IPC-TM-650 EN 2022 试验方法--.pdf - 第778页

NOTE: Figure 1 T est Set-up Material in this T est Methods Manual was voluntarily established by T echnical Committees of the IPC. Thi s mate rial is ad visory o nly and its use or adaptation is entirely voluntary . IPC …

100%1 / 824
the sample/coupon weight be recorded to the near-
est 0.0001 g. Note that the sample/coupon weight will not
settle completely.
These measurements characterize the bulk moisture content
of the test samples. If the moisture absorption rate is desired,
continue with process steps 3 through 5:
3. Measure and record ambient temperature and relative
humidity at the analytical balance measurement station.
4. The test sample/coupons
remain at the analytical
balance measurement station for 15 minutes +1/-0 min-
utes and procedure steps 2-3
be repeated.
5. Repeat step 4, taking measurements at 15 minute inter-
vals, for at least 4 hours.
The ambient temperature and humidity, the frequency
with which ambient conditions are recorded, the measure-
ment intervals between weighings and the number of weigh-
ings may be adjusted AABUS.
5.4 Calculations
Calculate the bulk moisture content using
the following equation:
Moisture Content (%) =
(
(Initial Weight) − (Post−Bake Weight)
(Post−Bake Weight)
)
X 100
Calculate the moisture absorption rate by plotting the bulk
moisture content versus time using the data recorded in Pro-
cedure steps 3 through 5 of 5.3.
Metals do not absorb moisture, and metal content in
the specimen will affect the accuracy of this determination. If
copper or other metals are likely to exceed 20% of the weight
of the specimen, this weight should be determined or esti-
mated, and subtracted from both the Initial Weight and the
Post-Bake Weight in the formula above. This correction factor
be AABUS.
5.5 Report
Report the bulk moisture content or moisture
absorption rate for the sample/coupon.
Number
2.6.28
Subject
Moisture Content and/or Moisture Absorption Rate, (Bulk)
Printed Board
Date
08/2010
Revision
shall
Note:
shall
shall
Note:
shall
IPC-TM-650
—
Page
2
of
2
NOTE:
Figure 1 Test Set-up
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
ASSOCIATION
CONNECTING
/
ELECTRONICS
INDUSTRIES
221
5
Sanders
Road
Northbrook,
IL
60062-61
35
IPC-TM-650
TEST
METHODS
MANUAL
1
.0
Scope
1.1
To
evaluate
the
contact
resistance
of
electrical
contacts
at
rated
current.
2
.0
Reference
Documents
2.1
Information
in
this
section
is
intended
to
parallel
the
test
method
described
in
EIA-RS-364/TP-06.
3
.0
Test
Specimen
3.1
The
mated
contacts
of
a
connector
mounted
and,
when
required,
terminated
in
its
normal
manner
or
a
mated
pair
of
individual
contacts.
When
mated
contact
pairs,
not
requiring
housings,
are
tested,
they
shall
be
rigidly
mounted
in
a
fixture
to
provide
mechanical
stability
and
to
insure
proper
mating
and
orienta¬
tion.
3.2
For
contacts
having
a
wire-hole,
crimp
or
other
termina¬
tion,
a
3-foot
length
of
continuous
wire
may
be
used
for
heat
dissipation.
The
wire
size
shall
be
specified
in
the
individual
contact
or
connector
specification.
3.3
Voltage
connections
may
be
attached
permanently
by
soldering,
crimping,
or
other
suitable
method.
3.4
Unless
otherwise
specified
in
the
individual
contact
or
connector
specification,
the
test
sample
shall
not
be
cleaned
by
any
means
prior
to
the
test
nor
shall
any
lubricants
or
other
coatings
be
applied.
4
.0
Apparatus
4.1
Voltmeter
(10000
ohms
per
volt
or
greater)
The
meter
accuracy
shall
be
such
that
the
voltage
value
is
mea¬
sured
accurately
within
5
percent.
4.2
Ammeter
The
meter
accuracy
shall
be
such
that
the
current
value
is
measured
accurately
within
5
percent.
4.3
Power
supply
capable
of
delivering
the
required
test
cur¬
rent.
Number
3.1
Subject
Contact
Resistance,
Connectors
Date
Revision
7/75
A
Originating
Task
Group
N/A
5.0
Procedure
5.1
The
contact
resistance
test
shall
be
conducted
using
a
circuit
as
shown
in
Figure
1
.
5.2
The
current
through
the
test
sample
shall
be
increased
to
the
value
specified
in
the
individual
contact
or
connector
specification
and
shall
be
maintained
until
temperature
stabili¬
zation
of
the
test
sample
at
that
current
is
attained.
Tempera¬
ture
stability
may
be
indicated
by
voltage
drop
stability.
5.3
The
voltage
drop
across
each
pair
of
mated
contacts
shall
be
measured
with
the
voltmeter
probes
(or
permanent
connection)
positioned
as
follows:
A.
Wire-Hole
—
On
the
contact
with
1/8
inch
of
insulator.
B.
Wrap-Post
—
On
the
wrap-post
adjacent
to
the
outer
turn
of
wire.
C.
Crimp
—
On
the
wire
(piercing
the
insulation)
within
1/8
inch
of
insulator.
NOTE:
IPC-TM-650
Page 2 of 2
Number
3.1
Subject
Contact
Resistance,
Connectors
Date
7/75
Revision
A
D.
Solder
Tab
—
On
the
printed
wiring
traces
as
close
to
the
termination
as
practicable.
E.
Press-Fit
—
On
the
pad
of
the
plated-through
hole
as
close
to
the
termination
as
practicable.
If
the
pad
of
the
printed
wiring
board
constitutes
one-half
of
the
mated
contact
pair,
the
voltmeter
probe
shall
be
posi¬
tioned
on
the
pad
immediately
adjacent
to,
but
not
touching,
the
mating
contact
(not
inside
the
insulator).
In
case
of
an
environment
resistant
(sealed)
connec¬
tor,
the
voltmeter
probes
shall
be
positioned
as
close
to
the
sealing
grommets
as
practicable.
5.4
The
contact
resistance
shall
be
calculated
by
dividing
the
voltage
drop
reading
by
the
current
reading.
The
value
thus
obtained
for
each
contact
shall
not
exceed
the
maximum
allowable
contact
resistance
as
defined
in
the
individual
con¬
tact
or
connector
specification.
5.5
For
voltage
drops
less
than
1.0
millivolt,
the
voltage
drop
across
each
pair
of
mated
contacts
with
the
current
succes¬
sively
in
both
directions
through
the
test
specimen
shall
be
measured.
The
contact
resistance
shall
be
calculated,
in
each
the
forward
and
reverse
directions,
by
dividing
the
voltage
drop
reading
by
the
current
reading.
The
average
of
the
two
resistance
values
thus
obtained
for
each
contact
shall
not
exceed
the
maximum
allowable
contact
resistance
as
defined
in
the
individual
contact
for
connector
specification.
6.0
Notes
6.1
Acceptance
criteria
shall
be
established
as
the
maxi¬
mum
level
at
which
stable
electrical
contact
is
maintained.
This
resistance
is
an
inherent
characteristic
of
any
given
con¬
nector
contact
design
and
is
(when
the
connector
is
properly
applied)
well
below
that
resistance
level
required
for
circuit
function.