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Some Commen PCB Terms-R-Z
Jun 25, 2018


Reference Designator The reference designator is generated from the Gerber data to provided additional data when loading components on the printed circuit board.  It defines the component and its placement on the board. 
Rework StencilA laser cut stencil used when a single component needs to be re-worked when the rest of the components are already soldered to the printed circuit board. 
RoutRout is the process of using a programmed rout machine to cut a PCB out of the manufacturing panel. 


Schematic A schematic is created as the first step of a PCB design.   It includes graphic symbols of the electrical connections and functions of the circuit board.
Selective Gold Selective Gold indicates that a specific area in the interior of the board would be plated.  This does not include gold fingers.
Short Refers to a short circuit in the circuit board.  A short could have been accidentally created in the design of the board or is a result of an error in the manufacturing process.  An electrical test can be used to identify the short to prevent it from passing final inspection.
Single Layer PCA Single Layer PCB is a PCB with copper features on only one side of the material of the board. 
SMT Laser Cut StencilUsed to apply solder paste to a printed circuit board to aid in the soldering of surface mount components.  The stencil is usually stainless steel and can be used many times in the electronics assembly process. 
Solder Paste Also called Solder Cream, is used to solder a surface mount component lead to a corresponding land (pad) on a printed circuit board. 
Solder SideThe solder side is the bottom side of the PCB.
Soft Gold Soft gold is commonly referred to as “wire bondable gold”.  It is softer than other gold finishes which allows it to be bonded to more easily for stronger and more conductive connections. The gold does not disappear at the point of soldering or wire bond which produces a stronger welded joint. 
Stencil Fiducials Stencil Fiducials are alignment marks.  If your screen printer is equipped with a vision system, fiducials half cut in the stencil to allow for the printer to automatically align the board with the stencil.  If you are manually aligning the stencil with the board, you could either full cut the fiducials or just use the surface mount pads. 
Step-and-Repeat The process of “stepping out” the individual boards in an array. Other terms used to describe an array are: panelized, stepped out, palletized and rout and retain. 


Tab RoutTab Rout is most commonly used when a single PCB is duplicated several times in an array.   Tab Rout arrays will leave a small tab on all four sides of the board attached to the other boards or to rails. 
TDR TestingTDR stands for Time Domain Reflectometer.  When using Controlled Impedance in a PCB a TDR test is used to verify the specific impedance requirements as needed. 
TolerancesThere are a variety of tolerances in the printed circuit board manufacturing process.  They are most often identified in a customer’s design files as + (plus) or – (minus) amount depending on the area and process of the board.  For example the overall thickness of a circuit board is typically going to be a +/- 10% of the overall thickness.  In this case a board requirement of .062” would still be within tolerance if the thickness was .068″. 
Tooling HoleTooling holes are commonly used in four corners of the rails of a PCB array.  They are used to aid in alignment and orientation when assembling the board.  The typical size is .125” and they are non-plated. 
Trapezoidal Apertures In laser cut stencils Trapezoidal Apertures are created by distorting the beam on the laser, creating a draft in the aperture wall.  Trapezoidal Apertures are effective if you plan on a long dwell time between printing of solder paste and placement of components.  The taper in the aperture wall causes the paste to sit on top of itself, rather than sliding out the sides
TwistTwist references the flatness of a printed circuit board where not all four corners of the board are able to touch at the same time on a flat plane.


Universal Frame Stencil

 A universal frame provides a solid frame to connect a frameless stencil.


V-ScoreA V-Score is a small grove that is cut into an array of PCBs so that after components are added they can easily be separated. 



Wire Bondable Gold

Wire bondable gold also called soft gold.  It is softer than other gold finishes which allows it to be bonded to more easily for stronger and more conductive and stronger connections.   It is 99.99% pure – 24 carat gold with a typical thickness of 30 to 50 micro inches of gold.



X-Outs An X-Out occurs when on an array of PCBs a single board fails electrical test or final inspection and are “X’ed out” with a marker to designate that they are not to be used.  Some customers or end users specify a percentage of X-Outs allowed while others require that there be no X-Outs in an array.  This should be specified when quoting the PCBs because additional costs may be incurred. 
X-AxisThe x-Axis is the horizontal (left and right) axis of a two-dimensional plot. 


Y AxisThe Y-Axis is the vertical (up and down) axis of a two-dimensional plot. 



Z-AxisWhere the xy-plane is horizontal then Z-axis would point up from the point where x and y meet. 

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