![]() Rose up from the severely unequal expansion rateīetween the ceramic chip and its leads created by contact soldering As the transition from Thru-Hole to SMT accelerated, an immediate drawback with the use of soldering irons and hot tweezersĪppeared: miniature ceramic chip capacitors and resistorsĬracked or fissured when soldered to the PCB. To solder reflow temperatures, many compounding problems. Nominal PCB assembly, a host of dissimilar materials can beįound: copper, fiberboard, ceramic, plastic, tin, lead, ![]() ![]() Irons, hot bars, thermodes and even wave soldering.Įlectrically sound and physically robust solder joints -īetween a chip's leads and its tinned copper pads - requiresĪttention to many process parameters. Quickly became preferred over the traditional contact methods (conductive) such as High volume conveyor ovens and hot air equipment (convective) Quickly lost favor with manufacturing and quality engineers. SMD's and chip miniaturization, any physical contact, conductive soldering Non-Contact of the AirPencilto Delicate Leads.Ī BRIEF HISTORY: CONVECTIVE vs CONDUCTIVE REFLOW: PCB soldering generally is divided into Is Shown Above Soldering a Quad Flat Pack (QFP). And the use of anĮSD wrist strap by the rework engineer or Printed circuit board assembly rework fromĪccidental static discharges. Prevent accidental skewing, misalignment, and/orĮlectronic components should be protected during Recommended to insure robust joints and to Temperatures greater than originally seen duringĭown of the solder joint is desirable and Should never be exposed to elevated reflow To an SMD that is being removed or replaced Hot air nozzles if with a larger SMD/BGA Hot Hot air pencil or with extra-low velocity To remove or replace SMD's, the air-stream mustīe pin-pointed precisely to the targeted leads Is best suited for placement of fine pitch and Is best suited for ceramic chip resistors and Non-contaminating hot air soldering (convection) Production, prototyping or in rework or repair. To soldering or desoldering tasks whether in Of high-volume production, some fundamental conclusions can be madeĪs just how to achieve premium solder joints at the bench: Performed at a benchtop should be held to the same equal standard Methodologies and exacting solder reflow prerequisitesĪre essential for many very critical quality reasons.Īnd since it only logically follows that all PCB tasks along with the most basic semiconductor data books Mimic the initial production soldering thermal profiles,Īny state-of-the-art, high volume PCB production process With preheating proved that it was then possible to Production world in the 1990's almost 10 years The hot air pencil made its entry into the PCB Obvious now, but it it was not always so. along with bottom-side PCB preheating seems whether in prototype, design or rework/repair Introduction of the hot air pencil as a soldering deviceįor surface mount devices for high quality soldering
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