7 - Hand soldering and assembly rework
7.2 - Soldering irons and tips
Soldering irons
Temperature controlled soldering iron
A temperature controlled soldering iron includes an elongated heater assembly with a hollow soldering tip at one end, containing a heating element and a temperature sensing element, which is responsive to the temperature of the tip. The heater assembly includes an outer conductive sheath concentrically disposed around an inner conductive sheath, both of which are attached to a steel bushing. A constantan rod is disposed within the inner sheath and connected to the bushing to form a thermocouple junction therewith. The heating element is connected at one end to the bushing and at the other end to a tubular conductor disposed around and insulated from the constantan wire. A temperature controller surveys the temperature sensed at the thermocouple junction by connection to the constantan wire and the outer sheath. The voltage applied between the tubular conductor and the inner sheath is automatically varied to control the temperature of the heater assembly.
A temperature controlled soldering iron includes an elongated heater assembly with a hollow soldering tip at one end, containing a heating element and a temperature sensing element, which is responsive to the temperature of the tip. The heater assembly includes an outer conductive sheath concentrically disposed around an inner conductive sheath, both of which are attached to a steel bushing. A constantan rod is disposed within the inner sheath and connected to the bushing to form a thermocouple junction therewith. The heating element is connected at one end to the bushing and at the other end to a tubular conductor disposed around and insulated from the constantan wire. A temperature controller surveys the temperature sensed at the thermocouple junction by connection to the constantan wire and the outer sheath. The voltage applied between the tubular conductor and the inner sheath is automatically varied to control the temperature of the heater assembly.
High frequency current soldering iron
The high frequency current soldering iron having faster heating capability as well as an ability to maintain a more constant soldering temperature. In a preferred embodiment, the high frequency current soldering iron employs a heating assembly having a sensor connected to a temperature controller and heating coils connected to a power source which are wrapped around a ceramic core. A tip assembly is provided having a copper based tip coated with an iron plating, and the tip assembly houses the part of the heating assembly having the sensor. The engaged tip assembly and the heating assembly are encased by a protective enclosure pipe except for the exposed tinned tip of the tip assembly for soldering. A temperature control unit is further provided to set the desired soldering temperature and to process the temperature detected by the sensor so as to effective an accurate control over the soldering tip temperature. The high frequency current soldering iron provides significantly improved accuracy in achievement of the soldering temperature and its maintenance while having a simple construction.
The high frequency current soldering iron having faster heating capability as well as an ability to maintain a more constant soldering temperature. In a preferred embodiment, the high frequency current soldering iron employs a heating assembly having a sensor connected to a temperature controller and heating coils connected to a power source which are wrapped around a ceramic core. A tip assembly is provided having a copper based tip coated with an iron plating, and the tip assembly houses the part of the heating assembly having the sensor. The engaged tip assembly and the heating assembly are encased by a protective enclosure pipe except for the exposed tinned tip of the tip assembly for soldering. A temperature control unit is further provided to set the desired soldering temperature and to process the temperature detected by the sensor so as to effective an accurate control over the soldering tip temperature. The high frequency current soldering iron provides significantly improved accuracy in achievement of the soldering temperature and its maintenance while having a simple construction.
Electric soldering iron delivering heat by change of state of a liquid heat transporting medium
A soldering device having a hollow and closed soldering element which contains a heat transporting medium. The soldering element is supported in a holder and may be slidably removed there from. The holder is also provided with a electric element for providing heat to a first heat transmission wall of the soldering element. The heat transporting medium absorbs thermal energy from the heating element through the first heat transmission wall and changes from the liquid phase into a vapor phase. The vapor supplies the thermal energy to a second heat transmission wall of the soldering element which is at a point of the element forming the soldering place which produces the heat necessary for the soldering operation. The vapor changes back into the liquid phase at the soldering place. A capillary mass of porous material is provided along the inside of the soldering element so that the liquid heat transporting medium can flow back through the porous mass from the second heat transmission wall back to the first heat transmission wall as a result of capillary action.
A soldering device having a hollow and closed soldering element which contains a heat transporting medium. The soldering element is supported in a holder and may be slidably removed there from. The holder is also provided with a electric element for providing heat to a first heat transmission wall of the soldering element. The heat transporting medium absorbs thermal energy from the heating element through the first heat transmission wall and changes from the liquid phase into a vapor phase. The vapor supplies the thermal energy to a second heat transmission wall of the soldering element which is at a point of the element forming the soldering place which produces the heat necessary for the soldering operation. The vapor changes back into the liquid phase at the soldering place. A capillary mass of porous material is provided along the inside of the soldering element so that the liquid heat transporting medium can flow back through the porous mass from the second heat transmission wall back to the first heat transmission wall as a result of capillary action.
Soldering tips
15 watts can be used for very small components and pads, 30–50 watts for larger components. Controlled heat irons are the best, but good results can be obtained from the inexpensive fixed temperature irons that have the proper tip wattage. Larger irons and "guns" should not be used except to solder very large components. Do not use these high power instruments on electronic assemblies or printed circuit boards.
The tip should be small enough so that the joint being soldered can be easily seen, but large enough to quickly transfer the heat required to raise the joint temperature to the solder melting point. Chisel (spade) tip is preferred that is between 1.25 mm and 2 mm across the spade for general purpose soldering. Smaller tips are required for small pads and surface mount components. The larger tip provides more heat which is required for desoldering using desoldering braid or solder pump.
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