection means of the fluid to be heated and injected by means of the heating and injection device 4, indicated altogether in the illustrations by the reference 9.

The selection means 9, in particular, are suited to select compressed air or an inert gas, preferably made up of nitrogen or carbon dioxide.

The use of an inert gas allows performing in the best possible way better-quality soldering, soldering of different types and soldering of components of different type.

With reference to the particular embodiment shown in the illustrations, the selection means 9 comprise a connection element 10, fastened to the support element 2, suited to connect the heating and injection device 4 to one between a source of compressed air 11 and a source of inert gas 12.

In particular, the connection element 10 can be composed of a solenoid valve or of a similar device.

The source of compressed air 1 1 and the source of inert gas 12 can be composed of respective tanks.

The selection means 9, furthermore, comprise control means, schematized in figure 3 and indicated with the reference 13, suited to pilot the connection element 10 between a first configuration, wherein the heating and injection device 4 is connected to the source of compressed air 11, and a second configuration, wherein the heating and injection device 4 is connected to the source of inert gas 12.

In particular, the control means 13 can be composed of an electronic control unit connected to the solenoid valve 10, of the type of a microprocessor system or the like, and/or of a respective software application.

Advantageously, the control unit 13 can be programmed so as to use air or inert gas depending on the soldering process to be carried out and the type of materials or components to be soldered.

This permits making soldering of better quality, making soldering of different types and making soldering of components of different types.

Different embodiments of the connection element 10 and of the control means

13 cannot however be ruled out.

The selection means 9 comprise input means of the compressed air and/or of the inert gas, indicated altogether in the illustrations with the reference 14.

In particular, the input means 14 comprise a first pipe 15 having an extremity connected to the heating and injection device 4 and an opposite extremity connected to the output of the solenoid valve 10.

Furthermore, the input means 14 comprise a second pipe 16 having an extremity connected to one of the inputs of the solenoid valve 10 and an opposite extremity connected to the source of compressed air 1 1.

The input means 14, furthermore, comprise a third pipe 17 having an extremity connected to one of the inputs of the solenoid valve 10 and an opposite extremity connected to the source of inert gas 12.

The body 6 of the heating and injection device 4 comprises a first inner chamber 18 which has a dispensing mouth 8.

The first chamber 18 houses a first section 7a of the heating element 7 suited to produce heat and is connected to the first pipe 15.

With particular but not limitative reference to the specific embodiment of the invention described herein, the section 7a is housed inside the first chamber 18 in correspondence to a front portion of the body 6 and is made up of the metal bulb of the glow plug 7.

In an assembly configuration in which the glow plug 7 is housed inside the body 6, an interspace is defined between the inner surface of the first chamber 18 and the outer surface of the metal bulb 7a.

Such interspace allows the recirculation of compressed air or of the inert gas introduced by the first pipe 1 around the metal bulb 7a and towards the outside through the dispensing mouth 8.

The body 6 also comprises a second inner chamber 19 that houses a section to be cooled 7b of the heating element 7.

The second chamber 19 is connected to a cooling pipe 20 suited to introduce compressed air and has an outlet opening 21 for the introduced air. The cooling pipe 20 can be connected to the source of compressed air 1 1 or to a supplementary source of compressed air.

In the assembly configuration, and with particular reference to the specific embodiment described here, an interspace is defined between the inner surface of the second chamber 19 and the outer surface of the second section 7b of the metal body of the glow plug 7.

Such interspace allows the recirculation of the air introduced by the cooling pipe 20 around the second section 7b and towards the outside through the outlet opening 21 to cool the second section 7b itself.

It is pointed out that with the words "front" and "rear" reference is made, in the present description and in a non-exclusive way, to the normal arrangement of the body 6 in relation to the direction of supply of the flow of air or inert gas towards the area to be soldered.

Advantageously, threaded means are provided which allow screwing on and screwing off the glow plug 7 inside the body 6 and which are made up of a screw 7c defined on the lateral outer surface in correspondence to a substantially median section of the glow plug 7 and of a corresponding nut screw 6d defined on a portion of the lateral inner surface of the body 6.

Usefully, the dispensing mouth 8 and the outlet opening 21 are defined in correspondence to a first and a second extremity 6a and 6b respectively of the body 6, which are opposite one another.

The first pipe 15 for introducing the air or the inert gas has an extremity fitted inside a first supply hole 22 defined as a through hole on the body 6, in correspondence to the first chamber 18, and the opposite extremity connected to the solenoid valve 10.

The cooling pipe 20 has an extremity fitted inside a second hole 23 for the air supply defined as a through hole on the body 6, in correspondence to the second chamber 19, and the opposite extremity connected to a source of compressed air.

The dosing and positioning means 5 comprise a spool 24 which is associated rotatable with the support element 2 and on which is wound a wire 25 of fusible metal material, of the type of tin, or a tin alloy or the like. In particular, the soldering unit 1 comprises means for supporting the spool 24, comprising a spindle 26 fixed to the support element 2 and fitted inside the hole of the spool 24.

The dosing and positioning means 5 also comprise a feed device 27 for feeding the free extremity of the wire 25 unwound from the spool 24 towards the area to be soldered.

The feed device 27 comprises a rectilinear guide channel for the sliding of the wire 25, of the type of a hole, a groove or the like.

Two counter-rotating wheels 28, at least one of which made to be a driving wheel, are arranged along a section of the channel 25, with the wire F engaged between them.

The wire 25 moved by the pair of wheels 28 inserts itself inside a cannula 29 arranged axially with respect to the wire sliding channel.

The cannula 29 has a free protruding extremity positionable in correspondence to the area to be soldered.

The feed device 27 can also comprise the verification of the end of the wire F on the spool 24 by means of a control encoder, not shown in the illustrations, suited to control the forward movement of the motor which causes the wire to run.

Alternatively, the feed device 27 can comprise at least a sensor of the type, e.g., of a position sensor, for detecting the position of the free extremity of the wire 25.

Advantageously, the soldering unit 1 can comprise a suction cup 30 associated with the support element 2 and suited to cool the heating and injection device 4. For a more precise display of the soldering process and a more accurate control of the automated movement means, the soldering unit 1 can comprise optical detection means 31 of the area to be soldered.

As shown in the illustrations, such optical detection means 31 can be composed of a camera (or the like) positionable on a supplementary support which extends from the support element 2.

The invention operates as follows.

The electronic control unit 13 is programmed and the use of air or inert gas is selected depending on the type of soldering and the type of component to be soldered.

The robotized arm 3 moves the soldering unit 1 until this is positioned with the dispensing mouth 8 and the cannula 29 in the proximity of the area to be soldered.

The introduction of compressed air or, alternatively, of inert gas into the first chamber 18 through the first pipe 15 and the simultaneous activation of the glow plug 7 with incandescence of the metal bulb 7a, allow heating the flow of air/inert gas which is directed and focalized by the dispensing mouth 8 towards the area to be soldered.

At the same time, the air introduced inside the second chamber 19 through the cooling pipe 20 allows maintaining the temperature of the heating and injection device 4 below potentially hazardous temperatures.

The wheels 28 of the feed device 27 turn and drag the wire 25 and push its free extremity through the cannula 29, as far as contact with the area to be soldered.

The heat accumulated by the area to be soldered, together with the heat of the air flow or of the inert gas emitted by the dispensing mouth 8, lead to the fusion of part of the metal material making up the wire 25, which deposits in correspondence to the area to be soldered.

The soldering unit 1 is subsequently moved away from the soldered area and/or positioned in correspondence to a new area to be soldered.

It has in practice been ascertained how the described invention achieves the proposed objects.

In particular the fact is underlined that the possibility of programming the control unit so as to use the air or the inert gas in accordance with the soldering ob to be done allows achieving the following objects:

- making soldering of better quality;

- making soldering of different types;

- making soldering of components of different types.