IPC-T-50F_.pdf.pdf - 第46页

Mark (Fabric) 44.0741 A heavy or light area in a fabric that is due to excessive or insuf f icient ﬁlling yarns. Mask 47.0742 see ‘ ‘Resist.’ ’ Mass Lamination 55.1443 The simultaneous lamination of a number of pre-etche…

Lyophobic 76.0730

A characterization of material that exists in a colloidal state

with a tendency to repel liquids.

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

’

1/2 H

’

▼

254mm [10"]

Object viewed

with unaided

eye

1/2 H

▼

▼▼

June 1996 IPC-T-50F

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

Microcomponents 30.0758

Small discrete components.

Microelectronics 30.0759

The area of electronic technology with, or applied to, the

realization of electronic systems from extremely-small

electronic elements, devices or parts.

Microprobe 92.0760

A small sharp-pointed object with a positional handle that

is used to make temporary electrical contact to a land on a

semiconductor for testing purposes.

Microsectioning 92.1447

The preparation of a specimen of a material, or materials,

that is to be used in a metallographic examination. (This

usually consists of cutting out a cross-section, followed by

encapsulation, polishing, etching, staining, etc.)

Microstrip 21.0761

A transmission-line conﬁguration that consists of a conduc-

tor that is positioned over, and parallel to, a ground plane

with a dielectric between them.

Microwave Integrated Circuit 21.0762

An integrated circuit that performs at microwave frequen-

cies.

Migration Rate 96.0763

The distance over which metal migration proceeds in a

given unit of time.

Migration Velocity 96.0764

see ‘‘Migration Rate.

Minimum Annular Ring 22.0766

see ‘‘Minimum Annular Width.’’

Minimum Annular Width 22.0765

The minimum width of metal(s) at the narrowest point

between the edge of a hole and the outer edge of a circum-

scribing land. (This determination is made to the drilled

hole on internal layers of multilayer printed boards and to

the edge of the plating on external layers of multilayer and

double-sided printed board.)

Minimum Electrical Spacing 21.1451

The minimum allowable distance between adjacent con-

ductors, at a given voltage and altitude, that is sufficient to

prevent dielectric breakdown, corona, or both, from occur-

ing between the conductors.

Minor Defect 91.0767

A defect that is not likely to result in a failure of a unit or

product or that does not materially reduce its usability for

its intendeded purpose.

Mirrored Pattern 24.0768

A pattern whose orientation denotes a transposition from

right reading. (See Figure M-2.)

Mis-Pick 44.0769

A break in the pattern of cloth from selvage to selvage that

is caused by a missing ﬁlling yarn.

Mislocated Bond 74.0770

see ‘‘Off Bond.’’

Misregistration 50.0771

Imperfect registration.

Mixed Component-Mounting Technology 70.1452

A component mounting technology that uses both through-

hole and surface- mounting technologies on the same pack-

aging and interconneting structure.

Mixed-Effects Model 91.0772

An experimental treatment that contains elements of both

ﬁxed-effects and random-effects models.

Mixed Technology 70.1757

In surface mounting, refers to mixing through hole compo-

nent and surface mounting components on the same side of

a printed circuit board.

Modal Form 25.0773

The technique whereby a data description or other pertinent

command is given only once at the beginning of a related

set of data.

Modification 77.0774

The revision of the functional capability of a product in

order to satisfy new acceptance criteria.

Module 80.0775

A separable unit in a packaging scheme.

Molecular Dye-Imaging Material 24.0776

see ‘‘Diazo Material’’

Monolithic Integrated Circuit 30.0777

An integrated circuit in the form of a monolithic structure.

Montreal Protocol 76.1758

An agreement by industrialized nations, at a meeting held

in Montreal, Canada, to eliminate chloroﬂuorocarbons

from all processes by 1995.

Mother Board 85.0778

A printed board assembly that is used for interconnecting

arrays of plug-in electronic modules. (See also ‘‘Back-

plane.’’)

June 1996 IPC-T-50F