Electric heating – Metal heating – For bonding with pressure
Patent
1990-06-27
1993-03-23
Evans, Geoffrey S.
Electric heating
Metal heating
For bonding with pressure
228230, 239135, 239437, 239455, 239502, 392379, 392408, B23K 1005, B23K 1012
Patent
active
051966670
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a device for making or undoing solder connections or joints between an electronic component, e.g. a SMD component provided with several connections, and a component carrier, with a heat source spaced from the solder connection, by means of which a hot air jet and/or stream of infrared energy is directed onto the solder connection and with a mask for defining the jet or energy stream.
As is known, electronic assemblies typically comprise a rigid or flexible support provided with conductors and onto which are soldered electronic components. Such components may be plug-in connecting pins for a so-called plug-in mounting which, in the support, are soldered in fastening holes and in through-connection holes, or components which are directly soldered onto the surface of the conductors for mechanical and electrical connection. Thus, the conductors do not have to be perforated or broken for receiving each component. An assembly made by the latter technology is known as surface mounted assembly (SMA). For particular applications, it is also conventional practice to use a mixed loading or insertion with plug-in and surface mounted components.
The device is used for surface mounting special surface mounted devices (SMDs), such as resistors, capacitors, diodes, transistors, integrated circuits and chip carriers. Unlike the components provided with pin connections, these components have connecting surfaces or short contact legs or members, which are directly soldered, i.e., without connecting wires, to the printed circuit board.
One soldering method usable for SMA technology is reflow soldering. A hot gas dryer is frequently used as the heat source. The hot air jet directed onto the soldering point melts the soldering tin or paste applied there.
Automatic loading or insertion machines are typically used, in particular, to produce SMA assemblies. These allow large-scale production. However, the purchase price and operating costs of such automatic machines are so high that it is not possible to economically deal with small runs.
Using reflow soldering, means are known for the production of small runs, for mixed loading, for loading or modifying individual printed circuit boards or for the replacement of individual components, in which hot air is blown by means of nozzles onto the particular component. Admittedly the jet guidance can be adapted to different component shapes by different, interchangeable nozzle inserts. However, as a result of considerable spreading of the air jet, the complete component is located in the hot air jet and, therefore, all of it is heated. As a result of the non-uniform heat absorption in the different component metals such as metal, ceramic and plastic, a risk arises that thermal stresses and hair cracks occur, which can have a disadvantageous influence on the operational reliability. Moreover, in view of the large number of different component shapes, it is necessary to purchase and furnish a large number of nozzle inserts. Insert replacement also provides relatively long changeover times.
EP-A-O 0 233 125 and DE-B-1 279 150 disclose devices for making and undoing soldered connections between electronic components and a component carrier, in which a hot air jet is directed onto the soldered connection and a mask is used for defining the hot air jet. The known device also has a movable mask carrier. It is formed by the casing receptacle fitted in transversely displaceable manner over the component carrier.
The object of the invention is to provide a means of the aforementioned type which permits a precise action on the soldered connections and component connections without directly thermally loading the other components and which also may easily and rapidly be handled.
A basic principle of the invention is that the heat ray is subdivided into individual partial rays which are directed in a positionally correct manner onto the connecting surfaces, leads and pins, so that heating is exclusively limited to these points. As the mask can be manufactured in a ratio of 1:1
REFERENCES:
patent: 3020714 (1962-02-01), Eggers et al.
patent: 3194014 (1965-07-01), Wilson, Jr.
patent: 3226768 (1966-01-01), Zelewsky et al.
patent: 3267249 (1966-08-01), Veth
patent: 3283124 (1966-11-01), Kawecki
patent: 3457386 (1969-07-01), Costello
patent: 3516155 (1970-06-01), Smith
patent: 3520055 (1970-07-01), Jannett
patent: 3586813 (1971-06-01), Cruickshank et al.
patent: 3868765 (1975-03-01), Hartleroad et al.
patent: 4156124 (1979-05-01), Macken et al.
patent: 4321738 (1982-03-01), Makhijani
patent: 4506820 (1985-03-01), Brucker
patent: 4620659 (1986-11-01), Holdway
patent: 4750664 (1988-06-01), Furtek
patent: 4789096 (1988-12-01), Dunn et al.
patent: 4812620 (1989-03-01), Hayakawa et al.
patent: 4847465 (1989-07-01), Toyama et al.
patent: 4854696 (1989-08-01), Guez
patent: 4961154 (1990-10-01), Pomerantz et al.
LandOfFree
Soldering and desoldering device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Soldering and desoldering device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Soldering and desoldering device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1353857