EP0958089A2

EP0958089A2 - Device for the selective, contactless soldering and unsoldering of components

Info

Publication number: EP0958089A2
Application number: EP96945466A
Authority: EP
Inventors: Ulrich Gerloff
Original assignee: Hahn Meitner Institut Berlin GmbH
Current assignee: Hahn Meitner Institut Berlin GmbH
Priority date: 1995-09-18
Filing date: 1996-09-18
Publication date: 1999-11-24
Also published as: WO1997012714A2; WO1997012714A3; DE19639993A1; DE19639993C2

Abstract

A device for the selective, contactless soldering or unsoldering of selected components has a soldering and precision positioning head for further processing, mounting or repairing boards with a high packing density of electronic components. The soldering and precision positioning head has as heating unit a halogen infrared radiator (HS) in a support (SH) for transmitting energy from the halogen infrared radiator (HS) to the component (BE) to be soldered or unsoldered, as well as a quartz glass capillary tube (QK) united with means for depositing and lifting a selected component. The top face of the quartz glass capillary tube (QK) is arranged in the focal point of the halogen infrared radiator (HS), inside a closed chamber (K) provided with a vacuum connection (VA). The top surface of the closed chamber (K) is a quartz glass pane (QS) arranged away from the focal point of the halogen infrared radiator (HS). The halogen infrared radiator (HS) is driven by a thermoelement (TE) connected to a temperature regulator (RT). This device may be used for processing very diverse components and is suitable as hand tool, in particular for servicing and repairing. It may be built as a compact arrangement into already known equipment with little mechanical outlay.

Description

description

Device for contactless, selective soldering or desoldering of components

description

Technical field

The invention relates to a device for non-contact, selective soldering or desoldering of components, the heating unit, means for contactless energy transfer from the heating unit to the component, means for storing or lifting a selected component to or from a solder joint and means for Monitoring of the temperature at the solder joint has.

PRIOR ART A device of the type mentioned can be found in the brochure from "Micro Electronic Systems, Inc.", 119 Northrup St., Brigdewater, CT 06752 USA, from 1991. In this fine walk and soldering system, which can be controlled almost completely automatically, the energy required for a soldering or desoldering process is provided by a hot gas (air or inert gas). However, the use of a hot flowing gas has the consequence that, on the one hand, the components that are to be selectively machined and small in size can be moved out of their position and therefore the one described in the above-mentioned. Brochure described for the positioning is large, and on the other hand, the working field is not sharply delimited because of the flowing gas. In addition, the profiles of the nozzles directed at the components to be machined must always be adapted to these components as a means for heat conduction, which adversely affects the handling of the device mentioned and entails high costs for necessary conversion / downtimes and the provision of various nozzle profiles.

The cheapest tool for selective but not non-contact soldering is the soldering iron in different versions. As a tip soldering iron, it is part of the standard equipment of repair stations in industry and trade. For components with a large number of pins (ICs), special heads are provided which are adapted to the mechanical dimensions of the integrated circuits, ie a special soldering iron must be available for each integrated component of a plantine, since a "flying head change" is not possible due to the heat capacity . On The main disadvantage of the piston is the mechanical stress on the joining partners, especially in the sensitive multilayer boards with their thin conductor tracks used today.

It is common practice when unsoldering multi-pole integrated circuits (ASICs, microprocessors, etc.) to cut off the individual pins with the side cutter and to try to remove them from the via holes using mechanical hand pumps and tweezers. The plated-through holes on the inner conductor tracks often loosen, so that the entire remainder of the printed circuit board is defective. The removed component is also defective, even if it turns out that it has not contributed to the malfunction of the overall circuit (component renewal on "suspicion"). The not very exact heat control of the soldering tips often leads to the detachment of the conductor tracks. When desoldering components in a fine pitch, short circuits can also occur in the circuit arrangements due to the necessary stability and the associated limited tapering of the soldering tips.

Non-contact soldering can be carried out in different ways. The advantages of hot gas guns are their value for money and the non-mechanical stress on the joining partners. A disadvantage is the poor focusability of the heat beam. A blow on adjacent and possibly temperature sensitive components can not be excluded. When soldering small SMD components, they can be blown away, as can the solder. An exact measurement of the soldering temperature and thus the possibilities of precise regulation of the hot air jet is not known in the case of such hot gas guns. Despite its low heat capacity, the temperature control of a hot gas can only be carried out with a not insignificant delay.

Due to the large amount of heat (approx. 3000 ° C), microflames are only suitable for soldering large, highly heat-conductive parts in electronics, e.g. Ground connections on housings. The microflame cannot be used for high-density electronic boards.

Induction and resistance soldering cannot be used for electronic parts due to the damaging effects of the electrical or magnetic fields. Black light emitters as blackened heated metal or ceramic plates emit in the long-wave IR range and would in principle be suitable as surface emitters for heating the solder joints. The beam can only be focused with special lenses for the wavelength range from 4 μm to 10 μm. In this area, however, the absorption coefficient of a tin-lead alloy shows low values.

With their bundled and coherent light of the same wavelength, Nd: Y AG semiconductor lasers are suitable and quickly switchable energy sources for soft soldering, since their wavelengths of 1.06 μm and 0.8 μm fall within the range of high absorption coefficients of soft solder. CO ₂ lasers with λ = 10.6 μm are less suitable. Due to the high investment costs, they are only conceivable for industrial assembly lines. Because of the high level of safety engineering involved, they appear unsuitable for manual hanging devices.

Such contactless soldering techniques are at least problematic for selective soldering or unsoldering, in particular of electronic components.

Solder wave baths, dip soldering and infrared soldering lines do not allow selective soldering or desoldering. Passing over a liquid solder wave or immersing it in a solder bath of printed circuit boards is suitable for industrial mass production or small series. It is omitted for repair purposes on boards. This also applies to the passage of assembled printed circuit boards under infrared sources within a defined temperature profile for series production.

For bonding chips, e.g. B. from US-A-4893 742 an ultrasonic laser soldering device is known. Here, a high-precision selective, but no contactless connection of the joining partners takes place. On the other hand, contactless joining of joining partners by means of energy radiation, in particular infrared radiation, but not selectively applicable, is by soldering e.g. known from DE-Al-27 35 231, EP-B-0 184 943, DD-A5-286 314 and US-A-5 060 288.

Presentation of the invention

The invention is based on the technical problem of designing the equipment required for selective, contactless soldering or unsoldering of components or components in such a way that ease of handling, automation, low technical and safety expenditure and inexpensive investment and operating costs as well as high quality and accuracy - even under difficult local conditions, e.g. high packing density - with a large variety of components / components as well as the lowest possible mechanical stress and minimal thermal stress on neighboring components / components or the other joining partner.

For this purpose, the solution according to the invention provides that a soldering and fine plaster head is provided, in which: the heating unit is a halogen infrared radiator, - the halogen infrared radiator is arranged in a radiator holder,

- The means for the contactless energy transfer from the halogen infrared emitter to deposit or lift off the selected component in a position in the quartz glass capillary tube which is changeable in relation to the selected component are combined, - The quartz glass capillary tube is arranged with its upper end face at the focal point of the halogen infrared emitter and the halogen Infrared radiator and the quartz glass capillary tube are mechanically and optically connected,

- The quartz glass capillary tube is arranged with at least its upper part and upper end face in a closed chamber provided with a vacuum connection, the upper cover of which is between an upper one

End face of the quartz glass capillary tube and the halogen infrared radiator and quartz glass pane arranged outside its focal point is formed, and the device has a thermocouple or an infrared detector with which the temperature of the solder joint is determined at at least one location of the energy transmission path from the halogen infrared radiator to the selected component will, and

- The thermocouple and / or the infrared detector with a temperature controller and this is connected to a control of the halogen infrared radiator.

The soldering and fine plaster head essential for the device according to the invention is inexpensive to manufacture and can be used variably. Depending on the application, interchangeable quartz glass capillary tubes can be used in three sizes, for example, with diameters between 4 mm and 9 mm and a length of 50 mm to 140 mm. The clear width of the capillary opening depends on the size and mass of the components to be deposited or lifted off and in the examples mentioned is in the range between 0.5 mm and 2 mm. The supply of the halogen infrared lamp with electrical energy takes place with harmless 12 volt low voltage. Due to the low-loss, total reflection-based and delay-free energy transport in the quartz glass capillary tube, the local working area is sharply limited and reaches the required operating temperature within seconds.

Locations of the energy transmission path from the halogen infrared radiator to the component to be soldered in or out, where the temperature can be determined at the soldering point, should be as close as possible to the soldering point. If this is not possible, this is the place for example the vicinity of the upper end face of the quartz glass capillary tube.

A particularly advantageous constructive embodiment of the solution according to the invention provides for the soldering and fine plaster head to arrange compactly in a housing at least the halogen infrared radiator and the chamber delimited by the quartz glass pane and a receiving block for the quartz glass capillary tube and having a gas connection. This compact arrangement forms an easily replaceable unit, with which unit the quartz glass capillary tube can be detachable, but can be connected in a vacuum-tight manner.

If, on the other hand, an easy interchangeability of quartz glass capillary tube and / or a unit with the halogen infrared radiator is desired, the solution according to the invention is designed in such a way that the quartz glass capillary tube is closely surrounded by a protective tube up to its lower end face and is detachably connected vacuum-tight to the unit mentioned.

A detachable connection for this and that structural design of the soldering and fine-plush head can be designed as a threaded or plug connection. In the case of a threaded connection, the height of the upper end face of the quartz glass capillary tube can be adjusted in the area of the thread height. So that quartz glass capillary tubes with different diameters can be exchanged quickly and easily in an existing receiving block, it has proven to be advantageous to fit a transition piece for receiving quartz glass capillary tubes with different diameters into the receiving block in a vacuum-tight manner.

The radiation that supplies the energy required to melt the soft solder is in the wavelength range from approx. 0.5 μm to 2 μm. In this area lead-tin Alloys have a high absorption coefficient. The absorption coefficient of materials from which circuit boards and electronic components usually consist only increases with longer-wave radiation. At the soldering point, the heat is generated by absorption and convection, locally limited, by focusing the radiation in the quartz glass rod serving as an optical waveguide. The capillary in the quartz glass rod has practically no effect on the function as an optical fiber. Designed as a quartz glass capillary tube, this inexpensive construction element combines both sequential tasks of energy transfer and the high-precision movement / positioning of the joining partners to be soldered or unsoldered, as well as simultaneous heating by means of electromagnetic (light) radiation and this supporting convection.

The entire device consists of a combination of devices and represents a soldering station that, for example, at repair workstations, the soldering or unsoldering of multi-pole electronic SMD (surface mounted device) components in fine pitch technology on standard circuit boards or on injection molded circuit boards (molded interconnected devices) three-dimensional arrangement.

For the industrial production of electronic assemblies, for example in SMD technology, in fully automatic manufacturing processes, the invention offers possibilities for re-fitting defective parts, for fitting special components and in particular for re-soldering damaged or potentially damaged solder joints.

In the embodiments of the invention, at least for the control of the halogen infrared radiator and for the actuation of the vacuum / gas connection

Chamber that communicates with the outside world via the bore in the quartz glass capillary tube

Connection is established, controls or control loops are provided. The signal processing takes place by means of a controller, a computer or a specific one

Process control, depending on the extent of the actual values recorded by detectors of a soldering station, predetermined target values and automatically controlled

Actuators. In any case, there are means for monitoring the temperature at the

Soldering and switching on and off as well as switching between vacuum and gas included in the chamber. The preferred training forms of

Invention provided on gas connection - for the supply of air or nitrogen to the soldering point - switchable vacuum connection of the chamber partially enclosing the quartz glass tube enables air during the heating process (or Nitrogen) at a very low flow rate compared to a device operated with hot gas. The air heated in the quartz glass capillary tube flows out at its lower end face, which is positioned close above the component to be soldered or unsoldered, and ensures additional, uniform heat distribution in the sense of forced convection. The main heat is generated at the solder joint by absorption of the joining partners. When the required temperature for desoldering has been reached, the lower end face of the quartz glass capillary tube is placed on the component, switched to vacuum by means of the switch, and the component is sucked through the quartz glass capillary tube. For the suction of components with an uneven surface, it has proven to be advantageous to cover the end of the quartz glass capillary tube with a temperature-resistant plastic ring that compensates for the unevenness and ensures a vacuum-tight seal between the quartz glass capillary tube and the component.

The quartz glass pane which forms the cover of the chamber in the soldering and fine plaster head can be designed without, but advantageously with a filter effect for visible light or also with a lens for an additional focusing effect. This additional focusing effect has proven to be particularly advantageous for the diameter of the quartz glass capillary tube <8 mm and a reduction in the focal point by the lens.

In an embodiment of the invention with its own inventive meaning, the soldering and fine walking head is designed as a hand-held device. This hand-held device forms a module of the device, which in particular comprises the control device and, if necessary, further modules, in particular the modules already mentioned as embodiments of the invention. In this handheld device, a housing with an electrical feed for the radiator is arranged around the halogen infrared radiator. Furthermore, this housing is connected to the chamber which partially encloses the quartz glass capillary tube. Means for a handle adjoin the chamber, which enclose the quartz glass capillary tube close to its lower end face and at the same time serve to protect the sensitive capillary tube during operation. The handle encloses the quartz glass capillary tube as a tight-fitting tube. In order to achieve better heat insulation, a heat-insulating mat can be provided between the quartz glass capillary tube and the handle. With such a hand-held device, in one embodiment the chamber is designed as a transition piece between the housing and the handle. In addition, a thermocouple can be guided through the vacuum gas connection into the chamber as close as possible to the upper end face of the quartz glass capillary tube, which is connected to the power supply of the halogen infrared radiator via a controller. The temperature at the more distant location of the solder joint can be determined by calibrating the temperature measured near the upper end face by means of a thermocouple, taking into account the length of the quartz glass capillary tube and its thermal conductivity. Switches, for example for the change in the chamber of the handheld device from compressed air to vacuum and vice versa and the like can be designed for manual or foot operation. When using the soldering and fine plush head as a machine head in automated systems, the structural details specifically provided for the hand-held device are not required or are provided in the modification appropriate there.

A change in the position of the quartz glass capillary tube relative to the selected component to be soldered in or soldered out can generally be brought about in a handheld device simply by moving the handheld device. However, the soldering and fine plaster head can also remain stationary and the selected component can be moved in all three spatial directions under the lower end face of the quartz glass capillary tube. As a rule, however, the component must be "bypassed" with the soldering and fine strapping head. For this reason and because its mass to be moved is less than that of a tray for circuit boards, the invention provides for both the handheld device and the machine head to be used in positioning devices with x, y and z travel options. In addition, such a head can be designed to be exchangeable with only minimal mechanical effort for commercially available "plaque arms".

The control of these movements is of course one of the tasks of process control. Their flexibility and efficiency should also make it possible, for example, to be able to call up profile data once saved for a large number of component profiles. The device according to the invention can thus be used flexibly for a large number of different components without impairing its ease of handling. This also applies to the fact that there is always a sharply delimited local working field with a variety of components in a simple manner with easily and quickly replaceable types of quartz glass capillary tubes. Further modules of devices according to the invention relate to additional devices and devices which are adapted in a special way to the requirements and circumstances of soldering and unsoldering processes.

This includes in particular that for the preheating of a Leiteφlatte to 100 ° C to 130 ° C in a soldering station with a soldering and fine plush head for selective soldering or desoldering of a component also a locally limited and positionable underheating is provided. This makes it possible to process multilayer structures with a thickness of up to 6 mm.

A preferred embodiment of the invention provides for at least one separately heatable insert made of a material whose thermal conductivity is greater than the thermal conductivity of the plate material to be arranged in an underheating consisting of a plate of good thermal conductivity and provided with heating connections. If such a plate can be moved laterally, the design can be limited to a single insert, preferably arranged in the middle of the plate.

In a special version, the insert is a glass cylinder and its separate heating is a halogen infrared radiator, the focal point of which is in the lower surface of the glass cylinder. This embodiment of the invention is particularly suitable for treating selected components in an assembled cassette, since the cassette can be guided over the warmer insert in a targeted manner, and the unselected components in the cassette are not exposed to unnecessarily high temperatures.

For the soldering or desoldering of components on / from a film, in another embodiment of the underheating it is provided that the plate is simultaneously designed as an upper cover plate of a vacuum chamber and is provided with holes, the diameter and distance of which from one another, as well as the perforated grid surface they form in its dimensions smaller than the film surface, which lies flat on the plate surface when vacuumed and closes this vacuum chamber. So far, a hole diameter of 1 mm and the hole spacing of 3 mm have proven favorable for this.

With regard to the way in which devices according to the invention can be determined which temperature prevails at the soldering point, has already been mentioned above mentions that measuring locations should be as close as possible to the soldering point, otherwise in the vicinity of the upper end face of the quartz glass capillary tube. The latter case allows the use of thermocouples. At these measuring locations it can be assumed that there are no influences which interfere with the temperature to be measured. With the help of calibration values to be calculated, conclusions can be drawn about the temperature that actually exists at the soldering point.

Simple equipment variants of devices according to the invention are therefore equipped with thermocouples. In the case of more convenient equipment variants with infrared detectors, pyrometers are preferably used, in which the axes of two rays emanating from one another at an acute angle to one another intersect at the temperature measurement location. The temperature measuring location is thereby identified and enables the correct distance of the pyrometer from the measuring location to be regulated or controlled. In addition, such a temperature measuring device can also be used to indicate via the process control when and in which direction the bypassing of a component to be soldered in or out is to be continued with the soldering and fine plaster head.

The field of soldering technology to be covered by the devices according to the invention also includes the supply and removal of solder. Due to the risk of blockage, a special pipette should be used instead of the quartz glass capillary tube to suck off the solder. In a further module, the invention provides an associated metering cartridge with a connection for a hose provided with a metering needle for a follow-up-free soldering agent.

The method of operation of devices according to the invention for soldering or unsoldering components by means of a soldering and fine plaster head can be described as follows:

The melting process can be controlled via the light source power, the irradiation time and the focus on the component. The radiation power and duration is controlled by the control unit according to the specified temperature setpoint (200 ° C to 220 ° C equal to the melting temperature of the solder), with the actual temperature measurement at the soldering point being measured without contact using an IR detector (pyrometer). Two red laser light beams are used to correctly set the distance of the pyrometer, which unite to form a point at the temperature measuring point should. With high components or optical shadows, temperature measurement can be switched using a thermocouple. Three types with different tip diameters are provided for quartz glass capillary tubes: for fine soldering with a diameter of 2 mm, for medium-sized objects with a diameter of 5 mm and for large objects with a diameter of 9 mm. The change is made by simply changing the plug.

With voluminous, e.g. Components up to 6 mm thick and / or components with a large number of pins or simultaneous soldering or soldering of many components in one operation, the platinum preheating with an underheating to about 100 ° C to 130 ° C is advantageous. Heating elements with halogen lamps or ceramic plates with PTC heating elements are used for this. The control unit regulates the warm-up speed and the preheating temperature according to specifications and enables the start of the soldering or unsoldering process.

For the assembly of SMD components and the application of solder paste, storage sockets and hose line connections for the dosing cartridge and the vacuum pipette are attached to the control unit. With the dosing cartridge, glue or solder paste can be fed to the board. Three options can be preset, the dosing is triggered via a central switch: a) Auto cycle: Repetitive paste points emerge from the dosing needle, whereby the cycle time and dosing quantity can be set using a potentiometer. b) Single cycle: One paste blotch of the set dose quantity occurs per switch operation. In order to avoid solder or adhesive flowing in, the pressure line is subjected to a slight permanent or pulse vacuum and is therefore relaxed. The pulse duration and the vacuum can be adjusted so that an optimal adaptation to different consistencies of the commercial pastes is achieved. c) Constant: For the duration of the switch operation, paste emerges from the dispensing needle as a thin strand.

The transport of components from storage containers within easy reach for loading circuit boards is advantageously carried out with the vacuum pipette, for which, depending on the component, a complete set of different mounting nozzles and suction cups is available. In principle, as with paste dosing, single and auto cycle can be set, however, the setting "constant" is for manual loading. expedient. The SMD component remains attached to the pipette until the switch is opened. It remains stuck in the applied solder paste and the soldering process can start.

The preparations for selective soldering and desoldering of components are the same:

The light soldering and, if necessary, the underheating setpoints are specified via buttons and potentiometers. After placing the pyrometer and the underheating plate, the control electronics of the light soldering device and the preheating are switched on. The rising temperature of the board is shown on a display, when the setpoint is reached, the next process step is released, the light soldering device is started: the control is activated, the halogen lamp is switched on and controlled via pulse width modulation. Components with a large number of pins are circumnavigated at a uniform speed of approx. 5 mm / s ... 8 mm / s until a signal registers that the melting temperature has been reached. The above The switch is deactivated and the halogen lamp is switched off. When desoldering, switching off also creates the vacuum. The resilient tip of the soldering head is placed in the center of the component and is lifted out of the liquid solder by the vacuum. When soldering, the head should not touch the component because it floats due to the solder surface tension and adjusts itself.

The entire control electronics and mechanics are housed in a 19 "standard housing. Explanations of the controls and connections are always on the front panel. The problem-free installation in a desktop shelf of a repair location is guaranteed.

Brief description of the drawings

Essential details of devices according to the invention are shown in the drawings. Show schematically:

1 shows a soldering and fine plush head designed as a hand-held device with connected control and operating elements and a Leiteφlatte (detail) with components to be soldered in or out;

FIG. 2 shows a shape of a soldering and fine plush head which differs somewhat from that of FIG. 1; Fig. 3 shows a soldering and fine plush head according to Fig. 2 as part of a manually or automatically controllable soldering station.

1 shows a hand-held device for soldering or unsoldering electronic components, which is particularly suitable for use in the service and repair area.

The heating energy is supplied by a halogen infrared radiator with a gold reflector HS, which is arranged in a radiator holder SH. A chamber K adjoins the lamp holder SH, which is separated from the beam chamber of the lamp HS by a quartz glass pane QS. A quartz glass capillary tube QK protrudes into the chamber K, through which the energy transfer takes place. The upper end face of the quartz glass capillary tube QK is arranged in the focal point of the halogen infrared radiator HS. The diameter of the quartz glass capillary tube QK is 4 mm to 9 mm, depending on the components to be soldered or soldered, and its length is 50 mm to 140 mm. The clear width is determined by the mass and size of the components to be deposited or lifted and, taking into account the above-mentioned values for diameter and length, is in the range between 0.5 mm and 2 mm. The chamber K has a vacuum connection VA, which can be switched over, so that air (alternatively nitrogen) is also transported through the connection VA / GA at a very low flow rate during the heating process. The heated air flows out of the quartz glass capillary tube QK, the lower end face of which is positioned just above the component BE to be machined, and ensures an even heat distribution there. The main heat is generated by absorption of the Leiteφlatte LP and the components BE. A thermocouple TE, which is led through the connection VA / GA into the chamber K, in conjunction with a temperature controller RT, ensures a temperature-controlled process sequence. If the solder has reached the melting temperature, the pump P is switched from compressed air to vacuum when unsoldering with a switch S. Then the flat ground quartz glass capillary tube QK provided on its lower end face and with a resilient plastic ring (not shown), around which a handle HG closes in the direction of the chamber K for the purpose of operability, is placed on the component BE, sucked in and removed from the lead plate LP lifted off. Large components, such as QFP (quad flat pack) with 256 connections, are moved with a distance of 1 mm to 3 mm between the quartz glass capillary tube (QK) and the connection legs on the outer edges until the solder melts. Experience has shown that the time for the displacement is between 3 mm / s and 15 mm / s.

The soldering of components (BE) is just as easy to handle. After solder paste has been applied with a pipette or repair template and the component (BE) has been pressed into the solder paste, the soldering process can begin. If conductive adhesive is to be used, a correspondingly lower temperature is set.

As can be seen from FIG. 2, the individual parts of the soldering and fine-plush head of a design different from FIG. 1 are arranged compactly in a housing G. The halogen infrared radiator HS is also arranged here in a radiator holder SH, which, however, is connected to a mounting block AB for quartz glass capillary tubes QK. The mounting block AB has a truncated conical recess with a reflector function, which serves as chamber K and is closed by a quartz glass pane QS. The vacuum gas connection VA / GA is guided through the mounting block AB into the chamber K, and the quartz glass capillary tube QK, which is surrounded by a protective tube SR with a thread, also projects into the chamber K. The height of the upper end face of the capillary tube QK can be adjusted using an adjusting nut JM be set so that the end face is exactly in the focus of the halogen infrared radiator SR. The thermocouple TE is arranged between the radiator holder SH and the quartz glass pane QS which closes the chamber K. Due to its compact arrangement, this specific embodiment can be installed interchangeably with little mechanical effort in commercially available devices that previously worked with hot gas.

In Fig. 3, the fitting of the soldering and fine plush head, designed according to Fig. 2, is shown in an automated or manually operated device. The energy transfer takes place through the quartz glass capillary tube QK to the component BE to be processed with the soldered connections LV to the conductor plate LP. By means of an underheater UH, the conductor plate is preheated to 100 ° C to 130 ° C. An infrared detector D, which is connected to a controller C for manual operation or to a personal computer PC for automatic process control, including the temperature setting on the component BE to be soldered or unsoldered, is used to measure the temperature on the component BE to be processed. Both the heating power of the halogen infrared radiator HS (cf. FIG. 2) and the heating power of the underheater UH can be set via the temperature controller RT in accordance with the measurement results transmitted to the controller C. A positioning unit PE enables the precise positioning of the component BE to be machined relative to the lower end face of the quartz glass capillary tube QK.

Large components (e.g. QFP-quad flat pack) are processed - as already described for the handheld device. If the speed when moving the outer edges by means of an xyz table, which is not shown here, is not sufficient, so that the temperature has already dropped sharply before the next movement, it is advantageous to insert at least two compact soldering and fine plastering heads in a row Use the direction of departure in a housing.

Increased ease of handling of devices according to the invention designed as a manual soldering station offers e.g. the arrangement of a camera aimed at the component to be soldered or unsoldered and a monitor for visual observation of the process sequence. In partially or fully automatic soldering stations, detectors deliver their measured actual values to the process control. From this, this generates the control signals required for actuators and can also be designed such that at least acoustic or optical warning signals are also emitted.

Commercial usability

The main area of application for devices according to the invention is in the selective non-destructive and contactless unsoldering or soldering of modern multi-pole electronic components (ICs) from / in densely populated circuit boards as well as in the reworking of boards from soldering systems with a high degree of automation to eliminate faulty solder joints and the manual soldering of special components in production, also where piston soldering has a negative impact on the joining partners due to physical effects (e.g. migration of the precious metal from thin gold-plated contact wires to sensors to the copper tip). In addition to the use of devices according to the invention in highly or fully automated industrial systems, soldering stations with different, less convenience - but in much larger numbers - can be used in particular in the craft of radio, television, video and computer technology and also in industrial companies who can install the system at downstream repair sites on production lines or automatic placement machines.

The use of devices according to the invention is that e.g. Usual multi-pole components (integrated circuits) can be replaced without risk of destruction of the board. As the integration trend of industrial products continues, more and more functions are combined in ICs and the number of

Single boards reduced. The main boards increase in value. For example, Today's motherboards of PCs, the graphics card, the controller functions of the mass storage drives and the interface modules, modern TV sets have fewer and fewer additional boards, so that replacing the board cannot be justified because of a defective component.

The advantages of the invention compared to conventional practice result from the contactless soldering / desoldering process, since there are no mechanical stresses on the joining partners, no migration of precious metals from the surface-treated wires to a soldering iron copper tip, no targeted blowing on the component and its surroundings with hot air and none Risk of destruction due to "overheating" of the board, since the board and soldering temperature is controlled electrically within narrow tolerance limits. The user sees the focused energy beam because part of the radiation is in the visible range. This makes it very easy to align the beam with a handheld device, especially since the soldering target is automatically illuminated.

The invention also contributes to improving the situation for people and the environment: Rising disposal costs for environmentally harmful materials (electronic waste) mean that there is a turning away from the circuit board or module exchange mentality. On average, over 90% of the components of a defective board are still fully functional and have been disposed of so far. A powerful and reliable soldering and desoldering system for highly integrated multi-pin SMD components enables complex circuit boards to be repaired.

Claims

claims

1. Device for non-contact, selective soldering or desoldering of components, the heating unit, means for contactless energy transfer from the

Heating unit for the component, means for storing or lifting a selected one

Component to or from a soldering point and means for monitoring the temperature at the soldering point, d a d u r c h g e k e n n z e i c h n e t, that a soldering and fine walking head is provided, in which:

- the heating unit is a halogen infrared radiator (HS),

- The halogen infrared radiator (HS) is arranged in a radiator holder (SH),

- The means for contactless energy transmission from the halogen infrared radiator (HS) to the selected, soldered or to be soldered component (BE) and the means for storing or lifting the selected component (BE) in one in its

Position relative to the selected component (BE) changeable quartz glass capillary tube (QK) are combined,

the quartz glass capillary tube (QK) is arranged with its upper end face in the focal point of the halogen infrared radiator (HS) and the halogen infrared radiator (HS) and the quartz glass capillary tube (QK) are mechanically and optically connected to one another,

- The quartz glass capillary tube (QK) is arranged with at least its upper part and upper end face in a closed, with a vacuum connection (VA) provided chamber (K), the upper cover of which between an upper end face of the quartz glass capillary tube (QK) and the halogen infrared radiator

(HS) and quartz glass plate (QS) arranged outside its focal point, and the device

- A thermocouple (TE) or an infrared detector (D), with which the temperature of the solder joint is determined at at least one location of the energy transmission path from the halogen infrared radiator (HS) to the selected component (BE), and

- The thermocouple (TE) and / or the infrared detector (D) with a temperature controller (RT) and this is connected to a control of the halogen infrared radiator (HS).

2. Apparatus according to claim 1, characterized in that arranged compactly in a housing (G) the soldering and fine plaster head at least the halogen infrared radiator (HS) and that of the quartz glass pane (QS) and a receiving block (AB) for the quartz glass capillary tube ( QK) and a chamber (K) with a vacuum gas connection (VA / GA).

3. Apparatus according to claim 1, characterized in that the quartz glass capillary tube (QK) of the soldering and fine plush head is closely enclosed by a protective tube close to its lower end face and is vacuum-tight with a halogen infrared radiator (HS), the radiator holder (SH) and the unit containing the quartz glass pane (QS) covering the chamber (K) is detachably connected.

4. Device according to one of claims 1 to 3, characterized in that a controller (C), a computer (PC) and / or an automatic process control for controlling actuators and for processing measurement and / or

Process flow data is assigned to a soldering station.

5. Device according to one of claims 1 to 4, characterized in that the vacuum connection (VA) of the quartz glass capillary tube (QK) partially enclosing chamber (K) of the soldering and fine plaster head is switchable as a gas connection (GA).

6. Device according to one of claims 1 to 5, characterized in that the thermocouple (TE) is arranged between the radiator holder (SH) and cover outside the chamber (K) in the soldering and fine plush head and via a temperature controller (RT) with the current supply of the Halogen infrared radiator (HS) is connected.

7. Device according to one of claims 1 to 5, characterized in that the thermocouple (TE) in the chamber (K) near the upper end face of the quartz glass capillary tube (QK) is arranged in the soldering and fine plush head and via a temperature controller (RT) with the Power supply of the halogen infrared radiator (HS) is connected.

8. Device according to one of claims 1 to 7, characterized in that a pyrometer is used as the infrared detector (D), which is equipped with two infrared laser diodes arranged at an acute angle to each other, the correct with the intersection of the axes of their emitted beams Specify the distance of the pyrometer from the measuring location.

9. Device according to one of claims 1 to 8, characterized in that a soldering station with a soldering head and a fine head comprises a module which contains a metering cartridge with a connection for a hose provided with a metering needle.

10. Device according to one of claims 1 to 9, characterized in that in a soldering station with a soldering and fine plush head for the selective soldering or desoldering of a component (BE) for a Leiteφlatte (LP) a locally limited and positionable underheating (UH) is provided.

11. The device according to claim 10, characterized in that at least one separately heatable insert made of a material whose thermal conductivity is greater than that of the plate material is arranged in a formed as a plate of good heat-conductive material and provided with heating connections underheating (UH).

12 Device according to claim 11, characterized in that the separately heatable insert is a glass cylinder and its separate heater is a halogen infrared radiator, the focal point of which is in the lower cover surface of the glass cylinder

13 Apparatus according to claim 11, characterized in that the plate of the lower heater (UH) is simultaneously designed as an upper cover plate of a vacuum chamber and provided with holes, the diameter and distance from each other as well as the perforated grid surface formed by them is smaller than a film surface with respect to its dimensions which, when vacuumed, closes this vacuum chamber lying flat on the surface of the plate

14 Device according to one of claims 1 to 13, characterized in that the quartz disc (QS) arranged in the soldering and fine plaster head is additionally designed as a filter for visible light

15 Device according to one of claims 1 to 13, characterized in that the quartz disk (QS) arranged in the soldering and fine plunge head is additionally designed as a focusing lens

16 Device according to one of claims 1 to 15, characterized in that the solder and fine walking head is designed as a hand-held device

17 Device according to claim 16, characterized in that

- A housing (G) with an electrical supply for the radiator (HS) is arranged around the halogen infrared radiator (HS) of the soldering and fine plaster head and this housing (G) is connected to the chamber (K) which partially encloses the quartz glass capillary tube (QK) , and - Means for a handle (HG) are connected to the chamber (K) and enclose the quartz glass capillary tube (QK) close to their lower end face

18. The apparatus according to claim 16, characterized in that the handle (HG) encloses the quartz glass capillary tube (QK) as a tight-fitting, substantially cylindrical tube.

19. The apparatus according to claim 16 or 17, characterized in that the chamber (K) is designed as a transition piece between the housing (G) and handle (HG).