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Cost Saving Wired Repairs: |
Reliable Manual Soldering, Now Also For Wired Components |
published in SMT 5 - 2008 |
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| The demise of classic printed circuit technology with wired components is still a long way off - since the 80s this robust type of component has been enjoying considerable popularity, especially in medical and defence sectors. Even though surface mount devices are still gaining market share the well proven through hole technology is still relied on by many users. The rework specialist MARTIN have developed a technology that ensures gentler, more effective and reliable rework also of these components - in the era of Lead Free.
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The leads of conventional components are inserted through holes in PCBs and soldered on the reverse. This process is referred to as through hole mounting and is superfluous for SMDs. Surface mounted devices, which, in contrast to wired components, do not have connecting leads, but instead are soldered directly on to the surface of a PCB. However, the technology of TH, despite trends towards SMT, is still popular with users. The soldering of wired components now works even better and avoids damage, such as lifted pads, etc.
For a number of years the key to successful rework of boards populated with surface mount components has been the use of an effective Underheater. Because of the higher thermal stress in lead free soldering, also for wired components, an effective Underheater is very advantageous for improved speed, reliability and ease of use. The cost/benefit ratio of using the Hot-Beam-03 Underheater also exceeds that of commonly used methods.
In no other area are there so many avoidable mistakes made as in manual soldering. There is therefore a case of only allowing well trained personnel to carry out manual soldering. Using Hot-Beam-03 substantially reduces the risks and increases productivity and joint quality.
The Hot-Beam-03 Underheater not only supports very gentle, stress free and precisely regulated rework of SMDs but also of wired components. This patented Rapid-IR Technology is compatible with through hole components and reduces the risk of lifted tracks and failed pads. MARTIN's practical lead free rework technology has been very successful in carefully reworking BGAs.
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| The soldering of one condenser with Hot-Beam 03 underheater |
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Gentle Manual Soldering Process Requirements |
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The move of the industry from leaded to lead free soldering has brought with it some completely new demands on rework stations. Especially for sensitive PCBs, BGAs, CSPs, QFNs etc, a gentle rework process had to be developed for the processing of such components. Lead free manual soldering today requires a soldering temperature 30° higher than for joints with leaded solder. The melting point of common lead free solder is around 217°C, however, temperatures of around 230° are needed around the solder joint. The maximum temperatures components can be exposed to between 240 and 260°C. It is therefore not just a matter of increasing the soldering iron tip temperature by 50°, which would bring with it high risks for components, the bonds between pads and board and distinctly reduce bit life. Years of experience in rework and dispensing technology, as well as constant and practical customer focused developments have enabled MARTIN to considerably reduce the risks for users by the introduction of Hot-Beam-03.
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No Overheating - Protection For Solder Bits, Components And Boards |
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Wired components are exposed to temperatures around 50° higher than surface mounted ones. Using MARTIN's Underheater brings users the advantage of lower soldering iron tip temperatures for lead free soldering of wired as well as surface mount components. The Hot-Beam-03 protects the solder bits by being able to determine the rate of heating and set temperature. This is not possible with most other Underheaters as they are unable to maintain a given temperature. The pre set holding temperature prevents any overheating of components, improves wetting and at the same time improves the life of solder bits and flux. Any flux is thus able to remain active for longer so that sufficient activity is left for the wetting phase. The Hot-Beam-03 can make a considerable cost reduction contribution in lead free soldering and it needs very little room: the Underheater will fit onto the smallest work bench - only measuring 290 x 140 x 40mm. The heated area is 100 x 130mm and delivers 500 Watt. MARTIN provides a range of PCB fixtures.
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User Friendly PCB Location |
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As rework demands that everything is quick and easy MARTIN offer a flexible tool, the Handy-Fix-05, for the rapid and exact clamping of printed circuit boards. Within seconds boards can be located as well as vertically adjusted. Stainless Steel clamps with practical snap closure hold PCBs varying is size from fingernail to A4. Even boards with very bulky connectors have plenty of space. The new Handy-Fix-05 is supplied as set, comprising: an ESD safe base plate, a magnetic and movable boards clamp and two magnetic supports. Users find this a very simple and effective way to present PCBs.
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| Hot-Beam-03 Underheater with adjustable Handy-Fix-05 Support for the rapid and exact clamping of PCBs |
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The Cost Effective Solution For Rework: Rapid-IR Technology. |
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This clever piece of equipment has very quickly found a firm place in the market for gentle rework. MARTIN can today be proudly look back on over 1000 units sold. The Rapid - IR Technology is a controlled, accelerated radiation heating process for printed circuit boards. A maximum permitted rate of heating of 3,5° C / second is applied to heat a board to a predetermined temperature. The Underheater then maintains the previously set temperature of up to 150°C. "This technology, compared with traditional rework stations, has a considerably faster heating rate than conventional ceramic IR heaters," according to Bernhard Martin, Managing Director. In addition the Hot-Beam-03 works according to the motto: "Learning by doing". The self learning unit has an Auto mode that integrates up to 11 application programs, so that temperature sensors are only needed for the start programming. This saves users time and costs and leads to considerably more effectiveness at work.
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Conclusion |
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MARTIN is a company that is currently amongst a very few offering professional Underheaters and, with 1000 units sold, is rated very highly as preferred rework station. The Hot-Beam-03 appeals not just because of faster desoldering but also by considerably reducing copper diffusion at through hole solder sites. At the same time the causes for cracks in PCBs as well as the risks of Popcorning and damaged pads are drastically reduced. The Popcorn effect can be caused by incorrect storage of components that leads to ingress of moisture, which can expand rapidly during heating.
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