IPC-TM-650 EN 2022 试验方法-- - 第304页

None Figure 1 Figure 2 The Institute for Int erconnecting and Packaging E lectronic Circuits 2215 S anders Road • Northbrook, IL 60062-6135 Material in this T est M ethods Manual was vol untaril y establis hed by T echni…

100%1 / 824
Figure 7 Corners Supports
R1 R1
R2
Supporting Jacks or Blocks
Figure 8 Highest Point Measurement
Measure at
This Point
Measure at
This Point
R2
R2
R1
IPC-TM-650
Page 5 of 5
Number
2.4.22
Subject
Bow
and
Twist
(Percentage)
Date
6/99
Revision
C
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I
PC-2422-7
I
PC-2422-8
None
Figure 1
Figure 2
The Institute for Interconnecting and Packaging Electronic Circuits
2215 Sanders Road • Northbrook, IL 60062-6135
Material in this Test Methods Manual was voluntarily established by Technical Committees of the IPC. This material is advisory only
and its use or adaptation is entirely voluntary. IPC disclaims all liability of any kind as to the use, application, or adaptation of this
material. Users are also wholly responsible for protecting themselves against all claims or liabilities for patent infringement.
Equipment referenced is for the convenience of the user and does not imply endorsement by the IPC.
Page 1 of 2
IPC-TM-650
TEST
METHODS
MANUAL
1
.0
Scope
This
method
covers
the
measurement
of
bow
and
twist
by
maximum
vertical
displacement
of
an
unre¬
strained
panel
of
either
cut
to
size
panels
or
finished
rigid
printed
boards
including
single-
and
double-sided,
multilayer,
and
the
rigid
segments
of
rigid
flex
printed
circuits.
This
test
method
is
only
applicable
to
laminates
greater
than
or
equal
to
0.5
mm
[0.020
in]
in
thickness.
This
test
method
can
also
be
used
after
etching
or
after
thermal
stress
with
requirements
as
agreed
between
user
and
vendor.
2
.0
Applicable
Documents
3
.0
Test
Specimen
The
test
specimen
for
incoming
inspection
shall
be
300
x
300
mm
±
2
mm
[12
x
12
in
±
0.08
in]
in
size.
For
smaller
panel
sizes
and
finished
printed
wiring
boards,
use
actual
size.
A
minimum
of
three
specimens
is
required
per
sample,
when
evaluating
pressed
laminate
sheets.
4
.0
Apparatus
4.1
Sample
Shear
4.2
Granite
Surface
Plate
or
Equivalent
4.3
Feeler
Gauges
or
Equivalent
4.4
Micrometer
5
.0
Test
Procedure
5.1
Preparation
of
the
Test
Specimen
5.1.1
For
laminate
sheet,
the
test
specimens
are
to
be
cut
in
such
a
fashion
as
to
minimize
mechanical
flexing.
5.1.2
For
cut
to
size
panels
or
printed
wiring
boards,
use
actual
size.
5.1.3
Mark
the
specimen
for
traceability.
No
mechanical
or
chemical
pre-cleaning
is
permitted
on
the
specimens.
5.2
Measurement
of
Bow
and
Twist
Number
2.4.22.1
Subject
Bow
and
Twist
—
Laminate
Date
Revision
5/93
C
Originating
Task
Group
5.2.1
Place
the
test
panels
on
the
surface
plate
such
that
the
maximum
vertical
displacement
is
observed.
The
panel
should
be
turned
over
in
establishing
the
maximum
vertical
displacement.
The
maximum
vertical
displacement
may
be
a
corner
or
a
side
of
the
test
specimen
as
illustrated
in
Figures
1
and
2.
5.2.2
Measure
the
maximum
vertical
displacement
by
inserting
the
feeler
gauges
between
the
surface
plate
and
the
bottom
surface
of
the
laminate.
5.2.3
Verify
the
thickness
measurement
by
measuring
the
total
thickness
of
the
feeler
gauges
with
the
micrometer.
5.2.4
Record
the
maximum
vertical
displacement
in
0.25
mm
[0.01
in].
One
value
is
recorded
per
test
specimen.
This
is
the
bow
and
twist
of
the
test
specimen.
IPC-TM-650
Number
Subject Date
Revision
Page 2 of 2
2.4.22.1
Bow
and
Twist
—
Laminate
5/93
C
5.3
Calculation
of
Results
5.3.1
Average
Bow
and
Twist
Results
Bow
and
Twist
=
Sum
of
the
Measured
Maximum
Vertical
Displacements
in
mm
[in]
Number
of
Test
Specimens
5.3.2
Maximum
Bow
and
Twist
Results
The
maximum
vertical
displacement
in
mm
[in]
obtained
for
each
lot
of
material.
6.0
Notes
6.1
This
is
the
referee
method;
other
methods
of
measure¬
ment
are
allowable,
if
agreed
upon
between
user
and
vendor.