Explanation of basic terms of SMT (2)

- Aug 18, 2018-

H.

Halides: a compound containing fluorine, chlorine, bromine, iodine, or astine.The catalyst part of the flux must be removed due to its corrosivity. Hard water: water containing calcium carbonate and other ions may accumulate on the inner surface of clean equipment and cause obstruction. Hardener(Hardener) : a chemical added to a resin to allow it to solidify in advance, that is, a Hardener. i.In-circuit test: a component-by-component test to verify the placement and direction of components. JJust-in-time (JIT Just on time) : minimize inventory by supplying materials and components directly to the production line before they are put into production. 

L.

Lead configuration: a conductor extending from a component that ACTS as a mechanical and electrical connection point. Line certification(production Line confirmation) : confirm that the production Line sequence is controlled and can produce reliable PCB as required. 

M

Machine vision(Machine vision) : one or more cameras used to help find component centers or improve the precision of the assembly of the system. Mean time between failure (MTBF Mean time between failure) : the average statistical time interval between expected failure of a potential operating unit, usually calculated per hour, and the results should indicate actual, expected, or calculated.

N

Nonwetting: a condition in which solder does not adhere to a metal surface.Due to contamination of the surface to be welded, non - wetting features visible bare base metals. 

O

Omegameter(Omegameter) ameter used to measure ion residues on PCB surfaces by dipping the assembly into a mixture of alcohol and water with known high resistivity, and subsequently measuring and recording a decrease in the resistivity due to ion residues.Open(Open) : the two electrical connection points (pins and pads) become separated, either due to insufficient solder or poor alignment of the junction pins. Organic activated (OA Organic activated) : as a kind of soldering system of active agent, Organic acids are water-soluble.

P

Packaging density(assembly density) : the number of components (active/passive components, connectors, etc.) placed on a PCB;Expressed as low, medium or high. Photoploter(photo plotter) : basic wiring diagram processing equipment used to produce original PCB wiring diagrams (usually in actual sizes) on photographic film. Pick-and-place: a programmable machine with a robotic arm that picks up components from the automatic feeder and moves them to a point on the PCB where they are pasted in the right direction. Placement equipment(Placement equipment) : a machine that attaches components to a PCB in combination with high speed and accurate positioning, divided into three types: SMD mass transfer, X/Y positioning, and online transfer systems that can be combined to adapt the components to the board design. 

R

Reflow soldering(Reflow soldering) : a process whereby surface-mount components are put into solder paste to achieve a permanent connection through various stages, including: preheating, stabilization/drying, backflow peak and cooling. Repair: the act of restoring the function of defective assembly. Repeatability(Repeatability) : the process ability to accurately re-enter a characteristic target.An indicator for evaluating processing equipment and its continuity. Rework: a repetitive process of bringing incorrect assembly back to compliance with specifications or contract requirements. Rheology(Rheology) : describes the flow of a liquid, or its viscosity and surface tension properties, such as solder paste

s.

Saponifier(Saponifier) : an aqueous solution of an organic or inorganic main ingredient and additive used to facilitate the removal of rosin and water-soluble flux by means of, for example, a dispersible cleaner. Schematic(Schematic) : a Schematic representation of a circuit layout using symbols, including electrical connections, components, and functions. Semi - aqueous cleaning (not completely clean water) : solvent cleaning, hot water washing and drying cycle technology. Shadowing(Shadowing) : in infrared reflow soldering, the body blocks energy from certain areas, resulting in insufficient temperature to completely melt the solder paste. Silver chromate test(Silver chromate test) : examination of the presence of a qualitative, halogenated ion in an RMA flux.(RMA reliability, maintainability, and availability)Slump: the diffusion of materials such as solder paste and glue before curing after screen printing. Solder bump(Solder ball) : a spherical Solder material bonded to the contact area of a passive or active component, acting as a connection to a circuit pad. Solderability(Solderability) : the ability of a conductor (pin, pad, or trace) to melt wet (into weldable) in order to form strong connections.

Solderability(Solderability) : the ability of a conductor (pin, pad, or trace) to melt wet (into weldable) in order to form strong connections. Soldermask(Soldermask) : process technology for printed circuit boards where all surfaces are covered by a plastic coating in addition to the connection points to be soldered. Solids(solid) : percentage of rosin weight in flux formula, (solid content)Solidus(Solidus) : temperature at which the solder alloy of some components begins to melt (liquefy). Statistical process control (SPC Statistical process control) : Statistical techniques are used to analyze the output of the process, use the results to guide actions, adjust and/or maintain the quality control status. Storage life: the time it takes for the glue to be stored and to remain useful. Deductive process(negative process) : electrical wiring is obtained by removing the selected portion of the conductive metal foil or covering. Surfactant(Surfactant) : a chemical added to water to reduce surface tension and improve wetting. Syringe(Syringe) a container of glue that drips through its narrow opening.

T

Tape-and-reel(Tape and reel) : the assembly is packed with Tape. On the continuous strip, the assembly is loaded into a pit. Thermocouple: a sensor made of two different metals that, when heated, produces a small dc voltage in a temperature measurement.Type I, II, III assembly(first, second, and third Type assembly) : PCB(I) with surface mounted components on one or both sides of the board;Hybrid technology (II) with pin components installed on the main surface and SMD components attached on one or both sides;Hybrid technology (III) features passive SMD components installed on the second surface and pin (through hole) components installed on the main surface. Tombstoning(assembly rising) : a weld defect in which the sheet element is pulled vertically so that the other end is not welded. UUltra-fine-pitch: pin center to center distance and conductor spacing is 0.010 "(0.25mm) or less.

V

Vapor degreaser(Vapor degreaser) : a cleaning system that suspends the object in the tank and condenses the heated solvent Vapor on the surface of the object. Void(Void) : a Void in a tin point formed by residual flux trapped in the air during reflux or before cure. YYield: the ratio of the number of components used at the end of a manufacturing process to the number of components submitted for production.