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.
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).
Bevel
An angled edge of a printed board.
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 the following thicknesses: 0.031",
0.094", and 0.126". A typical tolerance is within 10% of the
given thickness.
If you require a thickness other than those listed above, please go
to Contact Us page.
Book
A specified number of stacks of Prepreg plies which are assembled for
Curing in a lamination press.
Bond Strength
The force per unit area required to separate two adjacent layers of a
board by a force perpendicular to the board surface.
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.
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.
Build time
MCL operates on a 10-hour clock, 6-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.
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.
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.
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.
The outline is used to program the router. The dimensions are used to
insure proper scale and board measurement. The fabrication notes include
other pertinent information (copper weight, board thickness, stack-up
specifics, etc.). The drill chart contains symbols inside the outline
that are used to mark individual drill sizes and corresponding board
locations. The drill legend has the drill sizes, the needed tolerance,
and if they are to be Plated or Non-plated.
MCL orders do not require drawings or prints. Many received by MCL
are out of date, or have “Canned” notes that do not apply.
Our order form is the governing document for orders placed on our web
site. For our “Non-Design Review” orders we dismiss any
notes that are in conflict with the order form, or outside our stated
process capabilities. In the event that a drawing is not sent, we will
generate an in-house drill/fab drawing using the NC drill file for
hole location and the center of the Gerber file outline (or crop marks)
to obtain overall board dimensions. If the board dimension listed on
order form varies significantly from the Gerber outline, you will be
notified.
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.
Drilling
The act of forming holes (vias) in a substrate by mechanical or laser
means.
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.
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
(1-sided / 2-sided)
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.
Fiducial Mark
Fiducail 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.
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.
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.
Golden Board
See Known Good Board.
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.
With your gold selection, a standard 30-degree bevel will be added
to your edge connector. We can also bevel at 15 or 45 degrees upon
request. For multi-layer boards please insure adequate back set for
the bevels. Please mention this in the special instructions when placing
your order.
Due to the nature of gold tipping and unique board designs, we require
the design review on all orders with gold fingers. Also note that pricing
adjustments might be made based upon review of your files. We will
notify you immediately if this is the case.
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.
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.
(HASL) Hot Air Solder Leveling
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.
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.
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.
(KGB) Known Good Board
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.
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.
The pcb quick quote form can quote up to 8-layers. If your board has
a higher layer count, please complete our PCB RFQ Form.
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.
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.
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
(LPI) Liquid Photoimageable Soldermask
A mask sprayed on using photographic imaging techniques to control deposition.
MCL standard is LPI-Green.
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.
(NPTH) Non-Plated through holes
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].
Panel
A rectangular sheet of base material or metal-clad material of predetermined
size that is used for the processing of printed boards and, when required,
one or more test coupons.
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 Plating
The selective plating of a conductive pattern.
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.
Photo Print
The process of forming a circuit pattern image by hardening a photosensitive
polymeric material by passing light through a photographic film.
Phototool
A transparent film that contains the circuit pattern, which is represented
by a series of lines of dots at a high resolution.
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.
Prepreg
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.
(PTH) Plated Through-Hole
Holes that have copper plating in the hole barrels that make an electrical
connection between layers are defined as PTH’s.
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.
The pcb quote form allows quoting for all quantities up to 5,000 pieces.
If you need larger quantities or would like to schedule out shipments,
please complete our PCB RFQ Form.
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.
Minimum line width for legible printing is 0.007". Anything smaller
may result in missing or illegible marking on your boards. White is
our standard color but we also offer yellow. See Legend or Nomenclature.
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.
Cutouts are non-circular areas inside the board's outline that need
to be removed. If you select cutouts, we will remove up to 5 areas
per board. If your design has more than 5 cutouts, 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.
(SMOBC) Soldermask Over Bare Copper
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.
(SMT) Surface Mount Technology
Defines the entire body of processes and components that create printed
circuit board assemblies with leadless components.
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".
Please note: While we make every attempt to leave a mask "dam" between
surface mounts, fine pitch areas will be relieved in strips. Our manufacturing
process needs at least 0.005" mask "dam" between pads
in order to adhere to the board. Pad-to-pad spacing less than 0.013" will
not have soldermask between them.
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.
If you require a color other than green, blue, or black, please go
to our Contact Us page and click on the 'I have special request' button
under the subject line and explain your needs in more detail. This
will help to expedite your request.
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.
Tooling and test costs are influenced by the number of surface mount
sides. If there is no surface mount, the same solder mask film can
be used on both sides of the board. If there are surface mounts, we
need to produce different films for top and bottom side, as well as
potentially require electrical testing on both sides.
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.
Tab Routing (with & 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.
When this is selected on the order form “We” will take
your one up board files, and step and repeat as many images as will
fit into a 12"x14” (approximately) pallet. These Pallets
will have a standard space of 0.1” apart, with 4 (0.1”)
tabs positioned at our discretion along the edges, and surrounded by
a 0.5" boarder.
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).
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.
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.
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.
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.
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).
This method creates two beveled scoring lines along the perimeter
of your boards. This makes it easier to break apart the boards at a
later date. You would receive your boards in panel form like tab routing
(see Tab Routing).
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.
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