440:) one repair company estimates that the process, if there are no unexpected problems, takes about 80 minutes. On a forum where professional repair people discuss reflowing of laptop computer graphics chips, different contributors cite success rates (no failure within 6 months) of between 60 and 90% for reflowing with professional equipment and techniques, in equipment whose value does not justify complete reballing. Reflowing can be done non-professionally in a domestic oven or with a heat gun. While such methods can cure some problems, the outcome is likely to be less successful than is possible with accurate thermal profiling achieved by an experienced technician using professional equipment.
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Reballing involves dismantling, heating the chip until it can be removed from the board, typically with a hot-air gun and vacuum pickup tool, removing the device, removing solder remaining on the device and board, putting new solder balls in place, replacing the original device if there was a poor
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High quality demands or specific designs of SMDs require the precise application of solder paste before positioning and soldering the unit. The surface tension of the molten solder, which is on the board's solder pads, tends to pull the device into precise alignment with the pads if not initially
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Chips are at risk of being damaged by the repeated heating and cooling of reballing, and manufacturers' warranties sometimes do not cover this case. Removing solder with solder wick subjects devices to thermal stress fewer times than using a flowing solder bath. In a test twenty devices were
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The rework may involve several components, which must be worked on one by one without damage to surrounding parts or the PCB itself. All parts not being worked on are protected from heat and damage. Thermal stress on the electronic assembly is kept as low as possible to prevent unnecessary
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Properly carried out rework restores the functionality of the reworked assembly, and its subsequent lifetime should not significantly be affected. Consequently, where the cost of reworking is less than the value of the assembly, it is widely used in all sectors of the electronic industry.
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is usually the first step, followed by removing the SMD while the solder is molten. The pad array on the conductor board should then be cleaned of old solder. It is quite easy to remove these residues by heating them to melting temperature. A soldering iron or hot air gun can be used with
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between adjacent pads. Bad connections produced during assembly can be detected and the assembly reworked (or scrapped). Imperfect connections of devices which are not themselves faulty, which work for a time and then fail, often triggered by thermal expansion and contraction at
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Finally the newly placed SMD is soldered onto the board. Reliable solder joints are facilitated by use of a solder profile which preheats the board, heats all the connections between the unit and the PCB to the melting temperature of the solder used, then properly cools them.
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and rework, as they have many small, closely spaced pads on their underside which are connected to matching pads on the PCB. Connecting pins are not accessible from the top for testing, and cannot be desoldered without heating the whole device to the melting point of solder.
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The precise placement of the new unit onto the prepared pad array requires skillful use of a highly accurate vision-alignment system with high resolution and magnification. The smaller the pitch and size of the components, the more precise working must be.
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Assemblies which fail because of bad BGA connections can be repaired either by reflowing, or by removing the device and cleaning it of solder, reballing, and replacing. Devices can be recovered from scrapped assemblies for reuse in the same way.
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Manufacturer and service providers of communications-technologies, entertainment- and consumer-devices, industrial commodities, automobiles, medical technology, aerospace and other high power electronics rework when necessary.
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are glued to the pads on its underside; during assembly the balled package is placed on the PCB and heated to melt the solder and, all being well, to connect each pad on the device to its mate on the PCB without any extraneous
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160:(SMD). Mass processing techniques are not applicable to single device repair or replacement, and specialized manual techniques by expert personnel using appropriate equipment are required to replace defective components;
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reballed, some several times. Two failed to function, but were restored to full functionality after reballing again. One was subjected to 17 thermal cycles without failing.
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connection, or using a new one, and heating the device or board to solder it in place. The new balls can be placed via several methods, including:
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For the PS3 and Xbox mentioned above, the time is about 120 minutes if all goes well.
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Rework is practiced in many kinds of manufacturing when defective products are found.
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Using a BGA "preform" with embedded balls corresponding to the device pattern, or
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is a place to do this work—the tools and supplies for this work, typically on a
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Reflowing as a rework technique, similar to the manufacturing process of
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contractions of the board which might cause immediate or future damage.
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Repair VGA card by re-flowing solder on the board (using domestic oven)
168:(BGA) devices particularly require expertise and appropriate tools. A
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Permanent
Elastomeric/Semi-Elastomeric Ball Grid Array (BGA) Stencils
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Refinishing operation of an electronic printed circuit board assembly
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Poor solder joints because of faulty assembly or thermal cycling.
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with a hot-air gun to melt all solder joints between it and the
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In the 21st century, almost all soldering is carried out with
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Rework
Analysis of PS3 YLOD & Xbox RROD: Reflow vs Reball
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badcaps.net forum: Laptop reflowing improving reliability?
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Lean Supply
Solutions - Innovative Supply Chain Solutions
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49:. Unsourced material may be challenged and removed.
509:"Product Rework | Rework Process in Manufacturing"
534:"Reduce Manufacturing Rework: Five Steps to Take"
458:Using semiautomated or fully automated machinery.
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452:for both the balls and the solder paste or flux,
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593:Sparkfun tutorials: Reflow skillet, July 2006
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403:After fabrication of the BGA package, tiny
261:. Unsourced material may be challenged and
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281:Learn how and when to remove this message
212:Engineering parts changes, upgrades, etc.
192:X-ray picture of inadequate solder joints
109:Learn how and when to remove this message
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318:health and environmental hazards of lead
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384:Good solder joints between BGA and PCB
199:For electronics, defects may include:
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376:X-ray picture of good solder joints.
259:adding citations to reliable sources
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47:adding citations to reliable sources
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141:) is the repair or refinish of a
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41:Please help
36:verification
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485:Reflow oven
170:hot air gun
147:desoldering
131:electronics
543:2019-02-23
518:2020-06-02
496:References
391:(BGA) and
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271:July 2015
242:does not
178:workbench
151:soldering
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479:See also
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