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  • Activating

    A treatment that renders nonconductive material receptive to electroless deposition.

  • Additive Process

    A process for obtaining conductive patterns by the selective deposition of conductive material on clad or unclad base material.

  • Annular Ring

    That portion of conductive material completely surrounding a hole.

  • Aperture Information

    This is a text file describing the size and shape of each element on the board. These are also known as D-code lists. These lists are not necessary if your files are saved as Extended Gerber with embedded Apertures (274X).

  • Array

    A group of elements or circuits (or circuit boards) arranged in rows and columns on a base material.

  • Artwork

    An accurately scaled configuration used to produce the artwork master or production master.

  • Artwork Master

    The photographic film or glass plate that embodies the image of the PCB pattern, usually on a 1:1 scale.

  • Aspect Ratio

    A ratio of the PCB thickness to the diameter of the smallest hole.

  • Assembly

    A number of parts, subassemblies, or any combination thereof joined together.

  • Automated Optical Inspection (AOI)

    Visual inspection of the circuit boards using a machine scanner to assess workmanship quality.

  • Automatic Test Equipment (ATE)

    Equipment that automatically analyzes functional or static parameters in order to evaluate performance.

  • B-Stage Material

    Sheet material impregnated with a resin cured to an intermediate stage (B-stage resin). Prepreg is the popular term.

  • B-Stage Resin

    A thermosetting resin that is in an intermediate state of cure.

  • Backup Material

    A layer composed of phenolic, paper composite, or aluminum foil-clad fiber composite used during fabrication to prevent Burrs and to protect the drill table.

  • Barrel

    The cylinder formed by plating through a drilled hole.

  • Base Copper

    The thin copper foil portion of a copper-clad laminate for PCBs. It can be present on one or both sides of the board.

  • Base Material

    The insulating material upon which a conductive pattern may be formed. It may be rigid or flexible or both. It may be a dielectric or insulated metal sheet.

  • Base Material Thickness

    The thickness of the base material excluding metal foil or material deposited on the surface.

  • Bed-Of-Nails Fixture

    A test fixture consisting of a frame and a holder containing a field of spring-loaded pins that make electrical contact with a planar test object (i.e., a PCB).

  • Bleeding

    A condition in which a plated hole discharges process materials of solutions from voids and crevices.

  • Blind Via

    A conductive surface hole that connects an outer layer with an inner layer of a multi-layer board without penetrating the entire board.

  • Blister

    A localized swelling and separation between any of the layers of a laminated base material, or between base material or conductive foil. It is a form of Delamination.

  • Board Thickness

    MCL’s standard base thickness is 1/16 inch, which is also called out as 0.062″. We also offer many other thicknesses. A typical tolerance is within 10% of the given thickness.

  • Bond Strength

    The force per unit area required to separate two adjacent layers of a board by a force perpendicular to the board surface.

  • Book

    A specified number of stacks of Prepreg plies which are assembled for Curing in a lamination press.

  • Bow

    The deviation from flatness of a board, characterized by a roughly cylindrical or spherical curvature such that if the board is rectangular. Its four corners are in the same plane.

  • Build time

    MCL operates on a 10-hour clock, 5-day week (weekends and posted holidays are not counted). The cutoff time for receiving orders and files is 5:00p.m. EST. Some files have been known to take 45 minutes to navigate the web, so please allow for this.

  • Buried Via

    A via hole that does not extend to the surface of a printed board.

  • Burr

    A ridge left on the outside copper surface after drilling.

  • C-Stage

    The condition of a resin polymer when it is in a solid state with high molecular weight.

  • Capacitance

    The property of a system of conductors and dielectrics that permits storage of electricity when potential difference exists between conductors.

  • CEM1 or CEM3

    PCB material, both CEM1 and CEM3 are epoxy/fiberglass over a paper core, differing only in the type of paper used. These materials are less expensive, more punchable substitutes for FR4. Not a military grade material.
    CEM stands for composite epoxy material.

  • Chamfer

    A broken corner to eliminate an otherwise sharp edge.

  • Circuit

    The interconnection of a number of devices in one or more closed paths to perform a desired electrical or electronic function.

  • Circuitry Layer

    A layer of a printed board containing conductors, including ground and voltage planes.

  • Clad or Cladding

    A relatively thin layer or sheet of metal foil that is bonded to a laminate core to form the base material for printed circuits.

  • Cleanroom

    A room in which the concentration or airborne particles is controlled to specified limits.

  • Clearances

    A clearance (or isolation) is a term we use to describe the space from power / ground layer copper to through hole. To prevent shorting, ground and power layer clearances need to be .025” larger than the finish hole size for the inner layers. This allows for registration, drilling, and plating tolerances.

  • Component

    An electronic device, typically a resistor, capacitor, inductor, or integrated circuit (IC), that is mounted to the circuit board and performs a specific electrical function.

  • Component Hole

    A hole used for the attachment and electrical connection of a component termination, such as a pin or wire to the circuit board.

  • Component Side

    The side of the circuit board on which most of the components will be located. Also called the “top side.”

  • Computer-Aided Design (CAD)

    A software program with algorithms for drafting and modeling, providing a graphical representation of a printed board’s conductor layout and signal routes.

  • Computer-Aided Manufacturing (CAM)

    The use of computers to analyze and transfer an electronic design (CAD) to the manufacturing floor.

  • Computer-Integrated Manufacturing (CIM)

    Software that takes assembly data from a CAD or CAM package and, using a pre-defined factory modeling system, outputs routing of components to machine programming points and assembly and inspection documentation.

  • Conductor

    A thin conductive area on a PCB surface or internal layer usually composed of lands (to which component leads are connected) and paths (traces).

  • Conductor Spacing

    The distance between adjacent edges (not centerline to centerline) of isolated conductive patterns in a conductor layer.

  • Conductor Thickness

    The thickness of the conductor including all metallic coatings.

  • Conformal Coating

    An insulating protective coating that conforms to the configuration of the object coated and is applied on the completed board assembly.

  • Connector Area

    The portion of the circuit board that is used for providing electrical connections.

  • Controlled Impedance

    The matching of substrate material properties with trace dimensions and locations to create specific electric impedance as seen by a signal on the trace.

  • Copper (Finished Copper)

    This is how much copper your board will have on its surface. It is the copper foil thickness, plus plated copper, minus surface preparation. It is given in oz / per sq foot. 1 oz = a minimum of 0.0012”- 0.0014” thickness. We offer finished copper of 1-oz., 1.5-oz., 2.0-oz., and 2.5-oz. If you need a different finished copper amount, please complete our PCB RFQ Form.

  • Core Thickness

    The thickness of the laminate base without copper.

  • CTE

    Coefficient of thermal expansion. The measure of the amount a material changes in any axis per degree of temperature change.

  • Curing

    The act of applying heat to a material in order to produce a bond.

  • Cut lines

    The cut line is going to be used to program the router path and it represents the board outside edge. Our route tolerance is +/- 0.010″. It is recommended to keep outer layer copper 0.01” and inner copper 0.025” from the cut line to avoid contact with the board edge.

  • Date Code

    This selection will have us place the year and week of manufacture on your board. It can be etched on the board or part of the silkscreen.

  • Deburring

    Process of removing burrs after drilling.

  • Defect

    Any nonconformance to specified requirements by a unit or product.

  • Definition

    The fidelity of reproduction of pattern edges, especially in a printed circuit relative to the original master pattern.

  • Delamination

    A separation between any of the layers of the base of laminate or between the laminate and the metal cladding originating from or extending to the edges of a hole or edge of board.

  • Design Rule

    Guidelines that determine automatic conductor routing behavior with respect to specified design parameters.

  • Design Rule Checking

    The use of a computer program to perform continuity verification of all conductor routing in accordance with appropriate design rules.

  • Desmear

    The removal of friction-melted resin and drilling debris from a hole wall.

  • Dewetting

    A condition that results when molten solder has coated a surface and then receded, leaving irregularly shaped mounds separated by areas covered with a thin solder film and with the base material not exposed.

  • Dielectric

    An insulating medium that occupies the region between two conductors.

  • Digitizing

    The converting of feature locations on a flat plane to a digital representation in X-Y coordinates.

  • Dimensional Stability

    A measure of the dimensional change of a material that is caused by factors such as temperature changes, humidity changes, chemical treatment, and stress exposure.

  • Double-Sided Board

    A printed board with a conductive pattern on both sides.

  • Drawing or Print

    These usually include an outline of the board, dimensions, fabrication notes, a drill chart with legend.

  • Drill File (Excellon Drill File)

    It will have X & Y coordinates with tool sizes viewable in any text editor. It is this file that governs your finished hole sizes.

  • Drill Tool Description

    This is a text file describing drill tool number, corresponding size, quantity, and if the holes are to be plated or non- plated.

  • Drilling

    The act of forming holes (vias) in a substrate by mechanical or laser means.

  • Dry-Film Resists

    Coating material specifically designed for use in the manufacture of printed circuit boards and chemically machined parts. They are suitable for all photomechanical operations and are resistant to various electroplating and etching processes.

  • Dry-Film Soldermask

    Coating material (dry-film resist) applied to the printed circuit board via a lamination process to protect the board from solder or plating.

  • Electrical Test

    Testing is used primarily to test for opens and shorts. MCL recommends testing for all surface mount boards and multilayer orders (4 layers & up).

  • Electroless Copper

    A thin layer of copper deposited on the plastic or metallic surface of a PCB from an autocatalytic plating solution (without the application of electrical current).

  • Electroplating

    The electrodeposition of an adherent metal coating on a conductive object. The object to be plated is placed in an electrolyte and connected to one terminal of a direct current (DC) voltage source. The metal to be deposited is similarly immersed and connected to the other terminal.

  • ENIG

    Electroless Nickel under Immersion Gold finish. MCL offers ENIG finish for customers with lead-free product requirements.

  • Entry Material

    A thin layer of material composed of phenolic, aluminum foil, or paper that is placed on top of the panel prior to drilling to improve drill accuracy and prevent burrs and dents.

  • Epoxy

    A family of thermosetting resins. Epoxies form a chemical bond to many metal surfaces.

  • Epoxy Smear

    Epoxy resin that has been deposited on edges of copper in holes during drilling either as uniform coating or in scattered patches. It is undesirable because it can electrically isolate the conductive layers from the plated-through-hole interconnections.

  • Etchback

    The controlled removal of all components of the base material by a chemical process acting on the sidewalls of plated-through holes to expose additional internal conductor areas.

  • Etching

    The chemical, or chemical and electrolytic, removal of unwanted portions of conductive materials.

  • Excellon Drill File

    This is a type of drill file that MCL will accept.

  • Feed-Thru (Via)

    A plated through hole in a Printed Circuit Board that is used to provide electrical connection between a trace on one side of the Printed Circuit Board to a trace on the other side. Since it is not used to mount component leads, it is generally a small hole and pad diameter.

  • Fiducial Mark

    Fiducial marks are dots etched on board panel for which SMT assembly is required (provide viewing targets for camera to locate correct position). These marks should be in diameter of approx. 0.06″ and free from solder mask. There should be 2 sets of fiducials if fine-pitch components are use. The first set is called the panel mark, one for each panel corners (at lease .5″ from any panel tooling holes). The second set is called the local mark, one for each fine-pitch IC located at the absolute center position of that IC.

  • Files: Gerber

    Our Industry standard format for files used to generate artwork necessary for circuit board imaging. MCL’s preferred Gerber format is 274X, which embeds the apertures within the specific files (see Aperture information). If files are not saved in 274X, MCL will need “One” aperture list sent with the files.

  • Finished Copper

    This is how much copper your board will have on its surface. It is the copper foil thickness, plus plated copper, minus surface preparation. It is given in oz / per sq foot. 1 oz = a minimum of 0.0012”- 0.0014” thickness.

  • First Article

    A sample part or assembly manufactured prior to the start of production for the purpose of ensuring that the manufacturer is capable of producing a product that will meet specified requirements.

  • Flying Probe

    A testing device that uses multiple moving pins to make contact with two spots on the electrical circuit and send a signal between them, a procedure that determines whether faults exist.

  • FR1

    A paper material with a phenolic resin binder. FR-1 has a Tg of about 130°C. MCL does not offer FR1

  • FR2

    A paper material with phenolic resin binder similar to FR-1 but with a Tg of about 105°C. MCL offers this material for Single sided boards only.

  • FR3

    A paper material that is similar to FR-2 except that an epoxy resin is used instead of phenolic resin as a binder. Used mainly in Europe. MCL does not offer FR3.

  • FR4

    The UL-designated rating for a laminate composed of glass and epoxy that meets a specific standard for fire-retardance. FR-4 is the most common dielectric material used in the construction of PCBs.

  • G10

    A laminate consisting of woven epoxy-glass cloth impregnated with epoxy resin under pressure and heat. G10 lacks the anti-flammability properties of FR-4. Used mainly for thin circuits such as in watches.

  • Gerber

    A software format used by the photoplotter to describe the printed circuit board design.

  • Glass Epoxy

    A material used to fabricate Printed Circuit Boards. The base material (fiberglass) is impregnated with epoxy filler which then must have copper laminated to its outer surface to form the material required to manufacture Printed Circuit Boards.

  • Gold Fingers (Linear Inches)

    We can plate your edge connectors with Gold. (Approx. Ni / Min. 30 Au). The input here needs to be the distance between the outside edges of the outermost tabs.

  • Golden Board

    See Known Good Board

  • Ground Plane

    A conductor layer, or portion of a conductor layer, used as a common reference point for circuit returns, shielding, or heat sinking.

  • HAL

    Acronym HAL, which is the process of putting solder on exposed copper of the circuit board. Approx. 60/40 Tin/Lead mix is used. Also known as a SMOBC which is an acronym for Solder Mask Over Bare Copper.

  • HDI (High Density Interconnect)

    Ultra fine-geometry multi-layer PCB constructed with conductive microvia connections. These boards also usually include buried and/or blind vias and are made by sequential lamination.

  • Hole Breakout

    A condition in which a hole is partially surrounded by the land.

  • Hole Pattern

    The arrangement of all holes in a printed board with respect to a reference point.

  • Hot Air Solder Leveling (HASL)

    A method of coating exposed copper with solder by inserting a panel into a bath of molten solder then passing the panel rapidly past jets of hot air.

  • Imaging

    The process by which panelization data are transferred to the photo plotter, which in turn uses light to transfer a negative image circuitry pattern onto the panel.

  • Impedance

    The total passive opposition offered to the flow of electric current. This term is generally used to describe high-frequency circuit boards.

  • Inkjetting

    The dispersal of well-defined ink “dots” onto a PCB. Inkjet equipment uses heat to liquefy a solid ink pellet and change the ink into a liquid, which is then dropped via a nozzle onto the printed surface, where it quickly dries.

  • Inner-layers

    The internal layers of laminate and metal foil within a multi-layer board. Also known as Internal Signal Layers.

  • Insulation Resistance

    The electrical resistance of an insulating material that is determined under specific conditions between any pair of contacts, conductors, or grounding devices in various combinations.

  • Known Good Board (KGB)

    A board or assembly that is verified to be free of defects. Also known as a Golden Board.

  • Laminate

    The plastic material usually reinforced by glass or paper that supports the copper cladding from which circuit traces are created.

  • Laminate Thickness

    Thickness of the metal-clad base material, single- or double-sided, prior to any subsequent processing.

  • Laminate Void

    An absence of epoxy resin in any cross-sectional area that should normally contain epoxy resin.

  • Land

    The portion of the conductive pattern on printed circuits designated for the mounting or attachment of components. Also known as a pad.

  • Layer Sequence

    Please include a layer sequence or pass through marks so that we are able to build your order with the correct stack up.

  • Layers

    The plains of copper connected by the plated through holes. On board text such as company name, logo, or part number that is correct reading on the top layer will insure the layer are placed correctly.

  • Layup

    The process in which treated prepregs and copper foils are assembled for pressing.

  • Legend

    A format of lettering or symbols on the printed circuit board: e.g. part number, serial number, component locations, and patterns. See Nomenclature or Silk Screen.

  • Line

    See Conductor.

  • Liquid Photoimageable Soldermask (LPI)

    A mask sprayed on using photographic imaging techniques to control deposition. MCL standard is LPI-Green.

  • Lot

    A quantity of circuit boards that share a common design.

  • Lot Code

    Some Customers require a manufacturer’s lot code to be placed on the board for future tracking purposes. Your order form is how you select it. A drawing can specify the location, what layer and if it is to be in copper, mask opening, or silkscreen

  • Major Defect

    A defect that is likely to result in failure of a unit or product by materially reducing its usability for its intended purpose.

  • Mask

    A material applied to enable selective etching, plating, or the application of solder to a PCB. Also called soldermask or resist.

  • Measling

    Discrete white spots or crosses below the surface of the base laminate that reflect a separation of fibers in the glass cloth at the weave intersection.

  • Metal Foil

    The plane of conductive material of a printed board from which circuits are formed. Metal foil is generally copper and is provided in sheets or rolls.

  • Microsectioning

    The preparation of a specimen of a material, or materials, that is to be used in metallographic examination. This usually consists of cutting out a cross-section followed by encapsulation, polishing, etching, and staining.

  • Microvia

    Usually defined as a conductive hole with a diameter of 0.005” or less that connects layers of a multi-layer PCB. Often used to refer to any small geometry connection holes created by laser drilling.

  • Minimum Traces & Spacing

    Traces are the “Wires” of the Printed Circuit Board (also known as tracks). Spaces are the distances between traces, the distances between pads, or the distances between a pad and a trace. How wide is the smallest trace (line, track, wire), or space between traces or pads? Whichever is less of the two governs the order form selection. We offer widths down to 0.0059″.

  • Minor Defect

    A defect that is not likely to result in the failure of a unit of product or that does not reduce the usability for its intended purpose.

  • Multi-Layer Board

    Printed boards consisting of a number (four or more) of separate conducting circuit planes separated by insulating materials and bonded together into relatively thin homogeneous constructions with internal and external connections to each level of the circuitry as needed.

  • Net-List

    An ASCII list describes logical connections between component pins. Generated from schematic capture systems for transferring logical connections to layout systems. Other net-lists are generated from CAD/CAM system for board test and in-circuit test purposes.

  • Nomenclature

    Identification symbols applied to the board by means of screen printing, inkjetting, or laser processes. See Legend or Silk Screen.

  • Non-Plated through holes (NPTH)

    Holes that do not have copper in the hole barrels are defined as NPTH’s

  • Number of Holes

    This is the total number of holes in the board.

  • Outer-layer

    The top and bottom sides of any type of circuit board.

  • Pad

    See Land.

  • Pad Sizes

    Your outer layer pads need to be 0.017″ larger than the finish tool size (0.010” for vias). Your inner layer pads need to be 0.018″ larger than your finished tool size. If your design has any pad to trace junction minimum requirement, add that to the above numbers [0.017″ pad + 0.002″ junction should have 0.019″ pad].

  • Part Number

    The name or number associated with your printed circuit board. We use your part number throughout the entire order process for your convenience.

  • Pattern

    The configuration of conductive and nonconductive materials on a panel or printed board. Also, the circuit configuration on related tools, drawing, and masters.

  • Pattern Placing

    The selective plating of a conductive pattern.

  • Photo Print

    The process of forming a circuit pattern image by hardening a photosensitive polymeric material by passing light through a photographic film.

  • Photographic Image

    An image in a photo mask or in an emulsion that is on a film or plate.

  • Photoplotting

    Photoplotting is an electronic optical process to scan rasterized image data on films. Some times refer to as laser plotting. A photoplot is a film generated by photoplotter, or referred to as artwork required for PCB fabrication.

  • Phototool

    A transparent film that contains the circuit pattern, which is represented by a series of lines of dots at a high resolution.

  • Plated Through-Hole (PTH)

    Holes that have copper plating in the hole barrels that make an electrical connection between layers are defined as PTH’s.

  • Platen

    A flat plate of metal within the lamination press in between which stacks are placed during pressing.

  • Plating Void

    The area of absence of a specific metal from a specific cross-sectional area.

  • Plotting

    The mechanical converting of X-Y positional information into a visual pattern such as artwork.

  • Pregreg

    Sheet material (e.g. glass fabric) impregnated with a resin cured to an intermediate stage (B-stage resin).

  • Pressing

    The process by which a combination of heat and pressure are applied to a book, thereby producing fully cured laminated sheets.

  • Printed Board

    The general term for completely processed printed circuit or printed wiring configurations. It includes single, double-sided, and multi-layer boards, both rigid and flexible.

  • Printed Circuit

    A conductive pattern that comprises printed components, printed wiring, or a combination thereof, all formed in a predetermined design and intended to be attached to a common base. (In addition, this is a generic term used to describe a printed board produced by any of a number of techniques.)

  • Printed Wiring Board

    A part manufactured from rigid base material upon which completely processed printed wiring has been formed.

  • Pulse Plating

    A method of plating that uses pulses instead of a direct current.

  • Quantity

    Enter in the number of boards you need. If you do not know your desired quantity, enter in an approximate amount for pricing.

  • Readme File

    A text file included in the zip file, which provides necessary information needed to manufacture your order. Phone numbers or email addresses of designer or engineer contacts for this project should be included to expedite resolution of any potential manufacturing problems that could delay your order.

  • Reflow

    The melting of electrodeposited tin/lead followed by solidification. The surface has the appearance and physical characteristics of being hot-dipped.

  • Registration

    The degree of conformity to the position of a pattern, or a portion thereof, a hole or other feature to its intended position on a product.

  • Resin (Epoxy) Smear

    Resin transferred from the base material onto the surface of the conductive pattern in the wall of a drilled hole.

  • Resist

    Coating material used to mask or to protect selected areas of a pattern from the action of an etchant, solder, or plating. Also called soldermask or mask.

  • Revision

    If you have the same drawing number but updated revisions, please enter it here. This will avoid any confusion for manufacturing your desired boards. Please make sure that your revision number is included with your drawings in your Readme file.

  • Rigid-flex

    A PCB construction combining flexible circuits and rigid multi-layers usually to provide a built-in connection or to make a three-dimension form that includes components.

  • Rough Holes

    Holes with a copper burr around either the entry or exit hole and that lack a smooth barrel.

  • Router

    A machine that cuts away portions of the laminate to form the desired shape and size of the printed board.

  • Routing

    We offer many choices regarding routing. Excessive routing can increase PCB costs. If your PCB requires routing you may want to send the files directly to us to quote on the PCB RFQ Form.

  • Scoring

    A technique in which grooves are machined on opposite sides of a panel to a depth that permits individual boards to be separated from the panel after component assembly.

  • Screen Printing

    A process for transferring an image to a surface by forcing suitable media through a stencil screen with a squeegee.

  • Silk Screen

    Marking ink is used to identify components during later assembly and troubleshooting processes. This can be placed on one or two sides (in yellow or white), depending on the board design and application. We can include your company logo if it is provided on the drawing specs.

  • Single-Sided Board

    A printed board with conductive pattern on one side only.

  • Size X & Y

    All dimensions are in inches. If your board is in metric, please convert to inches.

  • Slots / Cutouts

    Slots are internal cutouts usually long and thin. By selecting Slots we will add up to 5 slots per board. If your design has more than 5 slots, additional costs may be needed.

  • Smallest Hole

    This is the final size of the hole. We will select a drill larger than the specified hole size to allow for plating thickness. Hole sizes greater than 0.020″ do not incur special costs.

  • Solder

    An alloy that melts at relatively low temperatures and is used to join or seal metals with higher melting points. A metal alloy with a melting temperature below 427°C (800°F).

  • Solder Leveling

    The process by which the board is exposed to hot oil or hot air to remove any excess solder from holes and lands.

  • Solder Mask

    Coating material used to mask or to protect selected areas of a pattern from the action of an etchant, solder, or plating. Also called resist or mask. LPI-Green is our standard color. However, we also offer additional colors of red, blue, & black.

  • Solder Mask (Artwork)

    To generate your soldermask artwork, add your smallest space measurement to the pad size. For boards with 0.006″ spaces, use a pad size up to +0.006″ up to 0.010″ for 0.010″. Spaces larget than 0.010″ should have a pad size of +0.010″.

  • Solder Mask Color

    LPI Green is our default solder mask color. We have options on the MCL website for additional colors of blue and black. Please note that there is an added charge for these other colors, and they can add an extra day to your build time due to the additional processes needed for the non-standard colors.

  • Soldermask Over Bare Copper (SMOBC)

    A method of fabricating a printed circuit board that results in final metallization being copper with no protective metal. The non-coated areas are coated by solder resist, exposing only the component terminal areas. This eliminates tin lead under the pads.

  • Step-and-Repeat

    A method by which successive exposures to a single image are made to produce a multiple image production master.

  • Stripping

    The process by which imaging material (resist) is chemically removed from a panel during fabrication.

  • Substrate

    A material on whose surface adhesive substance is spread for bonding or coating. Also, any material that provides a supporting surface for other materials used to support printed circuit patterns.

  • Subtractive Processing

    The method of selectively removing copper from a board to form a circuit. In this case, “subtractive” refers to the method of image transfer from a phototool or image file to the copper circuit.

  • Surface Mount

    The pitch of the surface mount is defined as the dimension in inches from center to center of surface mount pads. Standard pitch is >0.025″, fine pitch is 0.011″-0.025″, and ultra fine pitch is <0.011". As boards contain finer pitch, processing and test fixture costs increase.

  • Surface Mount Technology (SMT)

    Defines the entire body of processes and components that create printed circuit board assemblies with leadless components.

  • Tab Routing (with and without perforation holes)

    Rather that completing the route path around the board edge, “Tabs” are left so as to leave boards attached in pallets for ease in assembly.

  • Tab Routing with Perforation Holes

    Same as tab routing above with the exception that we add perforation holes along the tabs to make it easier to break apart your boards at a later date. We recommend tab routing if you plan to have your boards assembled.

  • Test Coupon

    A portion of a printed board or of a panel containing printed coupons used to determine the acceptability of such a board.

  • TG

    Glass transition temperature. The point at which rising temperatures cause the solid base laminate to start to exhibit soft, plastic-like symptoms. This is expressed in degrees Celsius (°C).

  • Thickness

    MCL’s standard base thickness is 0.062”. We also offer 0.031″, 0.094″, and 0.126″. MCL’s tolerance is within 10% of the given measurement.

  • Thief

    An extra cathode placed as to divert to itself some of the current from portions of the board which otherwise would receive too high a current density.

  • Tooling Holes

    The general term for holes placed on a PCB or a panel of PCBs for registration and hold-down purposes during the manufacturing process. Also known as Fabrication Hole, Pilot Hole, or Manufacturing Hole.

  • Top Side

    See Component Side.

  • Trace

    A common term for conductor. Also known as track.

  • Traveler

    The list of instructions describing the board, including any specific processing requirements. Also called a shop traveler, routing sheet, job order, or production order.

  • Twist

    A laminate defect in which deviation from planarity results in a twisted arc.

  • UL

    Underwriters Laboratories, Inc., an independent product safety testing and certification organization.

  • Underwriters Symbol

    A logotype denoting that a product has been recognized (accepted) by Underwriters Laboratories Inc. (UL).

  • UV Curing

    Polymerizing, hardening, or cross linking a low molecular weight resinous material in a wet coating ink using ultra violet light as an energy source.

  • V-Scoring

    Rather than completing a route path around the board edge, the edges are “scored” to allow breaking boards apart after assembly. This is another way to palletize / panelize the boards (see Tab Routing).

  • Via

    A plated through-hole that is used as an interlayer connection but does not have component lead or other reinforcing material inserted in it.

  • Void

    The absence of any substances in a localized area.

  • Wave Soldering

    A process wherein assembled printed boards are brought in contact with a continuously flowing and circulating mass of solder, typically in a bath.

  • Wicking

    Migration of copper salts into the glass fibers of the insulating material.

  • WIP

    An acronym for work in progress.

  • Zip File

    All files needed for the processing of your order must be compressed in a zip file. Due to the large amount of orders received, we are not able to accept individual layer files sent to us.

PCB Glossary

  • Solder Mask Color

    LPI Green is our default solder mask color. We have options on the MCL website for additional colors of blue and black. Please note that there is an added charge for these other colors, and they can add an extra day to your build time due to the additional processes needed for the non-standard colors.