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    What is an Automatic Test Equipment (ATE)?

    Automatic Test Equipment is equipment that automatically analyzes functional or static parameters in order to evaluate performance.

    What is an Automated Optical Inspection (AOI)?

    An automated optical inspection is the visual inspection of the circuit boards using a machine scanner to assess workmanship quality.

    What is an Assembly?

    An assembly is a number of parts, subassemblies, or any combination thereof joined together.

    What is Aspect Ratio?

    The aspect ratio is the ratio of the PCB thickness to the diameter of the smallest hole.

    What is an Artwork Master?

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

    What is an Artwork?

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

    What is an Array?

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

    What is Aperture Information?

    Aperture information 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).

    What is an Annular Ring?

    An annular ring is that portion of conductive material completely surrounding a hole.

    What is the Additive Process?

    The additive process is a process for obtaining conductive patterns by the selective deposition of conductive material on clad or unclad base material.

    What is Activating?

    Activating is a treatment that renders nonconductive material receptive to electroless deposition.


    What is a Burr?

    A burr is a ridge left on the outside copper surface after drilling.

    What is a Buried Via?

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

    What is 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.

    What is a Bow?

    A bow is a 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.

    What is a Book?

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

    What is Bond Strength?

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

    What is 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.

    What is a Blister?

    A blister is 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.

    What is a Blind Via?

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

    What is Bleeding?

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

    What is a Bed-Of-Nails Fixture?

    A bed-of-nails fixture is 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).

    What is Base Material Thickness?

    Base Material Thickness is the thickness of the base material excluding metal foil or material deposited on the surface.

    What is Base Material?

    Base Material is 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.

    What is 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.

    What is a Barrel?

    A barrel is a cylinder formed by plating through a drilled hole.

    What is Backup Material?

    Backup material is 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.

    What is B-Stage Resin?

    B-Stage resin is a thermosetting resin that is in an intermediate state of cure.

    What is B-Stage Material?

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


    What are 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.

    What is Curing?

    Curing is the act of applying heat to a material in order to produce a bond.

    What is CTE?

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

    What is Core Thickness?

    Core thickness is the thickness of the laminate base without copper.

    What is 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.

    What is Controlled Impedance

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

    What is the Connector Area

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

    What is Conformal Coating

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

    What is Conductor Thickness?

    Conductor thickness is the thickness of the conductor including all metallic coatings.

    What is Conductor Spacing?

    Conductor spacing is the distance between adjacent edges (not centerline to centerline) of isolated conductive patterns in a conductor layer.

    What is a Conductor?

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

    What is Computer-Integrated Manufacturing (CIM)

    CIM is the 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.

    What is Computer-Aided Manufacturing (CAM)

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

    What is a Computer-Aided Design (CAD)

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

    What is the Component Side

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

    What is a Component Hole?

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

    What is a Component?

    A component is 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.

    What are 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.

    What is a Cleanroom?

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

    What is Clad or Cladding?

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

    What is a Circuitry Layer?

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

    What is a Circuit?

    A circuit is the interconnection of a number of devices in one or more closed paths to perform a desired electrical or electronic function.

    What is Chamfer?

    A chamfer is a broken corner to eliminate an otherwise sharp edge.

    What is 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.

    What is Capacitance?

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

    What is C-Stage?

    C-Stage is the condition of a resin polymer when it is in a solid state with high molecular weight.


    What is a Dry-Film Soldermask?

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

    What are Dry-Film Resists?

    A dry-film resists is a 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.

    What is Drilling?

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

    What is a Drill Tool Description?

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

    What is a Drill File (Excellon Drill File)?

    A Drill File has X & Y coordinates with tool sizes viewable in any text editor. It is this file that governs your finished hole sizes.

    What is a Drawing or Print?

    A drawing or print usually includes an outline of the board, dimensions, fabrication notes, a drill chart with legend.

    What is a Double-Sided Board?

    A double-sided board is a printed board with a conductive pattern on both sides.

    What is Dimensional Stability?

    Dimensional stability is 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.

    What is Digitizing?

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

    What is Dielectric?

    Dielectric is an insulating medium that occupies the region between two conductors.

    What is Dewetting?

    Dewetting is 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.

    What is Desmear?

    Desmear is the removal of friction-melted resin and drilling debris from a hole wall.

    What is Design Rule Checking?

    Design rule checking is the use of a computer program to perform continuity verification of all conductor routing in accordance with appropriate design rules.

    What is a Design Rule?

    A design rule is guidelines that determine automatic conductor routing behavior with respect to specified design parameters.

    What is Delamination?

    Delamination is 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.

    What is a Definition?

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

    What is a Defect?

    Any nonconformance to specified requirements by a unit or product.

    What is Deburring?

    Deburring is the process of removing burrs after drilling.

    What is 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.


    What is an Excellon Drill File?

    An excellon drill file is a type of drill file that MCL will accept.

    What is Etching?

    Etching is the chemical, or chemical and electrolytic, removal of unwanted portions of conductive materials.

    What is an Etchback?

    An etchback is 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.

    What is an Epoxy Smear?

    An epoxy smear is 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.

    What is an Epoxy?

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

    What is an Entry Material?

    An entry material is 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.

    What is an ENIG?

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

    What is Electroplating?

    Electroplating is 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.

    What is an Electroless Copper

    An electroless copper is 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).

    What is an Electrical Test?

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


    What is an FR4?

    A FR4 is 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.

    What is an FR3?

    A FR3 is 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.

    What is an FR2?

    An FR2 is 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.

    What is an FR1?

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

    What is a Flying Probe?

    A flying probe is 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.

    What is the First Article?

    The first article is 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.

    What is 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.

    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.

    What is a 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.

    What is a Feed-Thru (Via)?

    Feed-thru via is 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.


    What is a Ground Plane?

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

    What is a Golden Board?

    A golden board is a board or assembly that is verified to be free of defects.

    What are 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.

    What is Glass Epoxy?

    Glass epoxy is 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.

    What is Gerber?

    Gerber is a software format used by the photoplotter to describe the printed circuit board design.

    What is a G10?

    A G10 is 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.


    What is Hot Air Solder Leveling (HASL)?

    HASL is 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.

    What is a Hole Pattern?

    A hole pattern is the arrangement of all holes in a printed board with respect to a reference point.

    What is a Hole Breakout?

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

    What is HDI (High Density Interconnect)?

    HDI is 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.

    What is HAL?

    Hal 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.


    What is Insulation Resistance?

    Insulation resistance is 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.

    What are Inner-layers?

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

    What is Inkjetting?

    Inkjetting is 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.

    What is Impedance?

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

    What is Imaging?

    Imaging is 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.


    What is a Known Good Board (KGB)?

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


    What is a 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.

    What is a Lot?

    A lot is a number of circuit boards that share a common design.

    What is Liquid Photoimageable Soldermask (LPI)?

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

    What is a Line?

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

    What is a Legend?

    A legend is 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.

    What is a Layup?

    Layup is the process in which treated prepregs and copper foils are assembled for pressing.

    What are Layers?

    Layers are 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.

    What is 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.

    What is Land?

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

    What is Laminate Void?

    Laminate void is an absence of epoxy resin in any cross-sectional area that should normally contain epoxy resin.

    What is Laminate Thickness?

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

    What is Laminate?

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


    What is a Multi-Layer Board?

    A multi-layer board is a printed board 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.

    What is a Minor Defect?

    A minor defect is 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.

    What are 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″.

    What is Microvia?

    Microvia is 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.

    What is Microsectioning?

    Microsectioning is 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.

    What is a Metal Foil?

    Metal foil is 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.

    What is a Measling?

    Measlings are 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.

    What is a Mask?

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

    What is a Major Defect?

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


    Number of Holes

    This is the total number of holes in the board.

    What are Non-Plated through holes (NPTH)?

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

    What is Nomenclature?

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

    What is a 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.


    What is the Outer-layer?

    The outer-layer is the top and bottom sides of any type of circuit board.


    What is Pulse Plating?

    Pulse plating is a method of plating that uses pulses instead of a direct current.

    What is a Printed Wiring Board?

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

    What is a Printed Circuit?

    A printed circuit is 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.)

    What is a Printed Board?

    A printed board is 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.

    What is Pressing?

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

    What is Pregreg?

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

    What is Plotting?

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

    What is a Plating Void?

    A plating void is the area of absence of a specific metal from a specific cross-sectional area.

    What is a Platen?

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

    What is a Plated Through-Hole (PTH)?

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

    What is a Phototool?

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

    What is 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.

    What is a Photographic Image?

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

    What is a Photo Print?

    A photo print is the process of forming a circuit pattern image by hardening a photosensitive polymeric material by passing light through a photographic film.

    What is Pattern Placing?

    Pattern placing is the selective plating of a conductive pattern.

    What is a Pattern?

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

    What are Part Numbers?

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

    What are 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].

    What is a Pad?

    A pad is the portion of the conductive pattern on printed circuits designated for the mounting or attachment of components.



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


    What is 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.

    What is a Router?

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

    What are Rough Holes?

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

    What is Rigid-flex?

    Rigid-flex is 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.


    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.

    What is a Resist?

    A resist is the 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.

    What is Resin (Epoxy) Smear?

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

    What is Registration?

    Registration is 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.

    What is Reflow?

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

    What is a Readme File?

    A Readme file is 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.


    What is Surface Mount Technology (SMT)?

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

    What is the Surface Mount

    Surface mount is 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.

    What is Subtractive Processing?

    Subtractive processing is 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.

    What is a 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.

    What is Stripping

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

    What is Step-and-Repeat?

    Step-and-repeat is a method by which successive exposures to a single image are made to produce a multiple image production master.

    What is Soldermask Over Bare Copper (SMOBC)?

    SMOBC is 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.

    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.

    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″.

    What is a Solder Mask?

    A solder mask is the 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.

    What is Solder Leveling?

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

    What is a Solder?

    A solder is 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).

    What is the 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.

    What are 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.

    Size X & Y

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

    What is a Single-Sided Board?

    A single-sided board is a printed board with conductive pattern on one side only.

    What is a Silk Screen?

    A silk screen is marking ink 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.

    What is Screen Printing?

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

    What is Scoring?

    Scoring is 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.


    What is a Twist?

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

    What is a Traveler?

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

    What is a Trace?

    A trace is a common term for a conductor. Also known as track.

    What is the Top Side

    The top side is the side of the circuit board on which most of the components will be located.

    What are Tooling Holes?

    Tooling holes are 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.

    What is a Thief?

    A thief is 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.

    What is 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.

    What is 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).

    What is a Test Coupon?

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

    What is Tab Routing with Perforation Holes?

    Tab routing with perforation holes is the 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.

    What is 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.


    What is UV Curing?

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

    What is an Underwriters Symbol?

    An underwriters symbol is a logotype denoting that a product has been recognized (accepted) by Underwriters Laboratories Inc. (UL).

    What is UL?

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


    What is a Void?

    The absence of any substances in a localized area.

    What is a Via?

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

    What is 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).


    What is WIP?

    WIP is an acronym for work in progress.

    What is Wicking?

    Wicking is the migration of copper salts into the glass fibers of the insulating material.

    What is Wave Soldering?

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


    What is a Zip File?

    A zip file contains all the files needed for the processing of your order. Due to the large amount of orders received, we are not able to accept individual layer files sent to us.