IPC-T-50F_.pdf.pdf - 第45页
Lyophobic 76.0730 A characterization of material that exists in a colloidal state with a tendency to repel liquids. M Machine Language 11.0732 The actual language, usually a binary code, that is used by a computer when i…
Light Mark (Fabric) 44.0708
A filling defect that extends across the width of a fabric
containing less than one pick per 25mm from nominal.
Limits of Size 20.0709
The specified maximum and minimum sizes.
Line 20.0710
see ‘‘Conductor.’’
Line Coupling 21.0711
The interaction between two transmission lines that is
caused by their mutual inductance and the capacitance
between them.
Lip Height 51.0712
The perpendicular distance from one primary cutting edge
to another.
Load Capacitance 21.0713
The capacitance seen by the output of a logic circuit or
other signal source.
Load Time 92.0714
The time it takes to load a unit in an inspection/test
machine and to perform any necessary programming or
machine alignment.
Local Fiducial 20.0715
A fiducial mark (or marks) used to locate the position of a
land pattern for an individual component on a printed
board.
Local Intelligence 25.0716
The capability of a work station to independently process
data without the use of a host or central processing unit.
Locating Edge 20.0028
A tooling feature in the form of the edge of a printed board.
Locating Edge Marker 20.0717
A symbol that is used to identify which edge of a printed
board is the index edge.
Locating Hole 20.0718
see ‘‘Tooling Hole.’’
Locating Notch 20.0719
A tooling feature in the form of a notch in a printed board.
Locating Slot 20.0720
A tooling feature in the form of a slot in a printed board.
Location Hole 20.1726
A hole or notch in the panel or printed board to enable
either to be positioned accurately.
Logic 21.0721
The functional digital circuits used to perform computa-
tional functions.
Logic Diagram 21.1440
A drawing that depicts the multistate device implementa-
tion of logic functions with logic symbols and supplemen-
tary notations that show the details of signal flow and con-
trol, but not necessarily the point-to- point wiring.
Logic Family 21.1441
A collection of logic functions using the same form of
electronic circuit, e.g., emitter-coupled logic (ECL),
transistor-transistor logic (TTL), complementary metal-
oxide semiconductor logic (CMOS).
Long-Term Capability 91.0722
The capability of a process that exhibits statistical control
over an extended period of time.
Loom Beam 44.0723
A large flanged cylinder onto which all warp yarns are
wound and from which the yarns enter the loom.
Loop Height 76.0725
The magnitude of deviation of a wire from a straight path
between its end attachment points.
Loop, Wire 76.0724
The curve (arc) in a bonding wire between its end attach-
ment points.
Loss Tangent 21.0726
see ‘‘Dissipation Factor.’’
Lot Size 91.1442
A collection of units produced in one continuous, uninter-
rupted fabrication run from which a sample is drawn and
inspected or tested in order to determine conformance with
acceptability criteria.
Luminance 24.0727
A measure of light flux reflected or emitted from a surface.
Luminous Energy 24.0728
A measure of light flux flow rate, usually in units of lumen-
seconds.
Luminous Flux 24.0729
A measure of flow of visible light energy past any given
point in space.
Lyophilic 76.1225
A characterization of material that readily goes into colloi-
dal suspension in a liquid.
IPC-T-50F June 1996
40
Lyophobic 76.0730
A characterization of material that exists in a colloidal state
with a tendency to repel liquids.
M
Machine Language 11.0732
The actual language, usually a binary code, that is used by
a computer when it performs operations.
Machined Contact 37.0731
A type of connector contact that consists of solid spring
metal that has been formed by machining. (See also
‘‘Sheet-Metal Contact.’’)
Magnification Power 92.0733
The ratio of the tangent of one-half of the angle (beta) sub-
tended by the image of an object (H), as seen through and
centered in the field of view of the magnification device, to
the tangent of one-half of the angle (alpha) subtended by
the object (H) as seen at 10 inches by the unaided eye. (See
Figure M-1.)
Major Defect 94.0734
A defect that is likely to result in a failure of a unit or
product or that materially reduces its usability for its
intended purpose.
Manhattan Distance 25.0735
The orthogonal distance between two points.
Manual Data Input 25.0736
Computer data that is manually generated with or without
the aid of a data-entry device, such as a keyboard, lightpen,
mouse, etc.
Manual Soldering 75.0737
see ‘‘Hand Soldering.’’
Manufacturing Drawing 26.1634
A working document that shows the dimensional limits or
grid locations that are applicable to any and all parts of a
product to be fabricated, including the arrangement of con-
ductors and nonconductive patterns or elements; the size,
type, and location of holes; and all other necessary infor-
mation.
Manufacturing Hole 20.0738
see ‘‘Tooling Hole.’’
Margin (Flat Cable) 37.0739
The distance between the reference edge of a flat cable and
the nearest edge of the first conductor. (See also ‘‘Edge
Spacing.’’)
Margin Width (Drill) 51.0740
The thickness of the cylindrical portion of a drill land that
is perpendicular to the leading edge.
IPC-I-002273
Figure M–1 Magnification power parameters
▼
▼
Magnifying aid focused so eye is
focused for infinity
Centered Image
of the Object
seen through aid
H
’
1/2 H
’
▼
β
▼
▼
▼
▼
254mm [10"]
Object viewed
with unaided
eye
H
1/2 H
▼
α
▼
▼
▼
▼
▼
▼
▼
▼▼
June 1996 IPC-T-50F
41
Mark (Fabric) 44.0741
A heavy or light area in a fabric that is due to excessive or
insufficient filling yarns.
Mask 47.0742
see ‘‘Resist.’’
Mass Lamination 55.1443
The simultaneous lamination of a number of pre-etched,
multiple-image, C-staged resin panels or sheets that are
sandwiched between layers of B-staged resin and coppper
foil. (See also ‘‘Cap Lamination’’ and ‘‘Foil Lamination.’’)
Mass Soldering 75.1678
Methods of soldering in which many joints are made in the
same operation.
Master Dot Pattern 26.0743
see ‘‘Hole Pattern.’’
Master Drawing 26.0744
A control document that shows the dimensional limits or
grid locations that are applicable to any and all parts of a
product to be fabricated, including the arrangement of con-
ductors and nonconductive patterns or elements; the size,
type, and location of holes; and all other necessary infor-
mation.
Master Line 22.0745
see ‘‘Design Width of Conductor.’’
Master Pattern 24.0746
see ‘‘Production Master
Maximum Material Condition (MMC) 22.0747
A drawing defining certain characteristics of the printed
board, such material within the stated limits of size.
Mealing 76.1814
A condition in the form of discrete spots or patches that
reveals a separation at the interface between a conformal
coating and a base material on the surface of a printed
board, on the surface of an attached component, or both.
Measling 55.0748
A condition that occurs in laminated base material in which
internal glass fibers are separated from the resin at the
weave intersection. (This condition manifests itself in the
form of discrete white spots or ‘‘crosses’’ that are below
the surface of the base material. It is usually related to
thermally-induced stress.) (See also ‘‘Crazing, Base Mate-
rial.’’)
Mechanical Stress 95.1755
To subject a mechanical component to a process of physi-
cal stress.
Mechanical Wrap 75.0749
The physical securing of a wire lead or component lead
around a solder terminal.
Meniscus 92.0750
The contour of a shape that is the result of the surface-
tension forces that take place during wetting.
Metal-Clad Base Material 41.1609
Base material covered with conductive foil on one or both
sides.
Metal-Clad Laminate 41.0752
see ‘‘Metal-Clad base Material.’’
Metal Core Printed Board 61.1587
Printed board using a metal core base material.
Metal Migration 96.1445
The electrolytic transfer of metal ions along an electrically
conductive path from one metal surface to another when an
electrical potential is applied to the two metal surfaces.
Metal Migrativity 96.0754
The comparative rate of the velocity of metal migration
under the same conditions.
Metal Surface Migration 96.1226
The migration of metal on the surface of an electrical insu-
lator.
Metal Through Migration 96.0662
The migration of metal through an electrical insulator.
Metalized Land Areas 22.1756
A pattern of conductive material used on a substrate to
interconnect electronic components. Widened conductor
areas used as attachment point for wire bonding or other
devices.
Metalization (n.) 53.0753
A deposited or plated thin metallic film that is used for its
protective and/or electrical properties.
Microbond 74.0756
A termination made with a small diameter wire, i.e.,
0.025-mm (0.001-inch) or less.
Microcircuit 30.0757
A relatively high density combination of equivalent circuit
elements that are interconnected so as to perform as an
indivisible electronic circuit component.
Microcircuit Module 86.1446
A combination of microcircuits or of microcircuits and dis-
crete components that are interconnected so as to perform
as an indivisible electronic circuit assembly.
IPC-T-50F June 1996
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