Major North American PCB suppliers are outsourcing significant portions of the manufacturing process to Asia based PCB companies without permission from, or knowledge of, their customers.

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Glossary of terms

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Term Definition
make before break   (MBB) Selected contacts in a connector that make an electrical circuit before breaking (open circuiting) other contacts.
male connectors   An insulated plastic moulding (sometimes called a housing) fitted with plug contacts.
manual pin routing   See board routing process.
manufacturer’s data specification sheet   It provides electrical and mechanical data about a part and is used as a source of information for library inputs, design activities, and material procurement.
manufacturing data   Information consisting of photoplotting files, drill files, pick-and-place files, bare and loaded board testing files, support drawings, and bills of materials required to do the actual fabrication, assembly and test of a PCA.
manufacturing engineering   The technical organization that is usually responsible for planning and implementing PCA production activities.
manufacturing execution system   (MES). Software systems designed to integrate with enterprise systems to enhance the shop-floor-control functionality that is usually inadequate in ERP systems. MES provides for shop floor scheduling, production and labor reporting, integration with computerized manufacturing systems such as automatic data collection and computerized machinery.
markings   Information imprinted on parts and circuit boards, such as reference designations, part or serial numbers, revision level, orientation or polarization symbols, bar codes, and electrostatic discharge (ESD) sensitivity.
mask   A chrome and glass pattern for a layer of the wafer used in the photolithography process for silicon device manufacture. Also refers to a material applied to enable selective etching, plating, or the application of solder to a PCB. Also called solder mask or resist.
mass lamination  A method for laminating four layer PCBs in very large quantities. The inner two layers of the PCB are imaged and etched back to back on a very large panel, often 36"x48" or larger. Many different PCBs can be imaged on a single piece of laminate. Etched innerlayers are combined with prepreg and foil and then laminated. Following lamination, targets etched on the innerlayers are located and tooling holes are produced therein. The large panel is then cut up into the discrete part numbers thereby allowing processing in a more manageable panel size that is order specific. This form of lamination is typically associated with lower layer count and low-medium density multilayers. See also pinless lamination.
mass soldering   The process of forming all solder joints on a PCA simultaneously (wave soldering, dip soldering, oven reflow, vapour phase soldering).
master artwork set   An accurately scaled, 1:1 pattern that is used as the source for producing working artwork films for circuit board fabrication.
master pattern drawing   A document that shows the dimensional limits or grid locations applicable to any or all parts of the circuit board. This also includes the arrangements of conductive and nonconductive patterns or elements, the size, type, and location of holes, and other information necessary to describe the product for fabrication.
material panel   Laminate, prepreg, and copper foil materials used for manufacturing circuit boards that are produced in standard sheet or panel sizes.
maximum/least material concept   Used in geometric dimensioning and tolerancing, maximum material describes the condition of a mechanical feature within a stated limit of size (minimum hole size, maximum shaft diameter). Least material describes the minimum size of a feature (maximum hole size, minimum shaft diameter).
MCM (Multi-Chip Module)   A chip package within which more than one bare semiconductor die is bonded directly to a substrate by flip-chip, TAB or wire bonding. MCMs can also contain sealed components and chip components. The most complex are really encapsulated PCBs.
MCR (Moulded Carrier Ring)   A type of fine-pitch package named from the method of supporting and protecting the leads. The leads are left straight, with their ends embedded in a strip of plastic, the ‘Moulded Carrier Ring’. The MCR is cut off, and the leads formed, only immediately before assembly, thus protecting them against handling damage.
measling   An internal defect in laminated base material in which the internal weave becomes visible, which takes the form of discrete white spots or crosses below the surface of the base laminate, reflecting a separation of glass fibres from the resin at weave intersections. Measling is usually due to thermally induced stress and indicates a weakened and unreliable substrate. (Also see ‘ crazing’)
mechanical shock and vibration   External forces imposed on an assembly by cyclical energy inputs (vibration) or a single, sudden high-energy input (shock).
media   The type of material used for product data and documentation, such as electronic (tape, CD disk) and drawings (paper, Mylar, film).
megabit   One million binary pieces (bits) of information.
MELF  (Metal Electrode Leadless Face). A (usually cylindrical) surface mount component package that has a metallic cap termination at each end instead of metallisation. Commonly used for diodes, capacitors and resistors.
meniscus   That part of the insulation coating on a dipped component which has flowed up onto the lead, such as on a dipped capacitor.
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.
metallisation   A metallic layer deposited on substrates and component terminations, either by itself or over a base metal, which makes it possible to create electrical and mechanical interconnections.
MHz   for megahertz (not MH)Z, Mhz, mhz)
micro ball grid array   (MBGA A method of mounting an integrated circuit or other component to a higher layer-count printed circuit board with an array of extremely small solder balls (or columns) at each contact, allowing for greater component density.
micron (µm)   Synonymous with micrometre (one millionth of an metre)
microprocessors   Integrated circuits that contain the entire central processing unit for a computing device, which reads and performs software instructions from a separate memory source.
micro-sectioning   The preparation of a specimen of a material, or materials, used in metallographic examination. This usually consists of cutting out a cross-section followed by encapsulation, polishing, etching, and staining.
microstripline   A type of high-frequency transmission line configuration that has a specific, characteristic impedance value. It consists of a conductor placed in a precise relationship with a ground or reference plane and surrounded by dielectric materials.
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.
microwave   Circuitry that operates at frequencies between 3 GHz and 300 GHz. See RF.
microwave integrated circuit module   (pMIC). A circuit assembly designed to function in the microwave frequency range. It usually contains a substrate with stripline circuitry and active chip devices, all sealed in a metal case for shielding purposes.
Mil   One thousandth of an inch. Can potentially be confused with a non-preferred abbreviation for millimetre
minimum conductor space   The smallest distance between any two adjacent conductors, such as traces, on a board.
minimum conductor width   The smallest width of any conductors, such as traces, on a board.
misregistration   Nonconformity of the position of a pattern (or a portion of the pattern), a hole, or other feature to its intended position on a printed board.
mixed analogue/digital   An integrated circuit or PCA that contains both analogue and digital circuitry.
mixed technology   When both through-hole and surface-mounting component types are used on the same assembly
mm (millimeter)   One thousandth of an metre
modelling   A design analysis method using a software description of n item (electrical or mechanical) to simulate its operation in response to set of stimuli,
motherboard   A circuit board (or assembly) used for interconnecting a number of plug-in electronic modules (‘daughter boards’).
moulded-in contacts   Connector contacts that are encapsulated during the moulding process and cannot be removed. They are normally only used where a fully-sealed connector is required.
mounting hole   A hole used for mechanical mounting of a printed board (e.g. to the chassis) or for mechanical attachment of components to the board. (also known as an ‘access hole’)
MSDS  (Materials Safety Data Sheet). Critical information regarding goods or substances that may be hazardous or dangerous. It summarizes the health and safety effects that may result from exposure to the chemical or hazardous material. The MSDS label includes information regarding significant physical hazards that may arise, i.e. fire, explosion or reactivity, health hazards that may be relevant, procedures for emergency and first aid and preparation date and subsequent changes to the MSDS.
MTBF (Mean Time Between Failures)   The statistical average time interval, based on the probability of failure of a product, to be expected between operating unit failures. Usually quoted in hours.
MTF   Multi-layer Thin Film
multichip module laminates   A type of printed circuit board design that allows for the placement of multiple integrated circuits or other components in a limited surface area.
multilayer (printed circuit board)   A PCB manufactured from (normally rigid) base material upon which completely processed printed wiring has been formed on more than two layers, each separated by insulating materials, and bonded together. Internal layers are connected to the outer layers by plated via holes.
multilayer lamination   See lamination.
Multiline tooling  The standard in multilayer tooling developed by Multiline Corp. (USA). Tyically a 4 slot (with 2 slots offset to avoid improper alignment) tooling system for multilayer core layup lamination.
multimeter   A portable test instrument which can be used to measure voltage, current, and resistance.